For resistor-string dac, what are the importants of opamp?

[shaq]

Dear all,

What specification of the opamp in resistor-string dac are importants that we need to take care?

Plz give me some suggestions. Thanks so much!!!!

 

[Yahia Muhammad]

Re: For resistor-string dac, what are the importants of opam

it's used as a buffer

 

[shaq]

Re: For resistor-string dac, what are the importants of opam

it's used as a buffer

ya, it's a buffer.

Should we need to take care about its input offset or unit-gain bandwidth etc. ?

 

[Yahia Muhammad]

Re: For resistor-string dac, what are the importants of opam

yes i think it must be taken care of
any offset will affect the following stages
if u are going to implement a two step ADC
the offset of the DAC will cause an error that will be multiplied by a gain
which might cause a severe error in the second ADC

 

[hung_wai_ming@hotmail.com]

You should consider what is the application of your DAC?
Your application will govern the settling time, output swing, speed, current consumption and so on for your op-amp

 

[keaton]

random offset