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19-2683; Rev 1; 2/03
MAX1997 Evaluation Kit
General Description
The MAX1997 evaluation kit (EV kit) is a fully assembled and tested surface-mount circuit board that provides voltages and features required for active-matrix thin-film transistor (TFT) liquid-crystal displays. The EV kit contains a step-up switching regulator, a positive threestage charge pump and linear regulator for the TFT gate-on supply, a negative three-stage charge pump and linear regulator for the TFT gate-off supply, a gamma reference, a low-voltage logic supply, and a high-current backplane buffer. The gate-on supply, gate-off supply, and gamma reference supply can be sequenced in any power-up order. The EV kit operates from a DC supply voltage of +2.7V to +5.5V. The step-up switching regulator is configured for a +9V output providing up to 250mA. The positive charge pump and regulator are configured for a +20V output using two charge-pump stages providing up to 10mA. The negative charge pump and regulator are configured for a -7V output using a single charge-pump stage providing up to 10mA. The gamma reference is configured for +8.6V providing up to 10mA. The lowvoltage logic linear-regulator is configured for +2.5V, providing up to 200mA. The backplane buffer is configured for +4.3V and can source or sink current peaks more than 300mA. The MAX1997 EV kit demonstrates low-quiescent current and high efficiency (85%) for maximum battery life. The EV kit features overload protection for the input and all outputs. Operation at 1.5MHz allows the use of tiny surface-mount components. The MAX1997 QFN package (0.8mm max) with low-profile external components allows this circuit to be less than 1.25mm high. o +2.7V to +5.5V Input Range o Output Voltages +9V Output at 250mA Step-Up Switching Regulator) +20V Output at 10mA (Positive Charge Pump and Linear Regulator) -7V Output at 10mA (Negative Charge Pump and Linear Regulator) +8.6V Output at 30mA (Gamma Reference Regulator) +2.5V Output at 200mA from 2.7V to 3.6V Input (Low-Voltage Logic Supply) +4.3V Output (300mA Peak Backplane Buffer Output) o Up to Three Positive and Three Negative ChargePump Stages o More than -20V Linear-Regulated Output (Resistor Adjustable) o More than +30V Linear-Regulated Output (with Additional Circuitry) o Greater than 85% Efficiency (Step-Up Switching Regulator) o 375kHz/750kHz/1.5MHz Selectable Step-Up Switching Frequency (Configured for 1.5MHz) o Programmable Power-Up Sequencing and SoftStart for All Outputs o Multilevel Protection Output Undervoltage Protection Input Overcurrent Protection Input Switch Disconnects Step-Up Output from Input Source Selectable Fault-Delay Period o Low-Profile Surface-Mount Components o Fully Assembled and Tested
Features
Evaluates: MAX1997
Ordering Information
PART MAX1997EVKIT TEMP RANGE 0C to +70C IC PACKAGE 32 QFN 5mm x 5mm
________________________________________________________________ Maxim Integrated Products
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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.
MAX1997 Evaluation Kit Evaluates: MAX1997
Component List
