Evaluates: MAX1703 19-1336 Rev 2 11/98 MAX1703 Evaluation Kit General Description Features The MAX1703 evaluation kit (EV kit) provides a regulat- 5.0V Output ed 5.0V output while operating on input voltages as low 1A Output Current as 1.2V. The input may be a DC source or a 1 to 3-cell battery. Efficiency is up to 95%, and output loads are 1.2V to 5.5V Input up to 1A. Up to 95% Efficiency The kit, which uses surface-mount components, is fully assembled and tested for quick evaluation. Jumpers 0.1A Shutdown Current are provided to select the output voltage, switching 300kHz PWM Operation mode, and shutdown control. Optional Low-Power Mode Small Surface-Mount Components Component List Ordering Information DESIGNATION QTY DESCRIPTION PART TEMP. RANGE PIN-PACKAGE MAX1703EVKIT 0C to +70C 16 Narrow SO C1, C2, C3 3 0.22F, 25V ceramic capacitors 100F, 10V low-ESR tantalum capacitor: C4 1 AVX TPSD107M010R0100 or Sprague 593D107X0010D 220F, 10V low-ESR tantalum capacitors C5, C6 2 AVX TPSE227M010R0100 or Sprague 593D227X0010E Component Suppliers C7 1 Not installed, optional user capacitor SUPPLIER PHONE FAX 0.5A, 20V Schottky diode D1 1 Motorola MBR0520L AVX (803) 946-0690 (803) 626-3123 Coilcraft (847) 639-6400 (847) 639-1469 4.7H, 3.2A power inductor Sumida CDH74-4R7 Coiltronics (561) 241-7876 (561) 241-9339 L1 1 Coilcraft DO3316-4R7, Motorola (602) 244-5303 (602) 244-4015 Coiltronics UP2B-4R7 or Sprague (603) 224-1961 (603) 224-1430 Sumida CDRH 104, 4746-JPS-007 Sumida (847) 956-0666 (847) 956-0702 J1, J2 2 3-pin jumpers J3, J4 2 2-pin jumpers R1, R7, R5 3 100k 1% resistors R2, R4, R6 0 Not installed, user-selected resistor R3 1 10, 5% resistor R8, R9 2 100k, 5% resistors R10, R11 2 1M, 5% resistors U1 1 MAX1703ESE None 4 Shunts None 1 3.40 X 2.40 printed circuit board None 1 MAX1703 data sheet Maxim Integrated Products 1 For free samples & the latest literature: MAX1703 Evaluation Kit power inductor must not saturate at the 3.2A peak cur- Quick Start rent produced by MAX1703. All inductors listed in the The MAX1703 EV kit is shipped fully assembled and component list have high current ratings and low coil tested. Follow these steps to verify board operation. Do resistance. not turn on the power supply until all connections The input and output capacitors must have low equiva- are completed. lent-series resistance (ESR) to handle the high peak 1) Verify that the shunts are connected as listed in currents found in switching regulators. Low ESR is Table 2 for a 5V output. especially critical in low-voltage circuits to reduce the 2) Connect a 1.2V to 5.5V supply to the VIN pad. The AC voltage across the capacitors. A higher ESR on the ground connects to the GND pad. output capacitor will increase the output ripple. 3) Connect a voltmeter to the VOUT pad. Consider using parallel capacitors to reduce the total ESR if the application requires lower output ripple. 4) Turn on the power, and verify that the output volt- age is 5V. A low-ESR input capacitor must be located physically close to the inductor. A Schottky diode is used for the 5) Connect a load if any. lower forward voltage drop as well as the fast switching Detailed Description characteristic. The diode selected for the evaluation Jumper Selections board was selected for its small size. The Schottky diode must be connected between LX and POUT as Four jumpers on the printed circuit board allow user close to the IC as possible. selection of several configurations. Table 1 lists the jumpers and their functions. Table 2 lists the jumper A separate low-noise ground plane connects pin 5 to positions when the board is set for normal 5V output the reference and signal grounds. This low-noise operation. ground plane is then connected to the power ground plane at the two PGND pins (Figure 4). Component Selection The final circuit performance is determined by the qual- ity of the components surrounding the MAX1703. The Table 1. Jumper Functions SHUNT JUMPER PIN CONNECTION MAX1703 OPERATION POSITION 1 & 2 ON connected to GND The MAX1703 is enabled. 2 & 3 ON connected to VOUT The MAX1703 is disabled. J1 ON is not controlled by Open ON must be driven by a signal connected to the ON pad. the board. CLK/SEL pin connected 1 & 2 Low-power mode, the MAX1703 operates in the PFM mode. to GND CLK/SEL pin connected J2 2 & 3 High-power mode, the MAX1703 operates in the PWM mode. to VOUT CLK/SEL connected to CLK/SEL pin can be driven by an external source to select the power Open CLK/SEL pad mode or a 200kHz to 400kHz signal to control the switching frequency. Shorted FB pin connected to GND VOUT preset to 5V. Output voltage determined by the R4-R5 resistor divider. Note: A J3 FB pin connected to the Open resistor must be installed in R4 to set the output voltage before resistor divider removing the shunt. VOUT connected to Shorted This jumper is necessary for normal circuit operation. pull-up resistors J4 The pull-up resistors are The J4 shunt should only be removed when testing the MAX1703 Open disconnected shutdown current. 2 Evaluates: MAX1703