Dear support team,
In my design I need two audio outputs having specification 600 ohm, 12 V & 150 ohm, 15 V. Please suggest me an audio codec & audio amplifier to meet my requirement. 3.3 V or 5 V supply voltages are preferable.
To help you it is good to have a little more information regarding your application. You mention a codec so I assume you need ADCs? Stereo? What sampling rate?
You also mention 12V and 15V, is this the output level you need to swing to? Is this single ended power rail or is it +-12V?
I will suggest some parts to look at for starters but the decision of which is best will depend on other constraints in your design.
First I will mention a couple of codecs that have a built in headphone amplifier circuit. This will allow it to easily drive a low impedance and you will not need much if any filtering on the output of the DAC. These are the ADAU1372 and the ADAU1361. Both of these parts have a maximum of 3.3V AVDD.
We do have some older parts that are a stereo DAC and run on 5V but they are nor recommended for new designs. We do have a newer DAC that operates on 5V power but it is a 12 channels DAC and it would require a buffer to drive 600 ohms and it requires a small filter.
Now for your question regarding the amplifier. Let me suggest you ask this question to the ADI folks on the "Amplifier" section of the forum. They can help guide you for that selection.
My requirement is output rms voltage will be 12V & 15V for 600 ohm & 150 ohm respectively. I have selected ADAU1961, but I am not sure whether it can drive the mentioned load at the mentioned voltage level.
No the ADAU1761 cannot drive that high of a signal level into that low of a load. The AVDD power for the part is 3.3V single ended so it is impossible to produce any voltage output greater than its power rails. There are no DACs that can even go up to its rails. You will not be able to find a DAC anywhere that can do this. The highest power rail will be 5V and those are rapidly disappearing. You will have to use an external buffer and amplifier to drive those kind of levels.
Let me refer you to the user guide for the AD1939 codec.
http://www.analog.com/media/en/technical-documentation/user-guides/UG-040.pdf There is a schematic for the evaluation board in this user guide. In it you will see how we took the differential output of the DAC and amplified it using op-amps powered by a +-12V power rail. The OP275 in this example cannot drive 150 ohms so you need to ask the experts in the Amplifiers section of this forum. Amplifiers They should be able to help you find the right solution.
Thanks for your suggestion Dave.
I have prepared one schematics, I want to share it with you for review & suggestion. Can I have your emil ID please.
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