Texas Instruments SN74LVC1G139DCUT

Overview

SN74LVC1G139DCUT from Texas Instruments is a single 2-to-4 line decoder IC with active-low outputs, designed for high-speed memory decoding and data routing in 1.65-V to 5.5-V systems. It features 4.9 ns max propagation delay at 3.3 V/15 pF, ±24-mA output drive at 3.3 V, Ioff support for live insertion, and operates across –40°C to 85°C. It serves as an address decoder in SSDs and AV receivers.

For engineers reviewing the SN74LVC1G139DCUT datasheet, SN74LVC1G139DCUT pinout, SN74LVC1G139DCUT application, or SN74LVC1G139DCUT equivalent, key selection criteria include its VSSOP-8 package, 2-bit address decoding logic, low ICC (≤10 µA), overvoltage-tolerant inputs (up to 5.5 V), and compatibility with partial-power-down system architectures.

Technical Context

The SN74LVC1G139DCUT implements combinational logic decoding where input B (MSB) and A (LSB) select one of four active-low outputs (Y0–Y3) per the function table. All outputs are CMOS-compatible, with matched propagation delays and rail-to-rail switching capability across its full 1.65–5.5-V supply range.

Its Ioff circuitry actively disables outputs during power-down, blocking reverse current flow when VCC = 0 V while inputs or outputs are biased to up to 5.5 V - enabling safe hot-plug operation in multi-rail systems. Input tolerance and output drive strength are specified across all valid VCC conditions, not limited to nominal 3.3 V.

Key Specifications

Pinout & Package

VSSOP-8 (DCU) package: 2.30 mm × 2.00 mm body, 0.5-mm lead pitch, exposed pad not present, RoHS-compliant NiPdAu lead finish, MSL Level-1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC1G139DCUT, SN74LVC139ADR offers channel density but sacrifices Ioff and package size, while 74AHC139PW,118 trades drive strength and power-down safety for broader 5-V compatibility - making SN74LVC1G139DCUT optimal for compact, mixed-voltage, hot-pluggable designs.

Availability

SN74LVC1G139DCUT is available at Aetrix Electronics and suitable for SSD firmware updates, AV receiver production, industrial HMI manufacturing, and embedded video analytics requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for SN74LVC1G139DCUT 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 over 50 years of innovation in high-reliability interface and signal-path components.

The SN74LVC1G139 belongs to TI's LVC logic family - engineered for low-voltage, high-speed, mixed-signal system interfacing with emphasis on power efficiency, voltage translation, and robustness in industrial and consumer electronics.

FAQ

What is the maximum propagation delay of the SN74LVC1G139DCUT at 3.3 V?

The maximum propagation delay (tpd) of the SN74LVC1G139DCUT is 4.9 ns under test conditions of VCC = 3.3 V ± 0.3 V and CL = 15 pF. This value applies to both A→Y and B→Y paths and is measured from 50% input transition to 50% output transition. The SN74LVC1G139DCUT achieves this performance while maintaining matched delays across all four outputs, critical for glitch-free memory decoding.

Does the SN74LVC1G139DCUT support operation below 1.8 V?

Yes, the SN74LVC1G139DCUT is fully specified from 1.65 V to 5.5 V. At 1.65 V, it delivers guaranteed VIH = 0.65×VCC, VIL = 0.35×VCC, and IOL/IOH ≥4 mA, enabling reliable use in ultra-low-power 1.8-V and 1.65-V systems such as battery-backed SSD controllers. The SN74LVC1G139DCUT maintains functional operation and parametric compliance across this entire range without derating.

Can unused inputs on the SN74LVC1G139DCUT be left floating?

No - all unused inputs on the SN74LVC1G139DCUT must be tied to a defined logic level (VCC or GND) to prevent undefined states, increased ICC, and potential oscillation. The datasheet explicitly requires this for proper device operation. Floating inputs may cause excessive current draw or metastability, especially in noisy industrial environments. The SN74LVC1G139DCUT has no internal pull-ups or pull-downs, so external biasing is mandatory.

What is the purpose of the Ioff feature in the SN74LVC1G139DCUT?

The Ioff feature in the SN74LVC1G139DCUT disables all outputs when VCC = 0 V, blocking current flow from powered inputs or outputs into the unpowered device. This protects against back-drive damage during hot-plug events, partial power-down, or board-level maintenance. With Ioff ≤ ±5 µA, the SN74LVC1G139DCUT meets JESD78 Class II latch-up immunity and enables safe integration into multi-rail systems without additional isolation circuitry.

Is the SN74LVC1G139DCUT pin-compatible with other 2-to-4 decoders in VSSOP-8?

No - the SN74LVC1G139DCUT has a unique pinout optimized for minimal trace length in dense layouts: A (1), B (2), Y3 (3), GND (4), Y2 (5), Y1 (6), Y0 (7), VCC (8). It is not pin-compatible with standard 74-series VSSOP-8 decoders like 74AHC139 or SN74LVC139 variants, which use different pin assignments for inputs, outputs, and power. Board redesign is required when substituting the SN74LVC1G139DCUT into existing footprints.