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Texas Instruments SNJ54ABT7819GB
- Part No.:
- SNJ54ABT7819GB
- Manufacturer:
- Texas Instruments
- Category:
- FIFOs Memory
- Package:
- 84-CPGA
- Datasheet:
-
SNJ54ABT7819GB.pdf
- Description:
- IC FIFO SYNC 1KX18 84CPGA
- Quantity:
- Payment:
- Shipping:
Inventory:3,506
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Product details
Overview
SNJ54ABT7819GB from Texas Instruments is a military-grade, clocked bidirectional FIFO memory IC with two independent 512 × 18 dual-port SRAM buffers operating in opposite directions. It features asynchronous or coincident free-running CLKA/CLKB clocks, programmable almost-full/almost-empty flags (AF/AEA and AF/AEB), and operates across –55°C to 125°C for avionics and defense data buffering.
For engineers reviewing the SNJ54ABT7819GB datasheet, SNJ54ABT7819GB pinout, SNJ54ABT7819GB application, or SNJ54ABT7819GB equivalent, key selection criteria include its 84-pin ceramic PGA (GB) package, 50-MHz max clock frequency, 9-ns access time at 50-pF load, dual synchronous port control logic, and MIL-PRF-38535 compliance for high-reliability embedded systems.
Technical Context
The SNJ54ABT7819GB implements two independent clocked FIFOs-FIFOA–B and FIFOB–A-each with 512 × 18-bit depth and separate flag logic synchronized to their respective ports' clocks (CLKA for IRA/ORA/HFA/AF/AEA; CLKB for IRB/ORB/HFB/AF/AEB). Its BiCMOS architecture enables fast 9-ns access while maintaining low power consumption under military temperature extremes.
Port-A (A0–A17) and Port-B (B0–B17) are fully bidirectional, controlled by chip selects (CSA/CSB), write/read selects (W/RA/W/RB), and enable signals (WENA/WENB/RENA/RENB). Flag programming uses PENA/PENB to latch A0–A7/B0–B7 as offset values for AF/AEA/AF/AEB before first write, supporting configurable almost-full (Y) and almost-empty (X) thresholds up to 255 words.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Depth | 512 × 18 × 2 - Two independent FIFOs, each storing 512 words of 18-bit data for full-duplex buffering. |
| Max Clock Frequency | 50 MHz - Supports high-speed data transfer between asynchronous domains without metastability risk. |
| Access Time | 9 ns @ 50-pF load - Enables tight timing margins in real-time signal processing and radar interface designs. |
| Operating Temperature | –55°C to 125°C - Qualified per MIL-PRF-38535 for deployment in airborne, spaceborne, and ground vehicle electronics. |
| Supply Voltage | 4.5 V to 5.5 V - Compatible with standard 5-V military power rails and tolerant of transient droop. |
| Flag Programmability | AF/AEA and AF/AEB offsets set via A0–A7/B0–B7 - Allows runtime-tunable buffer thresholds for adaptive flow control. |
| Output Drive | 24 mA sink / –12 mA source - Sufficient to drive terminated backplanes or multiple TTL loads without external buffers. |
Pinout & Package
SNJ54ABT7819GB uses an 84-pin Ceramic Pin Grid Array (CPGA) package (GB), designed for hermetic sealing and thermal stability in harsh environments. The package supports lead-free post-plating and complies with MIL-STD-883 requirements.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A17 | Port-A bidirectional data bus | 18-bit I/O path for FIFOA–B read/write; high-impedance when CSA or W/RA high. |
| B0–B17 | Port-B bidirectional data bus | 18-bit I/O path for FIFOB–A read/write; high-impedance when CSB or W/RB high. |
| CLKA / CLKB | Free-running port clocks | Synchronous edge-triggered timing references; support asynchronous or coincident operation. |
| CSA / CSB | Port chip select inputs | Enable port activity only when low; decouple FIFO access from system bus contention. |
| W/RA / W/RB | Port write/read direction control | High = write to FIFO; low = read from FIFO; also controls A0–A17/B0–B17 output enable. |
| WENA / WENB | Write enable inputs | Gate write operations when active-high and IRA/IRB high (FIFO not full). |
| RENA / RENB | Read enable inputs | Gate read operations when active-high and ORA/ORB high (FIFO not empty). |
| IRA / IRB | Input-ready flags (output) | Synchronized to CLKA/CLKB; low indicates corresponding FIFO is full and writes disabled. |
| ORA / ORB | Output-ready flags (output) | Synchronized to CLKA/CLKB; low indicates corresponding FIFO is empty and reads disabled. |
| AF/AEA / AF/AEB | Programmable almost-full/empty flags | Indicate FIFOA–B/FIFOB–A occupancy near threshold; default X=Y=128, programmable up to 255. |
