Texas Instruments SN74AHCT139PWRE4

Overview

SN74AHCT139PWRE4 from Texas Instruments is a dual 2-line-to-4-line decoder/demultiplexer in TSSOP-16 package, operating at 4.5–5.5 V, with propagation delays as low as 1 ns (tPLH/tPHL at CL = 15 pF), TTL-compatible inputs, and ±8 mA output drive. It serves in high-speed memory decoding and data-routing systems where minimal system delay is critical.

For engineers reviewing the SN74AHCT139PWRE4 datasheet, SN74AHCT139PWRE4 pinout, SN74AHCT139PWRE4 application, or SN74AHCT139PWRE4 equivalent, key selection criteria include its dual-decoder architecture with independent active-low enables (1G, 2G), guaranteed 16-pin TSSOP mechanical compatibility, 85°C industrial temperature rating, and verified 5-V logic-level interoperability with legacy TTL and CMOS systems.

Technical Context

The SN74AHCT139PWRE4 implements two independent 2-to-4 decoders, each with separate select inputs (A/B) and active-low enable (G). Its fully buffered inputs present only one normalized load, minimizing fanout burden on driving circuits.

Each decoder features noninverting outputs (Y0–Y3) and supports demultiplexing via the G input acting as a data line. The device meets JESD 17 latch-up immunity (>250 mA) and JESD 22 ESD ratings (2000-V HBM, 200-V MM, 1000-V CDM), ensuring robust operation in industrial environments.

Key Specifications

Pinout & Package

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

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual decoder/demultiplexer applications.

Compared with SN74AHCT139PWRE4, SN74AHCT138PWR offers greater decoding depth but lacks independent dual enables and requires PCB redesign, while 74LV139PWRE4 trades off 5-V noise immunity for broader voltage flexibility and lower quiescent power - making SN74AHCT139PWRE4 optimal for fixed 5-V industrial memory/data routing.

Availability

SN74AHCT139PWRE4 is available at Aetrix Electronics and suitable for industrial control systems, memory subsystems, and peripheral interface designs requiring stable component supply, long-term lifecycle support, and RoHS-compliant TSSOP packaging.

Supply support for SN74AHCT139PWRE4 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 decades of heritage in industry-standard logic families.

The SN74AHCT139PWRE4 belongs to TI's advanced high-speed CMOS (AHCT) logic portfolio, engineered specifically for low-propagation-delay memory decoding and data-routing applications in industrial and computing infrastructure.

FAQ

What is the maximum clock frequency supported by SN74AHCT139PWRE4?

The SN74AHCT139PWRE4 is not a clocked device and has no internal clock; it operates asynchronously. Its usable toggle rate is limited by propagation delay and load capacitance - with 15-pF loads, it reliably handles address/data transitions up to ~100 MHz (based on 8.5 ns tPD). System-level timing must account for worst-case delay plus setup/hold margins. SN74AHCT139PWRE4 does not specify a maximum frequency rating because it is combinational logic.

Can SN74AHCT139PWRE4 drive LEDs directly?

SN74AHCT139PWRE4 can sink or source up to 8 mA per output, sufficient to drive low-current indicator LEDs (e.g., 2-mA green LED with 1.8-V VF) using a series resistor (e.g., 390 Ω at 5 V). However, outputs are not designed for continuous DC current; sustained operation near 8 mA may elevate junction temperature. For high-brightness or multiplexed LED arrays, use external drivers. SN74AHCT139PWRE4 is intended for logic-level interfacing, not power switching.

Is SN74AHCT139PWRE4 pin-compatible with SN74HC139PWR?

No. Although both are dual 2-to-4 decoders in TSSOP-16, SN74AHCT139PWRE4 and SN74HC139PWR differ in input threshold voltages (AHCT: TTL-compatible; HC: CMOS-compatible), propagation delay (AHCT faster at 5 V), and output drive strength (AHCT: ±8 mA; HC: ±4 mA). Pin numbering matches, but electrical behavior is not interchangeable without verifying signal integrity and timing margins. SN74AHCT139PWRE4 requires explicit validation in HC-based designs.

Does SN74AHCT139PWRE4 require external pull-up resistors on outputs?

No. SN74AHCT139PWRE4 features totem-pole (push-pull) outputs capable of actively driving both high and low logic states. Pull-ups are unnecessary unless interfacing with open-drain systems or implementing wired-AND logic. In standard 5-V CMOS/TTL loads, SN74AHCT139PWRE4 outputs switch cleanly between VOH ≥3.8 V and VOL ≤0.44 V at 8 mA, meeting interface requirements without external components.

What is the thermal resistance (θJA) of SN74AHCT139PWRE4 in its TSSOP package?

The SN74AHCT139PWRE4 in the TSSOP-16 (PW) package has a specified junction-to-ambient thermal resistance (θJA) of 108°C/W under JEDEC-standard conditions (1-layer board, no copper pour). This value assumes minimal PCB copper; adding thermal vias and a 1-in² copper plane beneath the package can reduce effective θJA by ~30–40%. SN74AHCT139PWRE4 maximum power dissipation at 85°C ambient is ~185 mW (calculated from (125°C – 85°C)/108°C/W), consistent with typical 13-pF Cpd and 1-MHz operation.