Texas Instruments SN74LS153DR

Overview

SN74LS153DR from Texas Instruments is a dual 4-line-to-1-line data selector/multiplexer in a 16-pin SOIC package, operating over 0°C to 70°C, with typical propagation delay of 15 ns at V_CC = 5 V and I_OL = 8 mA, used for digital signal routing in TTL-compatible logic systems.

For engineers reviewing the SN74LS153DR datasheet, SN74LS153DR pinout, SN74LS153DR application, or SN74LS153DR equivalent, key selection considerations include its dual independent 4:1 multiplexing capability, TTL-level input compatibility, guaranteed fan-out of 10 LS-TTL loads, and RoHS-compliant NiPdAu lead finish with Level-1 moisture sensitivity rating.

Technical Context

The SN74LS153DR implements two identical 4-input multiplexers sharing common select (S0, S1) and enable (1G, 2G) controls, each with independent output (1Y, 2Y). Each multiplexer selects one of four data inputs (1A0–1A3 or 2A0–2A3) based on binary-coded select lines.

It operates strictly in the bipolar TTL logic family, requiring V_CC = 4.75 V to 5.25 V, with input thresholds defined at V_IL ≤ 0.8 V and V_IH ≥ 2.0 V, and outputs capable of sinking 8 mA while maintaining V_OL ≤ 0.5 V - fully compatible with legacy 74LS and 74L series systems.

Key Specifications

Pinout & Package

SN74LS153DR uses a 16-pin SOIC (D) package with 1.27 mm pitch, 7.5 mm body width, and 2.00 mm max height per TI drawing NS0016A. Pin 1 is located at the top-left corner with notch or beveled edge marking.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HC153DR and SN74LS253DR, the SN74LS153DR delivers optimal balance of legacy TTL compatibility, 8 mA output drive, and 15 ns speed - making it the preferred choice for retrofitting or maintaining existing LS-based designs without redesign.

Availability

SN74LS153DR is available at Aetrix Electronics and suitable for industrial PLC I/O expansion, legacy system data bus multiplexing, and test equipment signal switching requiring stable component supply and long-term obsolescence mitigation.

Supply support for SN74LS153DR 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 global semiconductor company founded in 1930, specializing in analog, embedded processing, and logic solutions with broad industrial and automotive qualification.

The SN74LS153DR belongs to TI's legacy 74LS logic family, designed specifically for backward-compatible upgrades of 74L and 74S systems while delivering improved speed-power trade-offs and manufacturing consistency.

FAQ

What logic family does the SN74LS153DR belong to, and why does it matter?

The SN74LS153DR belongs to the 74LS (Low-Power Schottky) TTL logic family. This matters because it defines strict input voltage thresholds (V_IL ≤ 0.8 V, V_IH ≥ 2.0 V), output drive capability (8 mA sink), and propagation delay (15 ns), ensuring interoperability with other 74LS, 74L, and 74S devices without level shifters or buffers. Using the SN74LS153DR in a mixed-logic system requires matching these electrical characteristics to avoid timing violations or signal integrity issues.

Can the SN74LS153DR replace the obsolete SN74153 or SN74S153 in an existing design?

Yes, the SN74LS153DR is a direct functional and pin-compatible replacement for SN74153 and SN74S153 in most cases. It retains identical pinout, DC electrical specifications, and 15 ns propagation delay - slightly faster than SN74153 (22 ns) and slower than SN74S153 (10 ns), but within acceptable margins for legacy timing budgets. The SN74LS153DR also features improved power efficiency versus SN74S153 and better noise immunity than SN74153, making it the recommended upgrade path.

What is the maximum clock frequency supported by the SN74LS153DR in a multiplexed data path?

The SN74LS153DR does not operate on a clock signal - it is asynchronous combinatorial logic. Its usable toggle rate is governed by propagation delay (15 ns max) and system setup/hold timing. In practice, it reliably supports data selection rates up to approximately 30 MHz in well-designed PCB layouts with proper decoupling. For higher-frequency applications, designers must verify that the total path delay (including select line routing and load capacitance) remains within the controller's timing budget - the SN74LS153DR itself imposes no clock limitation.

Does the SN74LS153DR support hot-swap or live-insertion in backplane applications?

No, the SN74LS153DR is not designed for hot-swap operation. It lacks power-up/down sequencing protection, bus-hold circuitry, or I²C-style open-drain outputs. Applying V_CC while inputs are driven, or removing power with active inputs, may cause latch-up or excessive current flow. For backplane applications requiring live insertion, consider purpose-built hot-swap controllers or buffer isolators upstream of the SN74LS153DR - the device itself must be powered and stabilized before enabling signal routing.

How does the enable logic (1G/2G) function in the SN74LS153DR, and what happens when both are asserted?

The SN74LS153DR uses active-low enables: 1G and 2G must both be low to activate their respective multiplexers. When either enable is high, its output (1Y or 2Y) enters high-impedance (Hi-Z) state - effectively disconnecting that channel from the bus. If both 1G and 2G are high, both outputs float Hi-Z, allowing safe wire-OR or bus-sharing configurations. This behavior is critical in shared-bus architectures where multiple SN74LS153DR devices coordinate access - the SN74LS153DR's enable structure prevents contention without external arbitration logic.