19-2961; Rev 0; 7/03 MAX1938 Evaluation Kit Features ♦ ±0.75% Output Voltage Accuracy ♦ Up to 90% Efficiency—No Heatsinks ♦ Up To 60A Output Current ♦ Quick-PWM™ Architecture Reduces Output Capacitors ♦ 8V to 14V Input Range (8V to 22V with Component Change) ♦ 500kHz Output Ripple Frequency ♦ MAX1937: AMD Hammer Compatible ♦ MAX1938: Intel VRM9.0/9.1 Compatible ♦ MAX1939: AMD Athlon Mobile Compatible Ordering Information PART MAX1938EVKIT TEMP RANGE IC PACKAGE -40°C to +85°C 28 QSOP Note: To evaluate the MAX1937 or MAX1939, request free samples along with the MAX1938EVKIT. ♦ Controlled (On-the-Fly) VID Voltage Transition ♦ Power-Good (PWRGD) Output ♦ User-Programmable Voltage Positioning ♦ Fully Assembled and Tested Component List DESIGNATION QTY DESCRIPTION C1, C4 2 2.2µF, 10V X5R capacitors (0805) Taiyo Yuden LMK212BJ225KG or equivalent C2 1 2.2µF, 16V X7R capacitor (1206) Taiyo Yuden EMK316BJ225ML or equivalent C3, C7 2 0.22µF, 10V X7R capacitors (0603) Taiyo Yuden LMK107BJ224KA or equivalent C5 1 C6 C8, C9, C17, C32 C10–C14 DESIGNATION QTY DESCRIPTION 0.01µF, 50V X7R capacitor (0603) Taiyo Yuden UMK107B103KZ or equivalent C15 1 C16 0 Not installed (0603) C18–C23 6 330µF, 25V Al electrolytic capacitors Sanyo 25MV330WX C24–C31 8 560µF, 4V OSCON (E) capacitors Sanyo 4SP560M 0.47µF, 10V X5R capacitor (0603) Taiyo Yuden LMK107BJ474KA or equivalent C33, C34, C45, C46 4 10µF, 16V X5R capacitors (1210) Taiyo Yuden TMK325BJ106MM or equivalent 1 47pF, 50V C0G capacitor (0603) Murata GRM39C0G470J050AD or equivalent C35–C44, C54–C57 0 Open 4 1000pF, 50V X7R capacitors (0603) Murata GRM39X7R102K or equivalent 5 1µF, 10V X7R capacitors (0805) Taiyo Yuden LMK212BJ105MG or equivalent C47–C53 0 Open CON1–CON6 6 Banana jacks, noninsulated D1 1 Diode (SOD123) Central Semiconductor CMHD4448 D2 1 Dual Schottky diodes SOT23 Central Semiconductor CMPSH-3A Quick-PWM is a trademark of Maxim Integrated Products. Intel is a registered trademark of Intel Corp. Athlon is a trademark of Advanced Micro Devices, Inc. ___________________________________________________________________________________________ Maxim Integrated Products 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. 1 Evaluates: MAX1937/MAX1938/MAX1939 General Description The MAX1938 evaluation kit (EV kit) is a fully tested and assembled power supply that demonstrates the full functionality of the MAX1937/MAX1938/MAX1939 family of synchronous, two-phase, step-down controllers. The circuit operates from an input supply range of 8V to 14V and provides VID-controlled CPU core voltage with up to 60A of output current. The EV kit comes with the MAX1938 installed, which provides a 5-bit VID code interface to meet Intel ® Voltage-Regulator Module (VRM) 9.0/9.1 specifications. The MAX1937 and MAX1939 can also be evaluated using the same board by replacing the MAX1938. The MAX1937 supports the AMD Hammer CPU VID codes, and the MAX1939 supports the AMD Athlon™ Mobile CPU VID codes. MAX1938 Evaluation Kit Evaluates: MAX1937/MAX1938/MAX1939 Component List (continued) DESIGNATION QTY DESCRIPTION Component Suppliers SUPPLIER PHONE WEBSITE D3, D4 0 Not installed (D-Pak) BI Technologies 714-447-2345 www.bitechnologies.com JU4–JU9 6 2-pin headers Central Semiconductor 631-435-1110 www.centralsemi.com L1, L2 2 0.60µH inductors Panasonic ETQP1H0R6BFA BI HM7340R50 (alternate) Fairchild 408-721-2181 www.fairchildsemi.com N1, N2, N3, N6, N7, N8 N-channel MOSFETs (D-Pak) IRF IRLR7811W International Rectifier 310-322-3331 www.irf.com 6 N4, N5, N9, N10 4 N-channel MOSFETs (D2-Pak) Fairchild ISL9N303AS3ST N11–N22 0 Not installed, 8-pin SO R1 1 10Ω ±5% resistor (0603) R2 1 51.1kΩ ±1% resistor (0603) R3 1 200kΩ ±1% resistor (0603) R4 1 68.1kΩ ±1% resistor (0603) R5, R8 2 3.3Ω ±5% resistors (0603) R6 1 100kΩ ±5% resistor (0603) R7 1 120kΩ ±5% resistor (0603) R9, R10 2 200Ω ±5% resistors (0603) R11, R12, R14, R15 4 2mΩ ±1%, 1W resistors (2512) Vishay WSL2512 or Panasonic ERJM1WTF2MU R17, R18 2 100Ω ±5% resistors (0603) R19 0 Not installed (0603) R20 0 Not installed (0603) PC board short U1 1 MAX1938EEI QSOP U2 1 6V linear regulator (D-Pak) Fairchild KA78M06R or Texas Instruments UA78M06CKTP None 6 Shunts Part of Kit 1 MAX1938EVKIT PC board Required Equipment The following equipment is required before beginning: • 8V to 14V, at least 150W power supply or battery • Adjustable load capable of sinking 60A at 0.8V • Two digital multimeters (DMMs) • Oscilloscope 2 Kamaya 260-489-1533 www.kamaya.com Murata 770-436-1300 www.murata.com Panasonic 714-373-7939 www.panasonic.com Sanyo 619-661-6835 www.sanyo.com Taiyo Yuden 408-573-4150 www.t-yuden.com Vishay 402-564-3131 www.vishay.com Note: Active electronic loads have a minimum input voltage required when sinking current. Make sure that the load is capable of sinking the necessary current at the lowest voltage. Take into account the voltage drop in the wires connecting the EV kit to the load. To minimize the voltage drop in the wires, two connectors are provided on the EV kit for the output allowing two wires to be connected in parallel. It is also acceptable to use two loads, each sinking half the current. Quick Start Follow these steps to verify operation of the MAX1938 EV kit. When making connections to the high-current input and output, make sure that the wire gauge is heavy enough to handle the necessary current and minimize voltage drop in these wires. Do not turn on the power supply until all connections are completed: 1) Preset the power supply between 8V and 14V. Turn off the power supply. 2) Select the desired output voltage using the VID_ jumpers (see Table 1 for a list of jumper settings and corresponding output voltages). 3) Verify that the pins of jumper EN are not shorted. 4) Connect the positive (+) power-supply output to the banana connector labeled IN on the MAX1938 EV kit. 5) Connect the negative (-) power-supply output to the banana connector labeled GND located near the center of the MAX1938 EV kit. 6) If available, connect the positive (+) power-supply sense lead to the pad labeled IN, and connect the negative (-) power-supply sense lead to the pad labeled GND (next to IN). ______________________________________________________________________________________ MAX1938 Evaluation Kit 8) If using an active load, connect the positive side of the load to the banana connectors labeled OUT (located at the top of the EV kit board). Two OUT connections are provided on the board so that two parallel wires can be used to connect the load. Alternatively, two loads can be connected in parallel, one to each OUT connector. Connect the negative side of the load to the banana connectors labeled GND (located near the top of the board by the OUT connectors). Two GND connections are provided for paralleling wires to the load or connecting multiple loads. 9) Use a DMM to monitor the output voltage. Connect the positive (+) terminal of DMM 2 to the pad labeled OUT (located in the upper-left corner of the EV kit board as shown in Figure 3). Connect the common (COM) or ground terminal of the DMM to the GND pad (located next to the OUT pad in the upper left corner). 10) If desired, connect an oscilloscope probe to the connector located between the OUT and GND banana connectors. The oscilloscope can then be used to observe the output ripple. 