When the AM26LV31 is driving a 100 load it exhibits an aprox 1 volt offset. Is this normal?

Robert Evans29

Prodigy 20 points

Other Parts Discussed in Thread: AM26LV31, AM26LV32, AM26LV31E

When the AM26LV31 is driving a 100 load it exhibits an aprox 1 volt offset.

Is this normal?

It works fine with the AM26LV32. ( the 32 RX has plenty of common mode rejection)

But, since we are seeing this offset we'd like to know more about the underlying

mechanism causing it.

robert.evans@in-phasetech.com

thank you.

over 8 years ago

0 Ron Michallick over 8 years ago

TI__Guru**** 164546 points

Robert,

I would not expect an offset, unless external pull up on port Y(A) and pull down on port Z(B) was too much current.

Are you saying the VOH and VOL of Y and Z do not match each other?

0 Robert Evans29 over 8 years ago in reply to Ron Michallick

Prodigy 20 points

No pull ups. Just a floating 100 ohm termination

The offset is on both sides of the resistor.

(with the required differential developed across the resistor)

-RMEvans

0 Ron Michallick over 8 years ago in reply to Robert Evans29

TI__Guru**** 164546 points

Robert,
I tested a few samples. I see less than 0.1V common mode shift.

I suggest the AM26LV31E as an drop in upgrade. It has better ESD performance, lower output impedance, better common mode matching, and more margin in the current limit.

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When the AM26LV31 is driving a 100 load it exhibits an aprox 1 volt offset. Is this normal?