19-2050; Rev 0; 5/01 MAX1776 Evaluation Kit Features ♦ +5.5V to +24V Input Voltage Range (for Fixed +5V Output) ♦ +4.5V to +24V Input Voltage Range (for +3.3V Output) ♦ Output Voltage Fixed +5V Adjustable Output (+1.25V to +23.5V) ♦ 500mA Output Current ♦ 3µA IC Shutdown Mode ♦ 8-Pin µMAX Package ♦ Surface-Mount Construction ♦ Fully Assembled and Tested Component List DESIGNATION QTY Ordering Information DESCRIPTION PART TEMP. RANGE IC PACKAGE -40°C to +85°C 8 µMAX C1 1 10µF ±10%, 25V, X5R ceramic capacitor (1812) Taiyo Yuden TMK432BJ106KM or TDK C4532X5R1E106M C2 1 100µF, 6.3V, 45mΩ low-ESR electrolytic capacitor (POSCAP) (D2) Sanyo 6TPC100M D1 1 1A, 30V Schottky diode Nihon EP10QY03 PHONE FAX L1 1 10µH inductor Sumida CDRH6D28-100NC Nihon 847-843-7500 847-843-2798 Sanyo 619-661-6835 619-661-1055 R1 0 Sumida 847-956-0666 847-956-0702 R2 0 Not installed (0603) Not installed, pads shorted with PC Taiyo Yuden 408-573-4150 408-573-4159 JU1, JU4 2 3-pin headers TDK 847-390-4373 847-390-4428 JU2, JU3 0 Not installed, pins 1 and 2 shorted with PC trace MAX1776EUA (8-pin µMAX) U1 1 None 2 Shunts None 1 MAX1776 PC board None 1 MAX1776 EV kit data sheet None 1 MAX1776 data sheet MAX1776EVKIT Component Suppliers SUPPLIER Note: Please indicate that you are using the MAX1776 when contacting these component suppliers. ________________________________________________________________ Maxim Integrated Products 1 For price, delivery, and to place orders, please contact Maxim Distribution at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. Evaluates: MAX1776 General Description The MAX1776 evaluation kit (EV kit) provides a +5.0V output voltage from a +5.5V to +24V input source. It delivers 500mA output current and operates up to 100% duty cycle at dropout. The MAX1776 is a stepdown switching regulator with an internal power switch. The EV kit is a fully assembled and tested surfacemount PC board. It can also be used to evaluate other output voltages in the +1.25V to +23.5V range by adding the feedback resistors and changing a jumper setting. Evaluates: MAX1776 MAX1776 Evaluation Kit Quick Start The MAX1776 EV kit is a fully assembled and tested surface-mount board. Follow the steps below to verify board operation. Do not turn on the power supply until all connections are completed. 1) Verify that shunts are across pins 1 and 2 of jumper JU1 (SHDN) and pins 1 and 2 of jumper JU4. 2) Connect a voltmeter and load (if any) to the VOUT pad. Connect the ground to the GND pad closest to VOUT. 3) Connect a +5.5V to +24V power supply to the VIN pad. Connect the power-supply ground to the GND pad closest to VIN. 4) Turn on the power supply, and verify that the output voltage is +5.0V. kit’s default setting provides the maximum 1.2A switch current limit. To change the switch current limit, cut open the PC board traces, shorting pins 1 and 2 of JU2 and JU3, and short the appropriate pins for the desired current limit (Table 2). Changing the current limit requires inductor L1 and output capacitor C2 to be replaced. Refer to the Recommended Components Table (Table 3) of the MAX1776 data sheet. Evaluating Other Output Voltages The default output for the MAX1776 EV kit is +5.0V. To generate output voltages other than +5.0V, set the JU4 shunt to pins 2 and 3 (Table 3), cut the PC board trace shorting the pads of R2, and install feedback resistors R1 and R2. Select feedback resistor R2 in the 10kΩ to 100kΩ range. R1 = R2 [(VOUT / 1.25V) - 1] To evaluate other output voltages, refer to Evaluating Other Output Voltages Detailed Description Shutdown Jumper Selection The MAX1776 EV kit features a shutdown mode that reduces quiescent current to 3µA (typ) to preserve battery life. Jumper (JU1) options select the circuit operating modes: shutdown or normal mode (Table 1). Adjustable Current Limit Table 2. Jumper JU2 and JU3 Functions JU2 SHUNT LOCATION JU3 SHUNT LOCATION MAX1776 SWITCH CURRENT LIMIT (A) 2 and 3 2 and 3 0.15 1 and 2 2 and 3 0.30 2 and 3 1 and 2 0.60 1 and 2* 1 and 2* 1.20 The MAX1776 EV kit can operate at different current limits after modification. Jumper (JU2 and JU3) options select the MAX1776 internal switch current limit. The EV *Default configuration: JU2 (1-2), JU3 (1-2) shorted by PC board trace. Table 1. Jumper JU1 Functions Table 3. Jumper JU4 Functions SHUNT LOCATION MAX1776 OUTPUT SHUNT LOCATION JUMPER CONNECTION MAX1776 OUTPUT 1 and 2 Connected to VIN MAX1776 enabled, VOUT = +5.0V 1 and 2 Connected to OUT Fixed output, VOUT = +5.0V 2 and 3 Connected to GND Shutdown mode, VOUT = 0V 2 and 3 Connected to a voltage-divider Adjustable output Connect external source to SHDN pad MAX1776 output depends on external SHDN signal None 2 SHDN PIN Note: Do not switch JU4 shunt location or leave JU4 floating (no shunt across JU4) when power is on. _______________________________________________________________________________________ MAX1776 Evaluation Kit GND 5 C1 10µF 25V 1 2 3 JU3 3 IN OUT 8 1 2 ILIM 3 R1 OPEN FB JU2 6 SHDN JU1 7 L1 10µH C2 100µF 6.3V GND 1 R2 SHORT (PC TRACE) ILIM2 LX 1 2 3 VOUT JU4 U1 MAX1776 1 2 3 Evaluates: MAX1776 VIN 4 D1 SHDN GND 2 Figure 1. MAX1776 EV Kit Schematic _______________________________________________________________________________________ 3 Evaluates: MAX1776 MAX1776 Evaluation Kit 1.0" 1.0" Figure 2. MAX1776 EV Kit Component Placement Guide— Component Side Figure 3. MAX1776 EV Kit PC Board Layout—Component Side 1.0" Figure 4. MAX1776 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. 4 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2001 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.