11) Turn on the power supply. 12) Using DMM 2, verify that the output voltage matches the voltage selected with the VID_ inputs. 13) Set the active load to the desired current (up to 60A), or connect a passive load to the output. 14) Verify that the correct output voltage appears on DMM 2. 15) To verify operation of the enable/shutdown feature, connect the pins of jumper EN using the shunt provided. The MAX1938 shuts down and the output voltage drops to zero. 16) Remove the shunt across jumper EN. The MAX1938 powers up and the output voltage returns to its nominal value. 17) To use the on-the-fly VID code feature, change the VID_ jumper settings (see Table 1). The output voltage changes to the newly selected value at a controlled rate without overshoot or undershoot. Detailed Description corresponding to each VID code. Either each VID_ input can be driven as a digital input, or the code can be set using the jumpers provided on the board. If the jumpers are used, short the pins of the VID_ jumper with the provided shunts to set the VID_ bits to logic 0. Remove the shunt from the jumper to set the corresponding bit to logic 1. If the VID_ inputs are driven as digital inputs, remove all the shunts from the VID_ jumpers. The VID code can be changed either when the converter is off or when it is functioning (on-the-fly). When the VID code is changed on-the-fly, the output voltage ramps up or down at a controlled rate until the new voltage is reached (refer to the MAX1937/MAX1938/ MAX1939 data sheet for more details). Enable Input (EN) The enable input can be used to enable or shut down the controller. This can be done either by using the EN jumper provided on the EV kit, or by driving the EN input as a digital input. When using the jumper, short the pins of the EN jumper to shut down or remove the short to enable the output (see Table 2). When using EN as a digital input, remove the shunt from the EN jumper. Drive EN high to enable the output or drive EN low for shutdown. Power-Good Output (PWRGD) Power-good (PWRGD) is an open-drain output with a 100kΩ external pullup resistor to VDD. This output is low if the output voltage deviates more than 12.5% from the value set by the VID code, and high when the output is in regulation. PWRGD is low when the part is in shutdown or during startup. Customizing the MAX1938 EVKIT Evaluating the MAX1937 or MAX1939 The MAX1938 EV kit comes with the MAX1938 installed, providing a VID code interface to meet Intel VRM9.0/VRM9.1 specifications. The MAX1937 and MAX1939 can also be evaluated using the same board by replacing the MAX1938. The MAX1937 supports the AMD Hammer CPU VID codes, whereas the MAX1939 supports the AMD Athlon Mobile CPU VID codes. To evaluate the MAX1937 or MAX1939, carefully remove the MAX1938 from the EV kit and replace it with the new part. Free samples of the MAX1937 and MAX1939 can be obtained from Maxim. The EV kit can be preconfigured with the MAX1937 or MAX1939 upon request. Setting the Output Voltage (VID_) The MAX1938 EV kit uses a 5-bit VID interface for selecting the output voltage. Table 1 shows the output voltages _______________________________________________________________________________________ 3 Evaluates: MAX1937/MAX1938/MAX1939 7) If the power supply does not have sense connections, use a DMM to monitor the input voltage on the board. Connect the positive terminal of DMM 1 to the pad labeled IN, and connect the common (COM) or ground terminal of the DMM to the pad labeled GND (next to the IN pad). Evaluates: MAX1937/MAX1938/MAX1939 MAX1938 Evaluation Kit Table 1. VID Programmed Output Voltage (VID0–VID4) VID4 VID3 VID2 VID1 