HCF4536B_02 Datasheet, PDF (9/13 Pages) STMicroelectronics – PROGRAMMABLE TIMER

HCF4536B
FUNCTIONAL TEST SEQUENCE
Inputs
Outputs
COMMENTS
Decade Out
In 1
Set
Reset
8-Bypass Q1 Thru
All 24 steps are in reset mode
Q24
H
L
H
H
L
Counter is in three 8-stage section in parallel
H
H
H
H
L
mode
L
H
H
H
L
First "H" to "L" Transition of Clock
H
L
H
H
H
255 "H" to "L" transitions are clocked in the
counter
L
H
H
H
H
The 255 "H" to "L" Transition
Counter converted back to 24 stages in series
mode.
L
L
L
L
H
Set and Reset must be connected together
and simultaneously go from "H" to "L"
H
L
L
L
H
In₁ switches to a "H"
L
L
L
L
L
Counter Ripples from an all "H" state to an all
"L" state
FUNCTIONAL TEST SEQUENCE
Test function has been included for the reduction
of test time required to exercise all 24 counter
stages.This test function divides the counter into
three 8-stage section and 255 counts are loaded in
each of the 8-stage sections in parallel. All
flip-flops are now at a "H". The counter is now
returned to the normal 24-steps in series
configuration. One more pulse is entered into In1
which will cause the counter to ripple from an all
"H" state to an all "L" state.
TEST CIRCUIT
C_L = 50pF or equivalent (includes jig and probe capacitance)
R_L = 200KΩ
R_T = Z_OUT of pulse generator (typically 50Ω)
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