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Texas Instruments SN74ACT7881-15PN
- Part No.:
- SN74ACT7881-15PN
- Manufacturer:
- Texas Instruments
- Category:
- FIFOs Memory
- Package:
- 80-LQFP
- Datasheet:
-
SN74ACT7881-15PN.pdf
- Description:
- IC FIFO SYNC 1KX18 12NS 80LQFP
- Quantity:
- Payment:
- Shipping:
Inventory:1,621
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Product details
Overview
SN74ACT7881-15PN from Texas Instruments is a 1024 × 18-bit clocked first-in, first-out (FIFO) memory IC with independent asynchronous read/write clocks, programmable almost-full/almost-empty flag, 11 ns access time at 50-pF load, and 67 MHz max clock frequency. It serves as a high-speed data buffering interface between mismatched-rate digital subsystems in telecom line cards and industrial protocol gateways.
For engineers reviewing the SN74ACT7881-15PN datasheet, SN74ACT7881-15PN pinout, SN74ACT7881-15PN application, or SN74ACT7881-15PN equivalent, key selection criteria include its dual-clock synchronization capability, 18-bit parallel I/O, 80-pin shrink quad flat package (PN), status flag timing behavior, and compatibility with SN74ACT7882/SN74ACT7884 for depth/width expansion.
Technical Context
The SN74ACT7881-15PN implements a synchronous FIFO architecture with separate WRTCLK and RDCLK domains, enabling true asynchronous data transfer across clock boundaries. Its internal 1024-word × 18-bit RAM array is managed by independent read and write pointers, with status flags (AF/AE, HF, IR, OR) generated synchronously to their respective clocks.
Flag logic supports user-programmable AF/AE offset (X = 0–511) via DAF control during reset, or default X = 256. Input-ready (IR) and output-ready (OR) flags are edge-triggered on WRTCLK and RDCLK respectively, ensuring deterministic handshake timing for bus interfacing without external arbitration logic.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Depth × Width | 1024 × 18 bits - provides 18.4 kbit buffer capacity for burst-mode data alignment |
| Max Clock Frequency | 67 MHz - enables 67 Mwords/s throughput per port for high-bandwidth bridging |
| Access Time | 11 ns @ 50-pF load - ensures sub-15 ns read/write latency critical for real-time control loops |
| Supply Voltage | 4.5 V to 5.5 V - compatible with standard 5-V TTL/CMOS logic rails and noise margins |
| Operating Temperature | 0°C to 70°C - rated for commercial-grade industrial control and communications equipment |
| Output Drive | –8 mA / +16 mA - directly drives 50-Ω transmission lines or multiple 74ACT inputs without buffers |
| Status Flags | AF/AE, HF, IR, OR - four dedicated open-drain outputs for hardware flow control and system monitoring |
Pinout & Package
SN74ACT7881-15PN uses an 80-pin shrink quad flat package (PN) with 0.5-mm lead pitch and exposed thermal pad. Pin numbering follows standard QFP top-view convention with corner pin 1 marked.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (RESET) | Asynchronous reset input | Active-low global initialization; requires ≥4 WRTCLK/RDCLK cycles to synchronize internal pointers and flags |
| 5 (RDCLK) | Read clock input | Free-running edge-triggered clock; data appears on Q0–Q17 after third rising edge post-write |
| 29 (WRTCLK) | Write clock input | Free-running edge-triggered clock; data latched from D0–D17 on rising edge when IR/WRTEN1/WRTEN2 high |
| 33 (AF/AE) | Programmable status output | Open-drain flag indicating FIFO occupancy near full/empty thresholds; polarity configurable via DAF during reset |
| 66 (OR) | Output-ready flag | High when FIFO contains ≥1 word; synchronized to RDCLK rising edge for glitch-free handshaking |
| D0–D17 (Pins 7–19, 26) | Data inputs | 18-bit parallel write bus; D0–D8 also carry AF/AE offset value (X) when captured by DAF transition |
| Q0–Q17 (Pins 38–39, 41–42, 44, 46–47, 49–50, 52–53, 55–56, 58–59, 61, 63–64) | Data outputs | 18-bit noninverting parallel read bus; tri-stated when OE = low; driven synchronously to RDCLK |
