SLVSFS6A May 2021 – September 2021 TPS629210-Q1
The TPS629210-Q1 is internally compensated to be stable with L-C filter combinations corresponding to a corner frequency to be calculated with Equation 17:
The LC output filters inductance and capacitance have to be considered together, creating a double pole, responsible for the corner frequency of the converter. Table 9-3 can be used to simplify the output filter component selection.
Proven nominal values for inductance and ceramic capacitance are given in Table 9-3 and are recommended for use. Different values can work, but care has to be taken on the loop stability which is affected. More information including a detailed LC stability matrix can be found in Optimizing the TPS62130/40/50/60 Output Filter Application Report.
Although the TPS629210-Q1 is stable without the pole and zero being in a particular location, an external feedforward capacitor can also be added to adjust their location based on the specific needs of the application. This can provide better performance in Power Save mode, improved transient response, or both.
A more detailed discussion on the optimization for stability versus transient response can be found in the Optimizing Transient Response of Internally Compensated DC-DC Converters Application Report and Feedforward Capacitor to Improve Stability and Bandwidth of TPS621/821-Family Application Report.