SEMICONDUCTOR TECHNICAL DATA
1
REV 6
Motorola, Inc. 1995
10/95
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High–Performance Silicon–Gate CMOS
The MC74HC257 is identical in pinout to the LS257. The device inputs are
compatible with standard CMOS outputs; with pullup resistors, they are
compatible with LSTTL outputs.
This device selects a (4–bit) nibble from either the A or B inputs as
determined by the Select input. The nibble is presented at the outputs in
noninverted form when the Output Enable pin is at a low level. A high level on
the Output Enable pin switches the outputs into the high–impedance state.
The HC257 is similar in function to the HC157 which do not have 3–state
outputs.
• Output Drive Capability: 15 LSTTL Loads
• Outputs Directly Interface to CMOS, NMOS, and TTL
• Operating Voltage Range: 2 to 6 V
• Low Input Current: 1 µA
• High Noise Immunity Characteristic of CMOS Devices
• In Compliance with the Requirements Defined by JEDEC Standard
No. 7A
• Chip Complexity: 108 FETs or 27 Equivalent Gates
LOGIC DIAGRAM
2
5
11
14
3
6
10
13
4
7
9
12
1
15
A0
A1
A2
A3
B0
B1
B2
B3
Y0
Y1
Y2
Y3
SELECT
OUTPUT
ENABLE
NONINVERTING
NIBBLE
OUTPUT
NIBBLE
A INPUT
NIBBLE
B INPUT
PIN 16 = V
CC
PIN 8 = GND
PIN ASSIGNMENT
13
14
15
16
9
10
11
125
4
3
2
1
8
7
6
Y3
B3
A3
OUTPUT
ENABLE
V
CC
Y2
B2
A2
Y0
B0
A0
SELECT
GND
Y1
B1
A1
FUNCTION TABLE
Inputs Outputs
Output
Enable Select Y0 – Y3
H X Z
L L A0 – A3
L H B0 – B3
X = don’t care
Z = high impedance
A0– A3, B0–B3 = the levels of the
respective Nibble Inputs.
D SUFFIX
SOIC PACKAGE
CASE 751B–05
N SUFFIX
PLASTIC PACKAGE
CASE 648–08
1
16
1
16
ORDERING INFORMATION
MC74HCXXXN
MC74HCXXXD
Plastic
SOIC
MC74HC257
MOTOROLA High–Speed CMOS Logic Data
DL129 — Rev 6
2
DC Supply Voltage (Referenced to GND)
DC Input Voltage (Referenced to GND)
DC Output Voltage (Referenced to GND)
DC Input Current, per Pin
DC Output Current, per Pin
DC Supply Current, VCC and GND Pins
Power Dissipation in Still Air Plastic DIP†
SOIC Package†
Lead Temperature, 1 mm from Case for 10 Seconds
(Plastic DIP or SOIC Package)
_
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
For high frequency or heavy load considerations, see Chapter 2 of the Motorola High–Speed CMOS Data Book (DL129/D).
RECOMMENDED OPERATING CONDITIONS
DC Supply Voltage (Referenced to GND)
DC Input Voltage, Output Voltage (Referenced to GND)
Operating Temperature, All Package Types
Input Rise and Fall Time VCC = 2.0 V
(Figure 1) VCC = 4.5 V
VCC = 6.0 V
ns
DC ELECTRICAL CHARACTERISTICS (Voltages Referenced to GND)
Minimum High–Level Input
Voltage
V
out
= 0.1 V or VCC – 0.1 V
|I
out
| v 20 µA
Maximum Low–Level Input
Voltage
V
out
= 0.1 V or VCC – 0.1 V
|I
out
| v 20 µA
Minimum High–Level Output
Voltage
Vin = VIH or V
IL
|I
out
| v 20 µA
Vin = VIH or VIL|I
out
| v 6.0 mA
|I
out
| v 7.8 mA
Maximum Low–Level Output
Voltage
Vin = VIH or V
IL
|I
out
| v 20 µA
Vin = VIH or VIL|I
out
| v 6.0 mA
|I
out
| v 7.8 mA
Maximum Input Leakage Current
Maximum Three–State
Leakage Current
Output in High–Impedance State
Vin = VIL or V
IH
V
out
= VCC or GND
Maximum Quiescent Supply
Current (per Package)
Vin = VCC or GND
I
out
= 0 µA
µA
NOTE: Information on typical parametric values can be found in Chapter 2 of the Motorola High–Speed CMOS Data Book (DL129/D).
This device contains protection
circuitry to guard against damage
due to high static voltages or electric
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, Vin and
V
out
should be constrained to the
range GND v (Vin or V
out
) v VCC.
Unused inputs must always be
tied to an appropriate logic voltage
level (e.g., either GND or VCC).
Unused outputs must be left open.