QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 412 LOW INPUT VOLTAGE, HIGH CURRENT BUCK CONTROLLER LTC3713 DESCRIPTION Demonstration Circuit 412 is a synchronous step-down the design for symmetric current limit. Please refer to TM regulator using the LTC3713 No R switching the Applications Requiring Symmetric Current Limit SENSE regulator controller. It can operate at low input voltage section in the LTC3713 data sheet for details. down to 1.7V and supply up to 10A of output current. Table 1. Performance Summary Higher current can be obtained by changing external components. DC412 provides a low input buck regulator PARAMETER CONDITION VALUE to supply lower voltages for microprocessors, DSPs, Input Voltage Range 1.7V to 6V and bus termination applications. An onboard boost Maximum Output V = 1.7V to 6V 10A IN converter generates the gate-drive voltage for the exter- Current nal power MOSFETs and allows the use of standard 5V Outputs* 0 to 10A 1.25V 3% logic-level N-Channel MOSFETs. Design files for this Typical Output Ripple 10MHz BW 10A Load V = 3.3V 15mV circuit board are available. Call the LTC factory. IN P-P Typical Load Regulation I = 0A to 10A V = 3.3V -10mV OUT IN JP1 sets the operation mode. The lower position selects Forced Continuous synchronous operation, which mini-Efficiency V = 3.3V, V = 1.25V, 83% IN OUT I = 10A OUT mizes noise and RF interference, and also allows the output to sink current for applications like bus termina- *Higher output current can be achieved by using higher current rating inductor and adding parallel MOSFETs (M3, M4). tors. RSNS1, RSNS2, R7, R8 and D1 help in modifiying QUICK START PROCEDURE Refer to Figure 1 for proper measurement equipment 3. Shunt JP2 and JP4 for operation. V goes to 0V OUT setup and follow the procedure below: with either JP2 or JP4 open. If JP3 is connected, overcurrent latchoff is disabled. Refer to the Applica- 1. Connect the input power supply to the VIN and GND tions Information section in the LTC3713 data sheet terminals. for details. NOTE: Do not increase V over 6V (If higher input IN 4. Set the FCB Jumper JP1 to the lower position to force voltage is desired, use higher voltage rating input continuous synchronous operation at light loads or capacitors. If the input voltage is always higher than to the upper position to enable discontinuous mode 4V, you probably want to consider using demo circuit operation at light loads. DC378, which features the LTC1778.) 5. When measuring the output ripple, see Figure 2 for 2. Connect the desired load between the VOUT and GND the proper technique using the scope probe. terminals. Soldered wires should be used to achieve optimum performance. 1 GND VIN QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 412 LOW INPUT VOLTAGE, HIGH CURRENT BUCK CONTROLLER + + + OVERCURRENT LATCHOFF DISABLE DISCONTINUOUS + CONTINUOUS + ENABLE LOAD ENABLE VIN2 Figure 1. Proper Measurement Equipment Setup Figure 2. Scope Probe Placement for Measuring Output Ripple 2 +