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19-2214; Rev 0; 10/01
MAX1895 Evaluation Systems
General Description
The MAX1895 evaluation systems are assembled and tested PC boards that demonstrate the MAX1895 highefficiency, wide brightness range CCFL backlight controller. The MAX1895EVSYS-S is designed for singlelamp applications and the MAX1895EVSYS-D is designed for dual-lamp applications. Both systems can control the brightness of the lamps through either the SMBus interface or by an on-board potentiometer. The systems include a Maxim SMBusTM interface board (MAXSMBUS), which allows an IBM-compatible PC to use its parallel port to emulate an Intel system management bus (SMBus) I2CTM interface. Windows 95/98(R)compatible software provides a user-friendly interface to exercise the features of the MAX1895. The program is menu-driven and offers a graphic interface with control buttons and status display. Note: Windows NT/2000 requires additional driver software; contact the factory. To evaluate the performance of the MAX1995, configure the MAX1895EVSYS for analog interface mode. There is no need to change the IC since the MAX1895's performance is identical to the MAX1995's performance. See Detailed Description of Hardware, Table 2 and Table 3.
Features
o Single Lamp Application (MAX1895EVSYS-S) Dual Lamp Application (MAX1895EVSYS-D) o 7V to 24V Input Range o Wide Brightness Adjustment Range o Open Lamp Protection with 2s Timeout o Brightness Adjustable through SMBus Interface or On-Board Potentiometer o No Flicker at Low Brightness o High Power-to-Light Efficiency o I2C/SMBus Compatible o Easy to Use Menu-Driven Software o Assembled and Tested o Includes: Windows 95/98-Compatible Software (3.5in Floppy Disk) and Demo PC Board
Evaluate: MAX1895/MAX1995
Ordering Information
PART MAX1895EVSYS-S MAX1895EVSYS-D TEMP RANGE 0C to +70C 0C to +70C NUMBER OF LAMPS 1 2
Component Suppliers
SUPPLIER Diodes Inc. Fairchild General Semiconductor International Rectifier Murata Sumida Taiyo Yuden TDK Toko Toshiba PHONE 805-446-4800 888-522-5372 760-804-9258 310-322-3331 770-436-1300 847-956-0666 800-348-2496 847-803-6100 847-297-0070 949-455-2000 FAX 805-446-4850 972-910-8036 760-804-9259
MAX1895EVSYS-S Component List
PART QTY 1 1 DESCRIPTION MAX1895 evaluation kit (for single-lamp application) Interface board MAX1895EVKIT-S
310-252-7175 770-436-3030 847-956-0702 847-925-0899 847-390-4405 847-699-1194 949-859-3963 PART MAX1895EVKIT-D QTY 1 1 MAXSMBUS
MAX1895EVSYS-D Component List
DESCRIPTION MAX1895 evaluation kit (for dual-lamp application) Interface board
Note: Please indicate you are using the MAX1895 when contacting these manufacturers.
SMBus is a trademark of Intel Corp. Windows is a registered trademark of Microsoft Corp. I2C is a trademark of Philips Corp.
MAXSMBUS
________________________________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim's website at www.maxim-ic.com.
MAX1895 Evaluation Systems Evaluate: MAX1895/MAX1995
MAX1895EVKIT Component List
DESIGNATION C1, C13, C14, C17 C2, C4, C6, C9, C10 QTY 4 DESCRIPTION See Table 4 D3 5 0.1F, 10V, X5R ceramic capacitors Murata GRP155R61A104K Taiyo Yuden LMK105BJ104MV TDK C1005X5R1A104K 100pF, 50V, NPO ceramic capacitor 0.01F, 16V, X7R ceramic capacitor 0.022F, 16V, X7R ceramic capacitor 15pF, 3.1kV, ceramic highvoltage capacitor Murata GRM42D1X3F150J TDK C4520C0G3F150K 1F, 25V, X7R ceramic capacitor Murata GRM31MR71E105K Taiyo Yuden TMK316BJ105KL TDK C3216X7R1E105K Not installed (Use two 0.47F, 25V capacitors for C11 and C12 to lower ESR and increase efficiency) 0.1F, 25V, X7R ceramic capacitor TDK C1608X7R1E104K 0.47F, 10V, X5R ceramic capacitor Taiyo Yuden LMK107BJ474KA TDK C1608X5R1A474K 0.01F, 50V, X7R ceramic capacitor See Table 4 100mA dual Schottky diode-- common anode Diodes Incorporated BAT54AW Central Semiconductor CMSSH-3A 1 DESIGNATION QTY DESCRIPTION Diode, 1N4148-type Fairchild MMSD4148 General Semiconductor 1N4148W Diodes Incorporated 1N4148W 2 10 right angle female receptacle Not installed 4-pin headers `T' 3-pin headers 2-pin header See Table 4 See Table 4 100k 1% resistor Not installed 100k 1% resistor 49.9k 1% resistor 10k 5% resistors 10k potentiometer (multiturn) 150 1% resistor (0603) 2k 5% resistor (0603) See Table 4 Transformer 93:1 Toko T912MG-1018 (BLC103B style) See Table 4 MAX1895EGI Shunts for JU2 (1-3), JU3 (1-4), JU4 (1-2), JU6 (1-2), JU7 (1-2)
