5 Apr
2007
5 Apr
'07
9:26 p.m.
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
transsitors
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
non-trivial :-)
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.
-tony