AMC1200b output voltage when VDD1 power down

Winnie Wang

Part Number: AMC1200B

dear team,

I have a quick question regarding AMC1200b, could you pls kindly help answer? thanks a lot.

When VDD1 power down, VINP and VINN has signal input, what is the output voltage VOUTP to VOUTN? consider two conditions as below.

VDD1 always zero but VDD2 has proper bias and there are input signals on VINP and VINN
VDD1 and VDD2 initially have good steady-state bias, then VDD1 is removed while the VINP and VINN signals are present

over 2 years ago

0 Tom Hendrick over 2 years ago

TI__Guru**** 171116 points

Hi Winnie,

The AMC1200 was our first isolated amplifier and did not have any 'fail-safe' features. So, to answer your questions, for both 1 and 2, without VDD1 present, there is no communication over the isolation barrier. In case 1, if VDD1 never powered up, the outputs are indeterminate. I suspect they may assume their default Vcm out state, but would need to verify that. In case 2, the output will saturate to either FS+ or FS- depending on the value of the last bit transferred over the barrier.

0 Winnie Wang over 2 years ago in reply to Tom Hendrick

TI__Intellectual 980 points

Hi, Tom

much appreciated your reply. then shall we have similar device which has "fail safe"?Thanks.

0 Tom Hendrick over 2 years ago in reply to Winnie Wang

TI__Guru**** 171116 points

You would need to use the AMC1300 or AMC1300B.

Amplifiers

Amplifiers forum

AMC1200b output voltage when VDD1 power down