Texas Instruments SN74AHC2G157HDCT3

Overview

SN74AHC2G157HDCT3 from Texas Instruments is a dual 2-line-to-1-line data selector/multiplexer in an 8-pin DCT package (2.95 × 2.80 × 1.1 mm), operating from 2.0 V to 5.5 V V_CC, with typical propagation delay of 6.2 ns at 3.0 V/15 pF, I_CC ≤ 2 µA at 25 °C, and true-output logic for routing one of two input bits to a single output pair (Y/Y̅) under strobe control. It serves in signal routing for low-voltage microcontroller I/O expansion and digital logic level translation.

For engineers reviewing the SN74AHC2G157HDCT3 datasheet, SN74AHC2G157HDCT3 pinout, SN74AHC2G157HDCT3 application, or SN74AHC2G157HDCT3 equivalent, key selection criteria include its dual-channel 2:1 multiplexing capability, guaranteed operation across industrial temperature (–40 °C to +85 °C), rail-to-rail input tolerance (VIH up to 5.5 V), low static current, and complementary true/inverted outputs.

Technical Context

The SN74AHC2G157HDCT3 implements positive-logic 2:1 multiplexing per channel using a common active-low strobe (G) that forces both Y and Y̅ low when high. When G is low, the A/B select line determines whether input A or B passes to Y (true) and Y̅ (inverted). Each channel operates independently with no internal inter-channel coupling.

It uses advanced CMOS AHC technology enabling full 2-V to 5.5-V operation, TTL-compatible input thresholds at all V_CC levels, and robust noise immunity-V_IHD = 3.5 V and V_ILD = 1.5 V at 5 V-with dynamic output voltage swing bounded by VOLP/VOLV specifications.

Key Specifications

Pinout & Package

Package: 8-pin DCT (Small Outline No-Lead, 2.95 mm × 2.80 mm × 1.1 mm, 0.65 mm pitch), moisture sensitivity level 1 (MSL-1), RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 2-line-to-1-line multiplexer applications.

Compared with SN74LVC2G157DCTR and 74AUP2G157GS,115, the SN74AHC2G157HDCT3 delivers the best balance of wide V_CC range (2–5.5 V), lowest I_CC among AHC-family 2G muxes, and fastest propagation-making it optimal for industrial systems requiring interoperability across legacy and modern voltage rails.

Availability

SN74AHC2G157HDCT3 is available at Aetrix Electronics and suitable for industrial automation interfaces, embedded sensor hubs, and programmable logic control modules requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for SN74AHC2G157HDCT3 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 headquartered in Dallas, Texas, delivering analog and embedded processing solutions for industrial, automotive, and personal electronics markets.

The SN74AHC2G157HDCT3 belongs to TI's AHC logic family-designed for high-speed, low-power, mixed-voltage digital signal routing in space-constrained industrial and automotive control units.

FAQ

What is the function of the G (strobe) pin on the SN74AHC2G157HDCT3?

The G pin is an active-low strobe enable input. When G is high, both Y and Y̅ outputs are forced low regardless of the states of A, B, or A/B. When G is low, the device performs normal 2:1 multiplexing based on the A/B select line. This feature allows global disabling of the output path-critical for bus contention avoidance and power-gated operation in the SN74AHC2G157HDCT3.

Does the SN74AHC2G157HDCT3 support 1.8 V operation?

No, the SN74AHC2G157HDCT3 has a minimum V_CC rating of 2.0 V per its recommended operating conditions. Attempting to operate below 2.0 V may result in undefined logic behavior, increased propagation delay, or failure to meet VOL/VOH specifications. For 1.8 V systems, consider the SN74LVC2G157DCTR instead of the SN74AHC2G157HDCT3.

Can unused inputs on the SN74AHC2G157HDCT3 be left floating?

No. Per the datasheet's Note 3, all unused inputs-including A, B, A/B, and G-must be held at either V_CC or GND to ensure proper device operation and prevent increased ICC or erratic switching. Floating inputs risk oscillation, excessive power draw, or false triggering, especially in noisy industrial environments where the SN74AHC2G157HDCT3 is commonly deployed.

What is the meaning of Y and Y̅ outputs on the SN74AHC2G157HDCT3?

Y is the true output and Y̅ is its logical inverse-both driven simultaneously from the selected input (A or B) when G is low. This complementary pair enables direct connection to differential receivers or latch-based sampling circuits without external inversion. The SN74AHC2G157HDCT3 guarantees matched propagation delays between Y and Y̅, supporting clean edge-aligned timing in synchronous designs.

Is the SN74AHC2G157HDCT3 pin-compatible with other 8-pin DCT logic muxes?

The SN74AHC2G157HDCT3 shares the same 8-pin DCT footprint and pin assignment with SN74LVC2G157DCTR and SN74AUP2G157GS,115, but electrical compatibility depends on V_CC, speed, and drive requirements. While mechanical mounting is identical, substituting without verifying VIH/VIL thresholds, propagation delay, and output drive strength may compromise system timing-always validate against the SN74AHC2G157HDCT3's specific operating conditions.