Is this a good design for having 2 power inputs for a PCB?

Question

I’m designing a PCB powered by a 3-cell LiPo battery. The battery provides +12V, which is stepped down to +5V using a buck converter. From there, the +5V is further stepped down to +3.3V using an LDO regulator. Both +5V and +3.3V are needed in the design, which is why I step the voltage down in this manner.

To simplify powering the circuit for programming the MCU, I’d also like to allow the circuit to be powered via USB (Type-C) without relying on the battery. I decided to use the TPS2121 power switch to manage the input power, so I can connect either the battery or the USB. Since both inputs are +5V, I followed the example schematic provided in section 10.5 Highest Voltage Operation (VCOMP) of the TPS2121 datasheet. This configuration is suitable since the current output matches my requirement (0.5A).

My Questions:

1) Hotplugging and Voltage Spikes:

If the TPS2121’s inputs are powered by the +5V from the buck converter and +5V from the USB Type-C, do I need to place a TVS diode at the input of the power switch for protection against voltage spikes during hotplugging(10.7 Hotplugging with TPS212x)? Considering that the PCB traces for the buck converter are short, and the USB cable length is under 1 meter, is there still a possibility of significant voltage spikes when hotplugging the USB?

2) Capacitor ESR:

Under section 11 Power Supply Recommendations of the datasheet, it mentions using low ESR ceramic capacitors with X5R or X7R dielectrics. What qualifies as "low ESR" in this case? Are all ceramic capacitors sufficient for this purpose, or are there specific ESR values I should aim for?

3) Schematic and Output Capacitor:

Did I correctly follow the recommended schematic? The datasheet schematic shows only one OUT pin, but based on the layout provided, I assumed the two OUT pins need to be connected together. Is this correct? Regarding the note about the system load (0.5A, 100µF) in the example, does this mean I should place a 100µF ceramic capacitor at the OUT pins to stabilize the output?

The schematic from the datasheet:

My schematic of the TPS2121:

The whole power schematic:

Answer 1

1. Yes the datasheet explicitly warns about spikes when hotplugging like USB. Even one meter and shorter cables have inductance. It is best to put protection than to damage the device.

2. There is no separate mention of ESR value, the intention is to say use low ESR ceramics and X5R and X7R capacitors are examples of low ERS capacitors.

3. Yes the packages have more than one IN pin and OUT pin and pins with same name must be connected together. The 100uF is just an example of input capacitance of next system load. With USB as source, you have a hard limit of 10uF directly on USB connector side. This mux has adjustable slew limits so it may tolerate more capacitanve than 10uF total on input and output, if it soft switches the USB to system capacitance. I would not put 100uF load after the mux unless it is guaranteed that it does not exceed surge limits of USB specs.