S 7V to 22V Input Range S Dynamically Selectable 1.5V/1.05V Output Voltage S Dynamically Adjustable Output Voltage Range (0 to 0.

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1 9-539; Rev 0; 6/0 MAX5035 Evaluation Kit General Description The MAX5035 evaluation kit (EV kit) demonstrates the standard 5A application circuit of the MAX5035. This DC-DC converter steps down from the industry standard to generate low-voltage core or chipset/ram bias supplies in computers. The EV kit provides a dynamically adjustable.5v/.05v output voltage from a 7V to 22V battery input range. It delivers up to 5A output current while achieving high efficiency. Programmed by a single resistor, the EV kit operates at 300kHz switching frequency and has superior line- and load-transient response. The EV kit is a fully assembled and tested PCB. It also allows the evaluation of other dynamically adjustable output voltages by varying the external reference input, which can be realized by changing resistors R, R2, and R3. Features S 7V to 22V Input Range S Dynamically Selectable.5V/.05V Output Voltage S Dynamically Adjustable Output Voltage Range (0 to 0.9V) S 5A Output Current S 300kHz Switching Frequency S Power-Good Output Indicator (PGOOD) S Low-Profile Surface-Mount Components S Fully Assembled and Tested Ordering Information PART TYPE MAX5035EVKIT+ EV Kit +Denotes lead(pb)-free and RoHS compliant. Component List DESIGNATION QTY DESCRIPTION C, C2 2 FF Q0%, 6.3V X5R ceramic capacitors (0402) TDK C005X5R0J05K Taiyo Yuden LMK05BJ05KV DESIGNATION QTY DESCRIPTION C2, C5 C9 6 Q20%, 6.3V X5R ceramic capacitors (0805) TDK C202X5R0J06M Murata GRM2BR6A06K C3 000pF Q0%, 50V ceramic capacitor (0402) TDK C005X7RH02K Murata GRM55R7H02K C4 FF Q0%, 25V X5R ceramic capacitor (0603) Murata GRM88R6E05K Taiyo Yuden GDK07BJ05KA C4, C5, C20, C2 4 C6 0 C7 Q20%, 25V X5R ceramic capacitors (20) TDK C3225X5RE06M Taiyo Yuden TMK325BJ06MM Not installed, 000FF, 50V aluminum electrolytic capacitor 0.FF Q0%, 25V X7R ceramic capacitor (0603) KEMET C0603C04K3RAC Murata GRM88R7E04K C8, C9, C3 0 Not installed, capacitors (0603) C0, C 2 330FF, 2.5V, 9mI polymer capacitors (D case) SANYO 2R5TPE330M9 (.8mm) Panasonic EEFSX0D33XR (6mI ESR,.9mm height) NEC TOK PSGD0E337M7 (7mI ESR, 2.8mm height) C22 D 0 D2 EN, FBSENSE, GATE, PGOOD, REF, SKIP 6 JU 680pF Q5%, 50V C0G ceramic capacitor (0603) TDK C608C0GH68J Not installed, 5.6V zener diode (SOT23) Green surface-mount LED (0805) Kingbright APHCM202VGC/Z-F0 Test points Keystone pin header Sullins PEC36SAAN Digi-Key S02E-02-ND or equivalent Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim Direct at , or visit Maxim s website at

