Texas Instruments SN74LVC1G139DCTT

Overview

SN74LVC1G139DCTT from Texas Instruments is a single 2-to-4 line decoder IC in an 8-pin SM8 (SSOP) package, designed for 1.65-V to 5.5-V V_CC operation. It decodes two address inputs (A, B) into four active-low outputs (Y0–Y3), supports 5-V tolerant inputs up to 5.5 V, delivers ±24-mA output drive at 3.3 V, and achieves 4.9 ns max propagation delay at 3.3 V/15 pF - enabling high-speed memory decoding in SSDs and AV receivers.

For engineers reviewing the SN74LVC1G139DCTT datasheet, SN74LVC1G139DCTT pinout, SN74LVC1G139DCTT application, or SN74LVC1G139DCTT equivalent, key selection criteria include its I_off partial-power-down capability, nanosecond-level t_pd matching across outputs, overvoltage-tolerant inputs, low 10-µA ICC, and NanoStar™ package footprint compatibility with space-constrained embedded designs.

Technical Context

The SN74LVC1G139DCTT implements a CMOS-based 2-bit binary decoder with B as MSB and all outputs active-low. Its functional truth table defines four mutually exclusive low states per input combination, with no enable pin - making it a dedicated decode-only device rather than a demultiplexer with control gating.

It features I_off circuitry that disables outputs during power-down to prevent back-drive current, supports down-translation (e.g., 5-V inputs with 3.3-V V_CC), and maintains latch-up immunity >100 mA per JESD78 Class II - critical for mixed-voltage board interfaces and hot-swap scenarios.

Key Specifications

Pinout & Package

SN74LVC1G139DCTT uses the 8-pin SM8 (SSOP) package, measuring 2.95 mm × 2.80 mm, with gull-wing leads and standard 0.65-mm pitch. This NanoStar™ package uses the silicon die as the structural element, eliminating traditional leadframe and mold compound for ultra-thin profile and thermal efficiency.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC1G139DCUR and SN74LVC1G139YZPR, the SN74LVC1G139DCTT offers the best balance of manufacturability (gull-wing leads), thermal performance, and legacy board compatibility - making it optimal for volume production of industrial and consumer electronics where assembly yield and test accessibility are prioritized.

Availability

SN74LVC1G139DCTT is available at Aetrix Electronics and suitable for SSD firmware updates, AV receiver memory expansion, and HD TV frame buffer selection requiring stable component supply across automotive-grade temperature ranges (–40°C to +85°C).

Supply support for SN74LVC1G139DCTT 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 expertise in high-reliability interface and signal-path ICs.

The SN74LVC1G139 series belongs to TI's LVC logic family, engineered for low-voltage, high-speed decoding in memory subsystems and data-routing applications where timing precision and voltage flexibility are critical.

FAQ

What is the function of the SN74LVC1G139DCTT?

The SN74LVC1G139DCTT is a 2-to-4 line decoder that accepts two binary inputs (A and B) and asserts exactly one of four active-low outputs (Y0–Y3) based on the input combination. It has no enable pin and operates across 1.65–5.5 V, making it suitable for address decoding in memory and peripheral interfaces. The SN74LVC1G139DCTT does not include latching or tri-state control - it is purely combinational logic.

Does the SN74LVC1G139DCTT support 5-V input signals when powered at 3.3 V?

Yes, the SN74LVC1G139DCTT inputs are overvoltage tolerant up to 5.5 V regardless of V_CC level. When V_CC = 3.3 V, A and B inputs can safely accept 5-V logic signals without external clamping or level translation - a key feature confirmed in the Recommended Operating Conditions table of the datasheet.

What package type is used for the SN74LVC1G139DCTT?

The SN74LVC1G139DCTT uses the SM8 (SSOP-8) package, also branded by Texas Instruments as NanoStar™. Its dimensions are 2.95 mm × 2.80 mm with 0.65-mm lead pitch and gull-wing terminations. This package is distinct from the VSSOP-8 (DCU) and DSBGA-8 (YZP) variants of the same device family.

How does the I_off feature work in the SN74LVC1G139DCTT?

The I_off circuitry in the SN74LVC1G139DCTT automatically disables all outputs when V_CC = 0 V, limiting off-state current to ±5 µA. This prevents damaging current backflow from live system traces into a powered-down section - essential for hot-plug, partial-power-down, and mixed-rail board architectures. The SN74LVC1G139DCTT maintains this behavior across –40°C to +85°C.

What is the maximum output drive capability of the SN74LVC1G139DCTT?

The SN74LVC1G139DCTT provides ±24-mA output drive at V_CC = 3.3 V, as specified under I_OH and I_OL in the Electrical Characteristics table. This allows direct interfacing with multiple LVC/LVT inputs or moderate capacitive loads (≤30 pF). Exceeding 24 mA per output or 100 mA total supply current risks violating absolute maximum ratings.