SNVU767A March 2022 – January 2024
Once the above connections are made and the appropriate jumpers are set, the EVM is ready to use.
The EVM is configured for a 5-V output, when used with the devices so noted in Table 1-1. The output voltage can be changed by changing the values of resistors R2 (RFBT) and/or R3 (RFBB). Depending on the output capacitors and the desired loop performance, a feed-forward capacitor, C5 (CFF) can be desirable. A space is available on the EVM for this optional component.
When using the devices in Table 1-1 listed as fixed, the output voltage is set by the device. In this case, RFBT (R2) must be populated with a zero Ohm resistor, and RFBB (R3) must be open.
The mode of operation is determined by the setting of the MODE jumper and the particular device option.
See the LM63635 and LM63635C data sheets for more information.
The RESET flag is used to indicate when the output voltage is within +/- 5 % of the regulated value. This EVM is configured with a 100 kΩ pull-up resistor from RESET to VCC (about 5V). A low on RESET indicates the output voltage is out of regulation. The pull-up resistor can be removed and the open-drain RESET pin can be used to control a system processor from the EVM. Be sure to limit the voltage on the RESET to less than the specified Abs max for this pin.
Some components in the EMI filter are not populated. The user is free to experiment with different EMI filter components as desired.
Loop gain measurements (Bode plots) can be made using the setup shown in Figure 1-4.
The EVM has been designed for maximum flexibility regarding component selection. This allows the user to place preferred components such as the inductor, the capacitors, or both, on the board and test the performance of the regulator. This way the power supply system can be tested before committing the design to production.