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Texas Instruments SNJ54ALS29843JT
- Part No.:
- SNJ54ALS29843JT
- Manufacturer:
- Texas Instruments
- Package:
- -
- Datasheet:
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SNJ54ALS29843JT.pdf
- Description:
- BUS DRIVER, ALS SERIES
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Product details
Overview
SNJ54ALS29843JT from Texas Instruments is a military-grade 9-bit transparent D-type latch with three-state outputs, designed for bus interface applications in high-reliability systems. It operates across –55°C to 125°C, features buffered OC control, power-up high-impedance, and delivers ±32 mA output drive at 5 V. It is used in wide address/data buses requiring parity support and direct bus driving without pull-ups.
For engineers reviewing the SNJ54ALS29843JT datasheet, SNJ54ALS29843JT pinout, SNJ54ALS29843JT application, or SNJ54ALS29843JT equivalent, this device serves as a bus-structured, noninverting 9-bit latch with military temperature rating, precise setup/hold timing (tsu = 2 ns, th = 4.5 ns), and robust 3-state control for legacy TTL-compatible systems.
Technical Context
The SNJ54ALS29843JT implements nine independent D-type latches with synchronous enable via clock (C) input and separate buffered output control (OC). Its PRE and CLR inputs provide asynchronous set/reset capability per latch group, and all outputs enter high-impedance during power-up/down - eliminating bus contention at startup.
It uses ALS (Advanced Low-Power Schottky) TTL logic, ensuring compatibility with standard TTL voltage thresholds (VIH = 2 V, VIL = 0.8 V) while delivering faster propagation (tPLH/tPHL ≤ 9.5 ns at CL = 50 pF) and lower ICC (55–85 mA) than earlier LS families. The bus-structured pinout minimizes trace routing complexity in backplane and memory expansion designs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4.5 V to 5.5 V - Ensures stable operation under noisy supply conditions typical in military avionics and ground vehicle electronics. |
| Operating Temp | –55°C to 125°C - Qualified for full military temperature range per MIL-PRF-38535, enabling use in harsh-environment embedded control. |
| IOL / IOH | 32 mA / –18 mA - Sufficient drive strength to directly load 50-pF bus lines without external buffers in legacy 8086/8088-based systems. |
| tsu / th | 2 ns / 4.5 ns - Tight timing margins allow integration into high-speed data capture paths with minimal hold-time violation risk. |
| tPZH / tPLZ | 7.3 ns / 9.7 ns - Fast 3-state enable/disable latency supports dynamic bus arbitration in multi-master architectures. |
| ICC (max) | 85 mA - Predictable power consumption simplifies thermal design for densely packed PCBs in sealed chassis. |
| VOH / VOL | 2.0 V / 0.5 V at IOL = 32 mA - Guaranteed TTL-compatible logic levels ensure interoperability with legacy peripherals and FPGAs. |
Pinout & Package
SNJ54ALS29843JT is supplied in a ceramic 300-mil Dual In-line Package (DIP) with JT suffix, featuring 24 pins and through-hole mounting. Pin spacing conforms to JEDEC MS-010AB standard.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 4, 5, 6, 7, 8, 9 | Data Inputs (1D–9D) | Noninverting D-type latch inputs; accept TTL-level signals and propagate to Q outputs on clock edge. |
| 10 | Output Control (OC) | Active-low buffered enable; places all nine Q outputs in high-impedance state regardless of clock or data state. |
| 11 | Clear (CLR) | Asynchronous active-low reset; forces all latch outputs low when asserted, independent of clock. |
| 12 | GND | Signal reference ground plane connection; must be low-inductance for noise immunity in mixed-signal boards. |
| 13 | VCC | +5 V power supply; requires local 0.1 µF ceramic decoupling adjacent to pin to suppress switching transients. |
| 14, 15, 16, 17, 18, 19, 20, 21, 22 | Outputs (1Q–9Q) | Three-state buffered outputs; drive bus lines directly with TTL-compatible VOH/VOL and high sink/source capability. |
| 23 | Preset (PRE) | Asynchronous active-low preset; forces all latch outputs high when asserted, overriding clock and data. |
| 24 | Clock (C) | Positive-edge-triggered latch enable; transparently passes D-inputs to Q-outputs on rising edge. |
Key Features
| Feature | Design Value |
|---|---|
| Power-Up High-Impedance | Outputs remain in Z-state during power ramp-up/down - prevents bus contention and eliminates need for external reset sequencing. |
