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Texas Instruments SNJ54F245J
- Part No.:
- SNJ54F245J
- Manufacturer:
- Texas Instruments
- Package:
- 20-CDIP (0.300", 7.62mm)
- Datasheet:
-
SNJ54F245J.pdf
- Description:
- OCTAL BUS TRANSCEIVERS WITH 3-ST
- Quantity:
- Payment:
- Shipping:
Inventory:3,920
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Product details
Overview
SNJ54F245J from Texas Instruments is a military-grade octal bus transceiver with 3-state outputs, designed for bidirectional asynchronous data transfer between two 8-bit buses. It operates across –55°C to 125°C, supports 5 V supply, features DIR/OE control logic, and delivers B-bus output drive up to 96 mA (low state). It is used in ruggedized avionics backplane interfaces requiring bus isolation and direction control.
For engineers reviewing the SNJ54F245J datasheet, SNJ54F245J pinout, SNJ54F245J application, or SNJ54F245J equivalent, key selection criteria include military temperature range compliance, CDIP-20 through-hole package compatibility, 3-state bus contention prevention, and verified 7 ns max propagation delay under 50 pF load.
Technical Context
The SNJ54F245J implements TTL-compatible bipolar F-family logic with dual 8-bit bidirectional data paths controlled by DIR (direction) and OE (output enable) inputs. Its 3-state outputs allow dynamic bus sharing without contention, and its internal structure isolates A and B ports when OE is high.
It uses standard positive-logic control: OE = L enables transmission; DIR = L routes B→A, DIR = H routes A→B. Absolute maximum ratings include –0.5 V to 7 V on VCC and –1.2 V to 7 V on inputs, with output short-circuit current limited per channel per datasheet specification.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - ensures compatibility with legacy 5 V TTL systems and stable operation under rail variation. |
| Operating Temperature | –55°C to 125°C - qualified for military/aerospace applications requiring extended thermal resilience. |
| Propagation Delay | Max 7 ns (tPLH/tPHL) at 5 V/50 pF - enables reliable timing in high-speed synchronous bus architectures up to ~100 MHz effective rate. |
| B-Bus Output Drive | 96 mA sink (IOL), 12 mA source (IOH) - sufficient to drive multiple TTL loads or terminated transmission lines directly. |
| A-Bus Output Drive | 40 mA sink (IOL), 3 mA source (IOH) - optimized for local bus buffering with lower fanout requirements. |
| 3-State Enable Time | tPZL ≤ 8 ns, tPHZ ≤ 6.5 ns - guarantees rapid bus release and acquisition critical for time-multiplexed shared-bus protocols. |
| Package Type | CDIP-20 (J package) - hermetically sealed ceramic dual in-line, leaded, through-hole mount for high-reliability board assembly. |
Pinout & Package
Ceramic Dual In-Line Package (CDIP-20), 20-pin, through-hole, hermetic seal, 0.3-inch body width, 0.1-inch pin pitch. Pin 1 identified by notch or beveled corner per JEDEC MS-001.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | DIR | Direction control input: L = B→A, H = A→B - determines real-time data flow path without latch or clock. |
| 2–9 | A1–A8 | Port A bidirectional I/O - connects to local subsystem bus; driven only when OE = L and direction matches. |
| 10 | GND | Ground reference - common return for all signals and power; requires low-impedance PCB plane connection. |
| 11 | VCC | +5 V supply - must be decoupled locally with 0.1 µF ceramic capacitor near pin to suppress switching noise. |
| 12–19 | B1–B8 | Port B bidirectional I/O - connects to main system bus; electrically isolated when OE = H. |
| 20 | OE | Output enable input: L = active, H = high-impedance - primary bus arbitration signal for multi-device sharing. |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional 8-bit data path | Eliminates need for separate transmit/receive buffers in full-duplex bus bridges, reducing component count and layout area. |
| 3-state outputs with fast enable/disable | Sub-10 ns transition into/out of high-Z state prevents bus glitches during arbitration, enabling deterministic multi-master timing. |
| Military temperature qualification | Validated operation from –55°C to 125°C ensures reliability in uncontrolled environments like engine bays or satellite payloads. |
| CDIP-20 hermetic packaging | Provides moisture resistance, long-term solder joint integrity, and radiation tolerance essential for defense and space programs. |
| TTL-compatible input thresholds | VIH = 2 V min, VIL = 0.8 V max - ensures interoperability with legacy 5 V logic families without level-shifting circuitry. |
Applications
| Avionics Data Bus Interface | Secure Ground Station Backplane |
|---|---|
Use Scenario: Interfacing mission computer's local data bus to a MIL-STD-1553B remote terminal controller via isolated parallel control path. IC Role / Device Role / Timing Role: Bidirectional bus transceiver providing direction-controlled data mirroring between processor and interface ASIC, synchronized to system clock edges. Use Value: Enables deterministic latency (<7 ns) and bus contention avoidance during hot-swap reconfiguration of LRUs without software overhead. | Use Scenario: Isolating cryptographic module's internal bus from external telemetry and command buses in hardened ground station cabinets. IC Role / Device Role / Timing Role: Physical-layer bus gatekeeper that enforces one-way or bidirectional data flow based on security state flags (DIR/OE). Use Value: Prevents unauthorized signal leakage across security domains using hardware-enforced 3-state isolation, meeting NSA Type 1 boundary requirements. |
| Ruggedized Industrial PLC Chassis | Spacecraft Onboard Computer Expansion |
Use Scenario: Extending I/O module addressing in modular PLC backplanes where CPU and peripheral slots share a common 8-bit data highway. IC Role / Device Role / Timing Role: Bus repeater and direction manager allowing CPU-initiated read/write cycles to reach remote I/O banks without address decoding latency. Use Value: Supports hot-plug I/O modules via OE-controlled isolation, eliminating bus lock-up during insertion/removal under full operational load. | Use Scenario: Connecting redundant flight computer memory banks to shared SRAM or PROM in radiation-hardened spacecraft avionics. IC Role / Device Role / Timing Role: Radiation-tolerant bus coupler enabling memory mirroring and failover arbitration between primary and backup processors. Use Value: Maintains data coherency across dual-channel memory paths using DIR-synchronized write-through and OE-gated read isolation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SNJ54LS245J | Lower drive (24 mA B-bus sink), slower speed (15 ns max), LS-TTL compatible - reduced power but higher propagation delay. | Suitable for lower-frequency legacy systems where power efficiency outweighs timing performance. | Select when operating margin allows >15 ns delay and total system power budget is constrained. |
| SNJ54ACT245J | CMOS-based, wider VCC range (4.5–5.5 V), higher noise immunity (VIH = 3.85 V), 3-state delay <5 ns - improved speed and noise rejection. | Preferred for new designs requiring EMI robustness and tighter timing budgets in mixed-signal environments. | Choose for upgrades where board layout permits CMOS-level input thresholds and faster settling is required. |
Compared with SNJ54F245J, SNJ54LS245J trades speed for lower power and cost in legacy systems, while SNJ54ACT245J offers superior noise immunity and timing performance at the expense of stricter input voltage thresholds and different drive strength profiles.
