View LM75B_4679986.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

LM75B
Digital temperature sensor and thermal watchdog
Rev. 02 -- 9 December 2008 Product data sheet
1. General description
The LM75B is a temperature-to-digital converter using an on-chip band gap temperature sensor and Sigma-Delta A-to-D conversion technique with an overtemperature detection output. The LM75B contains a number of data registers: Configuration register (Conf) to store the device settings such as device operation mode, OS operation mode, OS polarity and OS fault queue as described in Section 7 "Functional description"; temperature register (Temp) to store the digital temp reading, and set-point registers (Tos and Thyst) to store programmable overtemperature shutdown and hysteresis limits, that can be communicated by a controller via the 2-wire serial I2C-bus interface. The device also includes an open-drain output (OS) which becomes active when the temperature exceeds the programmed limits. There are three selectable logic address pins so that eight devices can be connected on the same bus without address conflict. The LM75B can be configured for different operation conditions. It can be set in normal mode to periodically monitor the ambient temperature, or in shutdown mode to minimize power consumption. The OS output operates in either of two selectable modes: OS comparator mode or OS interrupt mode. Its active state can be selected as either HIGH or LOW. The fault queue that defines the number of consecutive faults in order to activate the OS output is programmable as well as the set-point limits. The temperature register always stores an 11-bit 2's complement data giving a temperature resolution of 0.125 C. This high temperature resolution is particularly useful in applications of measuring precisely the thermal drift or runaway. When the LM75B is accessed the conversion in process is not interrupted (i.e., the I2C-bus section is totally independent of the Sigma-Delta converter section) and accessing the LM75B continuously without waiting at least one conversion time between communications will not prevent the device from updating the Temp register with a new conversion result. The new conversion result will be available immediately after the Temp register is updated. The LM75B powers up in the normal operation mode with the OS in comparator mode, temperature threshold of 80 C and hysteresis of 75 C, so that it can be used as a stand-alone thermostat with those pre-defined temperature set points.
2. Features
I Pin-for-pin replacement for industry standard LM75 and LM75A and offers improved temperature resolution of 0.125 C and specification of a single part over power supply range from 2.8 V to 5.5 V I I2C-bus interface with up to 8 devices on the same bus I Power supply range from 2.8 V to 5.5 V I Temperatures range from -55 C to +125 C
NXP Semiconductors
LM75B
Digital temperature sensor and thermal watchdog
I Frequency range 20 Hz to 400 kHz with bus fault time-out to prevent hanging up the bus I 11-bit ADC that offers a temperature resolution of 0.125 C I Temperature accuracy of: N 2 C from -25 C to +100 C N 3 C from -55 C to +125 C I Programmable temperature threshold and hysteresis set points I Supply current of 1.0 A in shutdown mode for power conservation I Stand-alone operation as thermostat at power-up I ESD protection exceeds 4500 V HBM per JESD22-A114, 450 V MM per JESD22-A115 and 2000 V CDM per JESD22-C101 I Latch-up testing is done to JEDEC Standard JESD78 which exceeds 100 mA I Small 8-pin package types: SO8, TSSOP8 and 3 mm x 2 mm XSON8U
3. Applications
I I I I System thermal management Personal computers Electronics equipment Industrial controllers
4. Ordering information
Table 1. Type number LM75BD LM75BDP LM75BGD Ordering information Topside mark LM75BD LM75B 75B Package Name SO8 TSSOP8 XSON8U Description plastic small outline package; 8 leads; body width 3.9 mm plastic thin shrink small outline package; 8 leads; body width 3 mm plastic extremely thin small outline package; no leads; 8 terminals; UTLP based; body 3 x 2 x 0.5 mm Version SOT96-1 SOT505-1 SOT996-2
LM75B_2
(c) NXP B.V. 2008. All rights reserved.
Product data sheet
Rev. 02 -- 9 December 2008
2 of 29
NXP Semiconductors
LM75B
Digital temperature sensor and thermal watchdog
5. Block diagram
VCC
LM75B
BIAS REFERENCE POINTER REGISTER COUNTER 11-BIT SIGMA-DELTA A-to-D CONVERTER CONFIGURATION REGISTER TEMPERATURE REGISTER TOS REGISTER THYST REGISTER OS
BAND GAP TEMP SENSOR
TIMER COMPARATOR/ INTERRUPT
OSCILLATOR
POWER-ON RESET
LOGIC CONTROL AND INTERFACE
002aad453
A2
A1
A0
SCL SDA
GND
Fig 1.
Block diagram of LM75B
6. Pinning information
6.1 Pinning
SDA SCL OS GND
1 2
8 7
VCC A0 A1 A2
SDA SCL OS GND
1 2 3 4
002aad455
8 7
VCC A0 A1 A2
LM75BD
3 4
002aad454
6 5
LM75BDP
6 5
Fig 2.
Pin configuration for SO8
Fig 3.
Pin configuration for TSSOP8
SDA SCL OS GND
1 2
8 7
VCC A0 A1 A2
LM75BGD
3 4 6 5
002aae234
Transparent top view
Fig 4.
LM75B_2
Pin configuration for XSON8U
(c) NXP B.V. 2008. All rights reserved.
Product data sheet
Rev. 02 -- 9 December 2008
3 of 29
NXP Semiconductors
LM75B
Digital temperature sensor and thermal watchdog
6.2 Pin description
Table 2. Symbol SDA SCL OS GND A2 A1 A0 VCC Pin description Pin 1 2 3 4 5 6 7 8 Description Digital I/O. I2C-bus serial bidirectional data line; open-drain. Digital input. I2C-bus serial clock input. Overtemp Shutdown output; open-drain. Ground. To be connected to the system ground. Digital input. User-defined address bit 2. Digital input. User-defined address bit 1. Digital input. User-defined address bit 0. Power supply.
7. Functional description
7.1 General operation
The LM75B uses the on-chip band gap sensor to measure the device temperature with the resolution of 0.125 C and stores the 11-bit 2's complement digital data, resulted from 11-bit A-to-D conversion, into the device Temp register. This Temp register can be read at any time by a controller on the I2C-bus. Reading temperature data does not affect the conversion in progress during the read operation. The device can be set to operate in either mode: normal or shutdown. In normal operation mode, the temp-to-digital conversion is executed every 100 ms and the Temp register is updated at the end of each conversion. During each `conversion period' (Tconv) of about 100 ms the device takes only about 10 ms, called `temperature conversion time' (tconv(T)), to complete a temperature-to-data conversion and then becomes idle for the time remaining in the period. This feature is implemented to significantly reduce the device power dissipation. In shutdown mode, the device becomes idle, data conversion is disabled and the Temp register holds the latest result; however, the device I2C-bus interface is still active and register write/read operation can be performed. The device operation mode is controllable by programming bit B0 of the configuration register. The temperature conversion is initiated when the device is powered-up or put back into normal mode from shutdown. In addition, at the end of each conversion in normal mode, the temperature data (or Temp) in the Temp register is automatically compared with the overtemperature shutdown threshold data (or Tth(ots)) stored in the Tos register, and the hysteresis data (or Thys) stored in the Thyst register, in order to set the state of the device OS output accordingly. The device Tos and Thyst registers are write/read capable, and both operate with 9-bit 2's complement digital data. To match with this 9-bit operation, the Temp register uses only the 9 MSB bits of its 11-bit data for the comparison. The way that the OS output responds to the comparison operation depends upon the OS operation mode selected by configuration bit B1, and the user-defined fault queue defined by configuration bits B3 and B4.
