OPA2314: About the noise of ADC collection circuit.

user5831375

Part Number: OPA2314
Other Parts Discussed in Thread: TLV2314

Hello ! I use OPA2314 and piezo electric sensor to design a device to collect pause walve signal. The Schematic and noise image is liking the image down. I am wondering the possiable reasons acoouting for the noise.Would please help me. Throug searching the revelated documents.The frequency of pause walve is no more than 30Hz. Thanks for replying.

over 5 years ago

0 kai klaas69 over 5 years ago

Guru 140200 points

Hi,

you should not connect a 100nF directly to the output of OPA2314. This can result in instability and oscillation. See section 7.3.7 of datasheet.

Kai

0 Paul Goedeke over 5 years ago in reply to kai klaas69

TI__Mastermind 30600 points

Hi User,

Kai has provided some valuable feedback - it looks like you've attached a big load to the output of the op-amp which cause instability and oscillation. I recommend taking a look at TI Precision Labs on stability where these issues are discussed: training.ti.com/ti-precision-labs-op-amps

Thanks,
Paul

0 user5831375 over 5 years ago in reply to kai klaas69

Prodigy 90 points

Thanks for replying, so inserting a resistor of 10 ohm of the output can solve the problem?

0 Paul Goedeke over 5 years ago in reply to user5831375

TI__Mastermind 30600 points

An isolation resistor would be a good idea. 10 ohms might do it, but you can confirm in simulation the phase margin and select the value that gives you the performance you desire.