DEMO MANUAL DC1730A LT3973 42V, 750mA Step-Down Regulator with 2.5A Quiescent Current DESCRIPTION Demonstration circuit 1730A features the LT3973, a mono- overvoltage conditions, the catch diode current is limited lithic step-down switching regulator which consumes only to protect the part. Users can populate R7 and R8 on the 2.5A quiescent current. The demo circuit is designed for EN/UVLO pin to provide a programmable undervoltage a 5V, 750mA output from a 5.6V to 42V input. The wide lockout. In addition, the shutdown feature can be utilized input range of the LT3973 allows a variety of input sources by placing jumper JP1 in the OFF position. including automotive batteries and 24V industrial supplies. The LT3973 data sheet gives a complete description of the In order to reduce the number of components and solution part, operation and application information. The data sheet size, the catch diode and boost diode are integrated. The must be read in conjunction with this quick start guide for switching frequency is adjustable up to 2.2MHz. At light working on or modifying the demo circuit 1730A. loads, the regulator operates in Burst Mode to maintain Design files for this circuit board are available at high efficiency and low output ripple. DEMO MANUAL DC1730A QUICK START PROCEDURE Demonstration circuit 1730A is easy to set up to evalu- NOTE. Make sure that the input voltage does not exceed ate the performance of the LT3973. Refer to Figure 2 for 42V. proper measurement equipment setup and follow the 5. Check for the proper output voltage. procedure below: NOTE. If there is no output, temporarily disconnect the 1. Place Jumper JP1 in the ON position. load to make sure that the load is not set too high or 2. With power off, connect the input power supply to VIN is shorted. and GND. 6. Once the proper output voltages are established, adjust 3. With power off, connect load from VOUT to GND. the loads within the operating range and observe the output voltage regulation, ripple voltage, efficiency and 4. Turn on the power at the input. other parameters. dc1730af 2