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XRP7620
4-Channel Adjustable Current I2C Controlled LED Driver
June 2009 Rev. 1.0.0
GENERAL DESCRIPTION
The XRP7620 is a multi purpose 4-channel independently adjustable current sink driver. Optimized for LED backlighting and RGBW/RGBA color mixing applications, the XRP7620 can also be used as a generic software programmable current sink I/O expander. Supporting an industry standard 2-wire I C serial interface, the XRP7620 provides full independent control of each channel and can be programmed up to a current of 31.5mA in steps of 0.5mA. Uniform display brightness is ensured through better than 3% channel to channel current matching. Five internal registers are provided to set operational configuration and individual channel current programmation. A specific shutdown mode allows the device to retain the previously loaded configuration - operational and current programming - in order to be reused upon the next enabling. The XRP7620 is designed to operate from a single cell lithium-ion battery or fixed 3.3V or 5.0V power rails and is available in a RoHS compliant, "green"/halogen free space saving 8-pin 2mmx3mm DFN package.
2
APPLICATIONS
* LCD Display & Keypad Backlighting * Color Coded Indicator Lighting * RGBW/RGBA Color Mixing * Cell Phones & Handheld Devices * Generic Current Sink I/O Expander
FEATURES
* 4-Channel LED Current Sink Driver * Individual Channel Current Control - Up to 31.5mA per channel / 0.5mA Steps - 100mV Channel Dropout Voltage * I2C Serial Interface * 2.7V - 5.5V Input Voltage Range * 3% Channel Current Matching * Register Retention in Shutdown * Shutdown Current <1A * Thermal and UVLO Built-in Protection * RoHS Compliant, "Green"/Halogen Free 2x3mm 8-Pin DFN package
TYPICAL APPLICATION DIAGRAM
Fig. 1: XRP7620 Application Diagram
Exar Corporation 48720 Kato Road, Fremont CA 94538, USA
www.exar.com Tel. +1 510 668-7000 - Fax. +1 510 668-7001
XRP7620
4-Channel Adjustable Current I2C Controlled LED Driver ABSOLUTE MAXIMUM RATINGS
These are stress ratings only and functional operation of the device at these ratings or any other above those indicated in the operation sections of the specifications below is not implied. Exposure to absolute maximum rating conditions for extended periods of time may affect reliability. VIN, SDA, SCL, LEDx .................................. -0.3V to 6.0V Storage Temperature .............................. -65C to 150C Power Dissipation ................... Internally Limited (Note 1) Lead Temperature (Soldering, 10 sec) ................... 300C ESD Rating (Human Body Model) ............................. 2kV
OPERATING RATINGS
Input Voltage Range VIN ...............................2.7V to 5.5V Junction Temperature Range ....................-40C to 100C Thermal Resistance JA ...................................... 59C/W
ELECTRICAL SPECIFICATIONS
Specifications with standard type are for an Operating Junction Temperature of TJ = 25C only; limits applying over the full Operating Junction Temperature range are denoted by a "*". Minimum and Maximum limits are guaranteed through test, design, or statistical correlation. Typical values represent the most likely parametric norm at TJ = 25C, and are provided for reference purposes only. Unless otherwise indicated, VIN = 2.7V to 4.6V, CIN = 1F, TA= -40C to 85C, TJ = -40C to 100C. Parameter Operating Input Voltage Range Operating Input Current DAC=000000 Operating Input Current LED Current accuracy (includes Line Regulation) -0.3 -5 -8 LED Current Matching Line Regulation Current DAC Resolution Current for DAC=000000 Current for DAC=000001 Maximum LED Current DAC=111111 0.35 30.50 0.50 31.75 6 2 0.65 33.00 -3 Min. 2.7 30 450 Typ. Max. 5.5 50 600 0.3 5 8 3 1 Units V A A mA % % % %/V Bit A mA mA * Applies to all LEDs Applies to all LEDs Applies to all LEDs For changes between any DAC code 000001 and higher. Current must change within this time after the last bit of LED data. VIN=2.7 to 5.5V Applies to changes between DAC code 000000 and higher or change from 0 to 1 for STATUS bits B5-B2 (channel enable). Current must change within this time after the last bit of LED data. VIN=2.7 to 5.5V * ILED=20mA; The voltage where LED current decreases 3% from nominal value at VLED = 1V. VIN=2.7 to 5.5V VIN=4.2V VIN=4.2V, TA=85C Regulator turns off * * * * * * * ILEDX=0, VIN=4.2V ILED1=ILED2=ILED3=ILED4=10mA, VIN=4.2V VLED = 0.2V to 2.7V ILEDX 6mA VLED = 0.2V to 2.7V ILEDX > 6mA For same DAC setting VLED = 0.2V to 2.7V, Note 2 Measured as IOUT /IOUT_AVG /V VLED = 0.2V to 2.7V, Note 3 Conditions
