MAX1637 Evaluation Kit The MAX1637 EV kit has excellent dynamic response to correct for fast output transients. This EV kit is a fully assembled and tested circuit board. Ordering Information PART TEMP. RANGE MAX1637EVKIT 0°C to +70°C ____________________________Features ♦ 4.5V to 22V Battery Voltage Range ♦ 4.5V to 5.5V Input Voltage Range (IC Power) ♦ Output Voltage: Fixed 1.7V, 7A (Circuit 1) Fixed 2.5V, 3A (Circuit 2) ♦ Circuit 1 Efficiency = 90% (VIN = 7V, VOUT = 1.7V @ IOUT = 3A) ♦ Circuit 2 Efficiency = 91% (VIN = 7V, VOUT = 2.5V @ IOUT = 3A) ♦ 3µA Max IC Shutdown Current ♦ Fast MOSFETs for Low Switching Losses ♦ Tight PC Board Layout for Low Switching Losses ♦ 300kHz Switching Frequency ♦ Surface-Mount Construction ♦ Fully Assembled and Tested IC PACKAGE 16 QSOP Component List DESIGNATION QTY C1, C2, C3, C4, C22 5 DESCRIPTION 10µF, 25V ceramic capacitors Tokin C34Y5U1E106Z or United Chemi-Con/Marcon THCR50E1E106ZT 4 470µF, 6.3V, 30mΩ, low-ESR tantalum capacitors Kemet T510X477M006 5 470µF, 4V, 55mΩ, low-ESR tantalum capacitors Sprague 594D477X0004R2T C9, C10, C17, C19 4 0.1µF ceramic capacitors C11, C16 2 1500pF ceramic capacitors C12, C15 2 1µF ceramic capacitors C13, C18 2 4.7µF, 16V tantalum capacitors Sprague 595D475X0016A2B C5, C6, C7, C20 OR C5, C6, C7, C8, C20 C14, C21, C23, C24 0 Not installed C25, C26 2 0.01µF ceramic capacitors 1 2A Schottky diode SGS-Thomson STPS2L25U or Nihon EC20QS03L 1 1A Schottky diode International Rectifier 10BQ040 or Motorola MBRS130LT3 D1 D4 DESIGNATION QTY D2, D3 2 DESCRIPTION Schottky diodes Central Semiconductor CMPSH-3 1 2.2µH power inductor Panasonic P1F2R0HL, Coiltronics UP4B-2R2, or Coilcraft DO5022P-222HC 1 10µH power inductor Sumida CDRH125-100, Coiltronics UP2B-100, or Coilcraft DO3316P-103 N1 1 N-channel MOSFET Fairchild FDS6612 or FDS9412, International Rectifier IRF7803, or Siliconix Si9804DY N2 1 N-channel MOSFET Fairchild FDS6680 or Siliconix Si4420DY N3 1 N-channel MOSFET International Rectifier IRF7403 or Siliconix Si4412DY 1 N-channel MOSFET International Rectifier IRF7413, Fairchild NDS8410A, or Siliconix Si4410DY L1 L2 N4 Component List continued on next page. ________________________________________________________________ Maxim Integrated Products 1 For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800. For small orders, phone 408-737-7600 ext. 3468. Evaluates: MAX1637 General Description The MAX1637 evaluation kit (EV kit) contains two separate switching-regulator circuits. The first circuit converts high-voltage battery power into a low-voltage supply rail for next-generation notebook CPU cores. Its output is fixed at 1.7V and delivers up to 7A output current with greater than 87% efficiency. The second circuit generates a low-voltage supply for general-purpose use. Its output is fixed at 2.5V and delivers up to 3A output current. The battery range for both circuits is 4.5V to 22V, and both require a separate 5V input voltage to power the MAX1637. Output voltages can be adjusted by changing the feedback resistor values. Evaluates: MAX1637 MAX1637 Evaluation Kit Component Suppliers Component List (continued) DESIGNATION R1 QTY 1 DESCRIPTION 0.010Ω, 1%, 1W resistor Dale WSL-2512-R010F SUPPLIER PHONE FAX AVX (803) 946-0690 (803) 626-3123 Central Semiconductor (516) 435-1110 (516) 435-1824 1 56.2kΩ, 0.1% resistor Dale TNPW-1206 series Coilcraft (708) 