2 DESIGNATION QTY DESCRIPTION JU2 JU3 L 4-pin header Sullins PEC36SAAN Digi-Key S02E-02-ND or equivalent Single-row 2-pin header Sullins PEC36SAAN Digi-Key S02E-02-ND or equivalent FH, 3.7mI, 7.5A power inductor Vishay/Dale IHLP4040DZERR0M0 N n-channel, logic-level MOSFET (SOT23) N2 0 Not installed, n-channel MOSFET (DPAK) Q 0 Not installed, transistor (SOT23) R 49.9kI Q resistor (0603) R2 54.9kI Q resistor (0603) Component List (continued) DESIGNATION QTY DESCRIPTION R3 97.6kI Q resistor (0603) R4 ki Q5% resistor (0603) R5 200kI Q resistor (0603) R6 4.7I Q5% resistor (0603) R7, R9, R5 R8 0 Not installed, resistors (0603) R8 0I Q5% resistor (0603) R0 40.2kI Q resistor (0603) R 00kI Q resistor (0603) R2 0kI Q NTC resistor (0603) Murata P8XH03F03RB R3 00kI Q5% resistor (0603) R4 0 Not installed, W resistor (252) R9 3.3I Q5% resistor (0805) 5A step-down regulator U (40 TQFN-EP*) Maxim MAX5035ETL+ 2 Shunts PCB: MAX5035 EVALUATION KIT+ *EP = Exposed pad. Component Suppliers SUPPLIER PHONE WEBSITE Central Semiconductor Corp Digi-Key Corp KEMET Corp Keystone Electronics Corp Kingbright Corporation Murata Electronics North America, Inc NEC TOK America, Inc Panasonic Corp SANYO Electric Co., Ltd Sullins Electronics Corp Taiyo Yuden TDK Corp Vishay Note: Indicate that you are using the MAX5035 when contacting these component suppliers. 2

3 Table. Default Shunt Positions Quick Start Recommended Equipment Adjustable 7V to 22V power supply, battery, AC adapter 5V at 00mA DC bias power supply Dummy load capable of sinking 5A Digital multimeter (DMM) 00MHz dual-trace oscilloscope Procedure The MAX5035 EV kit is fully assembled and tested. Follow the steps below to verify board operation. Caution: Do not turn on the power supply until all connections are completed. ) Verify that shunts are placed in their default positions, as shown in Table. 2) Connect the positive input of the adjustable 7V to 22V power supply to and the negative input of the power supply to. 3) Connect the positive input of the 5V/00mA power supply to and the negative input to (or add Q, R6, and R7 instead of the external power supply). 4) Connect the positive input of the electronic load to VOUT and the negative input to. 5) Connect the DMM to VOUT and. EV Kit Test: ) Turn on the 7V to 22V battery power prior to the 5V bias power; otherwise, the output undervoltage (UVP) FAULT latch is set, disabling the regulator until 5V power is cycled below the VCC POR (5V), or EN is toggled. 2) Observe the.5v Q0.3% at the VOUT with the DMM and/or oscilloscope. 3) Turn on the load and increase the current slowly to 5A and observe that the VOUT is.5v Q0.3% at all loads. JUMPER SHUNT POSITION FUTION JU -2 EN high JU2-2 Forced PWM JU3 One pin only.5v output Detailed Description of Hardware Jumper Settings Several jumper settings in the following tables illustrate features of the MAX5035 EV kit. Shutdown Control Input The EV kit features a 3-pin jumper (JU) that selects the shutdown control input. Table 2 lists the selectable jumper options. Pulse-Skipping Control Input The EV kit features a 4-pin jumper (JU2) for pulseskipping control input. This four-level input determines the mode of operation under normal steady-state conditions and dynamic output-voltage transitions. The default configuration has a shunt installed at pins -2 for lownoise, forced-pwm mode. Table 3 lists the other selectable jumper options. Refer to the Modes of Operation section in the MAX5035 IC data sheet for a more detailed description. External Gate The EV kit features a 2-pin jumper (JU3) that controls the gate of the external MOSFET (N). The external MOSFET can be controlled through the gate test point to dynamically adjust the REF voltage by forcing N to a low- or high-impedance state. The default configuration has a shunt installed on only one pin of JU3 to provide a.5v output. Table 4 lists the selectable jumper options. Table 2. Jumper JU Functions SHUNT POSITION *Default position. EN P MAX5035 OUTPUT -2* Connected to Enabled (V OUT =.5V/.05V) Shutdown mode 2-3 Connected to GND (V OUT = 0V) Not installed EN must be driven by an external signal connected to the EN test point Operation depends on the external EN signal levels 3

