DEMO MANUAL DC2015A LT8310/LT8311 48V to 12V/12A IN Forward Converter with Synchronous Rectification DESCRIPTION Demonstration circuit 2015A is a resonant reset forward The DC2015A takes advantage of the LT8310s input converter with synchronous rectification featuring the undervoltage and overvoltage protection to shutdown the LT 8310/LT8311 chipset. system when the input voltage is outside of the set limits. The DC2015A also has precise overcurrent protection This circuit was designed to demonstrate the high levels of that allows for continuous operation under short-circuit performance, efficiency, and small solution size attainable conditions. The low power dissipation under a short-circuit using these parts. It operates at 240kHz and produces a condition insures high reliability even during a prolonged regulated 12V, 12A output from an input voltage range output voltage short-circuit. of 36V to 72V: suitable for telecom, industrial, and other applications. It has an eighth-brick footprint area. Synchro- The LT8310/LT8311 data sheets give a complete descrip- nous rectification helps to attain efficiency exceeding 94%. tion of the parts, operation and application information. The data sheets must be read in conjunction with this The DC2015A circuit features soft-start which prevents quick start guide for demo circuit 2015A. output voltage overshoot on startup or when recovering from overload condition. Design files for this circuit board are available at DEMO MANUAL DC2015A QUICK START PROCEDURE Demonstration circuit 2015A is easy to set up to evaluate 4. Turn on the power at the input. the performance of the LT8310/LT8311. Refer to Figure1 Note. Make sure that the input voltage does not ex- for proper measurement equipment setup and follow the ceed100V. procedure below: 5. Check for the proper output voltage of 12V. Turn off NOTE. When measuring the output voltage ripple, care must the power at the input. be taken to avoid a long ground lead on the oscilloscope 6. Once the proper output voltages are established, con- probe. Measure the output voltage ripple by touching the nect a variable load capable of sinking 12A at 12V to probe tip and ground ring directly across the last output the output terminals +V and V . Set the current capacitor as shown in Figure 2. OUT OUT for 0A. 1. Set an input power supply that is capable of 36V to a. If efficiency measurements are desired, an ammeter 72V. Then turn off the supply. or a resistor shunt that is capable of handling 12ADC 2. Direct an airflow of 200LFM across the unit for sustained can be put in series with the output load in order to operation at full load. measure the DC2015As output current. 3. With power off, connect the supply to the input terminals b. A voltmeter with a capability of measuring at least 12V +V and V . IN IN can be placed across the output terminals in order a. Input voltages lower than 36V can keep the converter to get an accurate output voltage measurement. from turning on due to the undervoltage lockout 7. Turn on the power at the input. feature of the LT8310/LT8311. Note. If there is no output, temporarily disconnect the b. If efficiency measurements are desired, an ammeter load to make sure that the load is not set too high. capable of measuring 10ADC can be put in series with 8. Once the proper output voltage is again established, the input supply in order to measure the DC2015As adjust the load within the operating range and observe input current. the output voltage regulation, ripple voltage, efficiency c. A voltmeter with a capability of measuring at least and other desired parameters. 72V can be placed across the input terminals in order to get an accurate input voltage measurement. dc2015af 2