TPS7A7002: Output Discharge

Hi BJ,

I originally posted the following comments on another post but the same comments should apply for your case as well.

The resistors you currently have in the circuit are good according to the recommendation on the datasheet. The main reason for the residue voltage on the Vout when device is disabled is due to the fact that this device has no active pull down circuit. We would recommend using TPS7A92 with active pull down circuit if the residue voltage is a concern for the application.

There are multiple reason that could cause the residue voltage on the Vout even when device has been disabled by pulling down Enable. One more reason is due to the leakage from the internal pass device. Even when the pass FET device has been shut off, there is still leakage from the device that could pull Vout up with the small leakage being built up on the resistor divider. Other reason could be related with external circuitry that has shared the Vout pin; when you have other devices connected to the Vout pin, it could have leakage as well. With the resistors you have in the schematic, with 200K OHms resistance existed on the Vout, a 5-uA leakage could bring Vout to somewhere close to 1V. Since I have noticed several forum posts reporting similar concern over the residue voltage, I am setting up an bench to run some evaluation to see how big the leakage could be. I have studied the TPS7A7002 EVM on bench and with the resistors on the EVM which is 30KOhms, I am seeing little residue voltage. That's why I am suggesting you to reduce the resistance to ground, you could do this by reducing the resistor divider value or apply additional load that will be a load in parallel with the current. If you add another 1K Ohms resistor, the vout residue will be negligible. Please try it and let us know.

Regards,
Jason Song