LM75B_2
(c) NXP B.V. 2008. All rights reserved.
Product data sheet
Rev. 02 -- 9 December 2008
4 of 29
NXP Semiconductors
LM75B
Digital temperature sensor and thermal watchdog
In OS comparator mode, the OS output behaves like a thermostat. It becomes active when the Temp exceeds the Tth(ots), and is reset when the Temp drops below the Thys. Reading the device registers or putting the device into shutdown does not change the state of the OS output. The OS output in this case can be used to control cooling fans or thermal switches. In OS interrupt mode, the OS output is used for thermal interruption. When the device is powered-up, the OS output is first activated only when the Temp exceeds the Tth(ots); then it remains active indefinitely until being reset by a read of any register. Once the OS output has been activated by crossing Tth(ots) and then reset, it can be activated again only when the Temp drops below the Thys; then again, it remains active indefinitely until being reset by a read of any register. The OS interrupt operation would be continued in this sequence: Tth(ots) trip, Reset, Thys trip, Reset, Tth(ots) trip, Reset, Thys trip, Reset, etc. Putting the device into the shutdown mode by setting the bit 0 of the configuration register also resets the OS output. In both cases, comparator mode and interrupt mode, the OS output is activated only if a number of consecutive faults, defined by the device fault queue, has been met. The fault queue is programmable and stored in the two bits, B3 and B4, of the Configuration register. Also, the OS output active state is selectable as HIGH or LOW by setting accordingly the configuration register bit B2. At power-up, the device is put into normal operation mode, the Tth(ots) is set to 80 C, the Thys is set to 75 C, the OS active state is selected LOW and the fault queue is equal to 1. The temp reading data is not available until the first conversion is completed in about 100 ms. The OS response to the temperature is illustrated in Figure 5.
Tth(ots)
Thys
reading temperature limits OS reset OS active OS output in comparator mode
OS reset OS active
(1)
(1)
(1)
OS output in interrupt mode
002aae334
(1) OS is reset by either reading register or putting the device in shutdown mode. It is assumed that the fault queue is met at each Tth(ots) and Thys crossing point.
Fig 5.
OS response to temperature
LM75B_2
(c) NXP B.V. 2008. All rights reserved.
Product data sheet
Rev. 02 -- 9 December 2008
5 of 29
NXP Semiconductors
LM75B
Digital temperature sensor and thermal watchdog
7.2 I2C-bus serial interface
The LM75B can be connected to a compatible 2-wire serial interface I2C-bus as a slave device under the control of a controller or master device, using two device terminals, SCL and SDA. The controller must provide the SCL clock signal and write/read data to/from the device through the SDA terminal. Notice that if the I2C-bus common pull-up resistors have not been installed as required for I2C-bus, then an external pull-up resistor, about 10 k, is needed for each of these two terminals. The bus communication protocols are described in Section 7.10.
7.2.1 Bus fault time-out
If the SDA line is held LOW for longer than tto (75 ms minimum / 13.3 Hz; guaranteed at 50 ms minimum / 20 Hz), the LM75B will reset to the idle state (SDA released) and wait for a new START condition. This ensures that the LM75B will never hang up the bus should there be conflict in the transmission sequence.
7.3 Slave address
The LM75B slave address on the I2C-bus is partially defined by the logic applied to the device address pins A2, A1 and A0. Each of them is typically connected either to GND for logic 0, or to VCC for logic 1. These pins represent the three LSB bits of the device 7-bit address. The other four MSB bits of the address data are preset to `1001' by hard wiring inside the LM75B. Table 3 shows the device's complete address and indicates that up to 8 devices can be connected to the same bus without address conflict. Because the input pins, SCL, SDA and A2 to A0, are not internally biased, it is important that they should not be left floating in any application.
Table 3. Address table 1 = HIGH; 0 = LOW. MSB 1 0 0 1 A2 A1 LSB A0
7.4 Register list
The LM75B contains four data registers beside the pointer register as listed in Table 4. The pointer value, read/write capability and default content at power-up of the registers are also shown in Table 4.
Table 4. Register table R/W R/W read only R/W POR state 00h n/a 5000h Description Configuration register: contains a single 8-bit data byte; to set the device operating condition; default = 0. Temperature register: contains two 8-bit data bytes; to store the measured Temp data. Overtemperature shutdown threshold register: contains two 8-bit data bytes; to store the overtemperature shutdown Tth(ots) limit; default = 80 C. Hysteresis register: contains two 8-bit data bytes; to store the hysteresis Thys limit; default = 75 C.
Register Pointer name value Conf Temp Tos 01h 00h 03h
Thyst
02h
R/W
4B00h
LM75B_2
(c) NXP B.V. 2008. All rights reserved.
Product data sheet
Rev. 02 -- 9 December 2008
6 of 29
NXP Semiconductors
LM75B
Digital temperature sensor and thermal watchdog
7.4.1 Pointer register
The Pointer register contains an 8-bit data byte, of which the two LSB bits represent the pointer value of the other four registers, and the other 6 MSB bits are equal to 0, as shown in Table 5 and Table 6. The Pointer register is not accessible to the user, but is used to select the data register for write/read operation by including the pointer data byte in the bus command.
Table 5. B7 0 Table 6. B1 0 0 1 1 Pointer register B6 0 B5 0 B4 0 B3 0 B2 0 B[1:0] pointer value
Pointer value B0 0 1 0 1 Selected register Temperature register (Temp) Configuration register (Conf) Hysteresis register (Thyst) Overtemperature shutdown register (Tos)
Because the Pointer value is latched into the Pointer register when the bus command (which includes the pointer byte) is executed, a read from the LM75B may or may not include the pointer byte in the statement. To read again a register that has been recently read and the pointer has been preset, the pointer byte does not have to be included. To read a register that is different from the one that has been recently read, the pointer byte must be included. However, a write to the LM75B must always include the pointer byte in the statement. The bus communication protocols are described in Section 7.10. At power-up, the Pointer value is equal to 00 and the Temp register is selected; users can then read the Temp data without specifying the pointer byte.
7.4.2 Configuration register
The Configuration register (Conf) is a write/read register and contains an 8-bit non-complement data byte that is used to configure the device for different operation conditions. Table 7 shows the bit assignments of this register.
Table 7. Conf register Legend: * = default value. Bit B[7:5] B[4:3] Symbol reserved Access Value Description R/W 000* reserved for manufacturer's use; should be kept as zeroes for normal operation OS fault queue programming 00* 01 10 11 B2 OS_POL R/W 0* 1 queue value = 1 queue value = 2 queue value = 4 queue value = 6 OS polarity selection OS active LOW OS active HIGH
OS_F_QUE[1:0] R/W
LM75B_2
(c) NXP B.V. 2008. All rights reserved.