J1 JU1, JU8 JU2, JU3 JU4, JU6, JU7 JU5 M1 N1A/B, N2A/B R1 R2, R8 R3 R4 R5, R6, R9, R10 R7 R11 R12 R13-R17 T1 T2 U1 None
1 0 2 3 1 1 2 1 0 1 1 4 1 1 2 5 1 1 1 5
C3 C5 C7
1 1 1
C8
1
C11
1
C12
0
C15
1
C16
1
C18 D1, D4, D5, D6
1 4
D2
1
2
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MAX1895 Evaluation Systems
Quick Start
Required Equipment
Before you begin you will need the following equipment: * An IBM PC-compatible computer running Windows 95/98 * * A parallel printer port (this is a 25-pin socket on the back of the computer) A standard 25-pin, straight-through, male-to-female cable to connect the computer's parallel port to the Maxim SMBus interface board A DC power supply capable of supplying any voltage between 7V to 20V at 100mA to power the SMBus board A DC power supply capable of supplying a voltage between 7V to 24V at 2A to power the MAX1895 board A CCFL lamp with the following specifications: Maximum Strike Voltage 1.2kV Lamp Current 6mA Input Power 4W Note: Analog interface operation requires only a power supply (between 7V to 24V at 2A) and a CCFL lamp. WARNING! High voltages are present on this evaluation kit. Use caution when making connections and applying power. 5) Connect a cable from the computer's parallel port to the SMBus interface board. Use a straightthrough 25-pin female-to-male cable. To avoid damaging the EV kit or your computer, do not use a 25pin SCSI port or any other connector that is physically similar to the 25-pin parallel printer port. 6) The MAX1895.EXE software program can be run from the floppy or hard drive. Simply use the Windows program manager to run the program. If desired, you may use the INSTALL.EXE program to copy the files and create icons for them in the Windows 95/98 Start Menu. An uninstall program is included with the software. Simply click on the UNINSTALL icon to remove the EV kit software from the hard drive. 7) Connect a 7V to 20V DC power supply to the pads labeled POS9 and GND1 of the SMBus interface board. 8) Connect the 12V supply to the pads labeled VIN and GND. 9) Turn on both power supplies. 10) Start the MAX1895 program by opening its icon in the Start Menu. 11) Observe as the program automatically detects the address of the MAX1895 and starts the main program.
Evaluate: MAX1895/MAX1995
*
*
*
Detailed Description of Software
User-Interface Panel
The user interface is easy to operate using the mouse, or by using the tab key to navigate with the arrow keys. Each of the buttons corresponds to bits in the command and configuration bytes. Clicking on them generates the correct SMBus write operation to update the internal registers. The brightness of the lamp can be adjusted by either moving the trackbar or by entering a value between 0 and 31 into the edit field located below the trackbar. Pressing enter after typing in the new value updates the internal register. The SHMD register configures the operation of the device as described in Table 1. When the Automatic Read feature is enabled, the program polls the MAX1895 twice a second. The brightness, mode, and status are read and the appropriate fields are updated on the main display. Unchecking the checkbox can disable this feature and each field can be updated individually by clicking the appropriate button.
Procedure
1) Carefully connect the boards by aligning the 20-pin connector of the MAX1895 EV kit with the 20-pin header of the MAXSMBUS interface board. Gently press them together. The two boards should be flush against each other. 2) Do not turn on the power until all connections are made. 3) Connect the lamp to the high-voltage pads. 4) Set the jumpers to the following position: JU1 JU2 JU3 JU4 JU5 JU6 JU7 Open 1-3 1-4 1-2 Open 1-2 1-2
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MAX1895 Evaluation Systems Evaluate: MAX1895/MAX1995
The Brightness Cycle feature cycles the brightness through its entire range. The Status register indicates whether the lamp circuit has opened (Status1 low) or an overcurrent condition has occurred (Status0 low). The RESET button will set the MAX1895 and software to the POR state. If in doubt, click the reset button. formed by R1 and R2. Use the equation shown below to calculate the current limit: R2 2V x 1 R1 + R2 Current Limit (A) = x 5 RDS(ON) of N1 The MAX1895 EV kit (single lamp) is shipped with R1 = 100k, R2 open, and RDS(ON)-TYPICAL = 0.113. The dual lamp has an RDS(ON)-TYPICAL = 0.044.
