HCC4089B Datasheet, PDF (8/13 Pages) STMicroelectronics – BINARY RATE MULTIPLIER

HCC/HCF4089B
APPLICATION NOTES
For words of more than 4 bits, HCC/HCF4089B devices may be cascaded in two different modes : an Add
mode and a Multiply mode.
Two HCC/HCF4089B’s cascaded in the ”Add” mode with a preset number of 189.
Nota :
In the Add mode some of the gaps left by the more
significant unit at the count of 15 are filled in by the
less significant units. For example, when two units
are cascaded in the Add mode and programmed to
11 and 13, respectively, the more significant unit will
have 11 output pulses for every 16 input pulses and
the other unit will have 13 output pulses for every
256 input pulses for a total of
11
16
+
13
256
=
189
256
Two HCC/HCF4089B’s cascaded in the Multiply mode for Multiplication of two variables A and B with loop
circuit control.
When the loop stabilies rate R2 = rate R3, thus fclock ( ^A . ^B
16 16
) = fclock ( ¹ . ^N
16 16
) therefore N = A.B.
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