Texas Instruments 84092012A

Overview

84092012A from Texas Instruments is a military-grade dual 2-to-4 line decoder/demultiplexer in LCCC-20 package, operating over −55°C to 125°C. It features 2 V–6 V supply range, typical propagation delay of 30 ns at 6 V, ±4-mA output drive, and low ICC of 80 µA max. It serves as a high-speed memory decoder in avionics and defense computing systems.

For engineers reviewing the 84092012A datasheet, 84092012A pinout, 84092012A application, or 84092012A equivalent, key selection criteria include its extended temperature rating, LCCC hermetic packaging, dual independent enable inputs for cascading, and compatibility with HC logic families in radiation-tolerant or mission-critical control subsystems.

Technical Context

The 84092012A implements two fully buffered, independent 2-line-to-4-line decoders with active-low enables (1G, 2G). Each decoder accepts binary address inputs (A/B) and asserts one of four active-low outputs (Y0–Y3) when enabled - supporting both decoding and demultiplexing functions without external inversion.

Its CMOS architecture ensures low static current (≤80 µA), input leakage ≤1 µA, and rail-to-rail output swing. Propagation delays are tightly specified across −55°C to 125°C, with tpd = 44 ns max at 4.5 V and 38 ns max at 6 V under CL = 50 pF, enabling synchronization in high-reliability timing-critical data paths.

Key Specifications

Pinout & Package

LCCC-20 (FK) package: 20-terminal ceramic leadless chip carrier with J-lead geometry, hermetically sealed, designed for high-reliability board mounting via solder reflow or conductive epoxy.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SNJ54HC139J and SN54HC139W, 84092012A offers superior moisture resistance and mechanical robustness via LCCC-20 ceramic construction, making it the only option qualified for sustained operation in high-humidity, high-vibration aerospace enclosures without conformal coating.

Availability

84092012A is available at Aetrix Electronics and suitable for avionics data bus interface, tactical radar control logic, secure crypto module addressing, and missile guidance processor memory decode requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for 84092012A 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 high-reliability logic solutions, with decades of heritage in military and space-grade component development.

The 84092012A belongs to TI's SN54HC logic family, engineered specifically for high-speed, low-power decoding in mission-critical systems where extended temperature operation, hermetic packaging, and MIL-PRF-38535 compliance are mandatory design requirements.

FAQ

What is the absolute maximum supply voltage rating for the 84092012A?

The 84092012A has an absolute maximum supply voltage (VCC) rating of −0.5 V to 7 V, as specified in the Absolute Maximum Ratings table of TI's SCLS108D datasheet. Operation beyond this range risks permanent damage. For reliable functionality, the recommended operating range remains 2 V to 6 V across the full −55°C to 125°C temperature span. This margin allows for transient overshoot in harsh power environments while preserving latch-up immunity in the 84092012A.

Does the 84092012A support demultiplexing functionality, and how is it implemented?

Yes, the 84092012A supports demultiplexing via its active-low enable inputs (1G and 2G), which can serve as data lines. When used in demux mode, a single binary input pair (A/B) selects one of four outputs, while the enable pin controls data flow - for example, asserting 1G low passes the decoded pattern to outputs 1Y0–1Y3. This dual-role capability is explicitly confirmed in the Functional Description section of the 84092012A datasheet and eliminates need for additional logic in serial-to-parallel conversion circuits.

What is the guaranteed propagation delay for the 84092012A at 5 V and −55°C?

The 84092012A guarantees a maximum propagation delay (tpd) of 44 ns at VCC = 4.5 V and TA = −55°C, per the Switching Characteristics table in SCLS108D. At exactly 5 V, interpolation from adjacent test points (4.5 V and 6 V) yields a conservative upper bound of 42 ns. This value is validated across all LCCC-20 units screened to MIL-PRF-38535 Class V, ensuring deterministic timing in cold-start avionics systems where the 84092012A is deployed.

How many logic loads can the 84092012A drive, and what standard does this reference?

The 84092012A can drive up to 10 LSTTL loads, as stated in the device overview and confirmed in the Electrical Characteristics table under IOH/IOL conditions. This rating assumes standard LSTTL input thresholds (VIH = 2 V, VIL = 0.8 V) and accounts for the 84092012A's ±4-mA output drive capability at 5 V. The specification ensures interoperability with legacy military subsystems using 74LS-series components without level-shifting circuitry.

Is the 84092012A pin-compatible with commercial SN74HC139 variants in SOIC or TSSOP packages?

No, the 84092012A is not pin-compatible with commercial SN74HC139 variants. It uses a 20-terminal LCCC-20 (FK) footprint with different pin count, spacing, and terminal arrangement than the 16-pin D, DB, PW, or N packages. Pin mapping differs significantly - e.g., 84092012A includes dedicated NC pins and dual power/ground pairs absent in 16-pin variants. Direct substitution requires PCB redesign; only functional equivalence is assured, not mechanical or electrical drop-in replacement.