The TPS5516x-Q1 family of devices integrates not only the power switches but also the loop compensation network as well as many other control circuits which reduces the number of required external components. For the internal loop compensation to be effective, the selection of the external power circuits (power inductor and capacitor) must be confined. TI strongly recommends users selecting the component values as follows: 3.3-μH to 6.2-μH power inductor, 18-μF to 47-μF output capacitor, and 8.2-μF or greater input capacitor. Because the TPS5516x-Q1 device switches at about 2 MHz, a shielded inductor and X5R-type or X7R-type ceramic capacitors should be used for the power circuit.

Considering the component tolerance, the following power component values were selected for this design example:

• C_IN = 20 μF
• C_OUT = 22 μF
• L = 4.7 μH

For the input capacitor (C_IN), the voltage rating should be greater than the maximum input voltage (V_{IN_MAX}). Therefore, two, 10-μF X7R capacitors rated for 50 V were selected for this design example. Adding a small, high-frequency decoupling ceramic capacitor (C_VINP with a value of 100 nF typical) in parallel with the input capacitor is recommended to better filter out the switching noises at the VINP pin. Adding another decoupling ceramic capacitor (C_VINL with a value of 470 nF typical) is also recommended for the VINL pin.

The output capacitor (C_OUT), receives a voltage of 5 V. Considering some voltage-rating margin, two 10-μF X7R capacitors rater for 10 V or greater and one, 2.2-μF X7R-type capacitor rated for 10 V or greater in parallel were selected for the output capacitor. Adding a small, high-frequency decoupling ceramic capacitor (C_VOSN with a value of 100 nF typical) in parallel with the output capacitor is recommended to better filter out the switching noises at the VOUT_SENSE pin.

The power inductor (L) should be a shielded type, and it should not saturate during operation. The inductor should also be able to support the power dissipation under the maximum load. Use the calculations in the following sections to find the required current capabilities for the inductor.