NXP Semiconductors
74HC257; 74HCT257
Quad 2-input multiplexer; 3-state
V
I
negative
pulse
0V
t
W
90 %
V
M
10 %
t
f
t
r
t
r
t
f
90 %
V
M
10 %
t
W
V
M
V
M
V
I
positive
pulse
0V
V
CC
V
CC
G
VI
VO
RL
S1
DUT
RT
CL
open
001aad983
Measurement points are given in
and test data is given in
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.
R
L
= Load resistor.
Fig 8.
Table 9.
Type
74HC257
Test circuit for switching times
Test data
Input
V
I
V
CC
3V
t
r
, t
f
6 ns
6 ns
Load
C
L
50 pF
50 pF
R
L
1 kΩ
1 kΩ
Switch position
t
PHL
, t
PLH
open
open
t
PZH
, t
PHZ
GND
GND
t
PZL
, t
PLZ
V
CC
V
CC
74HCT257
74HC_HCT257_5
© NXP B.V. 2010. All rights reserved.
Product data sheet
Rev. 05 — 13 January 2010
10 of 17
PHILIPS [ NXP SEMICONDUCTORS ]
