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7490.chp
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1988-08-02
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977b
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66 lines
06/05/87
This IC is a Decade Counter. Features 3 independent
count modes: 1) BCD counter, 2) Symmetrical divide-by-10 counter,
and 3) divide-by-2 or divide-by-5 counter.
14
Input BD
Ro (1)
Ro (2)
NC
Vcc (+)
Rg (1)
Rg (2)
Output C
Output B
Gnd (-)
Output D
Output A
No connection
Input A
21
Has the 3 independ-
ent count modes.
Typical frequency
at 42 MHz.
------------------
Absolute Maximum
Ratings
------------------
Vcc : 5.25 volts.
Temp : 0-70 c.
Logic 1 : min. 2v.
Logic 0 : max. 0.8v.
The above are
inputs.
-----------------
Logic 1 output:
Min. 2.4 v.
Logic 0 output:
Max. 0.4 v.
-----------------
done
14
Input BD, goes to the second J-K FF.
Ro (1): Input of NAND gate.
Ro (2): Input of NAND gate.
NC
Vcc (+5 volts.)
Rg (1): Input of another NAND gate.
Rg (2): Input of another NAND gate.
Output C
Output B
Ground. (-)
Output D
Output A
NC
Input A. Clock input on the first J-K FF.