CD74HC251 Datasheet, PDF (1/7 Pages) Texas Instruments – High Speed CMOS Logic 8-Input Multiplexer; Three-State

Data sheet acquired from Harris Semiconductor
SCHS169
November 1997
CD74HC251,
CD74HCT251
High Speed CMOS Logic
8-Input Multiplexer; Three-State
[ /Title
(CD74
HC251
,
CD74
HCT25
1)
/Sub-
ject
(High
Speed
CMOS
Logic
8-Input
Multi-
plexer;
Three-
Features
Description
• Selects One of Eight Binary Data Inputs
• Three-State Output Capability
• True and Complement Outputs
• Typical (Data to Output) Propagation Delay of 14ns at
V_CC = 5V, C_L = 15pF, T_A = 25^oC
• Fanout (Over Temperature Range)
- Standard Outputs . . . . . . . . . . . . . . . 10 LSTTL Loads
- Bus Driver Outputs . . . . . . . . . . . . . 15 LSTTL Loads
• Wide Operating Temperature Range . . . -55^oC to 125^oC
• Balanced Propagation Delay and Transition Times
• Significant Power Reduction Compared to LSTTL
Logic ICs
• Alternate Source is Philips
- HC Types
- 2V to 6V Operation
- High Noise Immunity: N_IL = 30%, N_IH = 30% of V_CC
at V_CC = 5V
• HCT Types
- 4.5V to 5.5V Operation
- Direct LSTTL Input Logic Compatibility,
V_IL= 0.8V (Max), V_IH = 2V (Min)
- CMOS Input Compatibility, I_l ≤ 1µA at V_OL, V_OH
The Harris CD74HC251 and CD74HCT251 are 8-channel
digital multiplexers with three-state outputs, fabricated with
high-speed silicon-gate CMOS technology. Together with the
low power consumption of standard CMOS integrated cir-
cuits, they possess the ability to drive 10 LSTTL loads. The
three-state feature makes them ideally suited for interfacing
with bus lines in a bus-oriented system.
This multiplexer features both true (Y) and complement (Y)
outputs as well as an output enable (OE) input. The OE must
be at a low logic level to enable this device. When the OE
input is high, both outputs are in the high-impedance state.
When enabled, address information on the data select inputs
determines which data input is routed to the Y and Y out-
puts. The CD74HCT251 logic family is speed, function, and
pin-compatible with the standard 74LS251.
Ordering Information
PART NUMBER TEMP. RANGE (^oC) PACKAGE
PKG.
NO.
CD74HC251E
-55 to 125
16 Ld PDIP E16.3
CD74HCT251E
-55 to 125
16 Ld PDIP E16.3
CD74HC251M
-55 to 125
16 Ld SOIC M16.15
CD74HCT251M
-55 to 125
16 Ld SOIC M16.15
NOTES:
1. When ordering, use the entire part number. Add the suffix 96 to
obtain the variant in the tape and reel.
2. Wafer or die for this part number is available which meets all elec-
trical specifications. Please contact your local sales office or
Harris customer service for ordering information.
Pinout
CD74HC251, CD74HCT251
(PDIP, SOIC)
TOP VIEW
I₃ 1
I₂ 2
I₁ 3
I₀ 4
Y5
Y6
OE 7
GND 8
16 V_CC
15 I₄
14 I₅
13 I₆
12 I₇
11 S0
10 S1
9 S2
CAUTION: These devices are sensitive to electrostatic discharge. Users should follow proper IC Handling Procedures.
Copyright © Harris Corporation 1997
1
File Number 1489.1