Texas Instruments SN74AHCT157DG4

Overview

SN74AHCT157DG4 from Texas Instruments is a quadruple 2-line to 1-line data selector/multiplexer IC operating at 4.5V–5.5V V_CC, featuring TTL-compatible inputs, active-low strobe (G), true outputs, and 16-pin TSSOP packaging. It routes one of two 4-bit input words to four outputs based on address select (A/B) and strobe state, used in digital logic routing, bus arbitration, and signal path selection in industrial control and embedded systems.

For engineers reviewing the SN74AHCT157DG4 datasheet, SN74AHCT157DG4 pinout, SN74AHCT157DG4 application, or SN74AHCT157DG4 equivalent, this page delivers verified functional modes, switching characteristics (t_PLH/t_PHL ≤ 9.5 ns @ 5V, CL = 15 pF), absolute maximum ratings, thermal metrics (R_θJA = 135.9 °C/W), and real-world layout guidance for noise-sensitive 5V logic designs.

Technical Context

The SN74AHCT157DG4 implements positive-logic multiplexing with independent channel enable via common active-low strobe (G): when G = HIGH, all Y outputs are forced LOW; when G = LOW, each Y_n passes A_n or B_n based on the shared A/B select line. Its CMOS output stage drives ±8 mA at V_CC = 5V with VOL ≤ 0.44 V and VOH ≥ 3.8 V under load.

Designed for 4.5V–5.5V operation, it meets JESD 17 latch-up immunity (>250 mA), supports TTL-voltage compatible inputs (VIH = 2 V, VIL = 0.8 V), and exhibits low dynamic power dissipation (C_pd = 11 pF). Input transition rate is specified at ≤20 ns/V to ensure reliable timing margin across temperature (–40°C to +85°C).

Key Specifications

Pinout & Package

SN74AHCT157DG4 uses a 16-pin TSSOP (PW) package measuring 5.0 mm × 4.4 mm body size and 5.0 mm × 6.4 mm overall footprint, with 0.65 mm lead pitch and exposed pad not present. Pin 1 index is located at top-left corner with notch marking orientation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74AHCT157DR and SN74LVC157APWR, the SN74AHCT157DG4 offers optimal 5V system integration with industry-standard TSSOP thermal performance (R_θJA = 135.9 °C/W), making it ideal for space-constrained industrial PCBs requiring proven 5V interoperability and latch-up resilience.

Availability

SN74AHCT157DG4 is available at Aetrix Electronics and suitable for industrial automation, test equipment, and embedded control applications requiring stable component supply, long-term manufacturability, and automotive-qualified alternatives (e.g., SN74AHCT157-Q1) for future scalability.

Supply support for SN74AHCT157DG4 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 delivering analog, embedded processing, and logic solutions with emphasis on reliability, longevity, and industrial-grade qualification.

The SN74AHCT157DG4 belongs to TI's 74AHCT logic family, engineered for robust 5V operation in noise-prone environments-designed specifically for industrial control, instrumentation, and legacy-system interface bridging where TTL compatibility and latch-up immunity are critical.

FAQ

What is the maximum operating temperature for SN74AHCT157DG4?

The SN74AHCT157DG4 is rated for operation from –40°C to +85°C ambient temperature. This industrial temperature range is validated per TI's recommended operating conditions and supported by thermal characterization (R_θJA = 135.9 °C/W for PW package), ensuring reliable performance in factory-floor and outdoor-mounted electronics where thermal cycling occurs.

Does SN74AHCT157DG4 support 3.3V logic inputs?

No, SN74AHCT157DG4 does not reliably support 3.3V logic inputs. Its input thresholds are TTL-compatible (VIH = 2.0 V min, VIL = 0.8 V max) but require V_CC = 4.5–5.5 V for specification compliance. Applying 3.3V signals risks marginal switching and increased static current (II ≤ ±1 μA only within 0–5.5 V at V_CC = 5.5 V), so level translation is recommended for mixed-voltage systems.

How does the strobe (G) pin function in SN74AHCT157DG4?

In SN74AHCT157DG4, the G pin is an active-low strobe that globally disables multiplexing: when G = HIGH, all four Y outputs are forced LOW regardless of A/B or data inputs; when G = LOW, normal 2:1 selection resumes. This enables synchronized bus blanking, power-aware gating, or safe state initialization in safety-critical logic sequencing.

What is the typical power consumption of SN74AHCT157DG4 at 5V?

At V_CC = 5V and TA = 25°C, SN74AHCT157DG4 exhibits ICC ≤ 20 μA (max) under static conditions and ΔICC ≤ 1.5 mA per toggling input. Dynamic power is characterized by C_pd = 11 pF, yielding ~0.55 mW at 1 MHz toggle rate (P = C_pd × V_CC² × f), making it suitable for low-power industrial modules with burst-mode operation.

Can SN74AHCT157DG4 be used in place of SN74LS157?

SN74AHCT157DG4 can replace SN74LS157 in most 5V systems due to identical pinout, function table, and TTL-compatible inputs-but with key improvements: CMOS output drive (±8 mA vs. LS's ±8 mA sink only), lower ICC (20 μA vs. LS's 19 mA), and superior noise immunity. However, verify layout for TSSOP thermal relief and ensure G pin is actively driven, as LS157 lacks explicit strobe control in some variants.