Hi,
I would like to perform an output lightning protection performance test on an unpowered circuit composed of an OPA197 followed by passive components and a TVS diode.
In order to setup my test, I would like to have further information than what I found in OPA197 datasheet.
I found this figure concerning its output impedance, which is applicable with VS = ±18V, but my test must be done with OPA197 not powered:
I tried to determine unpowered OPA197 output impedance by generating a DC voltage on its output and measuring its current, but the result seems to depend on output voltage applied to the amplifier.
So my first question is: can you provide me any information on OPA197 output impedance when it is not supplied?
In order to perform my test, I use a generator able to make a pulse of 70V during 1ms (this time takes into account the rising edge time of the pulse which lasts around 500µs). The voltage seen by OPA197 depends on its output impedance because of external components:
On this circuit, VOUT represents the pulse generator (Vout = 70V if the TVS diode is not present, else around 57V).
Could you tell me how much power OPA197 can dissipate in these conditions, or how much current can flow on its output?
Regards,
Kevin Marchenay