Texas Instruments SN74LVC139ADBR

Overview

SN74LVC139ADBR from Texas Instruments is a dual 2-line to 4-line decoder/demultiplexer in SSOP-16 package, operating from 1.65 V to 3.6 V, with max propagation delay of 6.2 ns at 3.3 V and input tolerance up to 5.5 V. It features active-low enables, fully buffered inputs, and supports mixed-voltage translation between 3.3-V and 5-V logic systems in digital control and address decoding applications.

For engineers reviewing the SN74LVC139ADBR datasheet, SN74LVC139ADBR pinout, SN74LVC139ADBR application, or SN74LVC139ADBR equivalent, key selection criteria include its dual-decoder architecture, 16-pin SSOP footprint, latch-up immunity (>250 mA), ESD robustness (2000-V HBM), and compatibility with both LVC and older TTL-level signal environments.

Technical Context

The SN74LVC139ADBR integrates two independent 2-to-4 line decoders sharing no internal logic coupling - each has dedicated A/B select inputs and active-low G enable. Its CMOS LVC process ensures rail-to-rail output swing, low static current (<10 µA at 3.6 V), and input overvoltage tolerance enabling safe interfacing with 5-V drivers while powered at 1.8 V or 3.3 V.

Each decoder implements positive-logic decoding with active-high outputs (Y0–Y3) asserted only when G = L and unique AB combination matches; all outputs go high-impedance when G = H. The device does not include internal latches or memory - operation is purely combinational and synchronous with input transitions.

Key Specifications

Pinout & Package

SN74LVC139ADBR uses a 16-pin SSOP (Shrink Small Outline Package) with 0.65 mm pitch, 7.4 mm × 5.3 mm body size, and 2.0 mm max height. Pin 1 is marked by a beveled corner or index area on the top surface.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LV139ADR and 74AHC139PW, SN74LVC139ADBR uniquely balances 1.65–3.6 V operation, 5.5-V input tolerance, and 6.2 ns speed - making it the only choice for compact, low-power, mixed-voltage decoding where pin count and thermal profile (SSOP) matter.

Availability

SN74LVC139ADBR is available at Aetrix Electronics and suitable for memory address decoding, peripheral select logic, I/O port expansion, and mixed-voltage system translation requiring stable component supply and long-term industrial availability.

Supply support for SN74LVC139ADBR 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 technologies with over 50 years of innovation in high-reliability digital interface solutions.

The SN74LVC139ADBR belongs to TI's LVC logic family, designed specifically for low-voltage, high-speed, mixed-signal system interfacing where power efficiency, noise immunity, and voltage translation are critical.

FAQ

What is the maximum operating frequency supported by SN74LVC139ADBR?

The SN74LVC139ADBR does not specify a maximum clock frequency because it is a combinational logic device with no internal clock. Its usable speed is determined by propagation delay: max tpd = 6.2 ns at VCC = 3.3 V, supporting reliable operation in systems with address/data setup times ≥7 ns - typical for 16-MHz microcontroller buses or FPGA I/O interfaces. Always validate timing margins against actual load capacitance and trace routing.

Can SN74LVC139ADBR drive LEDs directly?

SN74LVC139ADBR outputs can sink up to 24 mA per channel at VCC = 3 V, which is sufficient to drive standard 2–20 mA indicator LEDs with appropriate series resistors. However, outputs are active-low and open-drain–like (no internal pull-up), so an external pull-up resistor to VCC is required. For sustained LED current, verify junction temperature rise using θJA = 82°C/W and ensure ambient stays below 70°C.

Is SN74LVC139ADBR pin-compatible with older 74LS139 devices?

No, SN74LVC139ADBR is not pin-compatible with 74LS139. While both are dual 2-to-4 decoders, 74LS139 uses a 16-pin DIP or SOIC package with different pin assignments - e.g., 74LS139 places GND at Pin 8 and VCC at Pin 16 (same as SN74LVC139ADBR), but its Y outputs and enable pins occupy distinct positions. The SN74LVC139ADBR follows TI's standardized LVC pinout for SSOP-16, requiring PCB redesign for drop-in replacement.

Does SN74LVC139ADBR require external pull-up resistors on its outputs?

Yes, SN74LVC139ADBR outputs are active-low and do not contain internal pull-ups. To achieve defined high-level logic states when deselected, external pull-up resistors (typically 1–10 kΩ to VCC) must be connected to each Y0–Y3 output. Values depend on bus capacitance and rise-time requirements - for 50 pF loads and <100 ns rise time, 4.7 kΩ is commonly used.

What is the recommended bypass capacitor for SN74LVC139ADBR?

Texas Instruments recommends a minimum 0.1 µF ceramic bypass capacitor placed as close as possible to the VCC (Pin 16) and GND (Pin 8) pins of SN74LVC139ADBR. For systems with high switching activity or multiple LVC devices on the same rail, add a bulk 4.7–10 µF tantalum or aluminum electrolytic capacitor nearby. Ensure low-inductance layout - capacitor pads should connect directly to power/ground planes with short, wide traces.