SNVSBW1B December 2021 – October 2023 LM63460-Q1
PRODUCTION DATA
Use a feedforward capacitor, CFF, to improve the phase margin and transient response of converter circuits that have low-ESR output capacitors. Because this capacitor can conduct noise from the output of the circuit directly to the FB node of the IC, connect a 1-kΩ resistor, designated as RFF in Figure 9-1, in series with CFF. If the ESR zero of the output capacitor is below 200 kHz, feedforward network components are not required.
Capacitor CFF has little effect if the output voltage is less than 2.5 V, so it can be omitted. If the output voltage setpoint is greater than 14 V, do not use CFF because it introduces too much gain at higher frequencies. Use the LM63460-Q1 quickstart calculator to review bode plot performance for a given combination of output capacitance and feedforward capacitance.