Product data sheet
Rev. 02 -- 9 December 2008
7 of 29
NXP Semiconductors
LM75B
Digital temperature sensor and thermal watchdog
Table 7. Conf register ...continued Legend: * = default value. Bit B1 Symbol Access Value Description OS operation mode selection 0* 1 B0 SHUTDOWN R/W 0* 1 OS comparator OS interrupt device operation mode selection normal shutdown OS_COMP_INT R/W
7.4.3 Temperature register
The Temperature register (Temp) holds the digital result of temperature measurement or monitor at the end of each analog-to-digital conversion. This register is read-only and contains two 8-bit data bytes consisting of one Most Significant Byte (MSByte) and one Least Significant Byte (LSByte). However, only 11 bits of those two bytes are used to store the Temp data in 2's complement format with the resolution of 0.125 C. Table 8 shows the bit arrangement of the Temp data in the data bytes.
Table 8. MSByte 7 D10 6 D9 5 D8 4 D7 3 D6 2 D5 1 D4 0 D3 Temp register LSByte 7 D2 6 D1 5 D0 4 X 3 X 2 X 1 X 0 X
When reading register Temp, all 16 bits of the two data bytes (MSByte and LSByte) are provided to the bus and must be all collected by the controller to complete the bus operation. However, only the 11 most significant bits should be used, and the 5 least significant bits of the LSByte are zero and should be ignored. One of the ways to calculate the Temp value in C from the 11-bit Temp data is: 1. If the Temp data MSByte bit D10 = 0, then the temperature is positive and Temp value (C) = +(Temp data) x 0.125 C. 2. If the Temp data MSByte bit D10 = 1, then the temperature is negative and Temp value (C) = -(2's complement of Temp data) x 0.125 C. Examples of the Temp data and value are shown in Table 9.
Table 9. Temp register value Hexadecimal value 3F8 3F7 3F1 3E8 0C8 001 000 7FF Decimal value 1016 1015 1009 1000 200 1 0 -1 Value +127.000 C +126.875 C +126.125 C +125.000 C +25.000 C +0.125 C 0.000 C -0.125 C
11-bit binary (2's complement) 011 1111 1000 011 1111 0111 011 1111 0001 011 1110 1000 000 1100 1000 000 0000 0001 000 0000 0000 111 1111 1111
LM75B_2
(c) NXP B.V. 2008. All rights reserved.
Product data sheet
Rev. 02 -- 9 December 2008
8 of 29
NXP Semiconductors
LM75B
Digital temperature sensor and thermal watchdog
Temp register value ...continued Hexadecimal value 738 649 648 Decimal value -200 -439 -440 Value -25.000 C -54.875 C -55.000 C
Table 9.
11-bit binary (2's complement) 111 0011 1000 110 0100 1001 110 0100 1000
For 9-bit Temp data application in replacing the industry standard LM75, just use only 9 MSB bits of the two bytes and disregard 7 LSB of the LSByte. The 9-bit Temp data with 0.5 C resolution of the LM75B is defined exactly in the same way as for the standard LM75 and it is here similar to the Tos and Thyst registers. The only MSByte of the temperature can also be read with the use of a one-byte reading command. Then the temperature resolution will be 1.00 C instead.
7.4.4 Overtemperature shutdown threshold (Tos) and hysteresis (Thyst) registers
These two registers, are write/read registers, and also called set-point registers. They are used to store the user-defined temperature limits, called overtemperature shutdown threshold (Tth(ots)) and hysteresis temperature (Thys), for the device watchdog operation. At the end of each conversion the Temp data will be compared with the data stored in these two registers in order to set the state of the device OS output; see Section 7.1. Each of the set-point registers contains two 8-bit data bytes consisting of one MSByte and one LSByte the same as register Temp. However, only 9 bits of the two bytes are used to store the set-point data in 2's complement format with the resolution of 0.5 C. Table 10 and Table 11 show the bit arrangement of the Tos data and Thyst data in the data bytes. Notice that because only 9-bit data are used in the set-point registers, the device uses only the 9 MSB of the Temp data for data comparison.
Table 10. MSByte 7 D8 6 D7 5 D6 4 D5 3 D4 2 D3 1 D2 0 D1 Tos register LSByte 7 D0 6 X 5 X 4 X 3 X 2 X 1 X 0 X
Table 11. MSByte 7 D8 6 D7
Thyst register LSByte 5 D6 4 D5 3 D4 2 D3 1 D2 0 D1 7 D0 6 X 5 X 4 X 3 X 2 X 1 X 0 X
When a set-point register is read, all 16 bits are provided to the bus and must be collected by the controller to complete the bus operation. However, only the 9 most significant bits should be used and the 7 LSB of the LSByte are equal to zero and should be ignored. Table 12 shows examples of the limit data and value.
LM75B_2
(c) NXP B.V. 2008. All rights reserved.
Product data sheet
Rev. 02 -- 9 December 2008
9 of 29
NXP Semiconductors
LM75B
Digital temperature sensor and thermal watchdog
Tos and Thyst limit data and value Hexadecimal value 0FA 032 001 000 1FF 1CE 192 Decimal value 250 50 1 0 -1 -50 -110 Value +125.0 C +25.0 C +0.5 C 0.0 C -0.5 C -25.0 C -55.0 C
Table 12.
11-bit binary (2's complement) 0 1111 1010 0 0011 0010 0 0000 0001 0 0000 0000 1 1111 1111 1 1100 1110 1 1001 0010
7.5 OS output and polarity
The OS output is an open-drain output and its state represents results of the device watchdog operation as described in Section 7.1. In order to observe this output state, an external pull-up resistor is needed. The resistor should be as large as possible, up to 200 k, to minimize the Temp reading error due to internal heating by the high OS sinking current. The OS output active state can be selected as HIGH or LOW by programming bit B2 (OS_POL) of register Conf: setting bit OS_POL to logic 1 selects OS active HIGH and setting bit B2 to logic 0 sets OS active LOW. At power-up, bit OS_POL is equal to logic 0 and the OS active state is LOW.
7.6 OS comparator and interrupt modes
As described in Section 7.1, the device OS output responds to the result of the comparison between register Temp data and the programmed limits, in registers Tos and Thyst, in different ways depending on the selected OS mode: OS comparator or OS interrupt. The OS mode is selected by programming bit B1 (OS_COMP_INT) of register Conf: setting bit OS_COMP_INT to logic 1 selects the OS interrupt mode, and setting to logic 0 selects the OS comparator mode. At power-up, bit OS_COMP_INT is equal to logic 0 and the OS comparator is selected. The main difference between the two modes is that in OS comparator mode, the OS output becomes active when Temp has exceeded Tth(ots) and reset when Temp has dropped below Thys, reading a register or putting the device into shutdown mode does not change the state of the OS output; while in OS interrupt mode, once it has been activated either by exceeding Tth(ots) or dropping below Thys, the OS output will remain active indefinitely until reading a register, then the OS output is reset. Temperature limits Tth(ots) and Thys must be selected so that Tth(ots) > Thys. Otherwise, the OS output state will be undefined.
LM75B_2
(c) NXP B.V. 2008. All rights reserved.