Simple SMBus Commands
There are two methods for communicating with the MAX1895: through the normal user-interface panel, or through the SMBus commands available from pressing the MAXSMBUS button. A display pops up that allows the SMBus protocols, such as Read Byte and Write Byte, to be executed. To stop normal user-interface execution so that it does not override the manually set values, turn off the timer by unchecking the Automatic Read checkbox. The SMBus dialog boxes accept numeric data in binary, decimal, or hexadecimal. Hexadecimal numbers should be prefixed by $ or 0x. Binary numbers must be exactly 8 digits.
Jumper JU2
Jumper JU2 sets the voltage on the MINDAC pin. This voltage sets the DAC's minimum scale output voltage, which sets the lamp brightness for the minimum DAC code. In the 1-2 position, MINDAC is connected to VCC. In this position, the lamp is completely off at the minimum scale. Additionally, the DPWM dimming function is disabled (refer to the MAX1895 data sheet). In the 1-3 position, MINDAC is connected to REF through a voltage-divider formed by R3 and R4. The voltage on MINDAC is approximately 0.67, allowing a minimum analog dimming range of 33% of maximum brightness. The DPWM dimming function still remains available. In the 1-4 position, MINDAC is connected directly to REF. The voltage on MINDAC is 2V effectively disabling analog dimming. Only DPWM dimming is available.
Detailed Description of Hardware
Jumper JU1
Jumper JU1 connects the current limit pin (ILIM) to VCC. With the shunt installed, the current limit is set to: 0.2V RDS(ON) of N1 With the shunt removed, the current limit is determined by the RDS(ON) of MOSFET N1 and the resistor-divider
Jumper JU3
Jumper JU3 sets the MAX1895 to either analog interface or SMBus interface. There are two possible settings in analog interface: negative scale and positive scale. In negative-scale analog interface (JU3 = 1-2), the brightness of the lamp decreases as the voltage on
Table 1. SH/SUS and SHMD Register Truth Table
SH/SUS 0 0 1 1 X SHMD2 0 0 0 0 1 SHMD1 X X 0 1 X SHMD0 0 1 X X X OPERATING MODE Operate Shutdown STATUS1 set Operate Shutdown STATUS1 set Shutdown STATUS1 set
4
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MAX1895 Evaluation Systems
pin CTL/SCL increases. In positive-scale ADC interface (JU3 = 1-3), the brightness of the lamp increases as the voltage on pin CTL/SCL increases. Jumper (JU3 = 1-4) enables the SMBus interface on the MAX1895. Refer to the MAX1895 data sheet for more information. Jumper JU6, position 1-2, is for SMBus operation. A 10k pullup resistor is connected to the SMBus clock signal. To use analog interface, install a shunt on JU5. This connects potentiometer R8 to the CRF/SDA pin voltage. When using this mode, jumper JU6 must be installed in the 2-3 position. This connects the wiper of R8 to the CTL/SCL pin. Adjusting R8 changes the voltage on this pin, which changes the brightness of the lamp.
Evaluate: MAX1895/MAX1995
Jumper JU4
Jumper JU4 connects the CRF/SDA pin to VCC either directly (position 2-3) or through a 10k resistor (position 1-2). Position 1-2 is for SMBus operation. A 10k pullup resistor is connected to the SMBus data signal. To use the analog interface, connect JU4 to position 2-3. The CRF/SDA pin sets the full brightness reference for the CTL/SCL pin. Connecting this pin directly to VCC sets the full brightness reference voltage to 5.3V. To use a voltage other than 5.3V, leave JU4 open and apply an external voltage to the pad CRF/SDA.
Jumper JU7
Jumper JU7, position 1-2, enables the MAX1895 unless the SMBus suspend line (SH/SUS) pulls low. In the 2-3 position, the MAX1895 is placed into shutdown mode.
Jumper JU8
Jumper JU8 connects the power-supply input for the gate drivers (VDD), to the 5.3V linear regulator output (VCC). To use a different voltage for the gate drivers, cut the trace shorting jumper JU8 and apply the desired voltage to the pad labeled VDD.
