How to settle DAC switching offset error?

[Syukri]

I've made one R-2R 8-bit DAC, but the ouput is not linear and error..then i've used resistor ladder approach and use transmission gate as switch....the output is ok when there is no switches...but after i put some switches...that the voltage start to drop from and the gnd refference is at 1.xx volt not 0 anaymore...

can i get a solution on how to

settle my switching offset error

Thanks in advance

Syukri

 

[sunking]

DAC switch error

Does the swithc is matched and large enough?

 

[Syukri]

Re: DAC switch error

yes the switched is matched, I've already put hard wired transmission gate in the series resistance...as for the switched to trigger the node to output I've use all same value of transistor size ratio....

I didn't understand what do u mean by large enough? can u please tell me...

Thanks Sir.

 

[pseudockb]

Re: DAC switch error

A larger transistor size means that the switch on resistance is smaller so that the signal can settle fully within a certain time period.

 

[Shaber_Mezbah]

DAC switch error

In case of R-2R DAC relatively larger width transistor to make the on resistance as small as possible.
the tradeoff are clockfeedthrough, charge injection missmatch with speed.