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Texas Instruments SNJ54AHC138W
- Part No.:
- SNJ54AHC138W
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- -
- Datasheet:
-
SNJ54AHC138W.pdf
- Description:
- 54AHC138 3-LINE TO 8-LINE DECODE
- Quantity:
- Payment:
- Shipping:
Inventory:200
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Product details
Overview
SNJ54AHC138W from Texas Instruments is a military-grade 3-line to 8-line decoder/demultiplexer in CFP-16 package, operating from 2 V to 5.5 V with propagation delays as low as 5.6 ns (VCC = 5 V, CL = 15 pF), designed for high-speed memory decoding and data-routing in aerospace and defense systems requiring −55°C to +125°C operation.
For engineers reviewing the SNJ54AHC138W datasheet, SNJ54AHC138W pinout, SNJ54AHC138W application, or SNJ54AHC138W equivalent, this page delivers verified functional behavior, thermal performance (RθJA = N/A per CFP package), enable-input logic mapping, and direct substitution guidance for legacy MIL-PRF-38535 systems.
Technical Context
The SNJ54AHC138W implements positive-logic binary decoding with three independent enable inputs: one active-high (G1) and two active-low (G2A, G2B), enabling flexible cascading without external inverters. Its function table confirms full 3-bit address selection (A0–A2) across eight active-low outputs (Y0–Y7).
Designed for MIL-PRF-38535 compliance, it features latch-up immunity >250 mA per JESD17 and ESD protection exceeding 2000 V HBM and 1000 V CDM. Input transition rate is specified at 20 ns/V (VCC = 5 V), ensuring robust timing margin in fast-switching environments.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 2 V to 5.5 V - supports dual-supply systems and battery-backed operation across military temperature range. |
| tPLH / tPHL (5 V, 15 pF) | 5.6 ns max - enables sub-10 ns system-level decode latency when paired with fast-enable memories. |
| Operating Temperature | −55°C to +125°C - qualified for extended-range military platforms including avionics and ground vehicle ECUs. |
| Output Drive (IOL/IOH) | ±8 mA at 5 V - sufficient to directly drive TTL loads or interface with AHC-family logic without buffers. |
| Input Clamp Current | ±20 mA - protects against transient overvoltage events during hot-swap or ESD exposure. |
| Power Dissipation Capacitance | 13 pF - determines dynamic power consumption at 1 MHz; critical for low-power standby mode estimation. |
Pinout & Package
SNJ54AHC138W uses a 16-pin Ceramic Flatpack (CFP) package with 0.050″ lead pitch and hermetic sealing. Body size is 10.4 mm × 5.4 mm; overall package size is 10.4 mm × 5.4 mm (pins included). Thermal pad not present.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0, A1, A2 | Binary address inputs | Select one of eight outputs; all three required for full decoding; CMOS-compatible voltage thresholds. |
| G1 | Active-high enable input | Enables decoder only when high; used for hierarchical enable control in multi-chip memory systems. |
| G2A, G2B | Active-low enable inputs | Both must be low to activate; allows OR-style enable logic without external gates in cascaded configurations. |
| Y0–Y7 | Active-low decoded outputs | Only one output asserts low per valid address/enable combination; open-drain behavior not supported. |
| VCC, GND | Power supply terminals | Requires local 0.1 µF ceramic decoupling; no internal ESD diodes to VCC/GND beyond spec-rated clamp current. |
Key Features
| Feature | Design Value |
|---|---|
| Triple enable architecture | Eliminates need for external inverters in 24-line or 32-line expansion schemes - reduces BOM count and layout area. |
| MIL-PRF-38535 qualification | Guarantees screening, testing, and traceability per military standard - required for flight-critical and secure comms hardware. |
| High-speed propagation | 5.6 ns max delay at 5 V enables synchronization with sub-10 ns memory access cycles - minimizes system-level wait states. |
| Latch-up immunity | Exceeds 250 mA per JESD17 - ensures survivability under single-event transients in radiation-prone environments. |
| ESD robustness | 2000 V HBM / 1000 V CDM - exceeds MIL-STD-883 method 3015.7, reducing field failure risk in handling and assembly. |
Applications
| Avionics Memory Decoding | Tactical Radio Baseband Routing |
|---|---|
Use Scenario: Selecting among 8 memory banks in a radar signal processor FPGA configuration PROM array. IC Role / Device Role / Timing Role: Address decoder providing synchronized chip-select strobes with <10 ns skew across all 8 outputs. Use Value: Enables deterministic boot sequence timing within 50 ns window, meeting DO-254 Level A timing closure requirements. |
Use Scenario: Routing digital audio/data streams between multiple modems and baseband processors in a software-defined radio. IC Role / Device Role / Timing Role: Demultiplexer steering time-division multiplexed I/Q samples to dedicated channel filters. Use Value: Sub-6 ns propagation ensures sample alignment across 8 parallel paths, preserving phase coherence in wideband OFDM signals. |
| Missile Guidance Interface Logic | Secure Satellite Telemetry Hub |
Use Scenario: Enabling discrete analog sensor conditioning channels based on real-time guidance mode commands. IC Role / Device Role / Timing Role: Enable-controlled decoder activating one of eight precision ADC front-ends per mission phase. Use Value: −55°C to +125°C operation and latch-up immunity ensure reliable channel selection during rapid thermal cycling in launch environments. |
Use Scenario: Managing telemetry packet routing between redundant command receivers and encrypted downlink transmitters. IC Role / Device Role / Timing Role: Cascaded decoder enabling one of eight secure crypto module interfaces using hardened enable tree. Use Value: Triple enable inputs allow fault-tolerant enable arbitration - any single enable line failure preserves safe default state (all outputs high). |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 3-to-8 decoder applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74AHC138N | Commercial-grade PDIP-16; same logic, but rated −40°C to +85°C and non-hermetic. | Approved for industrial control panels and test equipment - not qualified for flight or embedded defense use. | Select only for cost-sensitive, non-military designs where extended temperature and radiation tolerance are unnecessary. |
| SNJ54ACT138W | TTL-compatible input thresholds (VIH = 2 V min); slightly higher ICC (40 μA vs. 4 μA typical at 5.5 V). | Interoperable with legacy 5 V TTL buses; requires level-shifting when mixed with pure CMOS AHC families. | Choose when interfacing with older 74LS/74F systems - avoid in new AHC-only designs due to higher static power. |
Compared with SN74AHC138N and SNJ54ACT138W, the SNJ54AHC138W uniquely combines MIL-PRF-38535 screening, hermetic CFP packaging, and −55°C to +125°C operation - making it the sole option for space-constrained, high-reliability military subsystems demanding zero derating.
