Texas Instruments SN74AHCT157PWR

Overview

SN74AHCT157PWR from Texas Instruments is a quadruple 2-line to 1-line data selector/multiplexer IC designed for 4.5V–5.5V V_CC operation, featuring a common active-low strobe (G) input, true-data routing across four independent channels, and TTL-voltage-compatible inputs. It delivers 8mA output drive capability, 7.5ns typical propagation delay (CL = 15pF), and operates across –40°C to +85°C for industrial-grade logic interfacing in bus management and signal routing applications.

For engineers reviewing the SN74AHCT157PWR datasheet, SN74AHCT157PWR pinout, SN74AHCT157PWR application, or SN74AHCT157PWR equivalent, key selection criteria include its 16-pin TSSOP package, guaranteed 4.5V minimum supply voltage, latch-up immunity exceeding 250mA per JESD17, and compatibility with legacy TTL-level control signals in mixed-voltage digital systems.

Technical Context

The SN74AHCT157PWR implements four independent 2:1 multiplexers sharing a single active-low enable (G) input - when G is high, all Y outputs are forced low; when G is low, each Y output reflects the selected A or B input based on the common address select (A/B) line. Its positive-logic function table defines deterministic output behavior across all input combinations without internal latching or memory.

This device uses advanced CMOS technology to achieve TTL-compatible input thresholds (V_IL = 0.8V max, V_IH = 2.0V min) while maintaining CMOS-level power efficiency (I_CC ≤ 20μA at V_CC = 5.5V) and robust noise immunity (V_OL(P) ≤ 0.8V, V_OH(V) ≥ 1.8V under dynamic load).

Key Specifications

Pinout & Package

TSSOP-16 (PW) package: 5.0mm × 4.4mm body size, 1.2mm max height, 0.65mm lead pitch, exposed pad not present. RoHS-compliant, NIPDAU/SN lead finish, MSL Level-1.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 2:1 multiplexer applications.

Compared with SN74AHCT157PWR, SN74AHCT158PWR provides identical functionality with inverted outputs - useful for complemented logic but requiring signal polarity adjustment, while 74LVC157PW,118 offers superior speed and lower voltage operation but sacrifices 5V TTL compatibility essential for industrial retrofits and mixed-signal interfaces.

Availability

SN74AHCT157PWR is available at Aetrix Electronics and suitable for industrial control systems, test equipment signal routing, and embedded bus arbitration requiring stable component supply, long-term lifecycle support, and guaranteed RoHS compliance.

Supply support for SN74AHCT157PWR 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 leader specializing in analog, embedded processing, and logic solutions, with over 50 years of innovation in high-reliability logic families.

The SN74AHCT logic family targets industrial and automotive applications requiring TTL-compatible inputs, 5V operation, and robust ESD/latch-up performance - specifically engineered for signal integrity in electrically noisy environments.

FAQ

What is the maximum operating frequency supported by the SN74AHCT157PWR?

The SN74AHCT157PWR does not specify a maximum clock frequency in its datasheet, as it is a combinational logic device without internal clocking. Its usable data rate is determined by propagation delay (7.5ns max at CL = 15pF) and system-level timing margins. For reliable operation, input setup/hold times must be met relative to the strobe (G) and address (A/B) edges, supporting effective switching rates up to approximately 100MHz in well-designed PCB layouts with controlled trace impedance and proper decoupling.

Does the SN74AHCT157PWR require external pull-up or pull-down resistors on unused inputs?

Yes, all unused inputs of the SN74AHCT157PWR must be held at a defined logic level - either V_CC or GND - to prevent floating states that cause increased ICC, erratic output behavior, or ESD susceptibility. TI's application report SCBA004 explicitly mandates this practice. Leaving inputs unconnected violates recommended operating conditions and may result in unpredictable functional modes or accelerated device degradation over time.

Can the SN74AHCT157PWR operate reliably at 4.5V supply voltage?

Yes, the SN74AHCT157PWR is fully specified for operation at V_CC = 4.5V, with all electrical characteristics (including VOL ≤ 0.44V at I_OL = 8mA and t_PD ≤ 7.5ns) guaranteed across the full 4.5V–5.5V range. This makes it suitable for systems where 5V rails experience nominal droop under load, such as in power-constrained industrial modules or battery-backed subsystems.

Is the SN74AHCT157PWR pin-compatible with other packages in the same logic family?

No - the SN74AHCT157PWR uses the 16-pin TSSOP (PW) package with 0.65mm pitch and 5.0mm × 4.4mm body size. While functionally identical to SN74AHCT157DR (SOIC-D) and SN74AHCT157DBR (SSOP-DB), these variants have different footprints, thermal characteristics (e.g., R_θJA = 135.9°C/W for PW vs 82°C/W for DB), and soldering requirements. PCB layout and reflow profiles must be validated per package-specific mechanical drawings.

What is the purpose of the strobe (G) pin on the SN74AHCT157PWR?

The strobe (G) pin on the SN74AHCT157PWR is an active-low enable input that globally controls output state: when G = high, all four Y outputs are forced low regardless of A/B or data inputs; when G = low, the multiplexer functions normally, routing selected A or B inputs to corresponding Y outputs. This enables synchronized bus gating, power-aware signal isolation, and clean state initialization in complex digital systems.