2 Maximum Current Change Settling Time 60 150
s
*
s
Current Source Dropout Voltage Shutdown Supply Current Shutdown Supply Current Thermal Shutdown Die Temperature 125
0.1 0.01 150
0.15 1 5 175
V A A C
(c) 2009 Exar Corporation
2/11
Rev. 1.0.0
XRP7620
4-Channel Adjustable Current I2C Controlled LED Driver
Parameter Thermal Shutdown Hysteresis SDA, SCL Input Logic Low Voltage SDA, SCL Input Logic High Voltage SDA, SCL Timeout for Shutdown 1.6 90 150 Min. Typ. 15 0.4 Max. Units C V V ms * * Conditions Regulator turns on
I2C SPECIFICATION
S XRP7620 Address 7-bit R/W 1/0 A Status Data 8-bit A LED1 Data 8-bit A LED2 Data 8-bit A LED3 Data 8-bit A LED4 Data 8-bit A SP
Start Condition Acknowledgement - sent by the slave when R/W=0 - sent by master when R/W=1 Acknowledgement sent by the slave Fig. 2: Data Input Format
Stop Condition
I2C TIMING CHARACTERISTICS
Unless otherwise indicated, VIN = 2.7V to 4.6V, CIN = 1F, TA= -40C Parameter Serial Clock Frequency Bus Free Time between a STOP and a START Hold Time, Repeated START Condition STOP Condition Setup Time Data Hold Time Input Data Hold Time Data Setup Time SCL Clock Low Period SCL Clock High Period Rise Time of Both SDA and SCL Signals, receiving Fall Time of Both SDA and SCL Signals, Receiving Fall Time of SDA Transmitting Pulse Width of Spike Suppressed Capacitive Load for each Bus Line I2C Startup Time after UVLO clears Symbol fSCL tBUF tHD_STA tSU,STO tHD,DAT(OUT) tHD, DAT(IN) tSU, DAT tLOW tHIGH tR tF tF.TX tSP Cb tSRT 1.3 0.6 0.6 225 0 100 1.3 0.6 20+0.1Cb 20+0.1Cb 20+0.1Cb 0 300 300 250 50 400 1 900 900 Min. Typ. to 85C, TJ = -40C to 100C. Max. 400 Units KHz s s ms ns ns ns ms ms ns ns ns ns pF s Note 4,5 Note 4,5 Note 4,5, 6 Note 7 Note 4 Note 4 Conditions
Note 1: All parameters tested at TA=25 C. Specifications over temperature are guaranteed by design. Note 2: LED current matching is calculated by this equation:
I LED - I AVG x 100% Where IAVG is the average current of 4 channels. I AVG
(c) 2009 Exar Corporation 3/11 Rev. 1.0.0
XRP7620
4-Channel Adjustable Current I2C Controlled LED Driver
Note 3: Ling regulation is calculated by this equation:
I 2 - I1 1 Where I1 and I2 is the current at different VIN. x x 100% I AVG V
Note Note Note Note 4: 5: 6: 7: Guaranteed by design. Cb = total capacitance of one bus line in pF. tR and tF measured between 0.3 x VDD and 0.7 x VDD. ISINK 6mA. Cb =total capacitance of one bus line in pF. tR and tF measured between 0.3 x VDD and 0.7 VDD. Input filters on the SDA and SCL inputs suppress noise spikes less than 50ns.
BLOCK DIAGRAM
Fig. 3: XRP7620 Block Diagram
PIN ASSIGNEMENT
2mm x 3mm
VIN SDA SCL GND
1 2 3 4
8 7 6 5
LED1 LED2 LED3 LED4
DFN-8L
Fig. 4: XRP7620 Pin Assignement
(c) 2009 Exar Corporation
4/11
Rev. 1.0.0
XRP7620
4-Channel Adjustable Current I2C Controlled LED Driver PIN DESCRIPTION
Name VIN SDA SCL GND LED4 LED3 LED2 LED1 Pin Number 1 2 3 4 5 6 7 8 Description Connect a 1F decoupling capacitor between this pin and the ground pin (pin 4). I2C Interface Serial Data Input-Output. I2C Interface Serial Clock Input. Ground Signal. LED 4 Input. Connect a LED between this pin and VIN. Current Value is set by the serial interface. LED 3 Input. Connect a LED between this pin and VIN. Current Value is set by the serial interface. LED 2 Input. Connect a LED between this pin and VIN. Current Value is set by the serial interface. LED 1 Input. Connect a LED between this pin and VIN. Current Value is set by the serial interface.
