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 74HC257’s 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 µA).
- 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 µA) 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 µA (VI = VCC or GND). |
| ICC (supply current): | Typ microamps; spec sheet shows up to ≈80 µA (max conditions). |
| I/O tri-state leakage (IOZ): | Specified in datasheet (µA 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
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