DESIGNATION QTY C1, C2, C3 C4, C15 C5, C14 3 0 2 DESCRIPTION 4.7F 20%, 16V X5R ceramic capacitors (1210) TDK C3225X5R1C475M-1.15 Not installed, capacitor (1206) 10F 20%, 6.3V X5R ceramic capacitors (1206) TDK C3216X5R0J106M-0.85 1000pF 10%, 50V X7R ceramic capacitors (0603) TDK C1608X7R1H102K 0.01F 10%, 50V X7R ceramic capacitors (0603) TDK C1608X7R1H103K 0.47F 10%, 16V X7R ceramic capacitors (0805) TDK C2012X7R1C474K-0.60 100F 20%, 16V aluminum electrolytic capacitor (6.3mm x 5mm) Sanyo 16MV100UAX Not installed, capacitor (0603) 0.1F 10%, 50V X7R ceramic capacitors (0603) TDK C1608X7R1H104K 0.22F 10%, 10V X5R ceramic capacitor (0603) TDK C1608X5R1A224K 2.2F 10%, 16V X5R ceramic capacitor (0805) TDK C2012X5R1C225KT-0.95 1F 10%, 10V X7R ceramic capacitors (0805) TDK C2012X7R1A105K-1.15 0.1F 10%, 50V X7R ceramic capacitors (1206) TDK C3216X7R1H104K-0.85 0.47F 10%, 25V X5R ceramic capacitor (1206) TDK C3216X5R1E474KT-0.90 1F 10%, 25V X7R ceramic capacitor (1206) TDK C3216X7R1E105K-1.15 0.1F 10%, 16V X7R ceramic capacitor (0805) TDK C2012X7R1C104K-0.85 DESIGNATION QTY C40 1 DESCRIPTION 100pF 10%, 50V C0G ceramic capacitor (0603) TDK C1608C0G1H101K 1.0A, 30V Schottky diode (S-flat) Toshiba CRS02 200mA, 75V diodes (SOT23) Fairchild MMBD4148 (top mark 5H) 200mA, 25V dual Schottky diodes (SOT23) Fairchild BAT54S 2-pin headers 3-pin headers
D1 D2, D9
1 2
C6, C35, C39
3
D3-D8 JU1, JU2 JU3, JU4, JU8, JU11, JU14 JU5, JU6, JU7, JU9, JU10, JU12, JU13 L1 N1
6 2 5
C7, C18
2
C8, C11
2
7 1 1
4-pin headers 3H, 1.9A inductor Sumida CLS5D11HP-3R0NC 1.9A, 30V N-channel MOSFET (3-pin SuperSOT) Fairchild FDN357N 2.4A, -20V P-channel MOSFET (3-pin SuperSOT) Fairchild FDN304P Not installed, MOSFET (8) 3A, 25V PNP bipolar transistor (3-pin SuperSOT) Fairchild FSB749 200mA, 40V PNP bipolar transistors (SOT23) Fairchild MMBT3906 200mA, 40V NPN bipolar transistor (SOT23) Fairchild MMBT3904 1M 5% resistors (0805) 7.68k 1% resistor (0805) Not installed, resistor (0805) 51.1k 1% resistor (0805) 1.21k 1% resistor (0805) 150k 1% resistors (0805) 10 1% resistor (0805) 100k 1% resistor (0805) 523 1% resistor (0805)
C9 C10, C16, C34, C36, C37, C44, C45, C46 C12, C20-C27, C30, C31, C41, C42 C13
1
0
13
P1 P2 Q1
1 0 1
1
C17
1
Q2, Q4
2
C19, C43
2
Q3 R1, R9, R10, R13, R14, R15 R2 R3, R32-R37 R4 R5 R6, R27, R38, R39 R7 R8 R11
1 6 1 0 1 1 4 1 1 1
C28, C29
2
C32
1
C33
1
C38
1
2
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MAX1997 Evaluation Kit
Component List (continued)
DESIGNATION QTY R12, R16 R17, R19, R23 R18 R20 R21, R22, R24, R30 R25, R26 R28 R29 R31 U1 None None 2 3 1 1 4 2 1 1 1 1 14 1 DESCRIPTION 12.4k 1% resistors (0805) 39.2k 1% resistors (0805) 2.2k 5% resistor (0805) 118k 1% resistor (0805) 20k 1% resistors (0805) 6.8k 5% resistors (0805) 301k 1% resistor (0805) 24.3k 1% resistor (0805) 43.2k 1% resistor (0805) MAX1997ETJ (32-pin QFN) Shunts (JU1-JU14) MAX1997 PC board
6) Connect the positive terminal of the input power supply to the PIN pad. Connect the negative terminal of the input power supply to the PGND pad. 7) Turn on the power supply and verify that the stepup regulator output (VBST) is +9V. 8) Verify that the positive linear-regulator output (GON) is +20V. 9) Verify that the negative linear-regulator output (GOFF) is -7V. 10) Verify that the logic supply linear-regulator output (VLOG) is +2.5V. 11) Verify that the gamma reference linear-regulator output (VGAM) is +8.6V. 12) Verify that the high-current backplane buffer output (OUTB) is +4.3V. For instructions on selecting the feedback resistors for other output voltages, see the Output Voltage Selection section.
Evaluates: MAX1997
Quick Start
The MAX1997 EV kit is fully assembled and tested. Follow these steps to verify board operation. Do not turn on the power supply until all connections are completed.