ORDERING INFORMATION
Part Number XRP7620IH-F XRP7620IHTR-F XRP7620EVB Temperature Range -40CTJ+100C -40CTJ+100C Marking 7620I YYWWFX 7620I YYWWFX Package DFN-8L DFN-8L Packing Quantity Bulk 3K/Tape & Reel Note 1 Green Halogen Free Green Halogen Free I2C Address 0x70 0x70
XRP7620 Evaluation Board
"YY" = Year - "WW" = Work Week - "F"= Green/Halogen Free Package - "X" = Lot Number XRP7620 may be ordered with alternative I2C addresses - Contact your Exar Sales Representative for further information.
(c) 2009 Exar Corporation
5/11
Rev. 1.0.0
XRP7620
4-Channel Adjustable Current I2C Controlled LED Driver Typical Performance Characteristics
All data taken at VIN = 2.7V to 5.5V, TJ = TA = 25C, unless otherwise specified - Schematic and BOM from Application Information/Theory of Operation section of this datasheet. CH1 = SDA, CH2 = SCL, CH4 = ILED = 20mA/div
Fig. 5: LED Current Change Settling Time From 0.5mA to 31.5mA
Fig. 6: LED Current Change Settling Time From 0mA to 31.5mA
Fig. 7: SDA, SCL Timeout for Shutdown
Fig. 8: LED Current Change Settling Time From DAC 31.5mA to 0mA
Fig. 9: Line Regulation DAC = 101000 (20mA)
Fig. 10: Line Regulation LED1 DAC = 101000 (20mA)
(c) 2009 Exar Corporation
6/11
Rev. 1.0.0
XRP7620
4-Channel Adjustable Current I2C Controlled LED Driver
Fig. 11: Line Regulation @ TA = 25oC DAC = 111100 (30mA)
Fig. 12: Line Regulation @ TA = -40oC DAC = 111100 (30mA)
Fig. 13: Line Regulation @ TA = 85oC DAC = 111100 (30mA)
Fig. 14: Line Regulation @ TA = 25oC DAC = 001010 (5mA)
Fig. 15: Line Regulation @ TA = -40oC DAC = 001010 (5mA)
Fig. 16: Line Regulation @ TA = 85oC DAC = 001010 (5mA)
(c) 2009 Exar Corporation
7/11
Rev. 1.0.0
XRP7620
4-Channel Adjustable Current I2C Controlled LED Driver THEORY OF OPERATION I2C SERIAL INTERFACE
The XRP7620 has five data registers which can be programmed serially through the IC interface. The first register is a status register which has two bits used for shutdown/power up options, 4 bits used for individual LED ON/OFF control, one bit for over-temperature readback and one bit for undervoltage lockout readback. The next four registers are used to set the brightness levels of the four LEDs. LED Registers (x4) LED register bits B7-B2 In LED registers bits B7, B6, B5, B4, B3 and B2 represent the DAC codes D5-D0 used to set the LED current in the four LEDs, and B1 and B0 are not used. The following table lists the DAC codes and the corresponding current for each channel in mA:
B7-B2 000000 000001 000010 000011 B7 Status WZ LED1 LED2 LED3 LED4 D5 D5 D5 D5 B6 WP D4 D4 D4 D4 B5 D3 D3 D3 D3 B4 D2 D2 D2 D2
2
Current mA 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 9.5 10.0 10.5 11.0 11.5 12.0 12.5 13.0 13.5 14.0 14.5 15.0 15.5
B7-B2 100000 100001 100010 100011 100100 100101 100110 100111 101000 101001 101010 101011 101100 101101 101110 101111 110000 110001 110010 110011 110100 110101 110110 110111 111000 111001 111010 111011 111100 111101 111110 111111
Current mA 16.0 16.5 17.0 17.5 18.0 18.5 19.0 19.5 20.0 20.5 21.0 21.5 22.0 22.5 23.0 23.5 24.0 24.5 25.0 25.5 26.0 26.5 27.0 27.5 28.0 28.5 29.0 29.5 30.0 30.5 31.0 31.5
B3 D1 D1 D1 D1
B2 D0 D0 D0 D0
B1 -
B0 UVL -
000100 000101 000110 000111 001000 001001 001010 001011 001100 001101 001110 001111 010000 010001 010010 010011 010100 010101 010110 010111 011000 011001 011010 011011 011100 011101 011110 011111
LED4 LED3 LED2 LED1 OVT
Table 1: XRP7620 I C Register Bit Map
Status Register Status register bits B7 and B6 The following table defines the states for bits B7 and B6 of the STATUS register. They are used to put the XRP7620 into shutdown, standby, or active mode.