Key Features
| Feature | Design Value |
|---|---|
| Independent clock domains | Separate WRTCLK and RDCLK inputs eliminate clock domain crossing logic and reduce FPGA resource usage |
| Programmable AF/AE threshold | User-defined X (0–511) or default 256 enables precise tuning of flow-control trigger points for variable packet sizes |
| Expandable architecture | Supports cascaded word-depth expansion (e.g., 2048×18) and parallel word-width expansion (e.g., 1024×36) without external glue logic |
| Dual enable control per port | WRTEN1/WRTEN2 and RDEN1/RDEN2 provide redundant gating for robust multi-controller arbitration |
| Direct bus interface drive | ±16 mA output strength allows connection to backplane traces or legacy 5-V buses without level-shifting or buffering |
Applications
| Telecom Line Card Buffering | Industrial Protocol Gateway |
|---|---|
Use Scenario: Absorbing jitter between TDM framer and packet-switching ASIC in DSLAM line cards. IC Role / Device Role / Timing Role: Asynchronous FIFO buffer isolating 8 kHz TDM clock domain from 125 MHz Ethernet MAC clock domain. Use Value: Prevents data loss during clock rate mismatches using IR/OR handshaking and 67 MHz throughput. | Use Scenario: Bridging Modbus RTU serial data to EtherNet/IP packets in factory automation gateways. IC Role / Device Role / Timing Role: Data staging buffer decoupling slow RS-485 UART timing from high-speed Ethernet controller DMA bursts. Use Value: Enables deterministic packet assembly with AF/AE flag triggering firmware interrupt at 90% fill level. |
| Test Equipment Data Capture | DSP Co-Processor Interface |
Use Scenario: Capturing high-speed analog-to-digital samples from 100 MSPS ADC before host PC transfer. IC Role / Device Role / Timing Role: High-throughput FIFO capturing burst-mode ADC output synchronized to sampling clock. Use Value: 1024-word depth holds >10 µs of 100 MSPS data; 11 ns access time minimizes capture dead time. | Use Scenario: Interfacing fixed-point DSP core with external video preprocessing ASIC in embedded vision systems. IC Role / Device Role / Timing Role: Synchronizing 18-bit pixel data streams between DSP's 50 MHz bus and ASIC's 67 MHz pixel clock. Use Value: Dual-clock operation eliminates metastability risk; HF flag signals optimal DMA transfer window. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar FIFO memory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ACT7882-15PN | Same 1024×18 architecture but with 2048-word depth option; identical pinout and timing | Used where deeper buffering is required without changing PCB layout | Select when >1024-word depth is needed; shares same control logic and flag behavior |
| SN74ACT7884-15PN | 1024×9 configuration; half the data width but same clocking and flag architecture | Applied in cost-sensitive 9-bit or byte-aligned interfaces where full 18-bit width is unnecessary | Choose for narrower data paths; reduces pin count and board space while retaining dual-clock sync |
Compared with SN74ACT7882-15PN and SN74ACT7884-15PN, the SN74ACT7881-15PN offers the standard 1024×18 configuration optimized for balanced bandwidth and depth-making it the reference choice for general-purpose high-speed buffering where neither extreme depth nor minimal width is required.
Availability
SN74ACT7881-15PN is available at Aetrix Electronics and suitable for telecom infrastructure, industrial protocol gateways, automated test equipment, and embedded vision systems requiring stable component supply and long-term obsolescence management.
Supply support for SN74ACT7881-15PN 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 logic solutions with over 50 years of innovation in high-reliability interface and memory products.
The SN74ACT7881-15PN belongs to TI's Widebus™ family of high-speed FIFO memories, designed specifically for clock-domain isolation and burst-mode data buffering in communications and industrial control systems.
FAQ
What is the maximum operating frequency of the SN74ACT7881-15PN?
