DEMO MANUAL DC2221A LTC3807EFE Low Quiescent Current, High Voltage Step-Down Converter Description Demonstration circuit 2221A is a low quiescent current, The 40V rated MOSFETs, which are used on DC2221A, can synchronous buck converter featuring the LTC 3807EFE. be operated at their rated voltage. MOSFETs with higher This demo board converts a 16V to 38V input voltage to voltage rating can be used for more safety margin. a 12V at 15A output. The DC2221A supports the LFPAK, PowerPAK SO-8 and The main features of this board include an internal LDO Power 56 MOSFET packages. The following logic level for gate drive power from V or EXTV , RUN and (SV gate) MOSFETs can be used with DC2221A. IN CC PGOOD pins, a mode selector that allows the converter RJK0451DPB Renesas to run in constant current mode (CCM), pulse-skipping BSC093N04LS G Infineon or Burst Mode operation, and selectable current limit. Si4124DY Vishay The DC2221A supports an adjustable output voltage, FDS8447 Fairchild soft-start and tracking. The wide input voltage range of 16V to 38V is suitable for automotive and distributed DC For synchronization to an external clock, remove jumper power systems where low quiescent current is important. JP2 and apply sync signal on terminal SYNC. The LTC3807 data sheet gives a complete description of Design files for this circuit board are available at this part, operation and application information. The data GND VIN DEMO MANUAL DC2221A Quick s Dp Demonstration circuit DC2221A is easy to set up to evalu- 2. With power off, connect the input power supply to V IN ate the performance of the LTC3807EFE. Refer to Figure 1 and GND. for proper measurement equipment setup and follow the 3. Turn on the power at the input. Check for the proper procedure below: output voltage: NOTE. When measuring the input or output voltage ripple, V = 11.9V to 12.4V OUT care must be taken to avoid a long ground lead on the NOTE. If there is no output, temporarily disconnect the oscilloscope probe. Measure the input or output voltage load to make sure that the load is not set too high. ripple by touching the probe tip directly across the V IN or V and GND terminals or directly across relevant OUT 4. Once the proper output voltages are established, adjust capacitor. See Figure 2 for proper scope probe technique. the load within the operating range and observe the output voltage regulation, ripple voltage, efficiency and 1. Place jumper JP1 in the ON position. other parameters. I I IN OUT + + V SUPPLY LOAD IN Figure 1. Proper Measurement Equipment Setup + C OUT V GND OUT Figure 2. Measuring Input or Output Ripple Across Terminals or Directly Across Bulk Capacitor dc2221af 2 ure roce tart