Texas Instruments SN74F253N

Overview

SN74F253N from Texas Instruments is a dual 4-line to 1-line data selector/multiplexer with independent 3-state outputs, operating at 4.5–5.5 V supply voltage, 0°C to 70°C temperature range, and propagation delays as low as 1.7 ns (tPHL), used in bus-organized digital systems for parallel-to-serial conversion and signal routing.

For engineers reviewing the SN74F253N datasheet, SN74F253N pinout, SN74F253N application, or SN74F253N equivalent, key selection criteria include independent strobe-controlled 3-state outputs, TTL-compatible input thresholds (VIL = 0.8 V, VIH = 2 V), guaranteed 24 mA sink capability, and PDIP-16 package compatibility with legacy through-hole designs.

Technical Context

The SN74F253N implements two independent 4:1 multiplexer sections sharing common select inputs A and B, each with dedicated active-low strobe (G) control enabling high-impedance output states. Its logic diagram confirms full binary decoding via inverters and AND-OR gates, supporting simultaneous or isolated channel selection.

Each section drives its output (1Y or 2Y) only when its respective strobe is low; outputs enter high-impedance state when strobe is high. The device uses standard F-series TTL circuitry, delivering 2.4 V minimum VOH at −3 mA and 0.35 V maximum VOL at 24 mA, ensuring robust noise margins in mixed-logic systems.

Key Specifications

Pinout & Package

SN74F253N is supplied in a 16-pin plastic dual in-line package (PDIP-N), with 0.3-inch body width, through-hole mounting, and industry-standard pin spacing (0.1 inch). Pin 1 is located at the top-left corner adjacent to the notch or dot marking.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual 4:1 multiplexer applications.

Compared with SN74LS253N and SN74HC153N, the SN74F253N uniquely balances high-speed TTL performance (sub-10 ns delays) with robust 24 mA bus-driving capability-making it irreplaceable in legacy 5 V systems requiring both speed and load drive without level-shifting.

Availability

SN74F253N is available at Aetrix Electronics and suitable for microprocessor address decoding, legacy bus arbitration, and parallel-to-serial conversion requiring stable component supply and long-term obsolescence management.

Supply support for SN74F253N 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

Texas Instruments is a U.S.-based semiconductor company founded in 1930, specializing in analog, embedded processing, and logic solutions for industrial, automotive, and communications markets.

The SN74F253N belongs to TI's 74F TTL logic family, designed specifically for high-speed, high-drive digital systems requiring compatibility with legacy 5 V infrastructure and rigorous timing predictability.

FAQ

What is the maximum clock frequency supported by SN74F253N in multiplexing applications?

The SN74F253N does not operate on a clock signal-it is combinatorial logic. Its usable data rate depends on propagation delay and system setup/hold timing. With tPHL/tPLH ≤10 ns and typical bus loading, SN74F253N reliably supports data switching up to approximately 50 MHz in well-terminated 5 V TTL systems, provided input signals meet minimum pulse width requirements (≥8 ns).

Can SN74F253N be used with 3.3 V logic interfaces?

No-SN74F253N is strictly a 5 V TTL device. Its input thresholds (VIH = 2.0 V, VIL = 0.8 V) and output voltage levels (VOH ≥2.4 V, VOL ≤0.35 V at 24 mA) are specified only for 4.5–5.5 V VCC. Direct connection to 3.3 V logic risks undriven inputs and excessive current draw; level-shifting circuitry is required for interoperability.

Does SN74F253N have internal ESD protection diodes?

Yes-SN74F253N includes standard TTL input clamp diodes, rated for ±18 mA input clamp current (IIK) and −1.2 V minimum VIK. These protect against transient overvoltage but do not replace system-level ESD safeguards; external series resistors (≥100 Ω) are recommended for I/O pins exposed to handling or connectors.

What is the thermal resistance (θJA) of SN74F253N in PDIP package?

Texas Instruments does not publish θJA for SN74F253N in the SDFS064A datasheet. However, based on JEDEC-standard PDIP-16 package characteristics and F-series power dissipation (ICCL ≈23 mA at 5.5 V), typical θJA is ~70°C/W on 1-inch² FR-4 board with 2 oz copper. For thermal design, assume 125 mW max power dissipation and verify junction temperature under worst-case ambient and airflow conditions.

Are the 1G and 2G inputs compatible with open-collector drivers?

Yes-1G and 2G are active-low TTL inputs with standard input current specs (IIL = −0.6 mA, IIH = 20 µA). They can be directly driven by open-collector logic (e.g., 7405) or microcontroller GPIO pins configured with pull-up resistors (≤10 kΩ). No additional buffering is needed, and the inputs tolerate the full −1.2 V to 7 V input voltage range per absolute maximum ratings.