Jumpers JU5 and JU6
The jumper JU5 must be left open for SMBus operation to prevent loading to the SMBus data signal.
Table 2. Jumper Settings Description
JUMPER SHUNT LOCATION Open* JU1 Closed 1-2 JU2 1-3* 1-4 1-2 JU3 1-3 1-4* Open JU4 1-2* 2-3 FUNCTION Current limit is set by the resistor-divider formed by R1 and R2. (The MAX1895 EV kit is shipped with R1 = 100k and R2 open.)
0.2V RDS(ON) of N1 Note: Remove R1 before installing the shunt.
Current limit is set to: MINDAC = VCC: disables the DPWM chopping function. MINDAC 0.67V: MINDAC is connected to REF through a voltage-divider formed by R3 and R4. This voltage sets the DAC's minimum scale output voltage. MINDAC = 2V: MINDAC is connected to REF. Analog dimming is disabled. MODE = REF: (negative-scale analog interface), CTL/SCL = 0V results in maximum brightness. MODE = GND: (positive-scale analog interface), CTL/SCL = 0V results in minimum brightness. MODE = VCC: enable SMBus interface. Used for analog interface: drive CRF/SDA with an external voltage. The external voltage is the reference voltage. (JU3 must be in 1-2 or 1-3 position. JU5 = closed.) Used for SMBus interface: CRF/SDA connected to VCC through 10k pullup resistor. Used for analog interface: CRF/SDA = VCC. VCC is the full-brightness reference input voltage. (JU3 must be in 1-2 or 1-3 position. JU5 = closed.)
*Default position.
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MAX1895 Evaluation Systems Evaluate: MAX1895/MAX1995
Table 2. Jumper Settings Description (continued)
JUMPER SHUNT LOCATION Open* JU5 Closed 1-2* JU6 2-3 1-2* 2-3 Open Closed* FUNCTION Used for SMBus interface: drive CRF/SDA with SMBus data. Used for analog interface: drive CRF/SDA with analog voltage. (Connect JU2 to 1-2 position to use VCC as the analog voltage.) Used for SMBus interface: CTL/SCL connected to VCC through 10k pullup resistor. Used for analog interface: CTL/SCL connected to ADC reference input voltage (CRF/SDA) through potentiometer R8. Adjusting R8 changes the brightness. Used for SMBus mode: SH/SUS is connected to VCC through 10k pullup resistor. Places the MAX1895 into shutdown. Drive VDD (power supply for the gate drivers) with an external power supply. VDD is tied to VCC (pin 28, 5.3V linear regulator output).
JU7 JU8
*Default position
Table 3. Jumper Settings Quick Reference
JUMPER JU1 JU2 JU3 JU4 JU5 JU6 JU7 JU8 SMBUS DIGITAL INTERFACE Open 1-3 1-4 1-2 Open 1-2 1-2 Closed ANALOG INTERFACE Open 1-3 1-2 or 1-3 2-3 Closed 2-3 1-2 Closed
6
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MAX1895 Evaluation Systems Evaluate: MAX1895/MAX1995
Table 4. Components Different Between the Single-Lamp and Dual-Lamp Boards
DESIGNATION MAX1895EVKIT-S (SINGLE LAMP) QTY 1 DESCRIPTION 4.7F, 25V ceramic capacitor Taiyo Yuden TMK325BJ475MN TDK C3225X7R1E475M QTY 1 MAX1895EVKIT-D (DUAL LAMP) DESCRIPTION 10F, 25V ceramic capacitor Taiyo Yuden TMK432BJ106MM TDK C4532X7R1E106M 0.1F, 16V ceramic capacitor Murata GRM188R71C104K Taiyo Yuden EMK107BJ104KA TDK C1608X7R1C104K 15pF, 3kV high-voltage ceramic capacitor Murata GRM42D1X3F150J TDK C4520C0G3F150K 0.022F, 16V ceramic capacitor Murata GRP155R71C223K Taiyo Yuden EMK105BJ223KV TDK C1005X7R1E223K 6.2V zener diode Central Semiconductor