We are using the TPS259260 to switch isolated 12V to a DC-DC converter. An opto-isolator (TLP2745) is used allow the logic level controller to switch the 12V to the EN/UVLO pin to turn the TPS259260 on. The detail from the data sheet on the max 7V input voltage for the EN pin had been missed. This design has been in production for some time and we have not had a problem with it, but we want to correct the design to be in line with the data sheet.
The data sheet talks about limiting the current into the pin to be less than 20uA and that a 1M resistor is required to do this. But it is not clear to us how it does this. The part block diagram shows this pin inputting into a comparator would seem to indicate a high input impedance.
Would putting the 1M resistor in series with the 12V control signal be sufficient? How does this affect the TPS259260 turn off when the 12V control signal is switched to ground?
Thanks,
Dave