639-6400 (708) 639-1469 R3 1 100kΩ, 0.1% resistor Dale TNPW-1206 series Dale-Vishay (402) 564-3131 (402) 563-6418 Fairchild (408) 721-2181 (408)721-1635 International Rectifier (310) 322-3331 (310) 322-3332 R2 R4–R9 6 1MΩ, 5% resistors R10, R11 2 20Ω, 5% resistors (512) 992-7900 (512) 992-3377 1 0.020Ω, 1%, 0.5W resistor Dale WSL-2010-R020-F or IRC LR2010-R020-F IRC R12 Kemet (408) 986-0424 (408) 986-1442 Motorola (602) 303-5454 (602) 994-6430 130kΩ, 1% resistor Panasonic (714) 373-7939 (714) 373-7183 Sanyo (619) 661-6835 (619) 661-1055 SGS-Thomson (617) 259-0300 (617) 259-9442 Siliconix (408) 988-8000 (408) 970-3950 Sprague (603) 224-1961 (603) 224-1430 Sumida (847) 956-0666 (847) 956-0702 Taiyo Yuden (408) 573-4150 (408) 573-4159 Tokin (408) 432-8020 (408) 434-0375 Vishay/Vitramon (203) 268-6261 (203) 452-5670 R13 1 R14 1 100kΩ, 1% resistor U1, U2 2 MAX1637EEE JU1–JU6 6 2-pin headers None 1 MAX1637 PC board None 1 MAX1637 data sheet Quick Start The MAX1637 EV kit is fully assembled and tested. Follow these steps to verify board operation. Do not turn on the power supplies until all connections are completed. 1.7V Output (7A Configuration) 1) Connect a +4.5V to +22V supply voltage to the VBATT pad. Connect a separate +4.5V to +5.5V supply voltage to the VBIAS pad. Connect the grounds to the GND pads. Note: Please indicate that you are using the MAX1637 when contacting these component suppliers. 2.5V Output (3A Configuration) 1) Connect a +7V to +22V supply voltage to the VBATT pad. Connect a +4.5V to +5.5V supply voltage to the VBIAS pad. Connect the grounds to the GND pads. 2) Connect a voltmeter and load, if any, to the VOUT pad. 3) Turn on the VBATT power supply to the board first. 2) Connect a voltmeter and load, if any, to the VOUT pad. 4) Turn on the VBIAS power supply. Verify that the output voltage is 2.5V. 3) Turn on the VBATT power supply to the board first. 5) For other output voltages, refer to the Setting the Output Voltage section in the MAX1637 data sheet for instructions on selecting feedback resistors R13 and R14. 4) Turn on the VBIAS power supply. Verify that the output voltage is 1.7V. 5) For other output voltages, refer to the Setting the Output Voltage section in the MAX1637 data sheet for instructions on selecting feedback resistors R2 and R3. 2 _______________________________________________________________________________________ MAX1637 Evaluation Kit SHUNT LOCATION SKIP PIN OPERATIONAL MODE OFF Connected to GND Idle mode, pulse-skipping operation for highest lightload efficiency ON Connected to VBIAS Low-noise mode, fixed frequency PWM operation. Table 2. Jumpers JU3 and JU4 Functions SHUNT LOCATION SYNC PIN FREQUENCY (kHz) OFF Connected to VBIAS 300 ON Connected to GND 200 Detailed Description Both switching regulators require a bias supply voltage (VBIAS) to power the IC and provide gate-drive current. VBIAS must be in the range of 4.5V to 5.5V due to the MOSFETs selected, although the MAX1637 itself operates over a wider range (3.15V to 5.5V). The +5V VBIAS supply must be capable of sourcing at least 20mA. Actual VBIAS current draw is: Table 3. Jumpers JU5 and JU6 Functions SHUNT LOCATION SHDN PIN MAX1637 OUTPUT OFF Connected to VBIAS MAX1637 enabled ON Connected to GND Shutdown mode, VOUT = 0V Jumper Selection The 2-pin headers JU1 and JU2 select the mode of operation. Table 1 lists the selectable