| Buffered Control Inputs | OC, PRE, and CLR inputs have internal buffering - reduces DC loading on upstream drivers and improves fan-out capability. |
| Bus-Structured Pinout | D- and Q-pins arranged in parallel groups (1D–9D, 1Q–9Q) - enables straight-through PCB routing and minimizes crosstalk in wide-bus layouts. |
| Extra Bus Driving Latches | Nine-bit width supports parity-enabled 9-bit data/address paths - eliminates need for multiple 4-bit latches in memory expansion modules. |
| 3-State Output Drive | ±32 mA drive strength at 5 V - allows direct connection to terminated or unterminated buses up to 300 pF without interface components. |
Applications
| Industrial Backplane Bus Interface | Military Avionics Data Acquisition |
|---|---|
|
Use Scenario: Interfacing ADC/DAC modules to a 9-bit parallel data bus in a ruggedized flight control computer. IC Role / Device Role / Timing Role: Acts as a synchronized data capture latch, holding sampled analog values until read by the host processor via OC-gated bus access. Use Value: Power-up high-impedance prevents bus conflicts during cold start; military temp rating ensures reliability at altitude and under vibration. |
Use Scenario: Buffering sensor telemetry streams (e.g., pressure, temperature) onto a shared MIL-STD-1553B auxiliary bus controller interface. IC Role / Device Role / Timing Role: Provides isolated, glitch-free latching of 9-bit sensor words using PRE/CLR for fault recovery and OC for time-sliced bus sharing. Use Value: Buffered OC input enables clean bus arbitration; fast tPZH/tPLZ (<12 ns) supports sub-microsecond time-slot switching. |
| Ruggedized Memory Expansion Module | Legacy CPU Address Latch Bank |
|
Use Scenario: Extending 16-bit address space in a radiation-hardened 80C86-based system with parity-checked external RAM banks. IC Role / Device Role / Timing Role: Latches upper address bits and parity bit simultaneously; OC enables bank-select multiplexing without bus contention. Use Value: Nine-bit width accommodates 8-bit address + 1-bit parity; bus-structured pinout simplifies layout in constrained 2-layer PCBs. |
Use Scenario: Holding instruction fetch addresses in a real-time embedded controller based on the TMS320C25 DSP with external program memory. IC Role / Device Role / Timing Role: Functions as an address latch bank synchronized to the CPU's ALE-equivalent clock signal, with OC enabling memory-mapped I/O decoding. Use Value: Tight tsu/th (2 ns / 4.5 ns) meets strict timing budgets of 20-MHz DSP buses; ALS logic ensures noise margin in electrically noisy motor-control environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 9-bit bus interface latch applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ALS29843DW | Commercial-grade (0°C to 70°C), SOIC-24 package; identical logic function and pinout but lacks military qualification and ceramic packaging. | Suitable for industrial control panels or lab equipment where extended temperature range is not required. | Select when cost, board space, or reflow assembly are priorities over environmental ruggedness. |
| SN54ALS29844JT | Inverting D-input variant (vs. noninverting SNJ54ALS29843JT); same military temp range, package, and timing specs. | Required where upstream logic provides inverted data or where complementary latch behavior is needed in dual-bank architectures. | Choose only if system-level signal polarity mandates inversion - otherwise, SNJ54ALS29843JT is functionally preferred. |
Compared with SN74ALS29843DW and SN54ALS29844JT, the SNJ54ALS29843JT uniquely combines military temperature qualification, ceramic DIP packaging for hermetic reliability, and noninverting data path - making it the sole choice for deployed defense electronics requiring long-term stability under thermal cycling and mechanical shock.
Availability
SNJ54ALS29843JT is available at Aetrix Electronics and suitable for industrial backplane interfaces, military avionics data acquisition, and ruggedized memory expansion modules requiring stable component supply across extended lifecycle programs.
Supply support for SNJ54ALS29843JT 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 U.S.-based semiconductor leader with decades of heritage in logic, analog, and embedded processing technologies, serving aerospace, defense, and industrial markets.
