Evaluates: MAX830–MAX833 MAX831 Evaluation Kit _______________General Description The MAX831 evaluation kit (EV kit) provides a regulated 5.0V output voltage while operating on input voltages from 8.0V to 30V. It drives loads up to 1A with conversion efficiency greater than 80%. The MAX831 EV kit is a fully assembled and tested surface-mount printed circuit board. This kit comes with a 5V-output MAX831 IC, but it can also be used to evaluate the MAX833 (3.0V output), MAX832 (3.3V output), or MAX830 (adjustable output). Additional pads are provided on the board's solder side to accommodate the external feedback resistors used with the MAX830. ____________________________Features ♦ 8V to 30V Input Voltage Range ♦ 5V Output Voltage ♦ Up to 1A Continuous Output Current ♦ 140µA Shutdown Supply Current ♦ 8mA Quiescent Current ♦ Internal Power Switch ♦ Adjustable Current Limit ♦ Surface-Mount Construction ____________________Component List ♦ Fully Assembled and Tested DESIGNATION QTY DESCRIPTION C1, C2 2 33µF, 35V, low-ESR tantalum capacitor Sprague 595D336X0035R2B ______________Ordering Information C3, C4 2 220µF, 10V, low-ESR tantalum capacitor Sprague 595D227X0010R2B or AVX TPSE227M010R0100 PART MAX831EVKIT-SO C5 1 0.047µF ceramic capacitor R1, R2, R3 0 Open R4 1 10kΩ, 5% resistor D1 1 3A, 40V 1N5822 (SMT) Schottky diode Nihon NSQ03A04 Motorola MBRS340T3 L1 1 100µH, 1.3A inductor Coilcraft D03316-104 U1 1 Maxim MAX831CWE J1 1 2-pin header None 1 Shunt None 1 MAX831 PC board None 1 MAX831 data sheet TEMP. RANGE 0°C to +70°C PIN-PACKAGE Surface Mount ______________Component Suppliers SUPPLIER PHONE FAX AVX (207) 282-5111 (207) 283-1941 Coilcraft (708) 639-6400 (708) 639-1469 IRC (704) 264-8861 (704) 264-1972 Motorola (602) 244-3576 (602) 244-4015 Murata-Erie (814) 237-1431 (814) 238-0480 Nihon (805) 867-2555 (805) 867-2556 Sprague (603) 224-1961 (603) 224-1430 1 Maxim Integrated Products _______________________________________________________________ Call toll free 1-800-998-8800 for free samples or literature. MAX831 Evaluation Kit Table 1. Jumper J1 Functions SHUNT LOCATION OFF Floating ON Connected to GND The two-pin header J1 selects the shutdown mode. Table 1 lists the jumper selectable options. 1 VIN +8V to +30V C1 33µF 35V C2 33µF 35V 2 3 4 5 R3 OPEN 6 7 R2 OPEN 8 VIN Notes about Inductor Selection Evaluating the MAX832 and MAX833 The MAX831 can be replaced by a MAX833 to generate a 3.0V output voltage with output current up to 1A, or by a MAX832 to generate a 3.3V output voltage with output current up to 1A. The only modification required is to replace the IC. VSW VIN VSW U1 VIN VSW MAX831 VIN VSW GND GND ILIM VC GND GND SENSE SHUT L1 100µH 16 VOUT +5V 15 C3 220µF 10V D1 1N5822 14 C4 220µF 10V 13 12 11 R4 10k C5 0.047µF 10 9 J1 R1 0Ω MAX831 OUTPUT MAX831 Enabled, VOUT = 5.0V Shutdown Mode, VOUT = 0V The 100µH Coilcraft D03316-104 inductor that comes mounted with the EV kit has low resistance and a medium current rating (1.3A). It provides excellent performance over the line and load ranges of the MAX830/MAX831/MAX832/MAX833. For additional information on inductor selection, refer to the MAX830–MAX833 data sheet. _______________Detailed Description Jumper Selection –——— SHDN PIN SHDN GND Figure 1. MAX831 EV Kit Schematic Diagram _______________________________________________________________________________________ 2 Evaluates: MAX830–MAX833 ___________________Quick Reference The MAX831 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) Connect an 8V to 30V supply to the pad marked VIN. The ground connects to the GND pad. 2) Connect a voltmeter and load (if any) to the VOUT pad. 3) Remove the shunt on J1 for normal operation. 4) Turn on the power and verify that the output voltage is 5.0V. Instructions for modifying the board for different output voltages appear in the sections Evaluating the MAX832 and MAX833 and Other Output Voltages. Evaluates: MAX830–MAX833 MAX831 Evaluation Kit Other Output Voltages Reducing Current Limit The MAX831 can be replaced with a MAX830 to generate output voltages in the 2.5V to 25V range using external resistors. Besides replacing the IC, the only other modifications required are to cut the trace shorting resistor R1, add the output-voltage-divider resistors R1 and R2 (located on the board's solder side), and use low-ESR output capacitors with the proper voltage rating. The Pin Description section of the MAX830–MAX833 data sheet gives instructions for calculating the values of external feedback resistors R1 and R2. To reduce the output current to below 1A, or to reduce the peak current limit to below 1.3A, install the currentlimiting resistor, R3, onto the board's solder side. See Note 7 in the MAX830–MAX833 data sheet for instructions on selecting the resistor value. BOARD DIAGRAM DRAWN TO REDUCED SCALE. BOARD DIAGRAM DRAWN TO REDUCED SCALE. Figure 2. MAX831 EV Kit Component Placement Guide— Component Side Figure 3. MAX831 EV Kit Component Placement Guide— Solder Side BOARD DIAGRAM DRAWN TO REDUCED SCALE. BOARD DIAGRAM DRAWN TO REDUCED SCALE. Figure 4. PC Board Layout—Component Side Figure 5. 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. 3 ___________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 (408) 737-7600 © 1995 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.