Detailed Description
The MAX1997 EV kit contains a step-up switching regulator, a positive three-stage charge pump with positive high-voltage linear-regulator controller, a negative threestage charge pump with negative high-voltage linearregulator controller, a linear-regulator controller for gamma reference, a linear-regulator controller for lowvoltage logic supply, and a high-current backplane driver. The EV kit operates from a DC power supply between +2.7V and +5.5V, which can provide at least 2A. The circuit components are chosen for 1.5MHz. With different components, the switching frequency can be jumper selected between 375kHz, 750kHz, and 1.5MHz. The input and outputs of the EV kit are protected against output overloads. The EV kit features a shutdown mode to extend battery life. As configured, the step-up switching-regulator (VBST) generates a +9V output and can provide at least 250mA from a 2.7V input. The step-up switching-regulator output voltage can be adjusted up to +13V with
Recommended Equipment
* 2.7V to 5.5V, 2A DC power supply * One voltmeter
Procedure
1) Verify that there are no shunts across JU1, JU2, JU3, JU8, JU11, and JU12. 2) Verify that a shunt is across pins 1 and 2 of JU4, JU6, and JU9. 3) Verify that a shunt is across pins 1 and 3 of JU7 and JU10. 4) Verify that a shunt is across pins 1 and 4 of JU5 and JU13. 5) Verify that a shunt is across pins 2 and 3 of JU14.
Component Suppliers
SUPPLIER Fairchild Sanyo Sumida TDK Toshiba PHONE 888-522-5372 619-661-6322 847-545-6700 847-803-6100 949-455-2000 FAX -- 619-661-1055 847-545-6720 847-390-4405 949-859-3963 WEBSITE www.fairchildsemi.com www.sanyovideo.com www.sumida.com www.component.tdk.com www.toshiba.com/taec
Note: Please indicate that you are using the MAX1997 when contacting these component suppliers. _______________________________________________________________________________________ 3
MAX1997 Evaluation Kit Evaluates: MAX1997
feedback resistors (see the Output Voltage Selection section). As configured, the TFT gate-on supply (GON) uses two of the three positive charge-pump stages to generate approximately +25V and can provide greater than 10mA. The output is postregulated to +20V using a linear-regulator controller and an external PNP bipolar pass transistor. The positive linear-regulator's output can be adjusted between +1.25V and +25V or, with additional circuitry, to even higher voltages (see the Output Voltage Selection section). The first stage of the positive charge pump can be connected to the DC input source (INPUT) or the step-up switching regulator output (VBST). As configured, the TFT gate-off supply (GOFF) uses one of the three negative charge-pump stages to generate approximately -7.6V and can provide greater than 10mA. The output is postregulated to -7V using a linear-regulator controller and an external NPN bipolar pass transistor. The negative linear-regulator's output can be adjusted between 0 and -22V (see the Output Voltage Selection section). The first stage of the negative charge pump can be connected to the DC input source (INPUT) or the power ground (PGND). The gamma reference (VGAM) is set to +8.6V using a linear-regulator controller and an external PNP bipolar pass transistor. This gamma reference can provide greater than 30mA of current. The gamma linear-regulator's output can be adjusted between +1.25V and VSRC (see the Output Voltage Selection section). The step-up switching regulator provides power for the gamma reference through MOSFET N1, which is controlled by DRVA. The logic voltage supply (VLOG) is set to +2.5V using a linear-regulator controller and an external PNP bipolar pass transistor. This logic voltage supply can provide greater than 200mA of current. The logic voltage supply linear-regulator's output can be adjusted between +1.25V and the input voltage (see the Output Voltage Selection section). Power for the low-voltage logic linear regulator can be provided by the DC input sources (PIN) or (INPUT). The 300mA (peak) backplane buffer (OUTB) is set to +4.3V and uses a small 1F output filter capacitor. The buffer is powered from the step-up switching regulator output (VSRC) and its output can be adjusted between 0V and VSRC (see the Output Voltage Selection section). The EV kit also features power-up sequencing. After SHDN goes high and the input switch turns on, the logic voltage supply (VLOG) soft starts. When ONDC goes high, the step-up switching regulator soft starts and the gate-on supply, gate-off supply, and gamma buffer soft start in any sequence by setting the appropriate jumpers (see the Power-Up Sequencing section). The EV kit includes input-current-overload protection that shuts the circuit down if the input current exceeds a threshold for longer than the fault-delay period. The fault-delay period is jumper selectable between 22ms, 44ms, and 87ms. The input-current-overload threshold is set by resistor-dividers R4, R6, and R31, R38, and the RDS(ON) of MOSFET P1 or P2 (refer to the Setting the Input Overcurrent Threshold section in the MAX1997 data sheet for further details). The EV kit also includes output undervoltage protection that shuts the circuit down if any of the output voltages drop below approximately 80% of its nominal value for longer than the fault-delay period.
