DC1523A Analog Devices

DEMO MANUAL DC1523A LTC3789EGN: High Efficiency Synchronous 4-Switch Step-Up/Step-Down DC/DC Converter DESCRIPTION Demonstration circuit 1523A features the LTC 3789EGN, smooth transfer function through all operating modes a high efficiency switching step-up/down controller. The makes the product ideal for automotive, telecom and DC1523A input range is from 5V to 36V. The output volt- battery systems. age is 12V. The board is capable of delivering up to 5A of The MODE/PLLIN pin can select between pulse skipping output current over the input voltage range. mode and forced continuous mode operation and allows The LTC3789EGN is a high performance switching regula- the IC to be synchronized to an external clock. A Power tor controller designed to regulate the output using input Good output pin indicates when the output is within 7.5% voltages above, below or equal to the output voltage. of its set point. Synchronous operation provides very high efficiency, up Design files for this circuit board are available at to 97%. Constant frequency current mode architecture DEMO MANUAL DC1523A QUICK START PROCEDURE Demonstration circuit 1523A is easy to set up to evalu- 4. Turn on the power at the input. Increase V to between IN ate the performance of the LTC3789EGN. Please refer to 5V and 36V. The circuit will start and the output voltage Figure 1 for proper measurement equipment setup and will regulate at 12V 2%. The current draw at no load follow the procedure below. is 20mA to 60mA depending on the input voltage. 1. With power off, connect the input supply, load and 5. Apply load and observe output voltage regulation, ripple meters as shown in Figure 1. Preset the load to 0A and voltage, efficiency and other parameters. Efficiency and VIN supply to 0V. power loss at full load is shown in Figure 3. Continuous operation with full power and low input voltage may 2. Set the current limit of the input supply high enough require some airflow. so that the bench supply does not go into current limit mode. Figure 2 shows input current as a function of input voltage, at full load. Input current can reach 13A at 5V input voltage. 3. Place jumpers in the following positions: JP1 JP2 RUN MODE ON CCM + A POWER V LOAD SUPPLY DC1523A F01 Figure 1. Proper Measurement Equipment Setup dc1523af 2 V + A