CA3140

Nice pink noise generators for soothing your nerves. ;)

Cheers

Phil Hobbs

I was reading somewhere that the single CA3140 is automatically mil-spec temperature range...unfortunately these are duals.

I found this but I don't know how old it is:

"The CA3140 utilizes a MOSFET input and a bipolar output, making it a far more "bullet proof" device than the CA3130. The CA3140 has sufficient bandwidth to work nicely in scintillation tool preamp circuits, and Comprobe uses it for that purpose in its tools. Buckeye in Ohio even used a pair of CA3140 op amps in their neutron preamp circuits (the very high input impedance of FET input op amps makes this possible). Every CA3140 ever made is rated for the military temperature range, a feature one must pay dearly for in other op amps (this is also true for the CA3130 and a few other devices in the CA series, but sadly the dual version of the CA3140, the CA3240, is available only in the industrial temperature range). RCA sold the CA series to Harris who eventually sold it to Intersil, and Intersil continues to produce the CA3140. While far from perfect, with an MSRP as low as 29 cents each for a versatile mil spec temperature range op amp, you gotta to love the CA3140!"

CA3140 is a single op amp; the dual version is CA3240. Yeah, they're useful: the input current is in the picoamp range and the metal-case ones can be heattsinked (which might be important,because they worked on up to 44V power and took up to 5.5 mA quiescent current).

I recall a ramp generator (for a long heat-cycle control) that made good use of one. It could be adjusted for hours to days of steady dV/dt. Modern bootstrapped jFET inputs are better, but for pre-1980, it was hot stuff.

Fun. I remember using those (and the much superior CA3100) back in the early '80s.

The CA3100 had truly superior intermod behaviour for the time--it was used in early broadband microwave codecs at AEL Microtel, where I worked for a couple of years before grad school.

Cheers

Phil Hobbs

I prefer green or blue..

The CA3100 was unusual in that it was a bipolar video op amp that used CMOS (N and P) level shifters internally. That was pretty early for a BiCMOS process!

Cheers

Phil Hobbs