[sdiy] OTA performance (was SSM chip reissue)

[Neil Johnson]

Hi,

Justin Herrmann wrote:
> Datasheets for CA3280, LM13700, and NE5517 all claim "excellent matching"
> between the pairs, but none back up that claim with numbers or guaranteed
> matching specs. On the other hand, the SSM2164 claims "All channels are
> closely matched to within 0.07 dB at unity gain."

You need to learn to read datasheets properly.  The actual text you
are referring to gives the channel-to-channel gain matching as TYPICAL
values only, and two different values, namely 0.07dB at Av = 0dB (this
is the best case), and 0.24dB at Av = -40dB (after which they're too
embarrassed to tell you how bad it is).

> Has anyone compared how closely OTA devices within a package match? Is it
> just gm that's important here?

In devices like the 2164 it's a little bit more complicated than that.

Neil
-- 
http://www.njohnson.co.uk