I am using the AD8607, and occasionally there is a 6mA current fllowing into the input pins. Is this going to pose a problem? I can’t find any information on the maximum input current limit on the data sheet.
For our older data sheets that do not have any information on max input current (in this case, AD8607), the conservative rule of thumb is to assume that the max value is 5mA. For newer products, the max input current allowed into the input pin is shown in the absolute maximum ratings table. For instance, ADA4665-2 has 10mA as max input current in the abs max ratings table.
To limit current flowing into the input pin of the amplifer, place a series resistor at the input pins. However, under normal operating conditions, the series resistor introduces some disadvantages. The series resistor adds on thermal noise to the circuit. Also, bias current flowing through the resistor causes a voltage drop at the input that will be amplified by the noise gain to the output.
Bottomline is, always make sure that the input current to your amplifier is limited.