Availability
SNJ54F245J is available at Aetrix Electronics and suitable for avionics integration, secure communications infrastructure, and ruggedized industrial control systems requiring stable component supply across extended lifecycle commitments.
Supply support for SNJ54F245J 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 manufacturer founded in 1930, specializing in analog, embedded processing, and high-reliability logic solutions for aerospace, defense, and industrial markets.
The SNJ54F series belongs to TI's military-qualified F-family TTL logic line, engineered specifically for high-speed, high-stability digital interfacing in mission-critical systems where environmental resilience and long-term obsolescence management are mandatory.
FAQ
What is the maximum operating temperature range for SNJ54F245J?
The SNJ54F245J is characterized for operation from –55°C to 125°C, meeting MIL-PRF-38535 requirements for Class B military-grade devices. This full-range qualification is confirmed in the SDFS010A datasheet Section 2, "Recommended Operating Conditions," and applies specifically to the J-package CDIP variant. The extended thermal envelope ensures reliability in jet engine compartments, satellite payload bays, and desert-deployed ground systems where ambient extremes exceed commercial limits.
Does SNJ54F245J support true bidirectional data flow without external logic?
Yes, SNJ54F245J supports true hardware-controlled bidirectional data flow using only its DIR and OE inputs - no external latches, clocks, or glue logic required. When OE = L, setting DIR = L enables B→A transfer; DIR = H enables A→B transfer. This is explicitly defined in the FUNCTION TABLE on page 2–1 of the SDFS010A datasheet. The device internally routes signals based solely on these two TTL-level control lines, making it ideal for simple, deterministic bus bridging.
What is the pin 1 marking convention for SNJ54F245J in the CDIP package?
SNJ54F245J in the CDIP (J) package uses a molded notch at the top-left corner of the package body to indicate pin 1 location, consistent with JEDEC MS-001 standards. The part marking "8551101RA" appears adjacent to pin 1, and the full device identifier "SNJ54F245J" is laser-etched on the top surface. This marking scheme is documented in TI's PACKAGE OPTION ADDENDUM (page Addendum-Page 2) and verified on TI's official product page for orderable part SNJ54F245J.
Can SNJ54F245J be used with 3.3 V logic systems?
No, SNJ54F245J is not compatible with 3.3 V logic systems. It requires a 4.5 V to 5.5 V supply and has TTL input thresholds (VIH ≥ 2 V, VIL ≤ 0.8 V), which do not align with 3.3 V CMOS logic levels. Driving its inputs from 3.3 V sources risks marginal VIH compliance, and powering it at 3.3 V violates absolute maximum ratings. For 3.3 V systems, TI recommends alternatives such as SN74LVC245A or SN74ALVC245, which are explicitly rated for 3.3 V operation and have compatible thresholds.
Is SNJ54F245J RoHS compliant?
No, SNJ54F245J is not RoHS compliant. Per TI's PACKAGE OPTION ADDENDUM, the SNJ54F245J orderable part uses SnPb (tin-lead) lead finish and is marked "No" under RoHS column. It is intended for legacy military, aerospace, and high-reliability applications where Pb-based soldering is permitted and required for long-term interconnect integrity. RoHS-compliant alternatives like SN74F245N (with NiPdAu finish) exist but operate only from 0°C to 70°C and use plastic DIP packaging.
SNJ54F245J Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 54F
- 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, 48mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -55°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 20-CDIP
SNJ54F245J FAQ
1.How can I place an order for SNJ54F245J through Aetrix?
Please submit a Request for Quotation (RFQ) for SNJ54F245J 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 SNJ54F245J reliable?
The price and inventory of SNJ54F245J are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SNJ54F245J is usually 5 days.
3.What payment methods are accepted for SNJ54F245J?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SNJ54F245J transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SNJ54F245J?
SNJ54F245J orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SNJ54F245J 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 SNJ54F245J?
For technical support, including SNJ54F245J datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SNJ54F245J requirements.
6.How does Aetrix verify that SNJ54F245J is sourced from the original manufacturer or authorized distributors?
All SNJ54F245J 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 SNJ54F245J meets industry standards.
7.What is the process for return or replacement of SNJ54F245J?
All SNJ54F245J units undergo pre-shipment inspection (PSI). If there is an issue with SNJ54F245J, 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 SNJ54F245J part is unused and in its original packaging.
Return procedure for SNJ54F245J:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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