Philips Semiconductors
HCMOS family characteristics
FAMILY SPECIFICATIONS
Test circuit for 74HC
handbook, halfpage
VI
PULSE
GENERATOR
VCC
D.U.T
RT
VO
CL 50 pF
MGK565
CL = load capacitance including jig and probe capacitance
(see AC CHARACTERISTICS for values).
RT = termination resistance should be equal to the output impedance Zo of
the pulse generator.
Fig.5 Test circuit.
AC waveforms 74HC (continued)
handbook, full pagewidth
tf
OUTPUT
ENABLE
90%
50%
10%
tPLZ
OUTPUT
LOW-to-OFF
OFF-to-LOW
tPHZ
OUTPUT
HIGH-to-OFF
OFF-to-HIGH
10%
90%
MGK562
outputs
enabled
tr
VCC
tPZL
50%
GND
tPZH
50%
outputs
disabled
outputs
enabled
Fig.6 Propagation delays of 3-state outputs.
March 1988
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