CMPZ5234B Diodes Inc. BZX84C6V2 Fairchild Semiconductor MMBZ5234B 6.2V zener diode Central Semiconductor CMPZ5234B Diodes Inc. BZX84C6V2 Fairchild Semiconductor MMBZ5234B 1N4148-type diode Diodes Inc. 1N4148W Fairchild Semiconductor MMSD4148 General Semiconductor 1N4148W Dual Schottky common-cathode diode Central Semiconductor CMPSH-3C Diodes Inc. BAT54C Fairchild Semiconductor BAT54C General Semiconductor BAT54C 2N7002 MOSFET Central Semiconductor 2N7002 Diodes Inc. 2N7002 General Semiconductor 2N7002 Dual N-channel MOSFETs Fairchild Semiconductor FDS6930A 4.7k 5% resistor 20k 5% resistor 2k 5% resistor Not installed Transformer 93:1 Toko T912MG-1018 (BLC103B Style)
C1
C13
0
Not installed
1
C14
0
Not installed
1
C17
0
Not installed
1
D1
1
1N4148-type diode Diodes Inc. MMBD4148 Fairchild Semiconductor MMBD4148 General Semiconductor IMBD4148
1
D4
0
Not installed
1
D5
0
Not installed
1
D6
0
Not installed
1
M1
0
Not installed
1
N1, N2 R13 R14 R15 R16, R17 T2
2 0 0 0 2 0
Dual N-channel MOSFETs Fairchild Semiconductor FDC6561AN Not installed Not installed Not installed 0 resistors Not installed
2 1 1 1 0 1
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MAX1895 Evaluation Systems Evaluate: MAX1895/MAX1995
Figure 1. Main Display for MAX1895EVKIT 8 _______________________________________________________________________________________
VFB1
VFB2
VIN L D6* *SEE TABLE 4 J1-1 J1-3 J1-5 J1-7 GH2 J1-9 J1-11 2 REF LX2 19 1 L 3 BST1 18 4 BAT54A C10 0.1F 17 3 2 5 LX2 LX1 N2-B 2R C1* 6 N2-A 1 N2-A GH2 C9 0.1F D2 VDD VIN LX2 20 C2 0.1F JU2 3 MINDAC GND 4 R5 10k BST2 J1-13 J1-15 J1-17 J1-19 N.C. N.C. N.C. N.C. 21 GH2 SMBCLK SMBSUS SMBDATA N.C. 3 C5 0.01F JU1 1 ILIM REF 28 VCC 27 BATT 26 CCV 25 CCI 24 IFB 23 N.C. 22 VFB C6 0.1F R14* R1 100k 1% R16* IFB GND REF C16 0.47F VCC C15 0.1F
1
2 R
J1-2 J1-4 J1-6 J1-8 J1-10 J1-12 J1-14 J1-16 J1-18 J1-20
Figure 2. MAX1895 EV Kit Schematic
R2 OPEN REF 4 1 2
REF
R3 R4 49.9k 100k 1% 1%
3
VCC
4
VCC
3 MODE C3 100pF
1 5
JU3
U1 MAX1895
LX1
2 MODE
REF
VCC R6 10k 6 CRF/SDA GL1 7 CTL/SCL SH/SUS 8 JU8 C4 0.1F VDD N.C. 9 N.C. 10 N.C. 11 VDD 12 PGND 13 GL2 14 GL2 15 GH1 16
CRF/SDA
32
1
GH1 4 N1-B GL1 3 2 5 N1-A 1 GL2 6
JU4
SMBDATA
JU5
VCC R9 10k 12 JU7 SMBCLK SMBSUS 3 VCC R10 10k
R7 10k JU6
32
1
R8 SHORT PC TRACE SH/SUS
Evaluate: MAX1895/MAX1995
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CTL/SCL
MAX1895 Evaluation Systems
9
MAX1895 Evaluation Systems Evaluate: MAX1895/MAX1995
LX2
4
T1
6
2
10 VFB1 R12 2k
C8 15pF IFB (PIN 22) C7 0.022F
R17* D3 1N4148W LAMP1
M1* R11 150 1% C18 0.01F
D1*
2
T2* 10
D4* R15* C17* C13* R13* D5*
LX1
C12 OPEN
4
6
VFB2 C14* LAMP2
C11 1F *SEE TABLE 4
Figure 3. MAX1895 EV Kit Schematic--High-Voltage Section
1.0"
Figure 4. MAX1895 EV Kit Component Placement Guide--Component Side
10
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MAX1895 Evaluation System Evaluates: MAX1895
1.0"
Figure 5. MAX1895 EV Kit Component Placement Guide--Solder Side
1.0"
Figure 6. MAX1895 EV Kit PC Board Layout--Component Side
1.0"
Figure 7. MAX1895 EV Kit PC Board Layout--Solder Side
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 11 (c) 2001 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

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