OPA4342: OPA4342EA/250 hardware review

Hi Manjunath,

Sorry about the delayed response. The above circuit looks good. Is the purpose of R9 and R10 to create a simple voltage division? If so, please note that for an input signal of 3.3V, the actual input to the non-inverting input of the op-amp is about 1.9V. OPA4342 is a rail-to-rail input and output amplifier. This is accomplished by using a N-channel differential pair in parallel with P-channel differential pair at the input. The switch from N-channel to P-channel happens in the transition region at about 1.3V below Vcc. During this transition there may be small discontinuity in operation. One way to avoid this is to use an inverting buffer circuit similar to Figure 3 of the datasheet: www.ti.com/.../opa2342.pdf. You can pick the same resistor values to create a buffer circuit.

Finally, in your application if you are at a risk of going 0.3V or more below ground, I would recommend placing a schottky diode at the input to ground because a negative input voltage of greater than 0.3V will lock up the op-amp in an inoperative state. You can read more about this in the "Applications Information" section of the datasheet.

Best Regards,
Bala Ravi