Other Parts Discussed in Thread: SA5532,
Hi,
Good Day. what is the input impedance of TL072IDR and SA5532DR?
Please advise. Thank you very much.
Best Regards,
Ray Vincent
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Hi Ray,
the input impedances can be found in the datasheets. Look for "ZID" and "ZICM" (TL072) and "ri" (SA5532).
I think "ri" is the diffential input resistance which should be way lower than the common mode input resistance because of the internal input protection diodes across the inputs. But because of the very high input bias currents of up to 1000nA, the SA5532 is designed to be used in rather low ohmic circuits anyway. Only then the circuit benefits form the very low noise of SA5532.
The TL072 is a FET OPAmp with ultra high input impedances while the SA5532 is a bipolar OPAmp with way smaller input impedances.
Kai