Product data sheet
Rev. 02 -- 9 December 2008
10 of 29
NXP Semiconductors
LM75B
Digital temperature sensor and thermal watchdog
7.7 OS fault queue
Fault queue is defined as the number of faults that must occur consecutively to activate the OS output. It is provided to avoid false tripping due to noise. Because faults are determined at the end of data conversions, fault queue is also defined as the number of consecutive conversions returning a temperature trip. The value of fault queue is selectable by programming the two bits B4 and B3 (OS_F_QUE[1:0]) in register Conf. Notice that the programmed data and the fault queue value are not the same. Table 13 shows the one-to-one relationship between them. At power-up, fault queue data = 0 and fault queue value = 1.
Table 13. Fault queue table Fault queue value OS_F_QUE[0] 0 1 0 1 Decimal 1 2 4 6
Fault queue data OS_F_QUE[1] 0 0 1 1
7.8 Shutdown mode
The device operation mode is selected by programming bit B0 (SHUTDOWN) of register Conf. Setting bit SHUTDOWN to logic 1 will put the device into shutdown mode. Resetting bit SHUTDOWN to logic 0 will return the device to normal mode. In shutdown mode, the device draws a small current of approximately 1.0 A and the power dissipation is minimized; the temperature conversion stops, but the I2C-bus interface remains active and register write/read operation can be performed. When the shutdown is set, the OS output will be unchanged in comparator mode and reset in interrupt mode.
7.9 Power-up default and power-on reset
The LM75B always powers-up in its default state with:
* * * * * *
Normal operation mode OS comparator mode Tth(ots) = 80 C Thys = 75 C OS output active state is LOW Pointer value is logic 00 (Temp)
When the power supply voltage is dropped below the device power-on reset level of approximately 1.0 V (POR) for over 2 s and then rises up again, the device will be reset to its default condition as listed above.
LM75B_2
(c) NXP B.V. 2008. All rights reserved.
Product data sheet
Rev. 02 -- 9 December 2008
11 of 29
NXP Semiconductors
LM75B
Digital temperature sensor and thermal watchdog
7.10 Protocols for writing and reading the registers
The communication between the host and the LM75B must strictly follow the rules as defined by the I2C-bus management. The protocols for LM75B register read/write operations are illustrated in Figure 6 to Figure 11 together with the following definitions: 1. Before a communication, the I2C-bus must be free or not busy. It means that the SCL and SDA lines must both be released by all devices on the bus, and they become HIGH by the bus pull-up resistors. 2. The host must provide SCL clock pulses necessary for the communication. Data is transferred in a sequence of 9 SCL clock pulses for every 8-bit data byte followed by 1-bit status of the acknowledgement. 3. During data transfer, except the START and STOP signals, the SDA signal must be stable while the SCL signal is HIGH. It means that the SDA signal can be changed only during the LOW duration of the SCL line. 4. S: START signal, initiated by the host to start a communication, the SDA goes from HIGH to LOW while the SCL is HIGH. 5. RS: RE-START signal, same as the START signal, to start a read command that follows a write command. 6. P: STOP signal, generated by the host to stop a communication, the SDA goes from LOW to HIGH while the SCL is HIGH. The bus becomes free thereafter. 7. W: write bit, when the write/read bit = LOW in a write command. 8. R: read bit, when the write/read bit = HIGH in a read command. 9. A: device acknowledge bit, returned by the LM75B. It is LOW if the device works properly and HIGH if not. The host must release the SDA line during this period in order to give the device the control on the SDA line. 10. A': master acknowledge bit, not returned by the device, but set by the master or host in reading 2-byte data. During this clock period, the host must set the SDA line to LOW in order to notify the device that the first byte has been read for the device to provide the second byte onto the bus. 11. NA: Not Acknowledge bit. During this clock period, both the device and host release the SDA line at the end of a data transfer, the host is then enabled to generate the STOP signal. 12. In a write protocol, data is sent from the host to the device and the host controls the SDA line, except during the clock period when the device sends the device acknowledgement signal to the bus. 13. In a read protocol, data is sent to the bus by the device and the host must release the SDA line during the time that the device is providing data onto the bus and controlling the SDA line, except during the clock period when the master sends the master acknowledgement signal to the bus.
LM75B_2
(c) NXP B.V. 2008. All rights reserved.
Product data sheet
Rev. 02 -- 9 December 2008
12 of 29
NXP Semiconductors
LM75B
Digital temperature sensor and thermal watchdog
1 SCL SDA S 1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
9
0
0
1
A2 A1 A0 W
A
0
0
0
0
0
0
0
1
A
0
0
0
D4 D3 D2 D1 D0 A
P
device address START write device acknowledge
pointer byte device acknowledge
configuration data byte device acknowledge STOP
001aad624
Fig 6.
Write configuration register (1-byte data)
1 SCL SDA S 1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
9 (next)
0
0
1
A2
A1
A0 W
A
0
0
0
0
0
0
0
1
A
RS (next)
device address START write device acknowledge 1 SCL (cont.) SDA (cont.) 1 0 0 1 A2 A1 A0 R A 2 3 4 5 6 7 8 9 1 2
pointer byte device acknowledge RE-START
3
4
5
6
7
8
9
D7 D6 D5 D4 D3 D2 D1 D0 NA data byte from device
P
device address read device acknowledge
master not acknowledged
STOP
001aad625
Fig 7.
Read configuration register including pointer byte (1-byte data)
1 SCL SDA S 1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
9
0
0
1
A2
A1
A0 R
A
D7 D6 D5 D4 D3 D2 D1 D0 NA data byte from device
P
device address START read device acknowledge
master not acknowledged
STOP
001aad626
Fig 8.
Read configuration or temp register with preset pointer (1-byte data)
LM75B_2
(c) NXP B.V. 2008. All rights reserved.
Product data sheet
Rev. 02 -- 9 December 2008
13 of 29
NXP Semiconductors
LM75B
Digital temperature sensor and thermal watchdog
1 SCL SDA S 1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
9 (next)
0
0
1
A2
A1
A0
W
A
0
0
0
0
0
0
P1
P0
A
(next)
device address START write device acknowledge 1 SCL (cont.) SDA (cont.) D7 D6 D5 D4 D3 D2 D1 D0 A MSByte data device acknowledge 2 3 4 5 6 7 8 9 1 2
pointer byte device acknowledge
3
4
5
6
7
8
9
D7 D6 D5 D4 D3 D2 D1 D0 LSByte data device acknowledge
A
P
STOP
002aad036
Fig 9.
Write Tos or Thyst register (2-byte data)
1 SCL SDA S 1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
9
0 (next)
0
0
1
A2 A1 A0 W A
0
0
0
0
0
0
P1 P0 A RS (next)
device address START write device acknowledge 5678
pointer byte device acknowledge 9 1 2 3 4 5 6 7 8 9 1 RE-START
1 SCL (cont) SDA (cont) 1
2
3
4
2
3
4
5
6
7
8
9
0
0
1
A2 A1 A0 R
A
D7 D6 D5 D4 D3 D2 D1 D0 A' MSByte from device
D7 D6 D5 D4 D3 D2 D1 D0 NA LSByte from device master not acknowledged
P
device address read device acknowledge
master acknowledge
STOP
002aad037
Fig 10. Read Temp, Tos or Thyst register including pointer byte (2-byte data)
1 SCL SDA S 1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
9
0
0
1
A2 A1 A0 R
A
D7 D6 D5 D4 D3 D2 D1 D0 A' D7 D6 D5 D4 D3 D2 D1 D0 NA MSByte from device LSByte from device master not acknowledged
P
device address START read device acknowledge
master acknowledge
STOP
002aad038
Fig 11. Read Temp, Tos or Thyst register with preset pointer (2-byte data)
LM75B_2
(c) NXP B.V. 2008. All rights reserved.
