What is an HP1858-0054 transistor array?
ard at p850ug1.demon.co.uk
Thu Apr 5 15:26:09 CDT 2007
> Search for RCA CA3080, 3081, 3082 and also look at 3046. RCA did a large
> number of transistor arrays (and MOS transistor arrays).
I'm pretty sure I've checked it against all of those, and none make any
sense. Also, it's a 16 pin DIL pacakge, many of the transistor arrays
I've looked at are 14 pin DIL (or 10 / 12 lead metal cans)
Here's what I've discovered so far :
Pins 2 and 4 are grounded on the PCB, and are probably the emitters of 2
Pin 3 is linked to pin 6, then pulled up by a 464R ressitor. This goes to
the input of a '14 schmitt trigger. I guess pins 3 and 6 are collectors
of transistors in the chip
Pin 16 is not connected
Pins 7,8, 9 aren't connected either. They appear to be the 3 connections
of another transistor in the chip, with pin 89 as the base
> The common layouts were 8 common transisters with emitter(grounded) base
> and collectors brought to pins, 8 common collector (VCC) with emitter and
Certainly not either of those.
> base brought to pins. Others include differential amps, darlington arrays
> and some combination arrays. You have noticed there are a large number
> of parasitic diodes as a side effect of forming the devices on one die.
Yes, and they sure make sorting out the internal configuration
> FYI here is a sample of some of the devices:
> The common collector and common emitter devices were handy for LED
> segment and digit drivers but were not limited to those uses.
> Ca3081, ca3082 are examples of this.
FWIW, the display anode driver (segment driver) chip in the HP67
calculator is one of these. It's about the only non-custom chip you'll
find in an LED-display HP handheld calculator.
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