Texas Instruments SN74HC139PWR

Overview

SN74HC139PWR from Texas Instruments is a dual 2-line-to-4-line decoder/demultiplexer in TSSOP-16 package, operating from 2 V to 6 V with typical propagation delay of 10 ns at 5 V and ±4-mA output drive capability. It features two independent decoders, each with active-low enable (G) for cascading or data routing, and is used in high-speed memory decoding and address demultiplexing in microcontroller-based systems.

For engineers reviewing the SN74HC139PWR datasheet, SN74HC139PWR pinout, SN74HC139PWR application, or SN74HC139PWR equivalent, key selection criteria include its dual-decoder architecture, low ICC (80 μA max), LSTTL-load compatibility (up to 10 loads), and TSSOP-16 footprint suitability for space-constrained PCB layouts.

Technical Context

The SN74HC139PWR implements two fully buffered CMOS decoders sharing no internal logic-each operates independently with dedicated A/B select inputs and active-low G enable. Its outputs are active-low open-drain–compatible (high-impedance when disabled, low only on selected channel), enabling wired-OR configurations and direct interface with TTL loads.

Propagation delay is tightly controlled across voltage (2–6 V) and temperature (−40°C to +85°C), with tpd = 12 ns (max) at 6 V and 38 ns (max) at 2 V. Input hysteresis is not specified; all unused inputs must be tied to VCC or GND per TI's SCBA004 guidance to prevent floating-node-induced current leakage or oscillation.

Key Specifications

Pinout & Package

TSSOP-16 package (5.00 mm × 4.40 mm, 1.2 mm max height), RoHS-compliant, NIPDAU/SN lead finish, MSL Level-1 (260°C peak reflow).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HC139PWR, SN74HCT139PWR offers superior noise immunity in 5 V legacy systems but consumes ~15% more ICC; 74LV139PW delivers faster switching at 3.3 V but lacks 5 V input tolerance, limiting retrofit use.

Availability

SN74HC139PWR is available at Aetrix Electronics and suitable for industrial control panels, medical diagnostic interfaces, and test equipment requiring stable component supply with long-term lifecycle support.

Supply support for SN74HC139PWR 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 connectivity technologies, with over 90 years of innovation in industrial, automotive, and consumer electronics.

The SN74HC139PWR belongs to TI's 74HC logic family, designed for high-speed, low-power digital signal routing in memory subsystems and peripheral interface architectures.

FAQ

What is the maximum operating frequency supported by SN74HC139PWR?

The SN74HC139PWR does not specify a maximum clock frequency, as it is a combinational logic device. Its usable switching rate is determined by propagation delay: at 5 V, tpd = 10 ns typical, supporting reliable operation up to ~50 MHz in address decode paths with adequate setup/hold margins. System-level timing must account for worst-case tpd = 38 ns at 2 V.

Can SN74HC139PWR drive LEDs directly?

Yes - SN74HC139PWR outputs can sink up to 4 mA at 5 V (VOL ≤ 0.26 V), sufficient to drive low-current indicator LEDs with series resistors ≥ 1 kΩ. For higher-brightness LEDs requiring >5 mA, an external transistor buffer is recommended to avoid exceeding absolute max output current (±25 mA).

Is SN74HC139PWR pin-compatible with SN74LS139?

No - SN74HC139PWR (TSSOP-16) and SN74LS139 (SOIC-16 or PDIP-16) share identical pin functions and numbering, but differ in electrical characteristics: HC uses CMOS inputs (μA leakage), LS uses bipolar TTL inputs (mA-level input current). Physical pinout matches, but direct substitution requires verifying VCC, loading, and noise margin compatibility.

Does SN74HC139PWR require external pull-up resistors on outputs?

No - SN74HC139PWR outputs are push-pull (not open-drain), actively driving high or low. Pull-ups are unnecessary and may cause contention if connected to VCC while output is low. External pull-ups are only needed if interfacing with open-collector systems or implementing wired-OR logic with multiple decoders.

What is the thermal resistance (RθJA) of SN74HC139PWR in its TSSOP package?

The SN74HC139PWR in TSSOP-16 (PW) package has a junction-to-ambient thermal resistance (RθJA) of 108°C/W, per TI's SCLS108E datasheet. This value assumes standard JEDEC 2S2P board layout; actual performance improves with copper pour and thermal vias under the exposed pad (if present) - though PW package has no thermal pad.