4 Table 3. Jumper JU2 Functions SHUNT POSITION SKIP P OPERATIONAL MODE *Default position. Table 4. Jumper JU3 Functions *Default position. -2* Connected to Low-noise mode, forced-pwm operation -3 Connected to REF Pulse-skipping mode with forced-pwm during transitions -4 Connected to GND Pulse-skipping mode without forced-pwm during transitions Not installed Open Ultrasonic mode without forced-pwm during transitions SHUNT POSITION EXTERNAL GATE MAX5035 OUTPUT Installed Not installed* Connected to Pulled to GND by R3 Evaluating Other Dynamic Output Voltages The EV kit output is preset to.05v/.5v. However, the output voltage can also be adjusted between 0 and 2V (VFB = OUT) by selecting R, R2, and R3 values. The device regulates FB to the voltage set at REF. By changing the voltage at REF, the device can be used in applications that require dynamic output-voltage changes between two set points. Using the external gate signal, a resistor can be switched in and out of the REF resistor-divider, changing the voltage at REF. A logichigh on gate turns on the external n-channel MOSFET (N), forcing its drain to a low-impedance state. A logiclow on gate disables the n-channel MOSFET, so its drain is high impedance. The two output voltages (VFB = OUT) are determined by the following equations: R2 VOUT(LOW) = VREF R R2 + R2 + R3 VOUT(HIGH) = VREF R + R2 + R3 where VREF = 2V. Setting VOUT with a Resistive Voltage-Divider at FB Connecting FB to a resistive voltage-divider allows for output voltages above the reference voltage (0 to 0.9V range). To get an output above 2V, install resistor R9 with A logic-high on gate turns on the external MOSFET, effectively shorting R3 (V OUT =.05V through resistor-dividers R and R2). A logic-low on gate turns off the external MOSFET (V OUT =.5V through resistor-dividers R and R2 + R3). a 0kI Q resistor and replace R8 with the following equation: where VFB = VREF. V R8 OUT V FB = + R9 The switching frequency-setting input should then be adjusted by replacing the external resistor R5 (RTON) according to the following equations: V ( ) FB t SW = C TON R TON + 6.5kΩ VOUT t SW = f SW where CTON = 6.26pF, fsw = 300kHz, and VFB = VREF under normal operating conditions. Refer to the MAX5035 IC data sheet for selection of output capacitor and inductor values for output voltages greater than 2V. Transient Load Tester The EV kit features an optional transient load tester consisting of power MOSFET N2, R4, and termination resistor R5. For a more detailed description, refer to Application Note 752: Creating a Fast Load Transient at 4

5 5 Figure. MAX5035 EV Kit Schematic Q R6 R7 B D C4 FF 8 EP3 TON BST EP2 FB ILIM AGND 34 R2 54.9kI 3 2 N JU3 GATE REF R3 97.6k REF REF REF C3 000pF PGOOD R4 PGOOD 36 3 JU2 REF JU 2 2 EN VCC 37 4 C FF C2 FF EN ki D2 38 R 49.9kI 35 AGND EP 32 R9 LX LX R5 200kI C4 C5 C2 C0 330FF C6 V R6 4.7I C7 0.FF L FH C8 VOUT R4 R5 TP 4 3 FBSENSE FBSENSE V OUT R8 33 C3 R 00kI R0 40.2kI R2 0kI (NTC) REF R8 0I R7 R9 3.3I C22 680pF E C N2 VOUT V OUT.5V/.05V;5A +5V C20 C9 R3 00kI SKIP SKIP C 330FF C2 C5 C6 C7 C8 C9 MAX5035

6 Figure 2. MAX5035 EV Kit Component Placement Guide Component Side 6

7 .0 Figure 3. MAX5035 EV Kit PCB Layout Component Side.0 Figure 4. MAX5035 EV Kit PCB Layout Internal layer.0 Figure 5. MAX5035 EV Kit PCB Layout Internal Layer 2 7

8 .0 Figure 6. MAX5035 EV Kit PCB Layout Solder Side Figure 7. MAX5035 EV Kit Component Placement Guide Solder Side 8

9 REVISION NUMBER REVISION DATE DESCRIPTION Revision History PAGES CHANGED 0 6/0 Initial release 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, 20 San Gabriel Drive, Sunnyvale, CA Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.