| HFA / HFB | Half-full flags | Assert high when FIFO contains ≥256 words; used for coarse buffer level monitoring. |
| PENA / PENB | Flag offset programming enables | Latch A0–A7/B0–B7 as AF/AEA/AF/AEB offset values during reset sequence. |
| RSTA / RSTB | FIFO reset inputs | Asynchronous reset requiring four CLKA+CLKB edges; clears pointers, flags, and internal state. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent clock domains | CLKA and CLKB operate asynchronously or coincidentally, enabling seamless bridging between mismatched system clocks. |
| Programmable flag thresholds | AF/AEA and AF/AEB offsets configured via A0–A7/B0–B7 during reset, allowing custom flow-control sensitivity. |
| MIL-PRF-38535 qualification | Fully tested per military specification including screening, burn-in, and lot acceptance testing for Class B or S devices. |
| Simultaneous-switching noise mitigation | Fast 9-ns access with controlled slew rates minimizes ground bounce in high-density PCB layouts. |
| Microprocessor interface logic | Integrated CSA/CSB, W/RA/W/RB, and enable decoding eliminates need for external glue logic in 80Cxx or 68K-based systems. |
Applications
| Radar Signal Processing Interface | Avionics Data Bus Bridge |
|---|---|
Use Scenario: Real-time buffering of digitized IF samples between ADC and DSP in airborne pulse-Doppler radar. IC Role / Device Role / Timing Role: Bidirectional FIFO isolates ADC clock domain (CLKA) from DSP clock domain (CLKB), preventing timing skew and jitter accumulation. Use Value: 512-word depth absorbs burst-mode sampling gaps; 50-MHz clocks sustain 900 MB/s aggregate throughput across both ports. | Use Scenario: Interfacing MIL-STD-1553B remote terminal with ARINC 429 avionics subsystems in flight control computers. IC Role / Device Role / Timing Role: SNJ54ABT7819GB acts as a protocol-agnostic data pipe, synchronizing 1553B serial framing to ARINC 429 word-aligned transfers. Use Value: Programmable AF/AEA/AF/AEB flags enable dynamic throttle of data flow based on downstream buffer status, avoiding packet loss. |
| Secure Communications Crypto Module | Tactical Vehicle C4I System |
Use Scenario: Buffering encrypted payload between NSA-certified crypto engine and RF modem in SATCOM terminals. IC Role / Device Role / Timing Role: FIFO provides deterministic latency isolation between crypto ASIC (CLKA) and modem baseband processor (CLKB). Use Value: –55°C to 125°C operation ensures reliability in unheated vehicle-mounted enclosures; MIL-PRF-38535 traceability satisfies DoD supply chain requirements. | Use Scenario: Aggregating sensor data (GPS, INS, EO/IR) into unified tactical picture for dismounted soldier radios. IC Role / Device Role / Timing Role: Dual-port FIFO decouples heterogeneous sensor interfaces (SPI, LVDS, CMOS) from shared ARM-based host processor bus. Use Value: HFA/HFB half-full flags provide early warning of buffer congestion; RSTA/RSTB allow coordinated cold restart during field firmware updates. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar clocked bidirectional FIFO applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SNJ54ABT7819HT | Same die, 84-pin ceramic quad flat (HT) package instead of GB PGA; different thermal resistance and mounting method. | Preferred where surface-mount assembly and lower profile are required; less suitable for hermetic module integration. | Select HT for PCB space-constrained designs; GB remains optimal for high-reliability sealed modules. |
| SN74ABT7819N | Commercial-grade version (–40°C to 85°C), plastic DIP package, no MIL-PRF-38535 screening or extended temp range. | Valid for lab prototyping or non-mission-critical industrial use; lacks radiation tolerance and long-term reliability validation. | Use SN74ABT7819N only for development; SNJ54ABT7819GB required for deployed military hardware. |
Compared with SNJ54ABT7819HT and SN74ABT7819N, the SNJ54ABT7819GB delivers guaranteed operation over –55°C to 125°C, full MIL-PRF-38535 qualification, and ceramic PGA packaging essential for hermetic, high-vibration defense platforms-making it irreplaceable in flight-critical and strategic systems.
Availability
SNJ54ABT7819GB is available at Aetrix Electronics and suitable for radar signal processing, avionics data bus bridging, and secure communications crypto modules requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for SNJ54ABT7819GB 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 aerospace, defense, and industrial markets.
