output impedance of LMV342

Hiroshi Sato

Other Parts Discussed in Thread: LMV342, TLV342

Our customer trying to design an sensing circuit with LMV342 as below.

They want to know the output impedance of this circuit and LMV342 itself.

I think the the output impedance of this circuit is 100Ohm, but I can't find the output impedance of LMV342 in the datasheet.

Please let me know whether my understanding is correct or not and the output impedance of LMV342.

Thanks and best regards,

over 13 years ago

0 Neil Albaugh over 13 years ago

Genius 5430 points

Hiroshi-san;

There seems to be no output impedance specification in its data sheet and TI does not provide a SPICE or TINA model for this device. There fore the output impedance of your circuit is not determined-- but for sure it is not 100 ohms, due to the action of the negative feedback C1 R2.

0 Ron Michallick over 13 years ago

TI__Guru**** 157236 points

Hiroshi,

The open loop output impedance of the (TI) LMV342 is about 500 ohms (per TLV342 model).
However the output impedance of the whole circuit will be less.

The TLV342 model at http://www.ti.com/adc/docs/midlevel.tsp?contentId=55102 can also be used for the LMV342.
TI-Tina is available at no cost.

Regards,
Ron Michallick

0 Hiroshi Sato over 13 years ago in reply to Neil Albaugh

Expert 2590 points

Hello Neil-san,

Thank you for your comment, I'll tell the customer that.

0 Hiroshi Sato over 13 years ago in reply to Ron Michallick

Expert 2590 points

Hello Ron-san,

Thank you for your information, it is very useful. The customer recognize that circuit is not good, and trying to simulate with TLV342 model.

Thanks and best regards,

Hiroshi Sato

Amplifiers

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output impedance of LMV342