Q: TPS63020: VINA not connected to VIN, any issues? by 16027

We have a board that has a TPS63020. Its VINA and PSSYNC pins were tied together, but not tied to VIN. The data sheet recommends: "To make sure that the internal control circuits are supplied with a stable low noise supply voltage, a capacitor can be connected between VINA and GND. Using a ceramic capacitor with a value of 0.1uF is recommended. The value of this capacitor should not be higher than 0.22uF. If no capacitor is used at VINA, VINA should be connected directly to VIN." However, the block diagram shows an internal connection from VINA to VIN. Thus, it seems this pin is just to place a capacitor to filter the noise. Is this correct? If so, is there a reliability or some other issue of having VINA not connected? 

 

Q: Re: TPS63020: VINA not connected to VIN, any issues? by 1129650

 As stated in the datasheet (pg. 16), "if no capacitor is used at VINA, VINA should be connected directly to VIN."

If you don't use the 0.1uF bypass capacitor on VINA or connect VINA directly to VIN, you will be outside of recommended operating conditions and violating the specifications of the IC.

Please either use the bypass capacitor or connect VINA to VIN.