The SNJ54ALS29843JT belongs to TI's military-grade ALS logic family, engineered for high-reliability bus interfacing in legacy and upgrade systems where TTL compatibility, thermal resilience, and long-term obsolescence mitigation are critical.
FAQ
What is the operating temperature range of the SNJ54ALS29843JT?
The SNJ54ALS29843JT is characterized for operation from –55°C to 125°C, meeting full military temperature specifications per MIL-PRF-38535. This range enables deployment in extreme environments such as aircraft engine bays, ground vehicle power compartments, and space-qualified payload electronics where thermal cycling and sustained high ambient temperatures occur. The SNJ54ALS29843JT maintains specified timing and drive performance across this entire range.
Does the SNJ54ALS29843JT support true three-state operation during power-up?
Yes, the SNJ54ALS29843JT features guaranteed power-up high-impedance behavior: all nine Q outputs remain in high-impedance state until VCC stabilizes and valid control signals are applied. This eliminates bus contention at system startup and removes the need for external power-on reset circuitry to manage output states. The SNJ54ALS29843JT achieves this via internal bias networks that force OC-active behavior before logic initialization completes.
How does the SNJ54ALS29843JT differ from the SN74ALS29843 in terms of packaging and qualification?
The SNJ54ALS29843JT uses a ceramic 300-mil DIP (JT package) and is fully qualified to military standards including extended temperature operation (–55°C to 125°C), burn-in, and lot acceptance testing per MIL-PRF-38535. In contrast, the SN74ALS29843 is commercial-grade (0°C to 70°C) and offered in plastic SOIC (DW) or PDIP (NT) packages without hermetic sealing or military screening. The SNJ54ALS29843JT is the only version approved for flight-critical and field-deployed defense applications.
Can the SNJ54ALS29843JT be used alongside SN74ALS29844 devices on the same bus?
Yes, the SNJ54ALS29843JT and SN74ALS29844 can share the same bus when their OC inputs are independently controlled, because both devices have identical 3-state output characteristics, timing, and voltage thresholds. However, their data paths differ: SNJ54ALS29843JT has noninverting D-to-Q transfer, while SN74ALS29844 inverts. System-level logic must account for this polarity difference - the SNJ54ALS29843JT cannot substitute directly for SN74ALS29844 without redesigning upstream signal conditioning.
What are the key timing parameters that define bus arbitration capability for the SNJ54ALS29843JT?
The SNJ54ALS29843JT supports deterministic bus arbitration via tPZH (7.3 ns max) and tPZL (9.7 ns max) - the delays from OC deassertion to output transition into high-impedance. Combined with tPHZ (10.4 ns) and tPLZ (4.7 ns) - delays from OC assertion to high-impedance entry - these parameters enable sub-15 ns window control of bus ownership. This allows tightly coordinated multi-device sharing on a single 9-bit data path without glitches, as verified in TI's SDAS151A application notes.
SNJ54ALS29843JT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- *
- Package/Case:
- -
- Packaging:
- Bulk
- Product Status:
- Active
- Logic Type:
- -
- Number of Elements:
- -
- Number of Bits per Element:
- -
- Input Type:
- -
- Output Type:
- -
- Current - Output High, Low:
- -
- Voltage - Supply:
- -
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
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- Mounting Type:
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- Supplier Device Package:
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SNJ54ALS29843JT FAQ
1.How can I place an order for SNJ54ALS29843JT through Aetrix?
Please submit a Request for Quotation (RFQ) for SNJ54ALS29843JT 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 SNJ54ALS29843JT reliable?
The price and inventory of SNJ54ALS29843JT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SNJ54ALS29843JT is usually 5 days.
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SNJ54ALS29843JT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SNJ54ALS29843JT 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 SNJ54ALS29843JT?
For technical support, including SNJ54ALS29843JT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SNJ54ALS29843JT requirements.
6.How does Aetrix verify that SNJ54ALS29843JT is sourced from the original manufacturer or authorized distributors?
All SNJ54ALS29843JT 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 SNJ54ALS29843JT meets industry standards.
7.What is the process for return or replacement of SNJ54ALS29843JT?
All SNJ54ALS29843JT units undergo pre-shipment inspection (PSI). If there is an issue with SNJ54ALS29843JT, 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 SNJ54ALS29843JT part is unused and in its original packaging.
Return procedure for SNJ54ALS29843JT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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