The SN74ACT7881-15PN supports a maximum clock frequency of 67 MHz for both WRTCLK and RDCLK inputs under recommended operating conditions (VCC = 4.5 V to 5.5 V, TA = 0°C to 70°C). This rating is validated with CL = 50 pF and corresponds to the -15 speed grade, delivering guaranteed 11 ns access time. The device maintains full functionality across its entire specified voltage and temperature range at this rate.
How does the AF/AE flag programming work on the SN74ACT7881-15PN?
The AF/AE flag on the SN74ACT7881-15PN is programmed during reset using the DAF pin. Holding DAF low during RESET pulse captures D0–D8 as the AF/AE offset value X (0–511); holding DAF high selects the default X = 256. The SN74ACT7881-15PN asserts AF/AE high when FIFO occupancy is ≤ (X + 1) or ≥ (1025 – X) words, enabling precise flow-control threshold tuning without firmware intervention.
Is the SN74ACT7881-15PN pin-compatible with other devices in the SN74ACT788x family?
Yes, the SN74ACT7881-15PN is pin-to-pin compatible with SN74ACT7882-15PN and SN74ACT7884-15PN in the same 80-pin PN package. All share identical pin functions, electrical characteristics, and timing behavior-enabling direct substitution in existing designs when adjusting depth (7882) or width (7884) requirements without PCB revision.
What are the key timing parameters for read and write operations on the SN74ACT7881-15PN?
For write operations, SN74ACT7881-15PN requires WRTEN1/WRTEN2 high ≥5 ns before WRTCLK rising edge and D0–D17 stable ≥5 ns before that edge. For reads, OE/RDEN1/RDEN2 must be high ≥4 ns before RDCLK rising edge. Propagation delays are tpd = 3–12 ns (RDCLK→Q) and 2–8 ns (WRTCLK→IR), all specified at CL = 50 pF and VCC = 4.5 V.
Does the SN74ACT7881-15PN support expansion beyond its native 1024×18 capacity?
Yes, the SN74ACT7881-15PN supports both word-depth and word-width expansion. Depth expansion chains multiple devices serially using OR→IR handshaking; width expansion connects devices in parallel with shared clocks and combined D/Q buses. The SN74ACT7881-15PN's dedicated status flags and dual-enable inputs simplify expansion without external logic, enabling configurations like 2048×18 or 1024×36 while retaining full flag visibility.
SN74ACT7881-15PN Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ACT
- Package/Case:
- 80-LQFP
- Packaging:
- Tray
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Memory Size:
- 18K (1K x 18)
- Function:
- Synchronous
- Data Rate:
- 67MHz
- Access Time:
- 12ns
- Voltage - Supply:
- 4.5 V ~ 5.5 V
- Current - Supply (Max):
- 400µA
- Bus Directional:
- Uni-Directional
- Expansion Type:
- Depth, Width
- Programmable Flags Support:
- Yes
- Retransmit Capability:
- No
- FWFT Support:
- No
- Operating Temperature:
- 0°C ~ 70°C
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 80-LQFP (12x12)
SN74ACT7881-15PN FAQ
1.How can I place an order for SN74ACT7881-15PN through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ACT7881-15PN 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 SN74ACT7881-15PN reliable?
The price and inventory of SN74ACT7881-15PN are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ACT7881-15PN is usually 5 days.
3.What payment methods are accepted for SN74ACT7881-15PN?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74ACT7881-15PN transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74ACT7881-15PN?
SN74ACT7881-15PN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ACT7881-15PN 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 SN74ACT7881-15PN?
For technical support, including SN74ACT7881-15PN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ACT7881-15PN requirements.
6.How does Aetrix verify that SN74ACT7881-15PN is sourced from the original manufacturer or authorized distributors?
All SN74ACT7881-15PN 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 SN74ACT7881-15PN meets industry standards.
7.What is the process for return or replacement of SN74ACT7881-15PN?
All SN74ACT7881-15PN units undergo pre-shipment inspection (PSI). If there is an issue with SN74ACT7881-15PN, 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 SN74ACT7881-15PN part is unused and in its original packaging.
Return procedure for SN74ACT7881-15PN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SN74ACT7881-15PN Tags
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7201LA15JGI
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