DC1764A Analog Devices

DEMO MANUAL DC1764A LTC3122EDE High Efficiency 15V 2.5A Synchronous Step-Up Converter DESCRIPTION Demonstration circuit 1764A is a 5.5V input, 12V output Included on the board are jumpers for ON/OFF and oper- at 800mA DC/DC power supply featuring the LTC 3122. ating MODE, PWM or BURST. Terminals are included for The IC includes internal high and low side 2.5A switches connecting V and V as well as ON/OFF and SYNC. IN OUT and features selectable PWM or Burst Mode operation The LTC3122 data sheet gives a complete description of the for high efficiency at low output current. The board oper- IC operation and application information. The data sheet ates from an input voltage as low as 1.8V and continues must be read in conjunction with this quick start guide. to operate down to 500mV once started. The output is Design files for this circuit board are available at fixed at 12V although other voltages between 2.2V and DEMO MANUAL DC1764A QUICK START PROCEDURE This Demonstration circuit 1764A can be evaluated using 4. Connect a suitable load resistor or active load to the the setup shown in Figure 1. output terminals and verify that it meets specifications in the Performance Summary table. 1. Connect voltmeters to V and V , select upper posi- IN OUT tions for jumper JP1 (ON) and JP2 (PWM). 5. Use a scope to monitor the output voltage ripple in both PWM mode and Burst Mode operation by moving 2. With input power supply set for 0V, connect the supply the mode jumper JP2 to the appropriate position. See to V and GND terminals. IN Figure4 for correct method for evaluating output ripple. 3. Slowly increase the input power supply to 1.8V. Observe 6. Note: If jumper JP2 is set for Burst Mode operation, output voltage and verify that it meets the specifications maximum output current is limited to approximately in the Performance Summary table. 100mA at 5V . IN 6V, 3A - - Adjustable A V Load Power Supply V + A + Figure 1. Proper Measurement Equipment Setup dc1764af 2