Jumper Selection
Shutdown Mode (SHDN)
The MAX1997 features a shutdown mode that reduces the MAX1997 quiescent current to less than 1A. The 2-pin jumper JU1 selects the shutdown mode. Table 1 lists the selectable jumper options. Caution: Do not connect an external controller to the SHDN pad while a shunt is on JU1 since the external controller can be damaged.
Step-Up Regulator Logic Control Input (ONDC)
The MAX1997 features a logic control input (ONDC) that can enable/disable the step-up regulator, the OUTB regulator, and the sequencing timing block. The 2-pin jumper JU2 selects the control input. Table 2 lists the selectable jumper options.
Table 1. Jumper JU1 Functions
SHUNT LOCATION Installed None (default) None SHDN PIN Connected to GND Connected to IN through R9 External controller connected to SHDN pad drives SHDN pin MAX1997 EV KIT OUTPUT Disabled Enabled Logic high = enabled Logic low = disabled
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MAX1997 Evaluation Kit Evaluates: MAX1997
Table 2. Jumper JU2 Functions
SHUNT LOCATION Installed None (default) None ONDC PIN Connected to GND Connected to IN through R10 External controller connected to ONDC pad drives ONDC pin MAX1997 EV KIT OUTPUT Disable the step-up regulator, OUTB regulator, and the sequencing timing block Enable the step-up regulator, OUTB regulator, and the sequencing timing block Logic high = enabled, logic low = disabled
Table 3. Jumper JU3 Functions
SHUNT LOCATION 1-2 2-3 None (default) PFLT PIN Connected to IN Connected to GND Unconnected MAX1997 EV KIT FAULT-DELAY PERIOD (ms) 87 22 44
Table 4. Jumper JU4 Functions
SHUNT LOCATION 1-2 (default) 2-3 None FREQ PIN Connected to IN Connected to GND Unconnected MAX1997 EV KIT FREQUENCY 1.5MHz 375kHz 750kHz
Caution: Do not connect an external controller to the ONDC pad while a shunt is on JU2 since the external controller can be damaged.
larger inductor value (refer to the Inductor Selection section in the MAX1997 data sheet).
Power-Up Sequencing
The MAX1997 EV kit features an option to reconfigure the power-up sequence for the gate-on linear regulator, the gate-off linear regulator, and the gamma linear regulator in any order. After ONDC goes high, the capacitor at the CT pin is charged by an internal 5A current source. Each regulator is enabled when VCT exceeds the regulator's ON_ input. JU5, JU6, and JU7 connect the ON_ inputs to one of four selected levels, allowing flexible configuration of the sequence order. Note that while the gate-on supply can be enabled any time after ONDC goes high, its startup is delayed until
Fault-Delay Period Selection (PFLT)
The MAX1997 features an option to choose the faultdelay period. JU3 selects the fault-delay period for the MAX1997 EV kit. Table 3 lists the selectable jumper options.
