DAC->Op-amp.... I don't need to worry about offset voltages, seems too good to be true

Thread Starter

Robin66

Joined Jan 5, 2016
271
Hi, I'm working out the early stages for an amplifier. I've been looking at DAC modules and op-amps on RS and it seems that the offsets can be so low that I don't need to worry about trimming even down to 16bit res.

For example, this 16bit resistor string DAC is £3 from rs and it makes no mention of V offset but if my understanding of the resistor string method is correct, any zero-signal error will be negligible.

And this precision op-amp has rail-to-rail operation with <8uV offset.

By my calcs, for a DAC input of 0x0001 the DAC output voltage will be 2V/2^16 = 30uV. So worse case scenario the op-amp will introduce 25% LSB error, but in reality it'll probably be much less than this, and the temperature drift is minimal too.

So I can just plug the output of the DAC into the op-amp in an inverting configuration and I'm away. Is it really that simple?
 
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