Hope someone can help.
I have a single stage, single supply 15V, OPA1611 connected in a typical inverting configuration.
The inputs and outputs are ac-coupled through 10 uF caps.
At IN+, there is 1kohm which connects it to the reference circuit which is a 100k/100k voltage divider from 15V. There is a 2 uF decoupling cap.
At IN-, the input resistor R1 is 1kohm which connects to a 10uF coupling cap to the input source,
OUT is connected to a 10uF coupling cap. The feedback resistor R2 is 15k which connects to IN-.
During a DC check, I find that the measured current into this circuit is about 30 mA. I am expecting it to be 4 to 6 mA. IN-, IN+ and OUT are all at about 7.5V. The circuit is otherwise functional in terms of amplification. I see this same behaviour over a few boards and chips.
Q1. Is the excessive current drain due to values chosen for the biasing? Webench seems to recommend much smaller R1 and R2 values.
Q2. For this chip, is a resistive path required between OUT and GND?
Q3. The datasheet's application schematic shows dual supply operation, does anybody have any successful implementation with single supply, inverting amp configuration for this chip?
thanks n rgds.
