JAJSAY9L February 2009 – May 2018 LM26420
Additional filtering is required between VINC and AGND in order to prevent high frequency noise on VIN from disturbing the sensitive circuitry connected to VINC. A small RC filter can be used on the VINC pin as shown in Figure 30.
In general, RF is typically between 1 Ω and 10 Ω so that the steady state voltage drop across the resistor due to the VINC bias current does not affect the UVLO level. CF can range from 0.22 µF to 1 µF in X7R or X5R dielectric, where the RC time constant should be at least 2 µs. CF must be placed as close to the device as possiblewith a direct connection from VINC and AGND.