Category: Hardware
Product Number: AD8221
In my circuit, the AD8221 is used to measure external voltage sources. For this purpose, I have routed the inputs of the AD8221 (IN+, IN-) to the outside via a connector on the circuit board and then amplified the corresponding voltages with the AD8821 via a connector so that I can measure them with the ADC behind it.
The AD8221 is supplied with +-15V.
When the system is switched on everything works as expected, the problem occurs as soon as the supply voltage is switched off and the voltage source is still connected to the output, a current consumption of approx. 5mA occurs.
What exactly is the cause of this? Is it the protective diodes in the input that become conductive when the supply voltage is removed?
And how can I solve the problem?
