HD74CBT3257
4-bit 1-of-2 FET Multiplexer / Demultiplexer
ADE-205-624B (Z)
Rev. 2
Nov. 2001
Description
The HD74CBT3257 is a 4-bit 1-of-2 high-speed TTL-compatible FET multiplexer / demultiplexer. The
low on-state resistance of the switch allows connections to be made with minimal propagation delay.
Output enable (OE) and select control (S) inputs select the appropriate B1 and B2 outputs for the A-input
data.
Features
•
Minimal propagation delay through the switch.
•
5
Ω
switch connection between two ports.
•
TTL-compatible input levels.
•
Ultra low quiescent power.
-Ideally suited for notebook applications.
•
Package type
Product code example: HD74CBT3257TELL
Package type
TSSOP-16pin
Package code
TTP-16DA
Package suffix
T
Taping code
ELL(2000pcs / Reel)
Notes: 1. As for the Pb-free package is attached the “V” to the end of package code.
2. As for the Pb-free product is attached the “–E” to the end of product code.
HD74CBT3257
Function Table
Inputs
OE
L
L
H
H:
L:
X:
High level
Low level
Immaterial
S
L
H
X
Function
A port = B1 port
A port = B2 port
Disconnect
Pin Arrangement
S
1B1
1B2
1A
2B1
2B2
2A
GND
1
2
3
4
5
6
7
8
16 V
CC
15
OE
14 4B1
13 4B2
12 4A
11 3B1
10 3B2
9
3A
(Top view)
Rev.2, Nov. 2001, page 2 of 11
HD74CBT3257
Absolute Maximum Ratings
Item
Supply voltage range
Input voltage range
Input clamp current
Continuous output current
Continuous current through
V
CC
or GND
Maximum power dissipation
*2
at Ta = 25°C (in still air)
Storage temperature
Notes:
*1
Symbol
V
CC
V
I
I
IK
I
O
I
CC
or I
GND
P
T
Tstg
Ratings
−0.5
to 7.0
−0.5
to 7.0
−50
128
±100
500
−65
to 150
Unit
V
V
mA
mA
mA
mW
°C
Conditions
V
I
< 0
V
O
= 0 to V
CC
TSSOP
The absolute maximum ratings are values which must not individually be exceeded, and
furthermore, no two of which may be realized at the same time.
1. The input and output voltage ratings may be exceeded even if the input and output clamp-current
ratings are observed.
2. The maximum package power dissipation was calculated using a junction temperature of 150°C.
Recommended Operating Conditions
Item
Supply voltage range
Input voltage range
Output voltage range
Input transition rise or fall rate
Operating free-air temperature
Symbol
V
CC
V
I
V
I/O
∆t
/
∆v
Ta
Min
4.0
0
0
0
−40
Max
5.5
5.5
5.5
5
85
Unit
V
V
V
ns / V
°C
V
CC
= 4.5 to 5.5 V
Conditions
Note: Unused or floating inputs must be held high or low.
Rev.2, Nov. 2001, page 3 of 11
HD74CBT3257
Block Diagram
1A
4
2
1B1
3
1B2
2A
7
5
2B1
6
2B2
3A
9
11
3B1
10
3B2
4A
12
14
4B1
13
4B2
S
1
OE
15
Rev.2, Nov. 2001, page 4 of 11
HD74CBT3257
DC Electrical Characteristics
(Ta =
−40
to 85°C)
Item
Clamp diode voltage
Input voltage
Symbol
V
IK
V
IH
V
IL
On-state switch
*2
resistance
R
ON
V
CC
(V)
4.5
4.0 to 5.5
4.0 to 5.5
4.0
Min
2.0
Typ
14
*1
Max
−1.2
0.8
20
Unit
V
V
Ω
Test conditions
I
IN
=
−18
mA
V
IN
= 2.4 V,
I
IN
= 15 mA
Typ at V
CC
= 4.0 V
V
IN
= 0 V,
I
IN
= 64 mA
V
IN
= 0 V,
I
IN
= 30 mA
V
IN
= 2.4 V,
I
IN
= 15 mA
4.5
4.5
4.5
Input current
Off-state leakage
current
Quiescent supply
current
Increase in I
CC
*3
per input
Notes:
I
IN
I
OZ
I
CC
∆I
CC
0 to 5.5
5.5
5.5
5.5
5
5
10
7
7
15
±1.0
±1.0
3
2.5
µA
µA
µA
mA
V
IN
= 5.5 V or GND
0
≤
A, B
≤
V
CC
V
IN
= V
CC
or GND,
I
O
= 0 mA
One input at 3.4 V,
other inputs at V
CC
or
GND
For condition shown as Min or Max use the appropriate values under recommended operating
conditions.
1. All typical values are at V
CC
= 5 V (unless otherwise noted), Ta = 25°C.
2. Measured by the voltage drop between the A and B terminals at the indicated current through the
switch. On-state resistance is determined by the lower voltage of the two (A or B) terminals.
3. This is the increase in supply current for each input that is at the specified TTL voltage level
rather than V
CC
or GND.
Capacitance
(Ta = 25°C)
Item
Control input
capacitance
Input / output
capacitance
A port
B port
Symbol
C
IN
C
I/O (OFF)
V
CC
(V)
5.0
5.0
5.0
Min
Typ
3.5
9
5
Max
Unit
pF
pF
Test conditions
V
IN
= 0 or 3 V
V
O
= 0 or 3 V
OE
= V
CC
Note: This parameter is determined by device characterization is not production tested.
Rev.2, Nov. 2001, page 5 of 11
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