Page 1
TECHNICAL DATA
341
8-Input Data Selector/Multiplexer
with 3-State Outputs
High-Speed Silicon-Gate CMOS
The IN74ACT251 is identical in pinout to the LS/ALS251,
HC/HCT251. The IN74ACT251 may be used as a level converter for
interfacing TTL or NMOS outputs to High Speed CMOS inputs.
The device selects one of the eight binary Data Inputs, as
determined by the Address Inputs. The Output Enable pin must be at a
low level for the selected data to appear at the outputs. If Output
Enable is high, the Y and the Y outputs are in the high-impedance
state. This 3-State feature allows the IN74ACT251 to be used in busoriented systems.
•
TTL/NMOS Compatible Input Levels
•
Outputs Directly Interface to CMOS, NMOS, and TTL
•
Operating Voltage Range: 4.5 to 5.5 V
•
Low Input Current: 1.0 µA; 0.1 µA @ 25°C
•
Outputs Source/Sink 24 mA
IN74ACT251
ORDERING INFORMATION
IN74ACT251N Plastic
IN74ACT251D SOIC
TA = -40° to 85° C for all
packages
PIN ASSIGNMENT
FUNCTION TABLE
Inputs Outputs
A2 A1 A0 Output
Enable
YY
XX X H Z Z
L L L L D0 D0
L L H L D1 D1
L H L L D2 D2
L H H L D3 D3
H L L L D4 D4
H L H L D5 D5
H H L L D6 D6
H H H L D7 D7
D0,D1...D7=the level of the respective D
input
Z = high-impedance st ate
X = don’t care
LOGIC DIAGRAM
PIN 16 =V
CC
PIN 8 = GND
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IN74ACT251
342
MAXIMUM RATINGS
*
Symbol Parameter Value Unit
V
CC
DC Supply Voltage (Referenced to GND) -0.5 to +7.0 V
V
IN
DC Input Voltage (Referenced to GND) -0.5 to VCC +0.5 V
V
OUT
DC Output Voltage (Referenced to GND) -0.5 to VCC +0.5 V
I
IN
DC Input Current, per Pin
±
20
mA
I
OUT
DC Output Sink/Source Current, per Pin
±
50
mA
I
CC
DC Supply Current, VCC and GND Pins
±
50
mA
P
D
Power Dissipation in Still Air, Plastic DIP+
SOIC Package+
750
500
mW
Tstg Storage Temperature -65 to +150
°
C
T
L
Lead Temperature, 1 mm from Case for 10 Seconds
(Plastic DIP or SOIC Package)
260
°
C
*
Maximum Ratings are those values beyond which damage to the device may occur.
Functional operation should be restricted to the Recommended Operating Conditions.
+Derating - Plastic DIP: - 10 mW/°C from 65° to 125°C
SOIC Package: : - 7 mW/°C from 65° to 125°C
RECOMMENDED OPERATING CONDITIONS
Symbol Parameter Min Max Unit
V
CC
DC Supply Voltage (Referenced to GND) 4.5 5.5 V
VIN, V
OUT
DC Input Voltage, Output Voltage (Referenced to GND) 0 V
CC
V
T
J
Junction Temperature (PDIP) 140
°
C
T
A
Operating Temperature, All Package Types -40 +85
°
C
I
OH
Output Current - High -24 mA
I
OL
Output Current - Low 24 mA
tr, t
f
Input Rise and Fall Time
*
(except Schmitt Inputs)
V
CC
=4.5 V
V
CC
=5.5 V
0
0
10
8.0
ns/V
*
VIN from 0.8 V to 2.0 V
This device c ontains p rote ction ci rcuitr y to guard a gainst damage d ue to high st atic voltages or electr ic
fields. However, precautions must be taken to avoid applications of any voltage higher than maximum rated
voltages to this high-impedance circuit. For proper operation, V
IN
and V
OUT
should be constrained to the range
GND≤(V
IN
or V
OUT
)≤VCC.
Unused inputs must always be tied to an appropriate logic voltage level (e.g., either GND or V
CC
).
