Have a question about ADCs or DACs? Ask our Expert, Nick Gray

This thread has been closed to new questions.

However, we welcome you to Post Your Question about Communications in the element14 Community Wireless Communications Technology group. You'll find many fellow members and experts who have just the answer you're looking to find!

Thank You, Your Friends at element14 Community

Nicholas Gray

Nicholas has worked in the Semiconductor industry for over 30 years and has authored a number of published articles about data converters (ADCs and DACs) and signal integrity issues.

Top Replies

Parents

Former Member over 15 years ago

Hi!
For an audio application, I am thinking about using the TI PCM1792ADB.PCM1792ADB. DAC. Its datasheet (http://focus.ti.com/general/docs/lit/getliterature.tsp?genericPartNumber=pcm1792a&fileType=pdf) suggests a schematic in Figure 36 (Page 35) for converting the differential current output to single-ended voltage output using NE5534NE5534 and LT1028 op-amps on +-15V rails.
(a) Is it possible to reach a similar performance without the negative supply rail?
(b) Would the LTC6252 / LTC6253 op-amps run from 0V and 5V be a sensible choice, or should I use different op-amps?
(c) Will I have to make larger changes in the schematic, or are the op-amps drop-in replaceable?

Spida
Cancel
Vote Up 0 Vote Down

Sign in to reply

Cancel
nickgray over 15 years ago in reply to Former Member

Hello Spida,

Yes, it is possible to reach similar performance without a negative supply rail, but believe that 5V is insufficient voltage for this circuit because 2Vrms output of this circuit is the same as 5.66V peak-to-peak. However, if you use a rail-to-rail op-amps and 402 Ohms for the feedback resistors of U1 and U2, you can get about 1Vrms from the circuit. However, even rail-to-rail amplifiers will distort the signal as you approach the rails, so I am not sure that you can get the same performance with them.

As a result of your and other questions I have seen over the years, I wrote a blog on doing this. Please see it at http://www.element-14.com/community/blogs/analog-by-nickgray/2010/12/01/going-from-bipolar-to-unipolar-supplies.

- Nick Gray
Cancel
Vote Up 0 Vote Down

Sign in to reply

Cancel

Reply

nickgray over 15 years ago in reply to Former Member

Hello Spida,

Yes, it is possible to reach similar performance without a negative supply rail, but believe that 5V is insufficient voltage for this circuit because 2Vrms output of this circuit is the same as 5.66V peak-to-peak. However, if you use a rail-to-rail op-amps and 402 Ohms for the feedback resistors of U1 and U2, you can get about 1Vrms from the circuit. However, even rail-to-rail amplifiers will distort the signal as you approach the rails, so I am not sure that you can get the same performance with them.

As a result of your and other questions I have seen over the years, I wrote a blog on doing this. Please see it at http://www.element-14.com/community/blogs/analog-by-nickgray/2010/12/01/going-from-bipolar-to-unipolar-supplies.

- Nick Gray
Cancel
Vote Up 0 Vote Down

Sign in to reply

Cancel

Children

No Data