Texas Instruments SN74LV139APWT

Overview

SN74LV139APWT from Texas Instruments is a dual 2-line to 4-line decoder/demultiplexer operating from 2V to 5.5V, delivering 7.5ns maximum propagation delay at 5V, supporting mixed-mode voltage operation across all ports, and incorporating two active-low enable inputs for cascading or data routing in high-speed memory systems.

For engineers reviewing the SN74LV139APWT datasheet, SN74LV139APWT pinout, SN74LV139APWT application, or SN74LV139APWT equivalent, this device is selected for low-voltage, high-speed address decoding where Ioff-enabled partial-power-down operation and 16-pin TSSOP packaging are critical design requirements.

Technical Context

The SN74LV139APWT implements two independent positive-logic 2-to-4 decoders with active-low enables (1G, 2G), each accepting two address inputs (A0/A1) and driving four active-low outputs (Y0–Y3). All inputs are fully buffered, presenting only one normalized load to the driving circuit.

It features Ioff circuitry that disables outputs during power-down to prevent backflow current, and supports mixed-voltage interfacing-e.g., 3.3V inputs driving 2.5V outputs-within its 2V–5.5V VCC range and specified VIH/VIL thresholds.

Key Specifications

Pinout & Package

TSSOP-16 (PW) package: 5.00 mm × 6.4 mm body size, 0.65 mm lead pitch, 1.2 mm max height, moisture sensitivity level 1 (260°C reflow unlimited).

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 74LVC139ADTR2G, the SN74LV139APWT offers the optimal balance of industrial temperature range, Ioff safety, and 7.5ns speed at 5V - making it preferred for memory-intensive embedded systems where reliability under partial power-down is non-negotiable.

Availability

SN74LV139APWT is available at Aetrix Electronics and suitable for industrial control panels, medical instrumentation, and telecom infrastructure equipment requiring stable component supply across extended temperature and mixed-voltage conditions.

Supply support for SN74LV139APWT 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 90 years of innovation in high-reliability components.

The SN74LV139A product line targets high-speed, low-voltage memory decoding and data-routing applications - engineered specifically to minimize system-level propagation delay while maintaining robustness across industrial voltage and thermal ranges.

FAQ

What is the maximum propagation delay of the SN74LV139APWT at 3.3V operation?

The SN74LV139APWT has a maximum propagation delay of 13ns at VCC = 3.3V ± 0.3V with a 15pF load, as specified in Section 4.7 of the official datasheet. This value applies to transitions from address or enable inputs to any Y output, ensuring predictable timing in 3.3V memory subsystems. The SN74LV139APWT maintains consistent performance across its full operating range, with typical delays as low as 5.3ns under the same conditions.

Does the SN74LV139APWT support partial-power-down mode, and how is it implemented?

Yes, the SN74LV139APWT supports partial-power-down mode via its Ioff feature. When VCC = 0V, the Ioff circuitry disables all outputs, placing them in a high-impedance state to prevent damaging current backflow from live inputs or outputs. This behavior is explicitly characterized in Section 4.5 (Ioff ≤ 5µA), and applies across the full –40°C to +85°C temperature range. The SN74LV139APWT is designed for safe use in systems with staggered power sequencing or hot-plug modules.

Can the SN74LV139APWT interface between 5V and 3.3V logic domains without external level shifters?

Yes, the SN74LV139APWT supports mixed-mode voltage operation: inputs tolerate up to 5.5V regardless of VCC level, and outputs swing rail-to-rail within the applied VCC range. For example, with VCC = 3.3V, it accepts 5V address signals (VIH threshold = 2.31V) and drives 3.3V-compatible loads. This capability is confirmed in Section 4.3 (Recommended Operating Conditions) and eliminates the need for discrete level-shifting components in the SN74LV139APWT signal path.

What is the recommended bypass capacitor configuration for the SN74LV139APWT?

Texas Instruments recommends a 0.1µF ceramic bypass capacitor placed as close as possible to the VCC pin (Pin 16) with a low-inductance connection to GND (Pin 8). Section 7.1 specifies this value for optimal high-frequency noise suppression, and notes that paralleling a 1µF capacitor improves low-frequency filtering. Layout guidelines in Figure 7-2 emphasize minimizing trace length and using wide, direct ground return paths - critical for maintaining signal integrity in the SN74LV139APWT's high-speed operation.

Is the SN74LV139APWT pin-compatible with other members of the SN74LV139A family?

Yes, the SN74LV139APWT shares identical pinout and functionality with all SN74LV139A variants in 16-pin packages (SOIC-D, SSOP-DB, SOP-NS, TSSOP-PW, VQFN-RGY), as verified in Figure 3-1 and Table 3-1 of the datasheet. Pin assignments for 1G, 1A0, 1A1, 1Y0–1Y3, GND, 2Y3–2Y0, 2A1, 2A0, 2G, and VCC are standardized across all package types. Therefore, the SN74LV139APWT can be substituted for other SN74LV139A variants without PCB redesign - subject to mechanical and thermal constraints of the TSSOP package.