Switching Frequency Selection (FREQ)
The MAX1997 features an option to choose the switching frequency. JU4 selects the switching frequency for the MAX1997 EV kit. Table 4 lists the selectable jumper options. The EV kit is configured for 1.5MHz operation. Optimum performance at other frequencies requires a
Table 5. Jumper JU5 Functions
SHUNT LOCATION 1-2 1-3 1-4 (default) None ONN PIN Connected to VREF Connected to 2/3 VREF Connected to 1/3 VREF Connected to IN through R15 OPERATING MODE Gate-off linear-regulator controller power-up at VCT > VREF Gate-off linear-regulator controller power-up at VCT > 2/3 VREF Gate-off linear-regulator controller power-up at VCT > 1/3 VREF Gate-off linear-regulator controller disabled
Table 6. Jumper JU6 Functions
SHUNT LOCATION 1-2 (default) 1-3 1-4 None ONP PIN Connected to VREF Connected to 2/3 VREF Connected to 1/3 VREF Connected to IN through R14 OPERATING MODE Gate-on linear-regulator controller power-up at VCT > VREF Gate-on linear-regulator controller power-up at VCT > 2/3 VREF Gate-on linear-regulator controller power-up at VCT > 1/3 VREF Gate-on linear-regulator controller disabled
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MAX1997 Evaluation Kit Evaluates: MAX1997
Table 7. Jumper JU7 Functions
SHUNT LOCATION 1-2 1-3 (Default) 1-4 None ON2 PIN Connected to VREF Connected to 2/3 VREF Connected to 1/3 VREF Connected to IN through R13 OPERATING MODE Gamma linear-regulator controller power-up and VSRC switch enabled at VCT > VREF Gamma linear-regulator controller power-up and VSRC switch enabled at VCT > 2/3 VREF Gamma linear-regulator controller power-up and VSRC switch enabled at VCT > 1/3 VREF Gamma linear-regulator controller and VSRC switch disabled
Table 8. Jumper JU8 Functions
SHUNT LOCATION 1-2 2-3 None (default) FIRST STAGE POSITIVE CHARGE PUMP Connected to VBST Connected to INPUT Not used OPERATING MODE First stage of a three-stage charge pump connected to VBST First stage of a three-stage charge pump connected to INPUT Not used for one-stage or two-stage charge pumps
Table 9. Jumper JU9 Functions
SHUNT LOCATION 1-2 (default) 1-3 1-4 None SECOND STAGE POSITIVE CHARGE PUMP Connected to VBST Connected to previous stage charge-pump output Connected to INPUT Not used OPERATING MODE First stage of a two-stage charge pump connected to VBST Second stage of a three-stage charge pump First stage of a two-stage charge pump connected to INPUT Not used for one-stage charge pumps
Table 10. Jumper JU10 Functions
SHUNT LOCATION 1-2 1-3 (default) 1-4 THIRD STAGE POSITIVE CHARGE PUMP Connected to VBST Connected to previous stage charge-pump output Connected to INPUT OPERATING MODE One-stage charge pump connected to VBST Last stage of a two-stage or three-stage charge pump One-stage charge pump connected to INPUT
the end of the step-up switching regulator's soft-start. Tables 5, 6, and 7 list the jumper options.
Positive Charge Pump
The positive charge pump of the MAX1997 EV kit features an option to cascade up to three stages of charge pumps. Each charge-pump stage can be connected to INPUT, VBST, or the previous stage. JU8, JU9, and JU10 configure the number of stages and select the voltage source for the positive charge pump on the MAX1997 EV kit. Tables 8, 9, and 10 list the jumper options. The default configuration of the positive charge pump of the MAX1997 EV kit is a two-stage charge
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pump powered from VBST as indicated in Tables 9 and 10. Refer to the Charge Pumps section of the MAX1997 data sheet for information on selecting a charge-pump configuration.
Negative Charge Pump
The negative charge pump of the MAX1997 EV kit features an option to cascade up to three stages of charge pumps. Each charge pump stage can be connected to INPUT, PGND, or the previous stage. JU11, JU12, and JU13 configure the number of stages and select the voltage source for the negative charge pump on the MAX1997 EV kit. Tables 11, 12, and 13 list the jumper
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MAX1997 Evaluation Kit Evaluates: MAX1997
Table 11. Jumper JU11 Functions
SHUNT LOCATION 1-2 2-3 None (default) FIRST STAGE NEGATIVE CHARGE PUMP Connected to INPUT Connected to PGND Not used OPERATING MODE First stage of a three-stage charge pump connected to INPUT First stage of a three-stage charge pump connected to PGND Not used for one-stage or two-stage charge pump
Table 12. Jumper JU12 Functions
SHUNT LOCATION 1-2 1-3 1-4 None (default) SECOND STAGE NEGATIVE CHARGE PUMP Connected to INPUT Connected to previous stage charge-pump output Connected to PGND Not used OPERATING MODE First stage of a two-stage charge pump connected to INPUT Second stage of a three-stage charge pump First stage of a two-stage charge pump connected to PGND Not used for one-stage charge pump
Table 13. Jumper JU13 Functions
SHUNT LOCATION 1-2 1-3 1-4 (default) THIRD STAGE NEGATIVE CHARGE PUMP Connected to INPUT Connected to previous stage charge-pump output Connected to PGND OPERATING MODE One-stage charge pump connected to INPUT Last stage of a two-stage or three-stage charge pump One-stage charge pump connected to PGND
options. The default configuration of the negative charge pump of the MAX1997 EV kit is a one-stage charge pump powered from PGND as indicated in Table 13. Refer to the Charge Pumps section of the MAX1997 data sheet for information on selecting a charge-pump configuration.
