Texas Instruments SN74HCT139PWR

Overview

SN74HCT139PWR 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 10 ns typical propagation delay, ±4-mA output drive, and TTL-compatible inputs. It serves as a high-speed memory address decoder or data router in embedded control and industrial logic systems.

For engineers reviewing the SN74HCT139PWR datasheet, SN74HCT139PWR pinout, SN74HCT139PWR application, or SN74HCT139PWR equivalent, key selection criteria include active-low enable architecture, dual independent decoder operation, guaranteed 10 ns tpd at 5 V, and compatibility with LSTTL load driving requirements.

Technical Context

The SN74HCT139PWR implements two fully buffered, independent 2-to-4 line decoders sharing no internal signal paths. Each decoder features an active-low enable (G) input usable as a data line in demux mode, and outputs drive up to 10 LSTTL loads with rail-to-rail switching.

Its HCT logic family ensures TTL-voltage compatibility while maintaining CMOS power efficiency: ICC remains ≤80 µA max at 5.5 V, and input leakage is ≤1 µA. Propagation delay is specified down to 10 ns (typical) at 5.5 V with 50-pF load, enabling use in fast memory decode timing paths where system delay must be negligible relative to memory access time.

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.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual 2-to-4 decoder applications.

Compared with SN74HC139DR and 74LVC139APW, the SN74HCT139PWR uniquely balances 5-V TTL compatibility, TSSOP space savings, and industrial temperature support-making it the only choice for new 5-V embedded designs requiring surface-mount scalability and legacy interface assurance.

Availability

SN74HCT139PWR is available at Aetrix Electronics and suitable for industrial control panels, programmable logic controllers, and embedded instrumentation requiring stable component supply and long-term manufacturability.

Supply support for SN74HCT139PWR 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 ICs, with over 50 years of innovation in industrial, automotive, and communications markets.

The SN74HCT139PWR belongs to TI's HCT logic family-designed specifically for high-speed memory decoding and data-routing applications where TTL compatibility, low propagation delay, and industrial temperature operation are essential.

FAQ

What is the maximum clock frequency supported by SN74HCT139PWR in demultiplexer mode?

The SN74HCT139PWR does not operate on a clock signal-it is combinational logic. Its effective maximum data rate depends on propagation delay and load capacitance. With 10 ns typical tpd and 50-pF load, SN74HCT139PWR supports clean data routing up to ~50 MHz toggle rate in demux applications, assuming proper layout and termination.

Can SN74HCT139PWR drive LEDs directly without current-limiting resistors?

No. Although SN74HCT139PWR provides ±4-mA output drive, its outputs are active-low open-drain equivalents (not true open-drain) and lack internal current limiting. Driving LEDs directly risks exceeding absolute maximum output current (±25 mA) and damaging the device. Always use external series resistors sized for target LED current and VCC.

Is SN74HCT139PWR pin-compatible with SN74LS139N?

Yes-SN74HCT139PWR and SN74LS139N share identical logic functionality, pinout, and active-low output behavior. However, SN74HCT139PWR operates at lower ICC (80 µA vs. ~25 mA), delivers higher output current (±4 mA vs. ±0.4 mA), and supports wider VCC tolerance (4.5–5.5 V). No PCB changes are needed for drop-in replacement in most 5-V systems.

Does SN74HCT139PWR require pull-up resistors on its outputs?

No. SN74HCT139PWR features totem-pole outputs capable of actively driving both high and low states. Pull-up resistors are unnecessary unless interfacing with open-collector systems or implementing wired-OR logic-scenarios not supported by this device's output structure.

What is the recommended bypass capacitor for SN74HCT139PWR?

Texas Instruments recommends a 0.1-µF ceramic capacitor placed as close as possible to the VCC (Pin 16) and GND (Pin 8) pins of SN74HCT139PWR. For noisy environments, paralleling with a 1-µF capacitor improves low-frequency decoupling. This minimizes supply-induced jitter and ensures stable switching performance across the −40°C to +85°C range.