Datasheet

SN74CBT3257
4-BIT 1-OF-2 FET MULTIPLEXER/DEMULTIPLEXER
SCDS017M − MAY 1995 − REVISED JANUARY 2004
4
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
switching characteristics over recommended operating free-air temperature range, C
L
= 50 pF
(unless otherwise noted) (see Figure 1)
PARAMETER
FROM
(INPUT)
TO
(OUTPUT)
V
CC
= 4 V
V
CC
= 5 V
± 0.5 V
UNIT
PARAMETER
(INPUT) (OUTPUT)
MIN MAX MIN MAX
UNIT
t
pd
†
A or B B or A 0.35 0.25 ns
t
pd
S
A 5.5 1.6 5 ns
t
S
B 5.7 1.6 5.2
ns
t
en
OE
A or B 5.6 1.8 5.1
ns
t
S
B 5.2 1 5
ns
t
dis
OE
A or B 5.5 2.2 5.5
ns
†
The propagation delay is the calculated RC time constant of the typical on-state resistance of the switch and the specified load capacitance, when
driven by an ideal voltage source (zero output impedance).
PARAMETER MEASUREMENT INFORMATION
V
OH
V
OL
From Output
Under Test
C
L
= 50 pF
(see Note A)
LOAD CIRCUIT
S1
7 V
Open
GND
500 Ω
500 Ω
t
PLH
t
PHL
Output
Control
Output
Waveform 1
S1 at 7 V
(see Note B)
Output
Waveform 2
S1 at Open
(see Note B)
t
PZL
t
PZH
t
PLZ
t
PHZ
3 V
0 V
V
OH
V
OL
0 V
V
OL
+ 0.3 V
V
OH
− 0.3 V
0 V
Input
3 V
3.5 V
VOLTAGE WAVEFORMS
PROPAGATION DELAY TIMES
VOLTAGE WAVEFORMS
ENABLE AND DISABLE TIMES
Output
t
pd
t
PLZ
/t
PZL
t
PHZ
/t
PZH
Open
7 V
Open
TEST S1
NOTES: A. C
L
includes probe and jig capacitance.
B. Waveform 1 is for an output with internal conditions such that the output is low except when disabled by the output control.
Waveform 2 is for an output with internal conditions such that the output is high except when disabled by the output control.
C. All input pulses are supplied by generators having the following characteristics: PRR ≤ 10 MHz, Z
O
= 50 Ω, t
r
≤ 2.5 ns, t
f
≤ 2.5 ns.
D. The outputs are measured one at a time with one transition per measurement.
E. t
PLZ
and t
PHZ
are the same as t
dis
.
F. t
PZL
and t
PZH
are the same as t
en
.
G. t
PLH
and t
PHL
are the same as t
pd
.
H. All parameters and waveforms are not applicable to all devices.
1.5 V 1.5 V
1.5 V 1.5 V
1.5 V 1.5 V
1.5 V
1.5 V
Figure 1. Load Circuit and Voltage Waveforms