OPA170: Schematic review

Shu-Cheng LIN

Guru 11785 points

Part Number: OPA170
Other Parts Discussed in Thread: REF5040, , ADC121C021

Hi Sirs,

Sorry to bother you.

Could you help review our schematic as below? please focus on U1, U2, U3

U1: LTC6652 & REF5040 colay

U2: OPA170

U3: ADC121C021

Any suggestion are welcome

Schematic: 20190923.pdf

over 4 years ago

0 Ron Michallick over 4 years ago

TI__Guru*** 139956 points

Shu-Cheng,

I suggest putting R2 and R3 in series and changing value to 2.5M ohm each. This reduces the voltage drop on the resistors with the same output gain and resistor power. Also change R8 to at least 100 ohms to improve the OPA170 buffer's phase margin from about 20 degrees to about 70 degrees.

0 Shu-Cheng LIN over 4 years ago in reply to Ron Michallick

Guru 11785 points

Hi Sirs,

Thanks for your reply.

May i know how about U1 REF5040 and U3 ADC121C021?

Could you help me to link or i need to post on different place?

Thanks!!

0 Ron Michallick over 4 years ago in reply to Shu-Cheng LIN

TI__Guru*** 139956 points

Shu-cheng,

Those devices look good to me. However, starting new posts with those part numbers will get to the engineers with the most knowledge about those specific devices.

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OPA170: Schematic review