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We do not have that performance specified (or characterized) on this device. This is a current output device, so I do not expect parasitic capacitance on the output will have any impact on the device performance. If I were to guess, I would estimate the pin capacitance as <50pF.
Your example circuits are transimpedance designs where the source C is a big part of the response equations.
And actually, if I had to guess I would bet they are under 10pF and what I would probably due (lacking this key spec) is add external C to proceed with a design.
There is quite a lot of transimpedance design stuff out there inside the TI environ - a lot of it from my original 1996 burrbrown articles - but here is a good one Xavier and I did some years back,
Thanks for this presentation! It was very informative.
I guess my confusion is rooted in how the input cap will affect the response key audible range? We recommend a very large cap in the feedback (2200pF) to create an LPF response to help attenuate the out-of-band noise. Wouldn't this cap dominate the response?
All that to say, I took a look at some of the design reviews and documentation I have from the original TIJ development team, but I could not find more info on this specification.
Thanks,
Paul
Also, if you want to discuss this directly, feel free to shoot an email to frost@ti.com.
Well Paul, I am not surprised the spec does not exist - the comms dacs are also missing a meaningful spec (they often just have a fill number that is the same across many parts).
The feedback cap is fine but will be giving a NG =1 at xover - which is also fine for most unity gain op amp or FDA solutions.
A source cap either from the DAC or externally will shape that NG up at xover, that can help phase margin - the designs I have been seeing put a large diff cap on the DAC outputs - that certainly effects the amplifier LG and phase margin, and swamps out the DAC parasitic.