Unused outputs must be left open.
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IN74ACT251
343
DC ELECTRICAL CHARACTERISTICS
(Voltages Referenced to GND)
V
CC
Guaranteed Limits
Symbol Parameter Test Conditions V
25 °C-40
°
C to
85°C
Unit
V
IH
Minimum High-Level
Input Voltage
V
OUT
=0.1 V or VCC-0.1 V 4.5
5.5
2.0
2.0
2.0
2.0
V
V
IL
Maximum Low Level Input Voltage
V
OUT
=0.1 V or VCC-0.1 V 4.5
5.5
0.8
0.8
0.8
0.8
V
V
OH
Minimum High-Level
Output Voltage
I
OUT
≤ -50 µA
4.5
5.5
4.4
5.4
4.4
5.4
V
*
VIN=VIH or V
IL
IOH=-24 mA
I
OH
=-24 mA
4.5
5.5
3.86
4.86
3.76
4.76
V
OL
Maximum Low-Level
Output Voltage
I
OUT
≤ 50 µA
4.5
5.5
0.1
0.1
0.1
0.1
V
*
VIN=VIH or V
IL
IOL=24 mA
I
OL
=24 mA
4.5
5.5
0.36
0.36
0.44
0.44
I
IN
Maximum Input
Leakage Current
VIN=VCC or GND 5.5
±
0.1
±
1.0
µ
A
∆
I
CCT
Additional Max.
I
CC
/Input
V
IN=VCC
- 2.1 V 5.5 1.5 mA
I
OZ
Maximum ThreeState Leakage
Current
V
IN
(OE)= VIH or V
IL
V
IN =VCC
or GND
V
OUT =VCC
or GND
5.5
±
0.5
±
5.0
µ
A
I
OLD
+Minimum Dynamic
Output Current
V
OLD
=1.65 V Max 5.5 75 mA
I
OHD
+Minimum Dynamic
Output Current
V
OHD
=3.85 V Min 5.5 -75 mA
I
CC
Maximum Quiescent
Supply Current
(per Package)
VIN=VCC or GND 5.5 8.0 80
µ
A
*
All outputs loaded; thresholds on input associated with output under test.
+Maximum test duration 2.0 ms, one output loaded at a time.
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IN74ACT251
344
AC ELECTRICAL CHARACTERISTICS
(VCC=5.0 V ± 10%, CL=50pF, Input tr=tf=3.0 ns)
Guaranteed Limits
Symbol Parameter
25 °C-40
°
C to 85°C
Unit
Min Max Min Max
t
PLH
Propagation Delay, Input A to
Output Y or Y (Figure 3)
2.5 15.5 2.0 17.0 ns
t
PHL
Propagation Delay, Input A to
Output Y or Y (Figure 3)
2.5 16.5 2.5 18.5 ns
t
PLH
Propagation Delay, Input D to
Output Y or Y (Figures 1,2)
2.5 12.0 2.0 13.0 ns
t
PHL
Propagation Delay, Input D to
Output Y or Y (Figures 1,2)
2.5 12.5 2.5 14.0 ns
t
PZH
Propagation Delay, Output Enable to
Output Y or Y (Figure 4)
1.5 8.5 1.5 9.0 ns
t
PZL
Propagation Delay, Output Enable to
Output Y or Y (Figure 4)
1.5 8.5 1.5 9.5 ns
t
PHZ
Propagation Delay, Output Enable to
Output Y or Y (Figure 4)
2.0 12.0 2.0 13.0 ns
t
PLZ
Propagation Delay, Output Enable to
Output Y or Y (Figure 4)
1.5 8.5 1.5 9.0 ns
C
IN
Maximum Input Capacitance 4.5 4.5 pF
Typical @25°C,VCC=5.0 V
C
PD
Power Dissipation Capacitance 70 pF
Figure 1. Switching Waveforms Figure 2. Switching Waveforms
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IN74ACT251
345
Figure 3. Switching Waveforms Figure 4. Switching Waveforms
EXPANDED LOGIC DIAGRAM
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