19-3415; Rev 0; 9/04 MAX1556 Evaluation Kit The MAX1556 evaluation kit (EV kit) is a fully assembled and tested circuit board that evaluates the MAX1556 and MAX1557 PWM step-down DC-DC converters. The circuit operates from 2.6V to 5.5V. The MAX1556 delivers up to 1.2A and has pin-selectable 1.8V, 2.5V, 3.3V, and adjustable output. The MAX1557 delivers up to 600mA and has pin-selectable 1V, 1.3V, 1.5V, and adjustable output. Each circuit features an on-board shutdown control. Component List DESIGNATION QTY DESCRIPTION Features ♦ Up to 97% Efficiency ♦ 95% Efficiency at 1mA Load Current ♦ 1MHz PWM Switching Frequency ♦ Tiny Inductors ♦ Pin-Selectable Output Voltages MAX1556: 3.3V, 2.5V, 1.8V, and Adjustable MAX1557: 1.5V, 1.3V, 1.0V, and Adjustable ♦ 1.2A Guaranteed Output Current (MAX1556) ♦ Voltage Positioning Optimizes Load-Transient Response ♦ Low 16µA Quiescent Current 2 10µF ±10%, 6.3V X5R ceramic capacitors (0805) Murata GRM21BR60J106K or equivalent ♦ Analog Soft-Start with Zero Overshoot Current C2, C7 2 22µF ±10%, 6.3V X5R ceramic capacitors (1206) Murata GRM31CR60J226K or equivalent C3, C8 0 Not installed, capacitors (0805) 2 0.001µF ±10%, 50V X7R ceramic capacitors (0402) Murata GRP155R71H102K or equivalent C1, C6 C4, C9 C5, C10 0 Not installed, capacitors (0603) C11 1 0.47µF ±10%, 6.3V X5R ceramic capacitor (0402) Murata GRM155R60J474K or equivalent JU1–JU6 6 3-pin headers L1 1 3.3µH inductor, 0.036Ω, 1.3A, 5.0mm x 5.0mm x 2.0mm Taiyo Yuden LMNP04SB3R3N L2 1 4.7µH inductor, 0.05Ω, 1.2A, 5.0mm x 5.0mm x 2.0mm Taiyo Yuden LMNP04SB4R7N R1, R3 0 Shorted on PC board, resistors (0603) R2, R4 0 Not installed, resistors (0603) R5 1 100Ω ±1% resistor (0402) U1 1 MAX1556ETB U2 1 MAX1557ETB None 6 Shunts, position 2 None 1 MAX1556 EV kit PC board ♦ Low 27µA Quiescent Current in Dropout ♦ Low 0.1µA Shutdown Current ♦ Small, 10-Pin, 3mm x 3mm TDFN Package ♦ Fully Assembled and Tested Ordering Information PART MAX1556EVKIT TEMP RANGE IC PACKAGE 0°C to +70°C 10 TDFN-EP* *EP = Exposed paddle. Component Suppliers SUPPLIER PHONE WEBSITE Murata 814-237-1431 www.murata.com Taiyo Yuden 408-573-4150 www.t-yuden.com Vishay 402-563-6866 www.vishay.com Note: Indicate that you are using the MAX1556 when contacting these component suppliers. Quick Start Recommended Equipment • One variable DC power supply capable of supplying up to 5.5V at 1.2A • One voltmeter (DMM) ________________________________________________________________ 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: MAX1556/MAX1557 General Description Evaluates: MAX1556/MAX1557 MAX1556 Evaluation Kit Procedure (MAX1556ETB) The MAX1556 EV kit is fully assembled and tested. Follow the steps below to verify board operation: 1) Select the desired output voltage with JU1, JU2, and JU3 (see Table 1). The EV kit is preset to a 1.8V output. 2) Connect the positive terminal of the voltmeter to the pad labeled OUT. Connect the ground terminal of the voltmeter to the pad labeled GND nearest the OUT pad. Connect a load from OUT to the GND pad closest to OUT. 3) Preset the power supply to between 2.6V and 5.5V, and turn the power supply off. Do not turn on the power supply until all connections are completed. 4) Connect the positive power-supply terminal to the pad labeled IN. Connect the power-supply ground to the pad labeled GND nearest the IN pad. 5) Turn on the power supply and verify the output voltage is the desired voltage from setting JU1, JU2, and JU3 (default is 1.8V). 5) Turn on the power supply and verify the output voltage is the desired voltage from setting JU4, JU5, and JU6 (default is 1.0V). Detailed Description The MAX1556 EV kit contains two separate PWM stepdown DC-DC converter circuits. Either circuit can be powered from a DC power supply with a 2.6V to 5.5V input range. The top and bottom circuit are separate from each other and do not share a common ground plane. The top circuit (MAX1556) provides pin-selectable output voltages of 3.3V, 2.5V, 1.8V, and adjustable at 1.2A. The bottom circuit (MAX1557) provides pin-selectable output voltages of 1.5V, 1.3V, 1.0V, and adjustable at 600mA. Pin-Selectable Output Voltages The MAX1556 output voltage is selected with