jumper options. The 2-pin headers JU3 and JU4 select the operating frequency. Table 2 lists the selectable jumper options. The EV kit’s components are selected for 300kHz operation. Component values might need to be changed if 200kHz operation is selected (refer to the Design Procedure section in the MAX1637 data sheet). Synchronize the oscillator to an external clock signal by driving the SYNC pad with a pulse train of 5V amplitude in the 240kHz to 340kHz frequency range. The 2-pin headers JU5 and JU6 select the shutdown mode. Table 3 lists the selectable jumper options. IBIAS = (QG1 + QG2) x f + ICC where Q G1 , Q G2 is the total gate charge of the MOSFETs at V GS = VBIAS, and I CC is the current drawn by the MAX1637 VCC input. Battery power must be applied prior to VBIAS power due to the output undervoltage lockout built into the MAX1637. If VBIAS is applied first, the circuit begins switching and attempts to bring up the output voltage. Since battery power is not present, the 20ms UVLO timer expires and the PWM is latched off until VBIAS or SHDN is cycled. _______________________________________________________________________________________ 3 Evaluates: MAX1637 Table 1. Jumpers JU1 and JU2 Functions 4 JU5 SYNC VBIAS SKIP REF ON/OFF VBIAS 4.5V TO 5.5V R5 1M R4 1M R6 1M 2 2 JU3 JU2 C12 1µF 1 1 VBIAS C26 0.01µF VCC 7 16 8 5 6 SYNC SKIP GND REF MAX1637 SHDN CC FB CSL CSH PGND DL LX DH BST 10 VGG 9 U1 R10 20Ω VCC C9 0.1µF VCC 4 3 2 1 12 11 15 14 13 C11 1500pF 4 C10 0.1µF 4 D2 CMPSH-3 C13 4.7µF 16V 1, 2, 3 N2 5, 6, 7, 8 1, 2, 3 N1 5, 6, 7, 8 D1 L1 2.2µH R1 0.010Ω 1% C5 470µF 6.3V C1 10µF 25V C6 470µF 6.3V C2 10µF 25V C14 OPEN C7 470µF 6.3V C3 10µF 25V C8 OPEN C4 10µF 25V CUT TRACE FOR REMOTE SENSING R3 100k 0.1% R2 56.2k 0.1% SENSE VOUT 1.7V VBATT 4.5V TO 22V Evaluates: MAX1637 MAX1637 Evaluation Kit Figure 1. MAX1637 EV Kit Schematic (1.7V, 7A) _______________________________________________________________________________________ _______________________________________________________________________________________ JU6 VBIAS SYNC SKIP REF ON/OFF R9 1M R8 1M R7 1M 2 2 JU4 JU1 C15 1µF 1 1 VBIAS C25 0.01µF VCC 8 5 6 7 16 C17 0.1µF SYNC SKIP GND REF MAX1637 SHDN CC FB CSL CSH PGND DL LX DH BST 10 VGG 9 VCC U2 R11 20Ω 4 3 2 1 12 11 15 14 13 C16 1500pF 4 C19 0.1µF 4 D3 CMPSH-3 C18 4.7µF 16V 1, 2, 3 N4 5, 6, 7, 8 1, 2, 3 N3 5, 6, 7, 8 D4 L2 10µH R12 0.020Ω 1% C21 OPEN C20 470µF 6.3V C22 10µF 25V C24 OPEN C23 OPEN CUT TRACE FOR REMOTE SENSING R14 100k 1% R13 130k 1% SENSE VOUT 2.5V VBATT 4.5V TO 22V Evaluates: MAX1637 VBIAS 4.5V TO 5.5V MAX1637 Evaluation Kit Figure 2. MAX1637 EV Kit Schematic (2.5V, 3A) 5 Evaluates: MAX1637 MAX1637 Evaluation Kit 1.0" Figure 3. MAX1637EV Kit—Component Placement Guide 6 1.0" Figure 4. MAX1637 EV Kit PC Board Layout—Component Side _______________________________________________________________________________________ MAX1637 Evaluation Kit Evaluates: MAX1637 1.0" 1.0" Figure 5. MAX1637 EV Kit PC Board Layout—Two Internal Ground Planes Figure 6. MAX1637 EV Kit PC Board Layout—Solder Side _______________________________________________________________________________________ 7 Evaluates: MAX1637 MAX1637 Evaluation Kit NOTES 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. 8 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 1998 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.