VID0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 VOUT (V) MAX1937 MAX1938 MAX1939 0 1.550 1.850 2.000 1 1.525 1.825 1.950 1 0 1.500 1.800 1.900 0 1 1 1.475 1.775 1.850 1 0 0 1.450 1.750 1.800 0 1 0 1 1.425 1.725 1.750 0 0 1 1 0 1.400 1.700 1.700 0 0 1 1 1 1.375 1.675 1.650 0 1 0 0 0 1.350 1.650 1.600 0 1 0 0 1 1.325 1.625 1.550 0 1 0 1 0 1.300 1.600 1.500 0 1 0 1 1 1.275 1.575 1.450 0 1 1 0 0 1.250 1.550 1.400 0 1 1 0 1 1.225 1.525 1.350 0 1 1 1 0 1.200 1.500 1.300 0 1 1 1 1 1.175 1.475 Shutdown 1 0 0 0 0 1.150 1.450 1.275 1 0 0 0 1 1.125 1.425 1.250 1 0 0 1 0 1.100 1.400 1.225 1 0 0 1 1 1.075 1.375 1.200 1 0 1 0 0 1.050 1.350 1.175 1 0 1 0 1 1.025 1.325 1.150 1 0 1 1 0 1.000 1.300 1.125 1 0 1 1 1 0.975 1.275 1.100 1 1 0 0 0 0.950 1.250 1.075 1 1 0 0 1 0.925 1.225 1.050 1 1 0 1 0 0.900 1.200 1.025 1 1 0 1 1 0.875 1.175 1.000 1 1 1 0 0 0.850 1.150 0.975 1 1 1 0 1 0.825 1.125 0.950 1 1 1 1 0 0.800 1.100 0.925 1 1 1 1 1 Shutdown Shutdown Shutdown Note: In the above table, a zero indicates VID_ is driven low or the jumper pin is connected. A 1 indicates VID_ is driven high or the jumper is not connected. Table 2. EN Jumper Functions EN JUMPER 4 FUNCTION OPEN Enable the output SHORT Shut down the output ______________________________________________________________________________________ _______________________________________________________________________________________ JU9 EN JU8 VID4 JU7 VID3 JU6 VID2 JU5 VID1 JU4 VID0 C4 2.2µF JU3 OPEN D1 R1 10Ω R4 68.1kΩ C5 0.47µF C6 47pF C15 0.0IµF VDD R17 100Ω R3 200kΩ R2 51.1kΩ R7 120kΩ C16 OPEN REF VPOS TIME EN VID4 VID3 VID2 VID1 VID0 VDD VCC C17 1000pF U1 FB DH2 LX2 BST2 DL2 CS2 PGND VLG CS1 OL1 BST1 LX1 DH1 14 17 18 16 20 19 21 22 24 23 27 25 26 PWRGD 15 MAX1938 9 ILIM 10 GND 11 GNDS 12 7 3 13 6 5 4 2 1 8 28 R20 SHORT C32 1000pF R8 3.3Ω R5 3.3Ω C14 1µF D2 C7 0.22µF C9 1000pF C8 1000pF C3 0.22µF N9 R9 200Ω R10 200Ω N5 N4 N1 R8 3.3Ω N6 N10 VCC R11 2mΩ R14 2mΩ D4 N7 D3 N2 VCC R6 100kΩ N17 N8 L2 0.60µH N20 R12 2mΩ R15 2mΩ N14 L1 0.60µH N3 N11 N18 N21 N15 N12 PWRGD N19 VCC N22 N16 OUT N13 Evaluates: MAX1937/MAX1938/MAX1939 KA78M06 1 3 IN U2 OUT GND 2 C2 C1 2.2µF 2.2µF JU2 OPEN MAX1938 Evaluation Kit Figure 1. MAX1938 EV Kit Schematic (Sheet 1 of 2) 5 6 OUT VCC OUT C47 OPEN VCC C53 OPEN C41 OPEN C29 560µF C23 330µF C52 OPEN C40 OPEN C28 560µF C22 330µF C51 OPEN C39 OPEN C27 560µF C21 330µF C50 OPEN C38 OPEN C26 560µF C20 330µF C49 OPEN C37 OPEN C25 560µF C19 330µF C48 OPEN C24 560µF C18 330µF C42 OPEN C30 560µF C43 OPEN C31 560µF C33 10µF C54 OPEN C44 OPEN C34 10µF C55 OPEN C12 1µF CON2 JU1 C57 OPEN C11 1µF C46 10µF C36 OPEN C56 OPEN C10 1µF C45 10µF C35 OPEN CON1 JU10 PROBE_JACK CON6 C13 1µF CON5 CON3 CON4 Evaluates: MAX1937/MAX1938/MAX1939 MAX1938 Evaluation Kit Figure 1. MAX1938 EV Kit Schematic (Sheet 2 of 2) ______________________________________________________________________________________ MAX1938 Evaluation Kit Figure 3. MAX1938 EV Kit PC Board Layout—Component Side _______________________________________________________________________________________ 7 Evaluates: MAX1937/MAX1938/MAX1939 Figure 2. MAX1938 EV Kit Component Placement Guide— Component Side Evaluates: MAX1937/MAX1938/MAX1939 MAX1938 Evaluation Kit Figure 4. MAX1938 EV Kit PC Board Layout—Inner Layer 2 8 Figure 5. MAX1938 EV Kit PC Board Layout—Inner Layer 3 ______________________________________________________________________________________ MAX1938 Evaluation Kit 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 _____________________ 9 © 2003 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products. Evaluates: MAX1937/MAX1938/MAX1939 Figure 6. MAX1938 EV Kit PC Board Layout—Solder Side