JU1 and JU2, as shown in Table 1. The MAX1557 output voltage is selected with JU4 and JU5, as shown in Table 2. Procedure (MAX1557ETB) Evaluating Other Output Voltages The MAX1556 EV kit is fully assembled and tested. Follow the steps below to verify board operation: 1) Select the desired output voltage with JU4, JU5, and JU6 (see Table 2). The EV kit is preset to a 1.0V output. The MAX1556 EV kit comes with the MAX1556 preset to a 1.8V output and the MAX1557 preset to a 1V output. To evaluate other voltages besides the preset values, set the MAX1556 (or MAX1557) to adjustable mode. The footprints for the feedback resistors are available on the backside of the evaluation kit. Refer to the Adjusting the Output Voltage section in the MAX1556 data sheet for a detailed description on calculating these feedback resistor values for the desired output voltage. Resistor R1 for the MAX1556 circuit (R3 on MAX1557) is shorted on the evaluation kit. This short must be cut prior to the placement of a resistor on the footprint. Resistor R2 for the MAX1556 circuit (R4 for MAX1557) is open and requires no modification before placing a resistor on the footprint. 2) Connect the positive terminal of the voltmeter to the pad labeled OUT2. Connect the ground terminal of the voltmeter to the pad labeled GND2 nearest the OUT2 pad. Connect a load from OUT2 to the GND2 pad closest to OUT2. 3) Preset the power supply to between 2.6V and 5.5V, and turn the power supply off. Do not turn on the power supply until all connections are completed. 4) Connect the positive power-supply terminal to the pad labeled IN2. Connect the power-supply ground to the pad labeled GND2 nearest the IN2 pad. Table 1. Output Voltage Selection (MAX1556ETB) JU1 JU2 JU3 MAX1556 VOUT 1 and 2 1 and 2 1 and 2 1.8V 1 and 2 2 and 3 1 and 2 2.5V 2 and 3 1 and 2 1 and 2 3.3V 2 and 3 2 and 3 1 and 2 ADJ — — 2 and 3 Shutdown Note: Default configuration is JU1, JU2, and JU3 (1 and 2). 2 _______________________________________________________________________________________ MAX1556 Evaluation Kit JU4 JU5 JU6 MAX1557 VOUT 1 and 2 1 and 2 1 and 2 1.0V 1 and 2 2 and 3 1 and 2 1.3V 2 and 3 1 and 2 1 and 2 1.5V 2 and 3 2 and 3 1 and 2 ADJ — — 2 and 3 Shutdown Note: Default configuration is JU4, JU5, and JU6 (1 and 2). External Shutdown Control The MAX1556 EV kit comes preset with SHDN and SHDN2 pulled high so that the MAX1556 and MAX1557 are enabled when the input voltage is applied. To operate the shutdown control from an external signal, remove the IN 9 IN_P shunt on JU3 for the MAX1556 (JU6 for the MAX1557). Apply a logic high to SHDN to enable the MAX1556, or apply a logic low to shut down the MAX1556. Apply a logic high to SHDN2 to enable the MAX1557, or apply a logic low to shut down the MAX1557. LX 8 C1 10µF R5 100Ω L1 3.3µH C2 22µF U1 1 IN MAX1556 PGND C11 0.47µF OUT 1 JU1 2 3 SHDN 10 1 3 5 2 JU3 1 2 3 JU2 6 OUT C3 OPEN C5 OPEN 7 R1 SHORT GND 4 GND R2 OPEN D1 SHDN SS 3 C4 0.001µF D2 GND 2 EXPOSED PAD CONNECTED TO GND Figure 1a. MAX1556 EV Kit Schematic (MAX1556) _______________________________________________________________________________________ 3 Evaluates: MAX1556/MAX1557 Table 2. Output Voltage Selection (MAX1557ETB) Evaluates: MAX1556/MAX1557 MAX1556 Evaluation Kit IN2 9 IN_P LX 8 C6 10µF L2 4.7µH C7 22µF U2 1 IN MAX1557 PGND OUT 1 JU4 2 3 SHDN2 10 1 3 5 2 JU6 1 2 3 JU5 6 OUT2 C8 OPEN C10 OPEN 7 R3 SHORT GND2 4 GND2 R4 OPEN D1 SHDN SS 3 C9 0.001µF D2 GND 2 EXPOSED PAD CONNECTED TO GND Figure 1b. MAX1556 EV Kit Schematic (MAX1557) 4 _______________________________________________________________________________________ MAX1556 Evaluation Kit Evaluates: MAX1556/MAX1557 Figure 2. MAX1556 EV Kit Component Placement Guide—Component Side Figure 3. MAX1556 EV Kit Component Placement Guide—Solder Side _______________________________________________________________________________________ 5 Evaluates: MAX1556/MAX1557 MAX1556 Evaluation Kit Figure 4. MAX1556 EV Kit PC Board Layout—Component Side Figure 5. MAX1556 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. 6 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2004 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.