QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 616 4MHZ, POLYPHASE HIGH EFFICIENCY SYNCHRONOUS BOOST CONVERTER LTC3425EUH DESCRIPTION Demonstration Circuit 616 is a synchronous, 4-phase Long wires run from input sources (such as wall adap- boost converter using the LTC3425. It is capable of op- tors) can cause large voltage spikes during initial plug- erating below 1V input. DC616A is set for 3.3V output. in. C5 and C15 are installed on DC616 to damp the pos- DC616B is set for 5V output. On each demo board, the sible voltage spikes. They are not required for applica- left circuit gives higher efficiency and current rating tions where input source is close to the regulator. while the right circuit has smaller size and lower cost. Please refer to Application Note 88 for details. The switching frequency is set at 1MHz per phase, Design files for this circuit board are available. Call minimizing inductor and capacitor size. A single resistor the LTC factory. at RT pin sets the frequency. If desired, the LTC3425 can be synchronized to an external clock. Table 1. DC616A Performance Summary (T = 25C unless otherwise noted) A PARAMETER CONDITION VALUE Minimum Input Voltage (Start-Up) 1V Output Voltage V (High Efficiency Circuit) V = 2V to 3V, I = 0A to 2.25A 3.3V 4% OUT1 IN OUT1 Output Voltage V (Low Cost Circuit) V = 2V to 3V, I = 0A to 1.8A 3.3V 4% OUT2 IN OUT2 Maximum Output Current (High Efficiency Circuit) V = 2V to 3V 2.25A IN Maximum Output Current (Low Cost Circuit) V = 2V to 3V 1.8A IN Typical Output Ripple V V = 2.4V, I = 1.8A (20MHz BW) 28mV OUT IN OUT PP Typical Switching Frequency (each phase) 1MHz V = 2.4V, I = 0.5A 93.0% Typical IN OUT1 Efficiency (High Efficiency Circuit) V = 2.4V, I = 2A 88.6% Typical IN OUT1 Logic Low Voltage-Off, -40C to 85C 0.25V MAX On/Off Control Logic High Voltage-On (Initial Start-Up), -40C to 85C 1V MIN Logic High Voltage-On (V >2.4V), -40C to 85C 0.65V MIN OUT 1 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 616 4MHZ, POLYPHASE HIGH EFFICIENCY SYNCHRONOUS BOOST CONVERTER Demo Circuit 616A = 3.3Vout 2.25A or 1.8A Demo Circuit 616B = 5Vout 2.0A or 1.5A 2