Tell me more ×
Electrical Engineering Stack Exchange is a question and answer site for electronics and electrical engineering professionals, students, and enthusiasts. It's 100% free, no registration required.
up vote 0 down vote favorite

I have a 14-bit DAC. Ramping the data pins linearly from the minimum of 0x0 to the maximum of 0x3FFF I see (using a scope) the analogue output voltage behaving as follows:

  1. In the first half (from 0x0 to 0x2000), the voltage ramps from 1V to 1.8V.
  2. In the second half (from 0x2000 to 0x3FFF), the voltage ramps from 0V to 1V.

Is this the expected behaviour? What output voltage range should I be expecting for the analogue output? Why is there a "break" at 0x2000?

share|improve this question
1  
Can you tell us what DAC are you using? – Bruno Ferreira Jul 5 '12 at 19:01
I am using the AD9775BSV. The datasheet is linked in the question. – Randomblue Jul 5 '12 at 19:02
Sorry, missed that. – Bruno Ferreira Jul 5 '12 at 19:04

1 Answer

up vote 1 down vote accepted

I've figured out part of the answer. The break is due to the two's complement option being turned on (see page 14):

Logic “0” (default) causes data to be accepted on the inputs as two’s complement binary. Logic “1” causes data to be accepted as straight binary.

share|improve this answer
That makes sense, in that case the voltage output is not linear. – Bruno Ferreira Jul 5 '12 at 19:17
Yeah, that's what I'm trying to figure out. I'm possibly a little off in my measurements. – Randomblue Jul 5 '12 at 19:21

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

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