[sdiy] cs4344 DAC output stage

[Jay Schwichtenberg]

Julian,

It depends on the DAC.

There are two main types of DACs now days. There are media player and stereo
(not 2 channels but something you plug into your stereo) ones.  Media player
stuff usually does not have any, they are made to drive headphones. A small
power amp is in the chip and they typically drive the headphones thru a
capacitor. Ones that you use in the stereo will typically have an active
filter (using op-amps) to roll of the high end for aliasing. For 44.1 KHz
sample rate that is somewhere between 20 KHz and 22 KHz. There might also be
a driver circuit after the filter. You can also find hybrids that have both
built in. These are usually used in home theater systems.

Look at a bunch of data sheets from Cirrus, Burr Brown/TI, AKM to get some
ideas. There use (don't know if there still is) to be a lot of app notes out
there for filter calcs, demo board schematics, interfacing and other things.

Jay

-----Original Message-----
From: synth-diy-bounces at dropmix.xs4all.nl
[mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of julian schmidt
Sent: Thursday, September 13, 2012 8:30 AM
To: Synth DIY
Subject: [sdiy] cs4344 DAC output stage

Hello all,

I'm designing a cortex M4 based audio/synth board using the cs4344 DAC 
and a cs5343 ADC.
As i'm new to designing with DAC/ADCs here's a question.

Is there an opamp needed for the DAC output stage?
I've seen opamp output stages in quite a few designs using different 
kinds of DACs, but the datasheet for the cs4344 just states some R/C 
filters after the dac output as reference design.

cheers,
julian
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