Texas Instruments SN74F253NS

Overview

SN74F253NS from Fairchild Semiconductor is a dual 4-input multiplexer with non-inverting 3-STATE outputs, operating at +4.5V to +5.5V supply voltage, with propagation delays as low as 2.5 ns (tPHL, In to Zn), and designed for bus-oriented digital systems requiring output isolation via independent OEa/OEb controls.

For engineers reviewing the SN74F253NS datasheet, SN74F253NS pinout, SN74F253NS application, or SN74F253NS equivalent, key selection criteria include common S0/S1 select logic, active-low output enables, 24 mA sink capability per output, high fan-out (150 U.L. HIGH / 40 U.L. LOW), and compatibility with TTL-level signaling in industrial control and data routing circuits.

Technical Context

The SN74F253NS implements two independent 4:1 multiplexers sharing S0 and S1 address inputs, each with dedicated active-low Output Enable (OEa, OEb) enabling true bus contention avoidance. Its logic equations define Za and Zb as product-of-sums expressions gated by OE states and minterms of S0/S1.

It operates within 0°C to +70°C ambient temperature, requires VCC = +4.5V to +5.5V, and meets TTL input thresholds (VIH ≥ 2.0 V, VIL ≤ 0.8 V) and output drive specs (VOH ≥ 2.4 V at IOH = −3 mA, VOL ≤ 0.5 V at IOL = 24 mA), ensuring interoperability with standard 74F logic families.

Key Specifications

Pinout & Package

SN74F253NS is supplied in a 16-lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300" wide, with through-hole mounting and industry-standard pin spacing.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual 4-input multiplexer applications.

Compared with SN74LS253N and SN74HC253N, the SN74F253NS delivers optimal balance of speed (≤6 ns typical delay), drive strength (24 mA), and TTL interoperability-making it the preferred choice for performance-critical industrial bus architectures where timing predictability and load drive are non-negotiable.

Availability

SN74F253NS is available at Aetrix Electronics and suitable for industrial PLC I/O expansion, legacy bus data multiplexing, and test equipment signal routing requiring stable component supply and long-term obsolescence management.

Supply support for SN74F253NS includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Fairchild Semiconductor was a leading US-based analog and discrete semiconductor manufacturer, acquired by ON Semiconductor in 2016; its 74F logic family remains widely deployed in industrial and military-grade systems.

The SN74F253NS belongs to Fairchild's 74F Fast TTL logic product line, engineered for high-speed digital control, data routing, and bus interface applications where propagation delay and drive strength are critical.

FAQ

What is the maximum operating temperature range for the SN74F253NS?

The SN74F253NS is specified for commercial operation from 0°C to +70°C ambient temperature. Its absolute maximum junction temperature is +150°C, and storage temperature range extends from −65°C to +150°C. This makes the SN74F253NS suitable for indoor industrial environments but not extended-temperature applications such as automotive under-hood or outdoor telecom enclosures without thermal derating.

Does the SN74F253NS support live insertion or hot-swap operation?

The SN74F253NS does not include built-in hot-swap protection features like slew-rate limiting or undervoltage lockout. However, its 3-STATE outputs and active-low OE inputs allow controlled bus entry/exit when sequenced properly. For safe live insertion, external current-limiting resistors and staggered VCC/GND connection are recommended-always verify timing margins using tPZH (3.0 ns min) and tPHZ (2.0 ns min) in the SN74F253NS datasheet.

Can the S0 and S1 inputs of the SN74F253NS be driven directly from a microcontroller GPIO?

Yes-the SN74F253NS S0 and S1 inputs meet standard TTL input thresholds (VIH ≥ 2.0 V, VIL ≤ 0.8 V) and draw only ±20 µA at valid logic levels. Most 5 V-tolerant microcontroller GPIOs (e.g., legacy 8051, PIC16F, AVR) can drive them directly without buffering. Confirm that the MCU's VOL stays below 0.8 V and VOH exceeds 2.0 V under loaded conditions per the SN74F253NS input current spec.

What is the purpose of the IOZH and IOZL parameters in the SN74F253NS datasheet?

IOZH and IOZL specify the leakage current into or out of the SN74F253NS outputs (Za/Zb) when in the high-impedance state-IOZH = +50 µA max at VOUT = 2.7 V (HIGH), IOZL = −50 µA max at VOUT = 0.5 V (LOW). These values quantify off-state isolation quality; low leakage ensures minimal bus loading and crosstalk when other devices drive the same line, critical for reliable multi-drop bus operation.

Is the SN74F253NS pin-compatible with the SN74F153?

No-the SN74F253NS and SN74F153 are not pin-compatible. While both are dual 4:1 multiplexers, the SN74F153 uses active-HIGH output enables and has different pin assignments (e.g., OEa/OEb on pins 1/15 vs. SN74F253NS on pins 7/13). Substituting them requires PCB redesign. Always verify pin mapping and enable polarity before replacement; the SN74F253NS datasheet confirms OEa/OEb are active LOW and located on pins 7 and 13 respectively.