0
\$\begingroup\$

ADC:ADC3424

The input is specified to be differential with each input swinging symmetrically around +-0.5V (i.e. 2Vpp with 1V input and G=1). I can't seem to find a suitable ADC driver for this. TI customer service suggested to use the THS4541 as it is supposed to be able to obtain these signals. However, nowhere in the datasheet can I find these output specifications. Instead, I find the following: THS4541

Instead of VCM+-0.5V, the output high and low is respectively 4.8V and 0.2V. What does this mean? As I have not been able to get more help from TI, could anyone here please help me to understand the datasheet specs (in case this ADC driver is in fact suitable), OR, possibly help me find one that will work.

Thanks!

Edit: So the Output voltage high/low are just the max/min ratings. The gain controls the swing and the +-0.5V offset is always centered around Vocm. The remaining question is, how is this +-0.5V offset controlled?

\$\endgroup\$

1 Answer 1

0
\$\begingroup\$

The whole misunderstanding was caused by the following sentence on page 42 of the ADC datasheet:

Each input pin (INP, INM) must swing symmetrically between (VCM + 0.5 V) and (VCM – 0.5 V), resulting in a 2-VPP (default) differential input swing.

So it was just a basic understanding of differential signals that was lacking. There is no offset, only gain and VCM.

\$\endgroup\$
1
  • \$\begingroup\$ You can accept your own answer if you wish. Doing so will help prevent this question from being automatically bumped up in the future. \$\endgroup\$
    – Wesley Lee
    Oct 27, 2017 at 1:40

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.