74HC257 Quad 2-input multiplexer IC

74HC257 IC Quad 2-input
multiplexer

The 74HC257 is a high-performance CMOS quad 2-input multiplexer that packages four independent 2-to-1 data selectors plus a common select input and a 3-state output enable. Each section selects between its A and B input pair and presents the selected signal on the corresponding Y output. Built in the HC family, the device combines low static power consumption with switching speeds suitable for bus-oriented systems and medium-speed logic.

Designed for bus interfacing and source-selection tasks, the 74HC257s three-state outputs let multiple devices share a common bus without loading it when output enable (G) is asserted high. The chip accepts standard CMOS input levels across a wide supply range and is pin-compatible with related HC logic, easing substitution and mixed-family designs. Typical use includes routing data lines, selecting between memory or peripheral sources, and simple data-path multiplexing.

Available in PDIP, SOIC, TSSOP and other packages with industry-standard pinouts, the
74HC257
is commonly used where compact, deterministic selection of parallel signals is required. Its low input currents and guaranteed noise margins make it a dependable building block for embedded systems, address/data multiplexing, and multi-source bus architectures.

Features:

Quad 2-input multiplexers with common select (A/B) and 3-state output enable (G).

Wide operating supply range: 2 V to 6 V.

Low power consumption (ICC typically very small; max 80 A).

Typical propagation delay for HC257 9 ns (fast switching in HC family).

3-state outputs allow bus-sharing without loading when disabled.

Low input current (typical 1 A) and good noise margins for robust logic.

Specifications:

Parameter

Value / Condition

Part / Function:

SN74HC257 Quad 2-input multiplexer, 3-state outputs.

Recommended VCC (HC):

2.0 V to 6.0 V.

Absolute-maximum VCC:

0.5 V to +7.0 V.

propagation delay (tpd):

9 ns See switching tables for VCC dependency.

Output drive:

6 mA output drive at VCC = 5 V (typical rating).

Input current (II):

Typ 1 A (VI = VCC or GND).

ICC (supply current):

Typ microamps; spec sheet shows up to 80 A (max conditions).

I/O tri-state leakage (IOZ):

Specified in datasheet (A range see electrical table).

Input thresholds (VIH / VIL):

VIH / VIL scale with VCC see recommended operating conditions.

Operating temperature (TA):

40 C to +85 C (commercial), versions to 55 C/+125 C for military CDIP.

Package options:

PDIP, SOIC, SOP, TSSOP, CDIP, LCCC

Pinout Diagram:

Footprint Diagram:

Applications:

Bus-oriented systems and multi-source bus interfacing.

Data path selection and routing in digital systems.

Address/data multiplexing for memory or peripheral selection.

Microcontroller / FPGA glue logic for source selection.

Package Contents:

1x
74HC257 Quad 2-input multiplexer IC

Datasheet