Regarding to the diagram i attached below, when the ISO7741 is unpowered with VCCO, however there is a pull-up resistor connected to OUTx pin of the ISO7741 to external power supply. Is there possibly a leakage path current passed though to the VCCO of the ISO7741? and VCCO will present a voltage?
Hi Brain,
Connecting OUTx pin to external power supply (which is ON) through a pull-up resistor when VCCO = 0V is going to violate the absolute maximum rating of OUTx pin as stated in datasheet, also shown below. Doing so can make VCCO powered-up through the ESD bypass diode. Based on the pull-up resistor value, it is also possible that the device fails to power-up completely as the drop across the pull-up resistor makes VCCO voltage drop. This can keep happening and device might keep switching between power-up and power-down modes.
Is there any particular reason why customer doesn't want to connect the external pull-up resistor to VCCO? It will also be a problem if VCCO and VCC2 are at different voltages. Thanks.
Regards,
Koteshwar Rao