Output Voltage Selection
Step-Up Switching-Regulator Output Voltage
The MAX1997 EV kit's step-up switching-regulator output (VBST) is set to +9V by feedback resistors R2 and R5. To generate output voltages other than +9V (up to +13V), select different external voltage-divider resistors (R2, R5). The output capacitors (C1, C2, and C3) are rated to +10V. To set the output voltage greater than +10V, use higher voltage-rated capacitors. Refer to the Main Step-Up Regulator, Output Voltage Selection section in the MAX1997 data sheet for instructions on selecting the resistors.
Power Source for the VLOG LinearRegulator Controller
The MAX1997 EV kit features an option to choose the power source of the logic supply linear regulator. JU14 selects the power source. Table 14 lists the selectable jumper options.
Table 14. Jumper JU14 Functions
SHUNT LOCATION 1-2 2-3 (default) None* VLOG POWER SOURCE Connected to PIN Connected to INPUT Unconnected
Gate-On Linear-Regulator Output Voltage
The MAX1997 EV kit's positive linear-regulator output (GON) is set to +20V by feedback resistors R28 and R30. To generate output voltages other than +20V (+1.25V to +25V), select different external voltagedivider resistors (R28, R30) and adjust the charge-pump input source and number of stages accordingly. The MAX1997 EV kit is not configured for charge-pump outputs greater than +28V. If linear regulator inputs greater than +28V or linear-regulator outputs greater than +25V
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*Since VLOG is enabled whenever SHDN is high, operating the circuit with no input source for VLOG causes an output undervoltage fault. Therefore, if the VLOG regulator is not used, connect its output or feedback input above the regulation threshold to prevent automatic shutdown after the fault-delay period.
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MAX1997 Evaluation Kit Evaluates: MAX1997
are needed, an NPN transistor must be added to the circuit to protect the DRVP pin (refer to the MAX1997 data sheet, Figure 4). Refer to the Linear-Regulator Controllers, Output Voltage Selection section in the MAX1997 data sheet for instructions on selecting the resistors. resistors (R20, R22) and an appropriate input voltage source. Refer to the Linear-Regulator Controllers, Output Voltage Selection section in the MAX1997 data sheet for instructions on selecting the resistors.
Logic Voltage Supply Linear-Regulator Output Voltage
The MAX1997 EV kit's logic voltage supply linear-regulator output (VLOG) is set to +2.5V by feedback resistors R12 and R16. To generate output voltages other than +2.5V (from +1.25 up to the input voltage), select different external voltage-divider resistors (R12, R16). Refer to the Linear-Regulator Controllers, Output Voltage Selection section in the MAX1997 data sheet for instructions on selecting the resistors.
Gate-Off Linear-Regulator Output Voltage
The MAX1997 EV kit's negative linear-regulator output (GOFF) is set to -7V by feedback resistors R27 and R29. To generate output voltages other than -7V (0 to -22V), select different external voltage-divider resistors (R27, R29) and adjust the charge-pump input source and number of stages accordingly. Note that the MAX1997 EV kit is not configured for charge-pump output voltages below -22V. Refer to the Linear-Regulator Controllers, Output Voltage Selection section in the MAX1997 data sheet for instructions on selecting the resistors.
High-Current Backplane Buffer Output Voltage
Resistors R21 and R24 set the MAX1997 EV kit's highcurrent backplane buffered output (OUTB) to a fixed ratio of the gamma linear-regulator's output (VGAM). When VGAM is +8.6V, OUTB is +4.3V. To set OUTB to a different ratio of VGAM, select different external voltage-divider resistors (R21, R24). Refer to the VCOM Buffer, Buffer Output Voltage section in the MAX1997 data sheet for instructions on selecting the resistors.
