DEMO MANUAL DC2434A LTC3864 60V Low IQ Step-Down DC/DC Converter with 100% Duty Cycle Capability Description Demonstration circuit 2434A is a high voltage, current- loads can be enabled with a jumper. A power good output mode DC/DC step-down converter featuring the LTC 3864. signal is provided. The board operates from an input range of 6V to 60V and This board is suitable for a wide range of automotive, provides a 12V, 5A output when the input exceeds 12V. telecom, industrial and other applications. The LTC3864 The PMOSFET architecture allows it to operate seamlessly is available in small 12-pin thermally enhanced MSOP and up to 100% duty cycle and function as a saturated switch DFN packages. For other output requirements, see the below the regulation threshold, down to 6V . It operates LTC3864 data sheet or contact the LTC factory. IN at 200kHz and may be synchronized to an external clock. Design files for this circuit board are available at A soft-start feature controls output voltage slew rate at DEMO MANUAL DC2434A Quick s tart p D Demonstration circuit 2434 is easy to set up to evaluate 3. Turn on the power at the input. the performance of the LTC3864. Refer to Figure 1 for NOTE. Make sure that the input voltage never exceeds 60V. proper measurement equipment setup and follow the 4. Check for the proper output voltage of 12V. Turn off procedure below: the power at the input. NOTE. When measuring the output voltage ripple, care must 5. Once the proper output voltage is established, connect a be taken to avoid a long ground lead on the oscilloscope variable load capable of sinking 5A at 12V to the output probe. Measure the output voltage ripple by touching the terminals +V and GND. Set the current for 0A. probe tip and ground ring directly across the last output OUT capacitor as shown in Figure 1. a. If efficiency measurements are desired, an ammeter or a resistor shunt that is capable of handling 5A 1. Set an input power supply that is capable of 6V to 60V DC can be put in series with the output load in order to to 13V. Then turn off the supply. measure the DC2434As output current. 2. With power off, connect the supply to the input terminals b. A voltmeter with a capability of measuring at least +V and GND. IN 12V can be placed across the output terminals in a. Input voltages lower than 6V can keep the converter order to get an accurate output voltage measurement. from turning on due to the undervoltage lockout 6. Turn on the power at the input. feature of the LTC3864. 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 5A or a resistor shunt can DC be put in series with the input supply in order to 7. Once the proper output voltage is again established, measure the DC2434As input current. adjust the load and/or input within the operating range and observe the output voltage regulation, ripple volt- c. A voltmeter with a capability of measuring at least age, efficiency and other desired parameters. 60V can be placed across the input terminals in order to get an accurate input voltage measurement. LOAD V V V IN IN OUT + + I I IN OUT + + + DC2434 F01 Figure 1. Proper Measurement Equipment Setup dc2434af 2 + ure roce