The SNJ54ABT7819GB belongs to TI's Widebus™ family of high-speed interface ICs, engineered specifically for deterministic, low-latency data buffering in mission-critical military electronics.
FAQ
What is the maximum clock frequency supported by the SNJ54ABT7819GB?
The SNJ54ABT7819GB supports a maximum clock frequency of 50 MHz for both CLKA and CLKB inputs. This rating is validated across the full military temperature range (–55°C to 125°C) and under worst-case voltage conditions (VCC = 4.5 V), ensuring reliable operation in high-performance radar and telemetry systems where timing margin is critical. The 50-MHz limit applies independently to each port.
How does the programmable almost-full/almost-empty flag work on the SNJ54ABT7819GB?
The SNJ54ABT7819GB provides two programmable flags-AF/AEA for FIFOA–B and AF/AEB for FIFOB–A-each configurable with independent almost-empty (X) and almost-full (Y) thresholds. After reset and before the first write, asserting PENA or PENB latches A0–A7 or B0–B7 as offset values. The flag goes high when FIFO occupancy ≤ X or ≥ (512 – Y); default values are X = Y = 128. This enables adaptive flow control without software intervention.
Is the SNJ54ABT7819GB compliant with MIL-PRF-38535?
Yes, the SNJ54ABT7819GB is fully compliant with MIL-PRF-38535, as confirmed by its release under DSCC SMD 5962-9470401QXA and 5962-9470401QYA. All parameters are tested per the specification, including environmental stress screening, burn-in, and lot acceptance testing. This compliance ensures suitability for Class B and Class S applications in U.S. Department of Defense systems requiring traceable, high-reliability components.
What is the function of the RSTA and RSTB pins on the SNJ54ABT7819GB?
RSTA and RSTB are asynchronous reset inputs for FIFOA–B and FIFOB–A, respectively. To initiate reset, both RSTA and RSTB must be held low for four consecutive low-to-high transitions of CLKA and CLKB. This sequence clears all internal pointers, forces AF/AEA and AF/AEB high, sets HFA and HFB low, and asserts ORB and ORA low. Reset is non-destructive to stored data but invalidates all flag states until clocks resume.
Can the SNJ54ABT7819GB operate with CLKA and CLKB running at different frequencies?
Yes, the SNJ54ABT7819GB explicitly supports asynchronous operation of CLKA and CLKB, meaning they may run at different frequencies, phases, or duty cycles. Each port's flag logic (IRA/ORA/HFA/AF/AEA for CLKA; IRB/ORB/HFB/AF/AEB for CLKB) is independently synchronized to its respective clock, eliminating metastability concerns. This capability is fundamental to its role as a clock-domain crossing bridge in heterogeneous embedded systems.
SNJ54ABT7819GB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 84-CPGA
- Packaging:
- Tray
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Memory Size:
- 18K (1K x 18)
- Function:
- Synchronous
- Data Rate:
- 50MHz
- Access Time:
- -
- Voltage - Supply:
- 4.5 V ~ 5.5 V
- Current - Supply (Max):
- 95mA
- Bus Directional:
- Bi-Directional
- Expansion Type:
- -
- Programmable Flags Support:
- Yes
- Retransmit Capability:
- No
- FWFT Support:
- No
- Operating Temperature:
- -55°C ~ 125°C (TA)
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 84-CPGA
SNJ54ABT7819GB FAQ
1.How can I place an order for SNJ54ABT7819GB through Aetrix?
Please submit a Request for Quotation (RFQ) for SNJ54ABT7819GB 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 SNJ54ABT7819GB reliable?
The price and inventory of SNJ54ABT7819GB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SNJ54ABT7819GB is usually 5 days.
3.What payment methods are accepted for SNJ54ABT7819GB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SNJ54ABT7819GB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SNJ54ABT7819GB?
SNJ54ABT7819GB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SNJ54ABT7819GB 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 SNJ54ABT7819GB?
For technical support, including SNJ54ABT7819GB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SNJ54ABT7819GB requirements.
6.How does Aetrix verify that SNJ54ABT7819GB is sourced from the original manufacturer or authorized distributors?
All SNJ54ABT7819GB 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 SNJ54ABT7819GB meets industry standards.
7.What is the process for return or replacement of SNJ54ABT7819GB?
All SNJ54ABT7819GB units undergo pre-shipment inspection (PSI). If there is an issue with SNJ54ABT7819GB, 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 SNJ54ABT7819GB part is unused and in its original packaging.
Return procedure for SNJ54ABT7819GB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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