DC1668B-A Analog Devices

DEMO MANUAL DC1668B-A LTM4627EV High Efficiency PolyPhase Step-Down Power Supply Description Demonstration circuit 1668B-A is a PolyPhase power sup- LTC6902 clock generator. The external clock interleaves ply featuring two LTM 4627 high efficiency synchronous the paralleled phases to minimize input and output ripple. buck Module regulators. The DC1668B-A input voltage DC1668B-A demonstrates that paralleling LTM4627 mod- range is between 4.5V to 20V with a jumper programmable ules is easy and reliable. These features and the availability output voltage from 0.6V to 3.3V. The demo circuit can of the LTM4627 in a compact thermally enhanced 15mm deliver up to 30A of load with excellent current-sharing. 15mm 4.32mm LGA package make the circuit ideal for Current derating may be necessary under certain operat- use in high density point of load regulation applications. ing conditions. Design files for this circuit board are available at The LTM4627 can be synchronized to an external clock be- DEMO MANUAL DC1688B-A Quick s p D Demonstration circuit 1668B-A is an easy way to evaluate 4. Vary the input voltage from 5V to 20V and adjust the the performance of paralleled LTM4627 modules. Please load current from 0A to 30A. V should remain OUT refer to Figure 2 for proper measurement equipment setup regulated at 1.8V 2%. Observe the load regulation, and follow the procedure below: output voltage ripple, efficiency and other parameters. Output voltage ripple should be measured at J6 with 1. With power off, connect the input power supply, load, a BNC cable and oscilloscope. The probe channel for meters, and V BNC cable as shown in Figure 2. OUT V should be set at 50 termination resistance to OUT Preset the load to 0A and V supply to be 0V. Place IN match the BNC cable. jumpers in the following positions for a typical 1.8V OUT application: 5. For optional load transient testing apply an adjustable positive pulse signal between IOSTEP CLK and GND JP2 JP7 JP6 pins. The pulse amplitude sets the load step current V Select RUN TRACK/SS OUT amplitude. The pulse width should be short (< 1ms) 1.8V OFF SOFT-START and pulse duty cycle should be low (< 15%) to limit the 2. Turn on the power at the input. Increase V to 12V thermal stress on the load transient circuit. The load IN (Do not hot-plug the input supply or apply more than step current can be monitored with a BNC connected the rated maximum voltage of 20V to the board or the to J5 (5mV/A). modules may be damaged). 3. Set the run pin jumper (JP7) to the ON position. The output voltage should be regulated. The output voltage meter should read 1.8V 2% (1.76V to 1.84V). dc1668baf 2 ure roce tart