Gamma Linear-Regulator Output Voltage
The MAX1997 EV kit's gamma linear-regulator output (VGAM) is set to +8.6V by feedback resistors R20 and R22. To generate output voltages other than +8.6V (+1.25V to VSRC), select different external voltage-divider
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MAX1997 Evaluation Kit Evaluates: MAX1997
L1 3H INPUT R38 150k 1% C40 100pF R31 43.2k 1% 25 OCN 27 26 R7 10 1% R4 51.1k 1% R6 150k 1% GATE FB OCP TGNDA 23 LX 20 24 R5 1.21k 1% LX D1 2 1 R2 7.68k 1% 1 R1 1M 3 C7 0.01F R3 OPEN C10 OPEN D9 C1 4.7F 16V C2 4.7F 16V C3 4.7F 16V C5 10F 6.3V VBST VBST PGND
C4 OPEN
3 7 8 P2 1 C9 100F 16V 6 5 3 2 4 P1 1
C6 1000pF R39 150k 1%
PIN PIN
VSRC VSRC C8 0.47F R8 100k 1% VP
2
3 N1 1
2
PGND
TGNDB
1
IN
29 JU2 R10 1M ONDC 1 2 3 1 2 3 JU4 C42 0.1F VLOG C14 10F C15 OPEN JU3 C41 0.1F PIN JU14 12 C43 2 1F 3 R12 12.4k 1% C16 OPEN 4 R16 12.4k 1% 3 1 Q1 INPUT SHDN JU1 R9 1M C11 0.47F 32 30 28 31 R11 523 1% R32 SHORT (PC TRACE)
IN
DRVA CT
11 5 1 D2 C12 0.1F VREF VREF C13 0.22F PGND
SHDN ONDC PFLT FREQ REF GND PGND DRV1 12 13 2 3
VREF
3
R17 39.2k 1%
U1 MAX1997
8 ON2 7 ONP ONN 6 FB1 R13 1M R14 1M R15 1M
IN VREF 2 1 C44 OPEN 4 JU5 3 VREF 2 1 4 JU6 3 VREF 2 1 4 JU7 3 R19 39.2k 1%
VSRC R18 2.2k 2 Q2 VGAM R21 20k 1% 3 R20 C17 118k 2.2F 1% 1 C39 1000pF
R33 SHORT (PC TRACE)
19
DRV2
DRVP FBP
22 21 9
R34 SHORT (PC TRACE) DRVP FBP DRVN FBN
C45 OPEN
C46 OPEN
R23 39.2k 1%
18 VSRC
FB2
DRVN FBN
R22 20k 1%
R35 10 SHORT (PC TRACE) 14 TP1 R37 SHORT (PC TRACE)
16 R36 SHORT (PC TRACE) C38 0.1F 17
VDDB FBNB FBPB OUTB
R24 20k 1%
C18 0.01F
15 C19 1F
OUTB
Figure 1. MAX1997 EV Kit Schematic (Sheet 1 of 2)
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MAX1997 Evaluation Kit Evaluates: MAX1997
LX C20 0.1F 3 D3 INPUT R 2 1 JU11 2 3 L 1 3 C26 0.1F 2 JU12 1 4 D4 INPUT R 2 L 1 3 2 JU13 1 C28 0.1F C29 0.1F INPUT VP VP VN R25 6.8k 1 DRVN DRVP R26 6.8k 2 1 Q4 3 GON C32 0.47F PGND R27 150k 1% C34 OPEN FBN VREF R29 24.3k 1% C36 OPEN FBP C35 1000pF R28 301k 1% C33 1F PGND 3 D5 INPUT R 2 L 1 R 2 L 1 2 JU10 3 1 4 2 C21 0.1F 3 D6 VBST R L 1 2 JU9 3 1 4 INPUT 2 C22 0.1F 3 D7 VBST R L 1 JU8 1 2 3 INPUT C23 0.1F 3 D8 VBST C24 0.1F 3 C25 0.1F
C27 4 0.1F
C30 0.1F
C31 0.1F
2 Q3 3 GOFF
C37 OPEN
R30 20k 1%
Figure 1. MAX1997 EV Kit Schematic (Sheet 2 of 2)
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MAX1997 Evaluation Kit Evaluates: MAX1997
Figure 2. MAX1997 EV Kit Component Placement Guide-- Component Side
Figure 3. MAX1997 EV Kit PC Board Layout--Component Side
Figure 4. MAX1997 EV Kit PC Board Layout--GND Layer 2
Figure 5. MAX1997 EV Kit PC Board Layout--GND Layer 3 11
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MAX1997 Evaluation Kit Evaluates: MAX1997
Figure 6. MAX1997 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.
12 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 2003 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

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