The OPA627's in my VSPS have blown.

Shoog · 10th January 2005, 11:01 PM

Hi there,
I came to use my VSPS phono amp, and nothing came out. Tested the circuit and everything measures fine. Looks like the input Fets of the OPA627's have been spiked somehow, and no longer work.
We had a lightning strike recently which took out my Modem, but I don't think it was this.
My question is can I protect the input Fets with diodes without degrading those sensitive little signals ?

Shoog

BrianL · 11th January 2005, 12:52 AM

Read the OPA627/637 datasheet and look at the section on
input protection.

If you use the external diodes and resistor, make sure the
diodes (or FETs wired as diodes) have the lowest capacitance
and flattest capacitance-vs-reverse-voltage, as well as low leakage.

10th January 2005, 11:01 PM	#1
Shoog diyAudio Member Join Date: Aug 2002 Location: Eire	The OPA627's in my VSPS have blown. Hi there, I came to use my VSPS phono amp, and nothing came out. Tested the circuit and everything measures fine. Looks like the input Fets of the OPA627's have been spiked somehow, and no longer work. We had a lightning strike recently which took out my Modem, but I don't think it was this. My question is can I protect the input Fets with diodes without degrading those sensitive little signals ? Shoog

11th January 2005, 12:52 AM	#2
BrianL diyAudio Member Join Date: Mar 2002 Location: USA	Read the OPA627/637 datasheet and look at the section on input protection. If you use the external diodes and resistor, make sure the diodes (or FETs wired as diodes) have the lowest capacitance and flattest capacitance-vs-reverse-voltage, as well as low leakage. __________________ bel

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