Availability
SNJ54AHC138W is available at Aetrix Electronics and suitable for avionics memory decoding, tactical radio baseband routing, and missile guidance interface logic requiring stable component supply across extended temperature and radiation-hardened environments.
Supply support for SNJ54AHC138W 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 aerospace component development.
The SNJ54AHC138W belongs to TI's military logic family, engineered specifically for high-speed, radiation-tolerant decoding in safety-critical platforms where long-term reliability and specification compliance outweigh cost sensitivity.
FAQ
What is the maximum clock frequency supported by SNJ54AHC138W?
The SNJ54AHC138W does not operate on a clock; it is a combinational logic device. Its speed is defined by propagation delay: 5.6 ns max (tPLH/tPHL) at VCC = 5 V and CL = 15 pF. This corresponds to a theoretical maximum toggle rate of ~179 MHz under ideal loading, but actual system frequency depends on board trace capacitance and fan-out.
Does SNJ54AHC138W support mixed-voltage operation (e.g., 3.3 V inputs with 5 V VCC)?
No. SNJ54AHC138W requires VIH ≥ 3.85 V and VIL ≤ 1.65 V when VCC = 5.5 V, per its recommended operating conditions. Driving it with 3.3 V logic levels violates the high-level input voltage spec and risks metastability or incomplete switching - level translation is mandatory for mixed-voltage interfaces.
Can SNJ54AHC138W be used as a demultiplexer, and how is data routed?
Yes. When one enable input (e.g., G1) is used as the data input and A0–A2 select the destination, SNJ54AHC138W functions as a 1-to-8 demultiplexer. The data appears inverted on the selected Yx output (active-low), while all other outputs remain high - matching standard demux behavior for negative-logic control paths.
What is the thermal resistance (RθJA) of SNJ54AHC138W in CFP package?
RθJA is not specified for SNJ54AHC138W because the CFP package is hermetically sealed with no standardized JEDEC thermal test board condition. TI provides no RθJA value for W-package devices; thermal design must rely on measured junction-to-case data or vendor-provided thermal simulation models for the specific PCB layout and heatsinking configuration.
Is SNJ54AHC138W pin-compatible with SN74AHC138 variants?
Yes - SNJ54AHC138W shares identical pin numbering and function mapping with all SN74AHC138 variants in 16-pin packages (D, DB, DGV, N, NS, PW, RGY), including the same A0–A2, G1/G2A/G2B, Y0–Y7, VCC, and GND assignments. Mechanical footprint differs, but electrical connectivity and logic behavior are fully aligned.
SNJ54AHC138W Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- *
- Package/Case:
- -
- Packaging:
- Bulk
- Product Status:
- Active
- Type:
- -
- Circuit:
- -
- Independent Circuits:
- -
- Current - Output High, Low:
- -
- Voltage Supply Source:
- -
- Voltage - Supply:
- -
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- -
- Supplier Device Package:
- -
SNJ54AHC138W FAQ
1.How can I place an order for SNJ54AHC138W through Aetrix?
Please submit a Request for Quotation (RFQ) for SNJ54AHC138W on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for SNJ54AHC138W reliable?
The price and inventory of SNJ54AHC138W are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SNJ54AHC138W is usually 5 days.
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SNJ54AHC138W orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SNJ54AHC138W order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for SNJ54AHC138W?
For technical support, including SNJ54AHC138W datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SNJ54AHC138W requirements.
6.How does Aetrix verify that SNJ54AHC138W is sourced from the original manufacturer or authorized distributors?
All SNJ54AHC138W products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that SNJ54AHC138W meets industry standards.
7.What is the process for return or replacement of SNJ54AHC138W?
All SNJ54AHC138W units undergo pre-shipment inspection (PSI). If there is an issue with SNJ54AHC138W, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The SNJ54AHC138W part is unused and in its original packaging.
Return procedure for SNJ54AHC138W:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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