The devices of the TPS6213x family are internally compensated to be stable with L-C filter combinations corresponding to a corner frequency to be calculated with Equation 13:

Equation 13.

Proven nominal values for inductance and ceramic capacitance are given in Table 10-1 and are recommended for use. Different values may 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 SLVA463.

The TPS62135x devices include an internal 15 pF feedforward capacitor, connected between the VOS and FB pins. This capacitor impacts the frequency behavior and sets a pole and zero in the control loop with the resistors of the feedback divider, per equation Equation 14 and Equation 15:

Equation 14.

Equation 15.

Though the TPS62135x devices are stable without the pole and zero being in a particular location, adjusting their location to the specific needs of the application can provide better performance in Power Save mode and/or improved transient response. An external feedforward capacitor can also be added. A more detailed discussion on the optimization for stability versus transient response can be found in SLVA289 and SLVA466.