Product data sheet
Rev. 02 -- 9 December 2008
14 of 29
NXP Semiconductors
LM75B
Digital temperature sensor and thermal watchdog
8. Application design-in information
8.1 Typical application
power supply
0.1 F
BUS 10 k PULL-UP RESISTORS I2C-BUS
10 k
VCC SCL SDA 8 2 1
10 k
A2 DIGITAL LOGIC A1 A0
LM75B
5 6 7 4 GND
3
OS
DETECTOR OR INTERRUPT LINE
002aad457
Fig 12. Typical application
8.2 LM75A and LM75B comparison
Table 14. LM75A and LM75B comparison LM75A no no no no 10 ns 100 ms / 100 ms 3.5 A >2000 V >200 V >1000 V lockup[2] LM75B yes yes yes yes 0 ns 10 ms / 100 ms 0.2 A >4500 V >450 V >2000 V Description availability of the XSON8U (3 mm x 2 mm) package type OS output auto-reset when SHUTDOWN bit is set in interrupt mode[1] support single-byte reading of the Temp registers without bus bus fault time-out (75 ms, 200 minimum data hold time ms)[3] (tHD;DAT)[4]
ratio of conversion time / conversion period (typical)[5] supply current in shutdown mode (typical value) HBM ESD protection level (minimum) MM ESD protection level (minimum) CDM ESD protection level (minimum)
[1]
This option is updated to be compatible with the competitive parts. When the OS output has been activated in the interrupt mode due to a temp limit violation, if the Configuration Shutdown bit B0 is set (to the LM75A), then the OS output activated status remains unchanged, while (to the LM75B) the OS will be reset. The latter is compatible with the operation condition of the competitive parts. The LM75 series is intentionally designed to provide two successive temperature data bytes (MSByte and LSByte) for the 11-bit data resolution and both bytes should be read in a typical application. In some specific applications, when only the MSByte is read using a single-byte read command, it often happens that if bit D7 of the LSByte is zero, then the device will hold the SDA bus in a LOW state forever, resulting in a bus hang-up problem, and the bus cannot be released until the device power is reset. This condition exists for the LM75A but not for the LM75B. For the LM75B the temperature can be read either one byte or two bytes without a hang-up problem. The bus time-out is included for releasing the LM75B device operation whenever the SDA input is kept at a LOW state for too long (longer than the LM75B time-out duration) due to a fault from the host. The trade-off for this option is the limitation of the I2C-bus low frequency operation to be limited to 20 Hz. This option is compatible with some of the latest versions of the competitive parts. The data hold time is improved to increase the timing margin in I2C-bus operation.
(c) NXP B.V. 2008. All rights reserved.
[2]
[3]
[4]
LM75B_2
Product data sheet
Rev. 02 -- 9 December 2008
15 of 29
NXP Semiconductors
LM75B
Digital temperature sensor and thermal watchdog
[5]
The LM75B performs the temperature-to-data conversions with a much higher speed than the LM75A. While the LM75A takes almost the whole of conversion period (Tconv) time of about 100 ms to complete a conversion, the LM75B takes only about 110 of the period, or about 10 ms. Therefore, the conversion period (Tconv) is the same, but the temperature conversion time (tconv(T)) is different between the two parts. A shorter conversion time is applied to significantly reduce the device's average power dissipation. During each conversion period, when the conversion is completed, the LM75B becomes idled and the power is reduced, resulting in a lesser average power consumption.
8.3 Temperature accuracy
Because the local channel of the temperature sensor measures its own die temperature that is transferred from its body, the temperature of the device body must be stabilized and saturated for it to provide the stable readings. Because the LM75B operates a a low power level, the thermal gradient of the device package has a minor effect on the measurement. The accuracy of the measurement is more dependent upon the definition of the environment temperature, which is affected by different factors: the printed-circuit board on which the device is mounted; the air flow contacting the device body (if the ambient air temperature and the printed-circuit board temperature are much different, then the measurement may not be stable because of the different thermal paths between the die and the environment). The stabilized temperature liquid of a thermal bath will provide the best temperature environment when the device is completely dipped into it. A thermal probe with the device mounted inside a sealed-end metal tube located in consistent temperature air also provides a good method of temperature measurement.
8.4 Noise effect
The LM75B device design includes the implementation of basic features for a good noise immunity:
* The low-pass filter on both the bus pins SCL and SDA; * The hysteresis of the threshold voltages to the bus input signals SCL and SDA, about
500 mV minimum;
* All pins have ESD protection circuitry to prevent damage during electrical surges. The
ESD protection on the address, OS, SCL and SDA pins it to ground. The latch-back based device breakdown voltage of address/OS is typically 11 V and SCL/SDA is typically 9.5 V at any supply voltage but will vary over process and temperature. Since there are no protection diodes from SCL or SDA to VCC, the LM75B will not hold the I2C lines LOW when VCC is not supplied and therefore allow continued I2C-bus operation if the LM75B is de-powered. However, good layout practices and extra noise filters are recommended when the device is used in a very noisy environment:
* * * *
Use decoupling capacitors at VCC pin. Keep the digital traces away from switching power supplies. Apply proper terminations for the long board traces. Add capacitors to the SCL and SDA lines to increase the low-pass filter characteristics.
LM75B_2
(c) NXP B.V. 2008. All rights reserved.
Product data sheet
Rev. 02 -- 9 December 2008
16 of 29
NXP Semiconductors
LM75B
Digital temperature sensor and thermal watchdog
9. Limiting values
Table 15. Limiting values In accordance with the Absolute Maximum Rating System (IEC 60134). Symbol VCC VI II IO(sink) VO Tstg Tj Parameter supply voltage input voltage input current output sink current output voltage storage temperature junction temperature at input pins at input pins on pin OS on pin OS Conditions Min -0.3 -0.3 -5.0 -0.3 -65 Max +6.0 +6.0 +5.0 10.0 +6.0 +150 150 Unit V V mA mA V C C
10. Recommended operating conditions
Table 16. Symbol VCC Tamb Recommended operating characteristics Parameter supply voltage ambient temperature Conditions Min 2.8 -55 Typ Max 5.5 +125 Unit V C
LM75B_2
(c) NXP B.V. 2008. All rights reserved.
