AMC7812 Internal DAC resistance

Carlos Luis Bernal Quintero

Other Parts Discussed in Thread: AMC7812

I'm using the AMC7812's DACs to margin some Voltage regulators. I have a series resitor connected between the AMC DAC output and the VR's feedback.

While the DAC is not configured the internal resistor ~10K affects my feedback voltage. How do you recomend to use the AMC to margin VRs?

over 12 years ago

0 Tony Calabria over 12 years ago

TI__Mastermind 43915 points

Hi Carlos,

I do not believe that the internal 10k pull down resistor can be disabled. Could you send a schematic of your output to show what you are doing.

Regards,

Tony Calabria

0 Carlos Luis Bernal Quintero over 12 years ago in reply to Tony Calabria

Prodigy 30 points

Thank you Tony.

Attached you'll find a simplified diagram of our margining interface

Regards,

CLBernal

0 Tom Hendrick over 12 years ago in reply to Carlos Luis Bernal Quintero

TI__Guru**** 175081 points

Hi Carlos,

The 10K internal to the AMC7812 cannot be disabled - have you considered using an analog switch to isolate your regulator? Perhaps something like the MAX4954 would be useful as a means to isolate/open the circuit.

0 Carlos Luis Bernal Quintero over 12 years ago in reply to Tom Hendrick

Prodigy 30 points

Thank you Tom.

That's what we will do for Rev B but i was looking for a software solution for Rev A.

Regards,

CLBernal

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AMC7812 Internal DAC resistance