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Texas Instruments SN54ALS245AJ
- Part No.:
- SN54ALS245AJ
- Manufacturer:
- Texas Instruments
- Package:
- 20-CDIP (0.300", 7.62mm)
- Datasheet:
-
SN54ALS245AJ.pdf
- Description:
- OCTAL BUS TRANSCEIVERS WITH 3-ST
- Quantity:
- Payment:
- Shipping:
Inventory:1,375
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Product details
Overview
SN54ALS245AJ from Texas Instruments is a military-grade octal bus transceiver with 3-state outputs, designed for asynchronous bidirectional data transfer between A and B buses in high-reliability systems. It operates from 4.5 V to 5.5 V, delivers max propagation delay of 5.5 ns at 5 V, features pnp input structure to reduce DC loading, and supports –55°C to 125°C operation in CDIP (J) package.
For engineers reviewing the SN54ALS245AJ datasheet, SN54ALS245AJ pinout, SN54ALS245AJ application, or SN54ALS245AJ equivalent, this page provides verified functional role, timing behavior under 50-pF load, 3-state control logic (DIR/OE), absolute maximum ratings, and direct alternatives for legacy aerospace and defense bus interface designs.
Technical Context
The SN54ALS245AJ implements dual-directional 8-bit data flow controlled by DIR (direction) and OE (output enable) inputs: when OE is low, data passes from A→B if DIR = high, or B→A if DIR = low; when OE is high, all outputs enter high-impedance state. Its ALS (Advanced Low-Power Schottky) logic family ensures compatibility with TTL-level signaling while minimizing power consumption.
It uses pnp-based input circuitry to reduce input current draw-critical for bus loading in multi-drop configurations-and supports direct drive of terminated transmission lines without external buffers. The device is qualified per MIL-PRF-38535 Class B for military applications, with full parameter testing across temperature extremes.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4.5 V to 5.5 V - Ensures robust operation across wide supply tolerance in avionics and industrial power rails. |
| Max tpd | 5.5 ns at VCC = 5 V, CL = 50 pF - Enables high-speed synchronous bus handshaking up to ~180 MHz effective throughput. |
| IOL (max) | 24 mA - Sufficient to drive standard 50-Ω terminated lines or multiple TTL inputs without fanout degradation. |
| VIK | –1.5 V - Negative clamp voltage protects against negative transients on bus lines during hot-swap or ESD events. |
| Operating Temp | –55°C to 125°C - Fully specified for extended temperature range required in military vehicle, radar, and space-qualified systems. |
| Package | CDIP (J), 20-pin - Hermetically sealed ceramic dual in-line package with gold-plated leads for long-term reliability and moisture resistance. |
Pinout & Package
SN54ALS245AJ is housed in a 20-pin Ceramic Dual In-Line Package (CDIP-J), with 0.3-inch body width, 0.1-inch lead pitch, and hermetic glass-seal construction suitable for high-reliability environments.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 4, 5, 6, 7, 8 | A1–A8 Inputs/Outputs | Port A bidirectional I/O pins - connect to source bus; direction determined by DIR and OE states. |
| 11, 12, 13, 14, 15, 16, 17, 18 | B1–B8 Inputs/Outputs | Port B bidirectional I/O pins - connect to destination bus; function mirrors A-side under DIR control. |
| 9 | GND | Ground reference for all internal logic and output drivers - must be low-inductance connection in noise-sensitive systems. |
| 10 | VCC | Positive supply rail - decoupling capacitor (0.1 µF ceramic + 10 µF tantalum) required within 1 cm of pin. |
| 19 | DIR | Direction control input - high enables A→B transfer, low enables B→A transfer (active-high logic). |
| 20 | OE | Output enable input - low enables transceiver, high places all A/B outputs in high-Z state (active-low logic). |
Key Features
| Feature | Design Value |
|---|---|
| pnp Input Structure | Reduces input current to ≤0.1 mA, lowering DC loading on driving sources and enabling higher fanout on shared buses. |
| 3-State Output Control | Independent DIR and OE inputs allow precise bus arbitration and isolation - critical for multi-master backplane architectures. |
| MIL-PRF-38535 Qualification | Full parametric testing across –55°C to 125°C ensures guaranteed performance in mission-critical defense electronics. |
| High Noise Immunity | VIH = 2.0 V / VIL = 0.7 V thresholds provide >0.4 V noise margin against ground bounce and crosstalk in dense PCB layouts. |
Applications
| Radar Signal Processing Backplane | Avionics Data Concentrator Unit |
|---|---|
Use Scenario: Bidirectional transfer of digitized IF samples between ADC/DAC modules and FPGA-based DSP engines across a 20-pin parallel bus. IC Role / Device Role / Timing Role: Octal transceiver managing time-critical data flow with sub-6 ns propagation delay and deterministic 3-state disable timing. Use Value: Enables deterministic latency budgeting in real-time radar processing chains where bus contention must be avoided during mode switching. | Use Scenario: Isolating ARINC 429 receiver buffers from shared system memory bus during flight control software updates. IC Role / Device Role / Timing Role: Bus isolator using OE-controlled high-Z state to prevent data corruption during hot firmware reflash operations. Use Value: Eliminates need for external bus switches or complex arbitration logic, reducing BOM count and board area in SWaP-constrained cockpits. |
| Tactical Vehicle Communication Hub | Electronic Warfare Front-End Interface |
Use Scenario: Interfacing legacy MIL-STD-1553B remote terminal data registers with modern ARM-based controller via parallel address/data bus. IC Role / Device Role / Timing Role: Level-shifting and bus-driving transceiver supporting TTL-compatible signaling across harsh EMI environments. Use Value: Provides robust DC coupling and transient immunity (VIK = –1.5 V) essential for survivability in electromagnetic pulse (EMP) scenarios. | Use Scenario: Routing wideband IF data between RF front-end ASICs and high-speed ADCs in phased-array jammer subsystems. IC Role / Device Role / Timing Role: High-speed octal buffer with matched propagation delays (tPLH/tPHL ≤ 10 ns) preserving signal integrity across 8-bit parallel paths. Use Value: Maintains inter-channel skew <1 ns, preventing timing misalignment that would degrade beamforming accuracy. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SNJ54AS245J | Faster tpd (max 7.5 ns), higher IOL (48 mA), but increased ICC (up to 143 mA) and lower noise margin (VIL = 0.8 V). | Better suited for speed-critical digital test equipment; less tolerant of marginal input noise in analog-adjacent systems. | Select SNJ54AS245J only when propagation delay <8 ns is mandatory and power budget allows ≥2× higher supply current. |
| SN74ALS245AN | Commercial temp range (0°C to 70°C), PDIP package, identical electrical specs except IOL limited to 24 mA and no MIL qualification. | Approved for non-military industrial control and instrumentation where extended temperature and radiation hardness are not required. | Choose SN74ALS245AN for cost-sensitive commercial designs with standard JEDEC-compliant assembly processes. |
Compared with SN54ALS245AJ, SNJ54AS245J trades higher speed and drive strength for greater power consumption and reduced noise immunity, while SN74ALS245AN sacrifices military reliability and temperature range for lower cost and broader commercial availability.
