Hi Edward,
Can the outputs of this op amp be tied to GND if unused?
This is not a good practice. Tie an op amp's output to GND is considered short circuit, since the node is low impedance and it is capable to source or sink in current.
Here is the recommended way to configured unused op amps.
1. The unused op amp should be placed in a linear mode, if the op amp is powered and unused.
2. If the above condition is established, then output has a feedback and tied to inverting input, which means the output is equal to the non-inverting input. If non-inverting input is tied to GND in this case, Vout's voltage should be close to GND (but not at GND). The Vout node may have offset voltage (Vos = uV to mV ) present or Ib mismatching at the input. In this scenario, it will be better off to leave the output node "open" or connect a 10kohm or similar load to GND, see the image below.
https://e2e.ti.com/blogs_/archives/b/thesignal/posts/the-unused-op-amp-what-to-do
https://www.ti.com/lit/ab/sboa204a/sboa204a.pdf?ts=1748390430267
If you have other questions, please let me know.
Best,
Raymond
Hi Edward,
What would happen if both inputs of the op amp and the output were tied to GND?
An op amp is operating in a nonlinear mode, similar to comparator. The output will be either up to Vcc or Vee, Chances are the Vout will go up to Vcc and it is in a saturation state. And you do not want to tie the Vout to GND under the scenario.
Best,
Raymond