WZ 0 0 1 1 WP 0 1 0 1 State Shutdown and reset registers to 00000000 Shutdown Keeps registers contents Standby Keeps registers contents Active IQ 0A 0A 30A Active LED Driver Off Off Off On
Table 2: XRP7620 Status Register Bits B7 and B6
Status register bits B5-B2 These bits are to control the LED On/Off individually. Putting 1 (logic high) will enable the driver and putting 0 (logic low) will disable the driver. Status register bits B1 and B0 These bits are the readback bits. Their values are 0 for normal operations. If overtemperature is detected, B1=1, and If undervoltage is detected, B0=1. The UVL threshold is approximately 2.4V.
(c) 2009 Exar Corporation 8/11
Table 3: LED Current DAC Settings
Rev. 1.0.0
XRP7620
4-Channel Adjustable Current I2C Controlled LED Driver
Addressing and Writing Data To write data to the XRP7620 one of the following two cycles must be followed: Easy shutdown/startup sequence [Slave Address with write bit][Data for Status] Full shutdown/startup sequence [Slave Address with write bit][Data for Status][Data for LED1][Data for LED2][Data for LED3][Data for LED4] Addressing and Reading Data To read data from the XRP7620 the following data cycle must be obeyed: [Slave Address with read bit][Data for Status][Data for LED1][Data for LED2][Data for LED3][Data for LED4]
SHORTED LEDS
If an LED shorts to the extent that the LED pin comes within 0.7V of VIN the LED channel may turn off because the drive circuitry effectively is in a dropout condition. The exact voltage will vary with programmed LED current.
PARALELLING CURRENT SINKS
The maximum programmable current per LED pin is 31.5mA. If a higher current is desired, 2, 3, or all 4 LED pins may be connected to share current. Although it is technically possible to program the channels to different values to add up to the desired total, it is recommended that paralleled channels be programmed to the same value.
SHUTDOWN OPTIONS
The XRP7620 can be placed in shutdown mode by holding both the SDA and SCL lines low for a minimum of typically 90ms. This puts a zero in bit 7 and bit 6 of the status register, which in turn will reset all bits of all registers. After any shutdown, the part can only be restarted through the I2C bus.
(c) 2009 Exar Corporation
9/11
Rev. 1.0.0
XRP7620
4-Channel Adjustable Current I2C Controlled LED Driver PACKAGE SPECIFICATION 8-PIN DFN
(c) 2009 Exar Corporation
10/11
Rev. 1.0.0
XRP7620
4-Channel Adjustable Current I2C Controlled LED Driver REVISION HISTORY
Revision 1.0.0 Date 06/04/2009 Initial release of datasheet Description
FOR FURTHER ASSISTANCE
Email: Exar Technical Documentation: customersupport@exar.com http://www.exar.com/TechDoc/default.aspx?
EXAR CORPORATION HEADQUARTERS AND SALES OFFICES
48720 Kato Road Fremont, CA 94538 - USA Tel.: +1 (510) 668-7000 Fax: +1 (510) 668-7030 www.exar.com
NOTICE
EXAR Corporation reserves the right to make changes to the products contained in this publication in order to improve design, performance or reliability. EXAR Corporation assumes no responsibility for the use of any circuits described herein, conveys no license under any patent or other right, and makes no representation that the circuits are free of patent infringement. Charts and schedules contained here in are only for illustration purposes and may vary depending upon a user's specific application. While the information in this publication has been carefully checked; no responsibility, however, is assumed for inaccuracies. EXAR Corporation does not recommend the use of any of its products in life support applications where the failure malfunction of the product can reasonably be expected to cause failure of the life support system or to significantly affect safety or effectiveness. Products are not authorized for use in such applications unless EXAR Corporation receives, writing, assurances to its satisfaction that: (a) the risk of injury or damage has been minimized; (b) the user assumes such risks; (c) potential liability of EXAR Corporation is adequately protected under the circumstances. Reproduction, in part or whole, without the prior written consent of EXAR Corporation is prohibited. or its in all
(c) 2009 Exar Corporation
11/11
Rev. 1.0.0

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