Input impedance of OPA360

Jaden Ghylin102047

Expert 1140 points

Other Parts Discussed in Thread: OPA360, LMH730216, TINA-TI

What isthe input impedance of OPA360 and also LMH730216 ?

Regards,

-Jaden

over 10 years ago

0 Jeffery Pfarr over 10 years ago

TI__Genius 14317 points

Jaden,

LMH730216 is an EV Module PN. What is the OA Part No.?

0 Jaden Ghylin102047 over 10 years ago in reply to Jeffery Pfarr

Expert 1140 points

Whoops. LMH6704 is the part #.

-Jaden

0 Jeffery Pfarr over 10 years ago in reply to Jaden Ghylin102047

TI__Genius 14317 points

Jaden,

TINA-TI had a model for the OPA360, so I ran an AC Analysis transfer function for Iin/ Vin (see attached screenshot) then inverted to get Vin/Iin = Zin. At 10 Hz, Zin is around 562 M ohm and at 10 MHz, Zin is around 1k ohms. I think this looks about right but is model dependent.

The LMH 6704 does not have a TINA-TI model but the input is specified to be 1 M ohm in parallel with 1 pF typical so this covers the gain of +1 and +2 cases. For the gain of -1 case, the input impedance is just the input resistor value of 465 ohms (likely with 1 pF cap to GND).

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Input impedance of OPA360