Tinco Brouwer writes:
>For a complete datasheet:
>http://www-s.ti.com/sc/psheets/schs045a/schs045a.pdf
I got the data sheet and ran in to a small problem. As a
computer user who happens to be blind, I have to run pdf
documents through a program to extract any text from them. I
think this particular document is probably an image scan from an
old data sheet since the CD4048 is ancient. What I got was a
front and back page identifying the data sheet as one for a
CD4048 and then four totally blank pages that should have had all
the good stuff but had nothing at all.
I connected a CD4048 to pull-up resistors on all its
inputs and control lines and began trying various combinations of
the control pins which are Pins 7, 9 and 10. It appears that Pin
9 changes the polarity of the output and 7 and 10 set whether the
chips ands or ors the inputs.
Here is what I am still not sure of:
Is the expansion pin bidirectional or just an input? My
chip only started working correctly after I connected that pin to
ground. I am not sure if it normally connects to the expansion
pin of a neighboring CD4048 or should be fed from the J output
which is Pin 1 of the neighboring CD4048.
The only other thing I haven't figured out yet is whether
all four possible states of Pins 7 and 10 are used. I did find
one combination in which the output went low upon grounding any
input so I assume that's the And condition. The Pin-out, by the
way, lists Pin 2 as a K(D) or another control line. It is the
Tristate line and can be permanently connected to VDD if the chip
is always in circuit.
Martin McCormick
--
Author: Martin McCormick
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