HEP 590 data?

On Sat, 05 Apr 2008 17:23:36 -0700, PhattyMo put finger to keyboard and composed:

- Franc Zabkar

Hmm,That's not quite right.. the HEP590 I have here,has 10 leads. I don't think it's a dual transistor either.IIRC it's something like an IF amplifier,or something?..kinda fuzzy.

Ahh! Here's some spec's that I found..

HEP590 Motorola, Inc. :: General Purpose RF-IF Amplifier Specsheet / Datasheet Power Gain Min. (dB)=25.0 Noise Figure Max. (dB)=5.0 f(test) (Hz) Test Frequency=60M P(D) Max.(W) Power Dissipation=680m Nom. Supp (V)=6.0 Status=Discontinued Package=Can Pins=10 Military=N

It's a Motorola MC1550, a differential amplifier good for IF and low RF work, but with an internal biasing network.

It's similar to the RCA CA3028, but never quite the same because of the internal biasing network.

The HEP line, at least the ICs, was mostly Motorola components renumbered. The "HEP" was of coure "Hobby, Experimenter, Professional" so it wsa about getting parts off a pegboard rather than a completely universal replacement line. They wanted their parts available, so that was one way of doing it. ECG/NTE came later, and they were a far better line of replacement parts. I seem to have discared the first HEP replacement guide I had, I think it fell apart, but the later one dating from about 1975 is pretty sparse in the cross-reference, and I immedately am reminded of how often there were mistakes in that cross-reference.

I know it's an MC1550 because it was something from Motorola's line, and that number jumped out when I was thinking about it. I looked up the schematic, and then an old magazine article that gave a partial internal diagram of the HEP590, and they match; even more definite is the external pinouts.

Michael

Ah-Ha! Thanks Much Michael!