TC74HC251AP/AF
TOSHIBA CMOS Digital Integrated Circuit
Silicon Monolithic
TC74HC251AP
,
TC74HC251AF
8-Channel Multiplexer (3-state)
The TC74HC251A is a high speed CMOS 8-CHANNEL
MULTIPLEXER fabricated with silicon gate C
2
MOS technology.
It achieves the high speed operation similar to equivalent
LSTTL while maintaining the CMOS low power dissipation.
One of eight date input signals (D0-D7) is selected by decoding
of the address input (A, B, C). The selected data appears on two
outputs; non-inverting (Y) and inverting (W). When the strobe
input is held high, both outputs are in the high-impedance state.
All inputs are equipped with protection circuits against static
discharge or transient excess voltage.
TC74HC251AP
Features
•
•
•
•
•
•
•
•
High speed: t
pd
= 15 ns (typ.) at V
CC
= 5 V
Low power dissipation: I
CC
= 4
μA
(max) at Ta = 25°C
High noise immunity: V
NIH
= V
NIL
= 28% V
CC
(min)
Output drive capability: 10 LSTTL loads
Symmetrical output impedance: |I
OH
| = I
OL
= 4 mA (min)
Balanced propagation delays: t
pLH
∼
t
pHL
−
Wide operating voltage range: V
CC
(opr) = 2~6 V
Pin and function compatible with 74LS251
TC74HC251AF
Weight
DIP16-P-300-2.54A
SOP16-P-300-1.27A
: 1.00 g (typ.)
: 0.18 g (typ.)
Pin Assignment
1
2007-10-01
TC74HC251AP/AF
IEC Logic Symbol
Truth Table
Inputs
Select
C
X
L
B
X
L
A
X
L
Strobe
Outputs
Y
Z
D0
W
Z
ST
H
L
D0
D1
D2
D3
D4
D5
D6
D7
L
L
L
H
H
H
H
L
H
H
L
L
H
H
H
L
H
L
H
L
H
L
L
L
L
L
L
L
D1
D2
D3
D4
D5
D6
D7
X: Don’t care
H: High impedance
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2007-10-01
TC74HC251AP/AF
System Diagram
3
2007-10-01
TC74HC251AP/AF
Absolute Maximum Ratings (Note 1)
Characteristics
Supply voltage range
DC input voltage
DC output voltage
Input diode current
Output diode current
DC output current
DC V
CC
/ground current
Power dissipation
Storage temperature
Symbol
V
CC
V
IN
V
OUT
I
IK
I
OK
I
OUT
I
CC
P
D
T
stg
Rating
−
0.5~7
−
0.5~V
CC
+
0.5
−
0.5~V
CC
+
0.5
±
20
±
20
±
25
±
50
Unit
V
V
V
mA
mA
mA
mA
mW
°C
500 (DIP) (Note 2)/180 (SOP)
−
65~150
Note 1: Exceeding any of the absolute maximum ratings, even briefly, lead to deterioration in IC performance or
even destruction.
Using continuously under heavy loads (e.g. the application of high temperature/current/voltage and the
significant change in temperature, etc.) may cause this product to decrease in the reliability significantly
even if the operating conditions (i.e. operating temperature/current/voltage, etc.) are within the absolute
maximum ratings and the operating ranges.
Please design the appropriate reliability upon reviewing the Toshiba Semiconductor Reliability Handbook
(“Handling Precautions”/“Derating Concept and Methods”) and individual reliability data (i.e. reliability test
report and estimated failure rate, etc).
Note 2: 500 mW in the range of Ta
= −40~65°C.
From Ta
=
65 to 85°C a derating factor of
−10
mW/°C shall be
applied until 300 mW.
Operating Ranges (Note)
Characteristics
Supply voltage
Input voltage
Output voltage
Operating temperature
Symbol
V
CC
V
IN
V
OUT
T
opr
Rating
2~6
0~V
CC
0~V
CC
−
40~85
Unit
V
V
V
°C
0~1000 (V
CC
=
2.0 V)
Input rise and fall time
t
r
, t
f
0~500 (V
CC
=
4.5 V)
0~400 (V
CC
=
6.0 V)
ns
Note:
The operating ranges must be maintained to ensure the normal operation of the device.
Unused inputs must be tied to either VCC or GND.
4
2007-10-01
TC74HC251AP/AF
Electrical Characteristics
DC Characteristics
Test Condition
Characteristics
Symbol
V
CC
(V)
2.0
High-level input
voltage
V
IH
⎯
Ta
=
25°C
Min
1.50
3.15
4.20
⎯
⎯
⎯
Ta
= −
40~85°C
Max
⎯
⎯
⎯
Typ.
⎯
⎯
⎯
⎯
⎯
⎯
Min
1.50
3.15
4.20
⎯
⎯
⎯
Max
⎯
⎯
⎯
Unit
4.5
6.0
2.0
V
0.50
1.35
1.80
⎯
⎯
⎯
⎯
⎯
0.50
1.35
1.80
⎯
⎯
⎯
⎯
⎯
Low-level input
voltage
V
IL
⎯
4.5
6.0
2.0
V
1.9
4.4
5.9
4.18
5.68
⎯
⎯
⎯
⎯
⎯
⎯
⎯
⎯
2.0
4.5
6.0
4.31
5.80
0.0
0.0
0.0
0.17
0.18
⎯
⎯
⎯
1.9
4.4
5.9
4.13
5.63
⎯
⎯
⎯
⎯
⎯
⎯
⎯
⎯
High-level output
voltage
V
OH
V
IN
=
V
IH
or
V
IL
I
OH
= −
20
μ
A
I
OH
= −
4 mA
I
OH
= −
5.2 mA
I
OL
=
20
μ
A
I
OL
=
4 mA
I
OL
=
5.2 mA
4.5
6.0
4.5
6.0
2.0
V
0.1
0.1
0.1
0.26
0.26
±
0.5
±
0.1
0.1
0.1
0.1
0.33
0.33
±
5.0
±
1.0
μ
A
μ
A
μ
A
Low-level output
voltage
V
OL
V
IN
=
V
IH
or
V
IL
4.5
6.0
4.5
6.0
6.0
6.0
6.0
V
3-state off leak
current
Input leakage
current
Quiescent supply
current
I
OZ
I
IN
I
CC
V
IN
=
V
IH
or V
IL
V
OUT
=
V
CC
or GND
V
IN
=
V
CC
or GND
V
IN
=
V
CC
or GND
4.0
40.0
AC Characteristics
(C
L
=
15 pF, V
CC
=
5 V, Ta
=
25°C, input: t
r
=
t
f
=
6 ns)
Characteristics
Output transition time
Propagation delay time
(D-Y)
Propagation delay time
(D-W)
Propagation delay time
(A, B, C-Y)
Propagation delay time
(A, B, C-W)
3-state output enable time
Symbol
t
TLH
t
THL
t
pLH
t
pHL
t
pLH
t
pHL
t
pLH
t
pHL
t
pLH
t
pHL
t
pZL
t
pZH
Test Condition
⎯
Min
⎯
Typ.
4
Max
8
Unit
ns
⎯
⎯
14
24
ns
⎯
⎯
15
24
ns
⎯
⎯
19
31
ns
⎯
⎯
19
31
ns
⎯
⎯
10
18
ns
5
2007-10-01
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