Product data sheet
Rev. 02 -- 9 December 2008
17 of 29
NXP Semiconductors
LM75B
Digital temperature sensor and thermal watchdog
11. Static characteristics
Table 17. Static characteristics VCC = 2.8 V to 5.5 V; Tamb = -55 C to +125 C; unless otherwise specified. Symbol Tacc Tres tconv(T) Tconv IDD(AV) Parameter temperature accuracy temperature resolution temperature conversion time conversion period average supply current Conditions Tamb = -25 C to +100 C Tamb = -55 C to +125 C 11-bit digital temp data normal mode normal mode normal mode: I2C-bus inactive normal mode: fSCL = 400 kHz VIH VIL VI(hys) IIH IIL VOL ILO Nfault HIGH-level input voltage LOW-level input voltage I2C-bus active; Min -2 -3 0.7 x VCC -0.3 -1.0 -1.0 1 Typ[1] 0.125 10 100 100 0.2 300 150 Max +2 +3 200 300 1.0 VCC + 0.3 0.3 x VCC +1.0 +1.0 0.4 0.8 10 6 Unit C C C ms ms A A A V V mV mv A A V V A
shutdown mode digital pins (SCL, SDA, A2 to A0) digital pins A2, A1, A0 pins HIGH-level input current LOW-level input current LOW-level output voltage output leakage current number of faults digital pins; VI = VCC digital pins; VI = 0 V SDA and OS pins; IOL = 3 mA IOL = 4 mA SDA and OS pins; VOH = VCC programmable; conversions in overtemperature-shutdown fault queue default value
hysteresis of input voltage SCL and SDA pins
Tth(ots)
overtemperature shutdown threshold temperature hysteresis temperature input capacitance
-
80
-
C
Thys Ci
[1]
default value digital pins
-
75 20
-
C pF
Typical values are at VCC = 3.3 V and Tamb = 25 C.
LM75B_2
(c) NXP B.V. 2008. All rights reserved.
Product data sheet
Rev. 02 -- 9 December 2008
18 of 29
NXP Semiconductors
LM75B
Digital temperature sensor and thermal watchdog
300 IDD(AV) (A) 200
002aae198
300 IDD(AV) (A) 200 VCC = 5.5 V 4.5 V 3.3 V 2.8 V
002aae199
VCC = 5.5 V 4.5 V 3.3 V 2.8 V
100
100
0 -75
-25
25
75
125 Tamb (C)
0 -75
-25
25
75
125 Tamb (C)
Fig 13. Average supply current versus temperature; I2C-bus inactive
0.5 IDD(sd) (A) 0.4
002aae200
Fig 14. Average supply current versus temperature; I2C-bus active
0.5 VOL(OS) (V) 0.4 VCC = 5.5 V 4.5 V 3.3 V 2.8 V
002aae201
0.3
VCC = 5.5 V 4.5 V 3.3 V 2.8 V
0.3
0.2
0.2
0.1
0.1
0 -75
-25
25
75
125 Tamb (C)
0 -75
-25
25
75
125 Tamb (C)
Fig 15. Shutdown mode supply current versus temperature
0.5 VOL(SDA) (V) 0.4
002aae202
Fig 16. LOW-level output voltage on pin OS versus temperature; IOL = 4 mA
2.0 Tacc (C) 1.0
002aae203
0.3
VCC = 5.5 V 4.5 V 3.3 V 2.8 V
0 0.2 -1.0
0.1
0 -75
-25
25
75
125 Tamb (C)
-2.0 -75
-25
25
75
125 Tamb (C)
Fig 17. LOW-level output voltage on pin SDA versus temperature; IOL = 4 mA
Fig 18. Typical temperature accuracy versus temperature; VCC = 3.3 V
LM75B_2
(c) NXP B.V. 2008. All rights reserved.
Product data sheet
Rev. 02 -- 9 December 2008
19 of 29
NXP Semiconductors
LM75B
Digital temperature sensor and thermal watchdog
12. Dynamic characteristics
Table 18. I2C-bus interface dynamic characteristics[1] VCC = 2.8 V to 5.5 V; Tamb = -55 C to +125 C; unless otherwise specified. Symbol fSCL tHIGH tLOW tHD;STA tSU;DAT tHD;DAT tSU;STO tf tto
[1] [2] [3]
Parameter SCL clock frequency HIGH period of the SCL clock LOW period of the SCL clock hold time (repeated) START condition data set-up time data hold time set-up time for STOP condition fall time time-out time
Conditions see Figure 19
Min 0.02 0.6 1.3 100 100 0 100
Typ 250 -
Max 400 200
Unit kHz s s ns ns ns ns ns ms
SDA and OS outputs; CL = 400 pF; IOL = 3 mA
[2][3]
75
These specifications are guaranteed by design and not tested in production. This is the SDA time LOW for reset of serial interface. Holding the SDA line LOW for a time grater than tto will cause the LM75B to reset SDA to the idle state of the serial bus communication (SDA set HIGH).
SDA tf tLOW tr SCL tHD;STA S tHIGH tSU;STA tHD;DAT tSU;STO Sr P S
002aab271
tSU;DAT tf
tHD;STA
tSP
tBUF tr
Fig 19. Timing diagram
LM75B_2
(c) NXP B.V. 2008. All rights reserved.
Product data sheet
Rev. 02 -- 9 December 2008
20 of 29
NXP Semiconductors
LM75B
Digital temperature sensor and thermal watchdog
13. Package outline
SO8: plastic small outline package; 8 leads; body width 3.9 mm SOT96-1
D
E
A X
c y HE vMA
Z 8 5
Q A2 A1 pin 1 index Lp 1 e bp 4 wM L detail X (A 3) A
0
2.5 scale
5 mm
DIMENSIONS (inch dimensions are derived from the original mm dimensions) UNIT mm inches Notes 1. Plastic or metal protrusions of 0.15 mm (0.006 inch) maximum per side are not included. 2. Plastic or metal protrusions of 0.25 mm (0.01 inch) maximum per side are not included. OUTLINE VERSION SOT96-1 REFERENCES IEC 076E03 JEDEC MS-012 JEITA EUROPEAN PROJECTION A max. 1.75 0.069 A1 0.25 0.10 A2 1.45 1.25 A3 0.25 0.01 bp 0.49 0.36 c 0.25 0.19 D (1) 5.0 4.8 0.20 0.19 E (2) 4.0 3.8 0.16 0.15 e 1.27 0.05 HE 6.2 5.8 L 1.05 Lp 1.0 0.4 Q 0.7 0.6 v 0.25 0.01 w 0.25 0.01 y 0.1 0.004 Z (1) 0.7 0.3 0.028 0.012
0.010 0.057 0.004 0.049
0.019 0.0100 0.014 0.0075
0.244 0.039 0.028 0.041 0.228 0.016 0.024
8o o 0
ISSUE DATE 99-12-27 03-02-18
Fig 20. Package outline SOT96-1 (SO8)
LM75B_2 (c) NXP B.V. 2008. All rights reserved.
Product data sheet
Rev. 02 -- 9 December 2008
21 of 29
NXP Semiconductors
LM75B
Digital temperature sensor and thermal watchdog
TSSOP8: plastic thin shrink small outline package; 8 leads; body width 3 mm
SOT505-1
D
E
A
X
c y HE vMA
Z
8
5
A2 pin 1 index
A1
(A3)
A
Lp L
1
e bp
4
detail X wM
0
2.5 scale
5 mm
DIMENSIONS (mm are the original dimensions) UNIT mm A max. 1.1 A1 0.15 0.05 A2 0.95 0.80 A3 0.25 bp 0.45 0.25 c 0.28 0.15 D(1) 3.1 2.9 E(2) 3.1 2.9 e 0.65 HE 5.1 4.7 L 0.94 Lp 0.7 0.4 v 0.1 w 0.1 y 0.1 Z(1) 0.70 0.35 6 0
Notes 1. Plastic or metal protrusions of 0.15 mm maximum per side are not included. 2. Plastic or metal protrusions of 0.25 mm maximum per side are not included. OUTLINE VERSION SOT505-1 REFERENCES IEC JEDEC JEITA EUROPEAN PROJECTION ISSUE DATE 99-04-09 03-02-18
Fig 21. Package outline SOT505-1 (TSSOP8)
LM75B_2 (c) NXP B.V. 2008. All rights reserved.
