TPS7H1121 may use of a combination of tantalum and ceramic capacitors to achieve good volume to capacitance ratio. Table 9-2 highlights some of the supported capacitors. TI recommends to follow proper derating guidelines as recommended by the capacitor manufacturer based upon output voltage and operating temperature.

TI recommends to use a polymer or tantalum capacitor along with a 0.1µF and 1μF ceramic capacitors implemented as bypass capacitors. The device is stable for input and output tantalum, polymer or ceramic X7R capacitor values or networks with bulk capacitance’s ranging from 6.8µF to 880µF (some values within this range may require the use of external compensation). However, the dynamic performance of the device varies based on load conditions, the capacitor values used (including ESR) and utilization of the external compensation STAB pin. Bulk output capacitance less than 22µF and capacitance exceeding 220µF, should generally use an external compensation network applied to the STAB pin to achieve robust stability margins. Thorough stability analysis should always be performed to ensure that requisite stability margins are attained across the entirety of the mission profile.

Bulk output capacitor ESR is significantly affects system stability; the TPS7H1121 was designed to achieve wide gain and phase margins with tantalum or polymer surface mount capacitors with low ESR. Ceramic capacitors are also supported, however ceramic capacitors have lower output capacitance and ESR such that an external compensation network may be necessary to achieve stability targets.