Availability
SN54ALS245AJ is available at Aetrix Electronics and suitable for radar signal processing backplanes, avionics data concentrators, tactical vehicle communication hubs, electronic warfare front-end interfaces, and other high-reliability embedded systems requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for SN54ALS245AJ 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 components for industrial, automotive, aerospace, and defense markets.
The SN54ALS245AJ belongs to TI's military logic family, engineered specifically for ruggedized, extended-temperature bus interfacing in mission-critical systems where failure is not an option.
FAQ
What is the maximum propagation delay of the SN54ALS245AJ under standard test conditions?
The SN54ALS245AJ has a maximum propagation delay (tpd) of 5.5 ns at VCC = 5 V, CL = 50 pF, and TA = –55°C to 125°C. This value applies to both A→B and B→A data paths and is measured from input transition (1.3 V threshold) to output crossing 1.3 V, per Figure 1 in the SDAS272A datasheet.
Does the SN54ALS245AJ support hot insertion or live bus swapping?
The SN54ALS245AJ is not explicitly rated for hot insertion, but its –1.5 V input clamp voltage (VIK) and 3-state output architecture provide inherent protection against bus contention during partial power-up. For certified hot-swap operation, external current-limiting and sequencing circuitry must be added per MIL-STD-1547 guidelines.
Can the SN54ALS245AJ be used interchangeably with the SN74ALS245A in a design?
No - the SN54ALS245AJ and SN74ALS245A are not interchangeable without validation. While electrically identical, SN54ALS245AJ is MIL-PRF-38535 qualified with full parameter testing over –55°C to 125°C and hermetic CDIP packaging, whereas SN74ALS245A is commercial-grade (0°C to 70°C) in plastic packages. Substitution requires redesign verification for thermal, mechanical, and reliability compliance.
What is the recommended decoupling strategy for the SN54ALS245AJ in high-speed layouts?
Place a 0.1 µF X7R ceramic capacitor and a 10 µF tantalum capacitor between VCC (pin 10) and GND (pin 9), located within 1 cm of the SN54ALS245AJ. Use short, wide traces; avoid vias in decoupling paths. For multi-device buses, add one 0.1 µF cap per IC and a bulk 47 µF electrolytic near the board's main 5-V regulator.
Is there a -1 version of the SN54ALS245AJ with enhanced output drive capability?
No - the –1 version (e.g., SN74ALS245A-1N) exists only for commercial-grade devices and increases IOL to 48 mA. The SN54ALS245AJ retains the standard 24 mA IOL rating per output and does not have a –1 variant. This is explicitly stated in the datasheet: "There is no -1 version of the SN54ALS245A."
SN54ALS245AJ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 54ALS
- Package/Case:
- 20-CDIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Active
- Logic Type:
- Transceiver, Non-Inverting
- Number of Elements:
- 1
- Number of Bits per Element:
- 8
- Input Type:
- -
- Output Type:
- 3-State
- Current - Output High, Low:
- 12mA, 12mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -55°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 20-CDIP
SN54ALS245AJ FAQ
1.How can I place an order for SN54ALS245AJ through Aetrix?
Please submit a Request for Quotation (RFQ) for SN54ALS245AJ 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 SN54ALS245AJ reliable?
The price and inventory of SN54ALS245AJ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN54ALS245AJ is usually 5 days.
3.What payment methods are accepted for SN54ALS245AJ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN54ALS245AJ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN54ALS245AJ?
SN54ALS245AJ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN54ALS245AJ 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 SN54ALS245AJ?
For technical support, including SN54ALS245AJ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN54ALS245AJ requirements.
6.How does Aetrix verify that SN54ALS245AJ is sourced from the original manufacturer or authorized distributors?
All SN54ALS245AJ 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 SN54ALS245AJ meets industry standards.
7.What is the process for return or replacement of SN54ALS245AJ?
All SN54ALS245AJ units undergo pre-shipment inspection (PSI). If there is an issue with SN54ALS245AJ, 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 SN54ALS245AJ part is unused and in its original packaging.
Return procedure for SN54ALS245AJ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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