Nexperia
74HC85; 74HCT85
4-bit magnitude comparator
74HC_HCT85 All information provided in this document is subject to legal disclaimers. © Nexperia B.V. 2018. All rights reserved.
Product data sheet Rev. 3 — 20 April 2018
10 / 19
11.1 Waveforms and test circuit
aaa-028464
An, Bn, In input
V
I
GND
Qn output
V
OH
V
OL
t
PLH
t
THL
t
TLH
V
X
V
Y
t
PHL
V
M
V
M
Measurement points are given in Table 8.
V
OL
and V
OH
are typical voltage output levels that occur with the output load.
Figure 7. Word A inputs (An), word B inputs (Bn) and expansion inputs (In) to the outputs (Qn) propagation delays
and the output transition times
Table 8. Measurement points
Input OutputType
V
I
V
M
V
M
V
X
V
Y
74HC85 V
CC
0.5V
CC
0.5V
CC
0.1 V
CC
0.9 V
CC
74HCT85 3 V 1.3 V 1.3 V 0.1 V
CC
0.9 V
CC
001aah768
t
W
t
W
t
r
t
r
t
f
V
M
V
I
negative
pulse
GND
V
I
positive
pulse
GND
10 %
90 %
90 %
10 %
V
M
V
M
V
M
t
f
V
CC
DUT
R
T
V
I
V
O
C
L
G
Test data is given in Table 9.
Definitions test circuit:
R
T
= termination resistance should be equal to output impedance Z
o
of the pulse generator.
C
L
= load capacitance including jig and probe capacitance.
Figure 8. Test circuit for measuring switching times