Product data sheet
Rev. 02 -- 9 December 2008
22 of 29
NXP Semiconductors
LM75B
Digital temperature sensor and thermal watchdog
XSON8U: plastic extremely thin small outline package; no leads; 8 terminals; UTLP based; body 3 x 2 x 0.5 mm
SOT996-2
D
B
A
E
A
A1
detail X terminal 1 index area e1 L1
1
e
b
4
v w
M M
CAB C
C y1 C y
L2
L
8 5
X
0
1 scale
2 mm
DIMENSIONS (mm are the original dimensions) UNIT mm A max 0.5 A1 0.05 0.00 b 0.35 0.15 D 2.1 1.9 E 3.1 2.9 e 0.5 e1 1.5 L 0.5 0.3 L1 0.15 0.05 L2 0.6 0.4 v 0.1 w 0.05 y 0.05 y1 0.1
OUTLINE VERSION SOT996-2
REFERENCES IEC --JEDEC JEITA ---
EUROPEAN PROJECTION
ISSUE DATE 07-12-18 07-12-21
Fig 22. Package outline SOT996-2 (XSON8U)
LM75B_2 (c) NXP B.V. 2008. All rights reserved.
Product data sheet
Rev. 02 -- 9 December 2008
23 of 29
NXP Semiconductors
LM75B
Digital temperature sensor and thermal watchdog
14. Soldering of SMD packages
This text provides a very brief insight into a complex technology. A more in-depth account of soldering ICs can be found in Application Note AN10365 "Surface mount reflow soldering description".
14.1 Introduction to soldering
Soldering is one of the most common methods through which packages are attached to Printed Circuit Boards (PCBs), to form electrical circuits. The soldered joint provides both the mechanical and the electrical connection. There is no single soldering method that is ideal for all IC packages. Wave soldering is often preferred when through-hole and Surface Mount Devices (SMDs) are mixed on one printed wiring board; however, it is not suitable for fine pitch SMDs. Reflow soldering is ideal for the small pitches and high densities that come with increased miniaturization.
14.2 Wave and reflow soldering
Wave soldering is a joining technology in which the joints are made by solder coming from a standing wave of liquid solder. The wave soldering process is suitable for the following:
* Through-hole components * Leaded or leadless SMDs, which are glued to the surface of the printed circuit board
Not all SMDs can be wave soldered. Packages with solder balls, and some leadless packages which have solder lands underneath the body, cannot be wave soldered. Also, leaded SMDs with leads having a pitch smaller than ~0.6 mm cannot be wave soldered, due to an increased probability of bridging. The reflow soldering process involves applying solder paste to a board, followed by component placement and exposure to a temperature profile. Leaded packages, packages with solder balls, and leadless packages are all reflow solderable. Key characteristics in both wave and reflow soldering are:
* * * * * *
Board specifications, including the board finish, solder masks and vias Package footprints, including solder thieves and orientation The moisture sensitivity level of the packages Package placement Inspection and repair Lead-free soldering versus SnPb soldering
14.3 Wave soldering
Key characteristics in wave soldering are:
* Process issues, such as application of adhesive and flux, clinching of leads, board
transport, the solder wave parameters, and the time during which components are exposed to the wave
* Solder bath specifications, including temperature and impurities
LM75B_2 (c) NXP B.V. 2008. All rights reserved.
Product data sheet
Rev. 02 -- 9 December 2008
24 of 29
NXP Semiconductors
LM75B
Digital temperature sensor and thermal watchdog
14.4 Reflow soldering
Key characteristics in reflow soldering are:
* Lead-free versus SnPb soldering; note that a lead-free reflow process usually leads to
higher minimum peak temperatures (see Figure 23) than a SnPb process, thus reducing the process window
* Solder paste printing issues including smearing, release, and adjusting the process
window for a mix of large and small components on one board
* Reflow temperature profile; this profile includes preheat, reflow (in which the board is
heated to the peak temperature) and cooling down. It is imperative that the peak temperature is high enough for the solder to make reliable solder joints (a solder paste characteristic). In addition, the peak temperature must be low enough that the packages and/or boards are not damaged. The peak temperature of the package depends on package thickness and volume and is classified in accordance with Table 19 and 20
Table 19. SnPb eutectic process (from J-STD-020C) Package reflow temperature (C) Volume (mm3) < 350 < 2.5 2.5 Table 20. 235 220 Lead-free process (from J-STD-020C) Package reflow temperature (C) Volume (mm3) < 350 < 1.6 1.6 to 2.5 > 2.5 260 260 250 350 to 2000 260 250 245 > 2000 260 245 245 350 220 220
Package thickness (mm)
Package thickness (mm)
Moisture sensitivity precautions, as indicated on the packing, must be respected at all times. Studies have shown that small packages reach higher temperatures during reflow soldering, see Figure 23.
LM75B_2
(c) NXP B.V. 2008. All rights reserved.
Product data sheet
Rev. 02 -- 9 December 2008
25 of 29
NXP Semiconductors
LM75B
Digital temperature sensor and thermal watchdog
temperature
maximum peak temperature = MSL limit, damage level
minimum peak temperature = minimum soldering temperature
peak temperature
time
001aac844
MSL: Moisture Sensitivity Level
Fig 23. Temperature profiles for large and small components
For further information on temperature profiles, refer to Application Note AN10365 "Surface mount reflow soldering description".
15. Abbreviations
Table 21. Acronym A-to-D CDM ESD HBM I2C-bus I/O LSB LSByte MM MSB MSByte POR Abbreviations Description Analog-to-Digital Charged Device Model ElectroStatic Discharge Human Body Model Inter-Integrated Circuit bus Input/Output Lease Significant Bit Least Significant Byte Machine Model Most Significant Bit Most Significant Byte Power-On Reset
LM75B_2
(c) NXP B.V. 2008. All rights reserved.
Product data sheet
Rev. 02 -- 9 December 2008
26 of 29
NXP Semiconductors
LM75B
Digital temperature sensor and thermal watchdog
16. Revision history
Table 22. LM75B_2 Modifications: LM75B_1 Revision history Release date 20081209 Data sheet status Product data sheet Change notice Supersedes LM75B_1 Document ID
*
added XSON8U package option (affects Section 2 "Features", Table 1 "Ordering information", Section 6.1 "Pinning", Table 14 "LM75A and LM75B comparison", Section 13 "Package outline") Product data sheet -
20081204
LM75B_2
(c) NXP B.V. 2008. All rights reserved.
Product data sheet
Rev. 02 -- 9 December 2008
27 of 29
NXP Semiconductors
LM75B
Digital temperature sensor and thermal watchdog
17. Legal information
17.1 Data sheet status
Document status[1][2] Objective [short] data sheet Preliminary [short] data sheet Product [short] data sheet
[1] [2] [3]
Product status[3] Development Qualification Production
Definition This document contains data from the objective specification for product development. This document contains data from the preliminary specification. This document contains the product specification.
Please consult the most recently issued document before initiating or completing a design. The term `short data sheet' is explained in section "Definitions". The product status of device(s) described in this document may have changed since this document was published and may differ in case of multiple devices. The latest product status information is available on the Internet at URL http://www.nxp.com.
17.2 Definitions
Draft -- The document is a draft version only. The content is still under internal review and subject to formal approval, which may result in modifications or additions. NXP Semiconductors does not give any representations or warranties as to the accuracy or completeness of information included herein and shall have no liability for the consequences of use of such information. Short data sheet -- A short data sheet is an extract from a full data sheet with the same product type number(s) and title. A short data sheet is intended for quick reference only and should not be relied upon to contain detailed and full information. For detailed and full information see the relevant full data sheet, which is available on request via the local NXP Semiconductors sales office. In case of any inconsistency or conflict with the short data sheet, the full data sheet shall prevail.
to result in personal injury, death or severe property or environmental damage. NXP Semiconductors accepts no liability for inclusion and/or use of NXP Semiconductors products in such equipment or applications and therefore such inclusion and/or use is at the customer's own risk. Applications -- Applications that are described herein for any of these products are for illustrative purposes only. NXP Semiconductors makes no representation or warranty that such applications will be suitable for the specified use without further testing or modification. Limiting values -- Stress above one or more limiting values (as defined in the Absolute Maximum Ratings System of IEC 60134) may cause permanent damage to the device. Limiting values are stress ratings only and operation of the device at these or any other conditions above those given in the Characteristics sections of this document is not implied. Exposure to limiting values for extended periods may affect device reliability. Terms and conditions of sale -- NXP Semiconductors products are sold subject to the general terms and conditions of commercial sale, as published at http://www.nxp.com/profile/terms, including those pertaining to warranty, intellectual property rights infringement and limitation of liability, unless explicitly otherwise agreed to in writing by NXP Semiconductors. In case of any inconsistency or conflict between information in this document and such terms and conditions, the latter will prevail. No offer to sell or license -- Nothing in this document may be interpreted or construed as an offer to sell products that is open for acceptance or the grant, conveyance or implication of any license under any copyrights, patents or other industrial or intellectual property rights.
17.3 Disclaimers
General -- Information in this document is believed to be accurate and reliable. However, NXP Semiconductors does not give any representations or warranties, expressed or implied, as to the accuracy or completeness of such information and shall have no liability for the consequences of use of such information. Right to make changes -- NXP Semiconductors reserves the right to make changes to information published in this document, including without limitation specifications and product descriptions, at any time and without notice. This document supersedes and replaces all information supplied prior to the publication hereof. Suitability for use -- NXP Semiconductors products are not designed, authorized or warranted to be suitable for use in medical, military, aircraft, space or life support equipment, nor in applications where failure or malfunction of an NXP Semiconductors product can reasonably be expected
17.4 Trademarks
Notice: All referenced brands, product names, service names and trademarks are the property of their respective owners. I2C-bus -- logo is a trademark of NXP B.V.
18. Contact information
For more information, please visit: http://www.nxp.com For sales office addresses, please send an email to: salesaddresses@nxp.com
LM75B_2
(c) NXP B.V. 2008. All rights reserved.
Product data sheet
Rev. 02 -- 9 December 2008
28 of 29
NXP Semiconductors
LM75B
Digital temperature sensor and thermal watchdog
19. Contents
1 2 3 4 5 6 6.1 6.2 7 7.1 7.2 7.2.1 7.3 7.4 7.4.1 7.4.2 7.4.3 7.4.4 7.5 7.6 7.7 7.8 7.9 7.10 8 8.1 8.2 8.3 8.4 9 10 11 12 13 14 14.1 14.2 14.3 14.4 15 16 17 17.1 17.2 General description . . . . . . . . . . . . . . . . . . . . . . 1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Ordering information . . . . . . . . . . . . . . . . . . . . . 2 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Pinning information . . . . . . . . . . . . . . . . . . . . . . 3 Pinning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Pin description . . . . . . . . . . . . . . . . . . . . . . . . . 4 Functional description . . . . . . . . . . . . . . . . . . . 4 General operation . . . . . . . . . . . . . . . . . . . . . . . 4 I2C-bus serial interface . . . . . . . . . . . . . . . . . . . 6 Bus fault time-out . . . . . . . . . . . . . . . . . . . . . . . 6 Slave address . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Register list . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Pointer register . . . . . . . . . . . . . . . . . . . . . . . . . 7 Configuration register . . . . . . . . . . . . . . . . . . . . 7 Temperature register. . . . . . . . . . . . . . . . . . . . . 8 Overtemperature shutdown threshold (Tos) and hysteresis (Thyst) registers . . . . . . . . . . . . 9 OS output and polarity . . . . . . . . . . . . . . . . . . 10 OS comparator and interrupt modes . . . . . . . 10 OS fault queue . . . . . . . . . . . . . . . . . . . . . . . . 11 Shutdown mode . . . . . . . . . . . . . . . . . . . . . . . 11 Power-up default and power-on reset . . . . . . . 11 Protocols for writing and reading the registers 12 Application design-in information . . . . . . . . . 15 Typical application. . . . . . . . . . . . . . . . . . . . . . 15 LM75A and LM75B comparison . . . . . . . . . . . 15 Temperature accuracy . . . . . . . . . . . . . . . . . . 16 Noise effect. . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Limiting values. . . . . . . . . . . . . . . . . . . . . . . . . 17 Recommended operating conditions. . . . . . . 17 Static characteristics. . . . . . . . . . . . . . . . . . . . 18 Dynamic characteristics . . . . . . . . . . . . . . . . . 20 Package outline . . . . . . . . . . . . . . . . . . . . . . . . 21 Soldering of SMD packages . . . . . . . . . . . . . . 24 Introduction to soldering . . . . . . . . . . . . . . . . . 24 Wave and reflow soldering . . . . . . . . . . . . . . . 24 Wave soldering . . . . . . . . . . . . . . . . . . . . . . . . 24 Reflow soldering . . . . . . . . . . . . . . . . . . . . . . . 25 Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Revision history . . . . . . . . . . . . . . . . . . . . . . . . 27 Legal information. . . . . . . . . . . . . . . . . . . . . . . 28 Data sheet status . . . . . . . . . . . . . . . . . . . . . . 28 Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 17.3 17.4 18 19 Disclaimers. . . . . . . . . . . . . . . . . . . . . . . . . . . Trademarks . . . . . . . . . . . . . . . . . . . . . . . . . . Contact information . . . . . . . . . . . . . . . . . . . . Contents. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 28 28 29
Please be aware that important notices concerning this document and the product(s) described herein, have been included in section `Legal information'.
(c) NXP B.V. 2008.
All rights reserved.
For more information, please visit: http://www.nxp.com For sales office addresses, please send an email to: salesaddresses@nxp.com Date of release: 9 December 2008 Document identifier: LM75B_2

▲Up To Search▲

Price & Availability of LM75B

	To Download LM75B Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .