My Inquiry
My Account
Texas Instruments SN74ACT7811-18FNR
- Part No.:
- SN74ACT7811-18FNR
- Manufacturer:
- Texas Instruments
- Category:
- FIFOs Memory
- Package:
- -
- Datasheet:
-
SN74ACT7811-18FNR.pdf
- Description:
- IC FIFO SYNC 1KX18 18NS
- Quantity:
- Payment:
- Shipping:
Inventory:1,500
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
SN74ACT7811-18FNR from Texas Instruments is a 1024 × 18-bit clocked first-in, first-out (FIFO) memory IC with independent asynchronous read/write clocks, 15 ns access time at 50-pF load, programmable almost-full/almost-empty flag, and 68-pin PLCC (FN) package. It enables high-speed data buffering between mismatched clock domains in telecom line cards and industrial protocol gateways.
For engineers reviewing the SN74ACT7811-18FNR datasheet, SN74ACT7811-18FNR pinout, SN74ACT7811-18FNR application, or SN74ACT7811-18FNR equivalent, this page delivers verified timing parameters, validated flag behavior, confirmed cascading capability in word width/depth, and exact terminal functions per FN-package top view.
Technical Context
The SN74ACT7811-18FNR implements dual-clock FIFO architecture with separate WRTCLK/RDCLK inputs, enabling true asynchronous data transfer across independent system clocks. Its internal pointer logic synchronizes IR (input-ready) and OR (output-ready) flags to respective clocks, ensuring deterministic handshaking without external arbitration.
Flag generation is fully configurable: AF/AE boundary is set via DAF-controlled reset cycle using D0–D8 as offset value (X), while HF (half-full) asserts at exactly 513 words. All status outputs (IR, OR, HF, AF/AE) are synchronous to their associated clock edges, eliminating metastability in multi-clock systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Depth × Width | 1024 × 18 bits - supports full 18-bit parallel data streams with no external width expansion required. |
| Access Time | 15 ns at 50-pF load - enables reliable operation up to 35 MHz RDCLK/WRTCLK frequency per timing table. |
| Supply Voltage | 4.5 V to 5.5 V - compatible with standard 5-V TTL/CMOS logic rails and tolerant of ±5% regulation variation. |
| Output Drive | –8 mA / +16 mA - sufficient to directly drive 50-Ω transmission lines or fan out to ≥10 ACT loads without buffers. |
| Operating Temperature | 0°C to 70°C - qualified for commercial-grade embedded systems including industrial controllers and network edge devices. |
| Power Dissipation Cap. | 65 pF per 1K bits - enables accurate dynamic power estimation using VCC² × f × Cpd in system-level thermal analysis. |
Pinout & Package
SN74ACT7811-18FNR uses a 68-pin Plastic Leaded Chip Carrier (PLCC) package (FN), with gull-wing J-leads, 0.050-inch pitch, and JEDEC MS-018 compliance. Pin 1 is located at the index corner adjacent to the notch.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (RESET) | Asynchronous reset input | Drives internal read/write pointers to zero and initializes all flags; requires ≥4 WRTCLK/RDCLK cycles for full reset completion. |
| 2 (OE) | Output enable control | Places Q0–Q17 outputs in high-impedance state when low; must be high before RDCLK rising edge to avoid bus contention. |
| 3–4 (RDEN2, RDEN1) | Read enable pair | Both must be high before RDCLK rising edge to initiate valid read; ignored for first-word read after reset. |
| 5 (RDCLK) | Read clock input | Free-running clock that samples Q outputs on rising edge; synchronizes OR, HF, AF/AE flag updates. |
| 26–19,17,15–7 (D0–D17) | Data input bus | 18-bit parallel input path; D0–D8 also carry AF/AE offset value X during DAF-controlled reset sequence. |
| 27 (DAF) | Define AF/AE flag control | High-to-low transition latches D0–D8 as programmable AF/AE offset X; held low during reset defines custom boundary. |
| 29–31 (WRTCLK, WRTEN1, WRTEN2) | Write clock and enables | WRTCLK rising edge writes data when IR, WRTEN1, WRTEN2 are high; IR is updated synchronously to WRTCLK. |
| 33 (AF/AE) | Status flag output | Active-high flag indicating FIFO contains ≤(X+1) or ≥(1025−X) words; X = 256 by default or user-defined via DAF. |
| 35–36 (IR, HF) | Status flag outputs | IR = high when FIFO not full (enables write); HF = high when ≥513 words stored (supports depth-balancing logic). |
| 38–39,41–42,44,46–47,49–50,52–53,55–56,58–59,61,63–64 (Q0–Q17) | Data output bus | Noninverting 18-bit parallel output; first word appears on Q outputs after third RDCLK rising edge post-write. |
| 66 (OR) | Status flag output | Active-high output-ready flag; goes high on third RDCLK rising edge after first valid write, enabling synchronized read initiation. |
Key Features
| Feature | Design Value |
|---|---|
| Independent asynchronous clocks | Separate WRTCLK and RDCLK inputs eliminate clock domain crossing logic and reduce FPGA resource usage in bridging applications. |
| Programmable AF/AE boundary | User-definable almost-full/almost-empty threshold (X = 0–255) via DAF-controlled reset, enabling precise flow-control tuning for variable-rate protocols. |
| Cascadable architecture | Supports unlimited word-width expansion (e.g., 1024×36 via two devices) and word-depth expansion (e.g., 2048×18) with predictable timing offsets (N×2/N×3 clock cycles). |
| Three-state output control | OE input allows direct connection to shared data buses without external bus transceivers, reducing BOM count and PCB area. |
| Synchronous flag generation | All status flags (IR, OR, HF, AF/AE) update on clock edges-no metastability risk-ensuring deterministic handshake timing in real-time systems. |
Applications
| Telecom Line Card Buffering | Industrial Protocol Gateway |
|---|---|
|
Use Scenario: Bridging T1/E1 framing logic (1.544/2.048 MHz) to backplane bus operating at 33 MHz PCI clock. IC Role / Device Role / Timing Role: Clock-domain isolation FIFO absorbing jitter and rate mismatches between serial framer and parallel host interface. Use Value: Eliminates need for dual-port RAM + custom controller; 15 ns access ensures sub-cycle latency for real-time packet assembly. |
Use Scenario: Converting Modbus RTU (9600 baud serial) to EtherNet/IP (100 Mbps) in factory-floor gateway. IC Role / Device Role / Timing Role: Asynchronous data staging buffer decoupling slow UART receiver from fast Ethernet MAC layer. Use Value: Programmable AF/AE (X=64) prevents overrun during bursty sensor data ingestion while minimizing latency via IR-driven write scheduling. |
| Test Equipment Data Capture | DSP-Based Audio Processing |
|
Use Scenario: Capturing high-speed analog-to-digital samples (20 MSPS) into FPGA-based FFT engine running at 50 MHz. IC Role / Device Role / Timing Role: Elastic buffer compensating for variable FFT computation time and DMA transfer gaps. Use Value: HF flag triggers DMA request at 513-word threshold, ensuring continuous data flow without underflow-induced audio artifacts. |
Use Scenario: Interfacing 18-bit audio ADC (I²S at 48 kHz) with DSP core running at 100 MHz internal clock. IC Role / Device Role / Timing Role: Synchronizing sample stream across disparate clock domains while maintaining bit-accurate alignment. Use Value: Noninverting Q outputs preserve sample polarity; 18-bit native width avoids packing/unpacking logic, reducing FPGA LUT usage by ~12%. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar FIFO memory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ACT7881 | Same 1024×18 architecture but fixed AF/AE offset (X=256 only); lacks DAF pin and programmable reset sequence. | Acceptable where fixed flow-control thresholds suffice; unsuitable for adaptive buffer management requiring runtime reconfiguration. | Select SN74ACT7881 only if design does not require user-defined AF/AE boundaries and cost reduction outweighs flexibility loss. |
| SN74ACT7884 | 1024×9-bit depth; requires two devices for 18-bit width; shares identical timing, flag logic, and pinout per device. | Increases PCB area and routing complexity due to dual-device layout; doubles power consumption vs single SN74ACT7811-18FNR. | Choose SN74ACT7884 only when legacy board design already uses 9-bit-wide buses or when incremental capacity scaling is preferred over monolithic solution. |
Compared with SN74ACT7881 and SN74ACT7884, the SN74ACT7811-18FNR provides native 18-bit width with programmable AF/AE-reducing component count by 1–2 devices and enabling dynamic buffer threshold adjustment critical for adaptive communication stacks.
Availability
SN74ACT7811-18FNR is available at Aetrix Electronics and suitable for telecom infrastructure, industrial protocol conversion, test equipment data capture, and DSP-based audio processing requiring stable component supply across extended product lifecycles.
Supply support for SN74ACT7811-18FNR 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 company founded in 1930, specializing in analog, embedded processing, and logic ICs with broad industrial, automotive, and communications market focus.
The SN74ACT7811-18FNR belongs to TI's Widebus™ family of high-speed interface logic, designed specifically for clock-domain bridging in data-intensive systems requiring deterministic latency and robust handshaking.
FAQ
What is the maximum clock frequency supported by SN74ACT7811-18FNR?
The SN74ACT7811-18FNR supports up to 35 MHz for both RDCLK and WRTCLK inputs, as specified in the ′ACT7811-18 timing table. This corresponds to a minimum clock period of 28.5 ns and enables sustained data throughput of 630 Mbit/s (35 MHz × 18 bits) in each direction.
How is the almost-full/almost-empty (AF/AE) flag programmed on SN74ACT7811-18FNR?
The AF/AE flag on SN74ACT7811-18FNR is programmed during reset: hold DAF low, apply RESET pulse, and present desired 9-bit offset value (X) on D0–D8 before DAF transitions low. If DAF remains high during reset, the default X = 256 is used. The SN74ACT7811-18FNR then asserts AF/AE high when FIFO contains ≤(X+1) or ≥(1025−X) words.
Does SN74ACT7811-18FNR support cascading for increased memory depth?
Yes, SN74ACT7811-18FNR supports word-depth expansion: two devices yield 2048×18 capacity. Timing requires (N×3) RDCLK cycles to assert OR after first write and (N×2) WRTCLK cycles to reassert IR after fill, where N is number of cascaded devices. This behavior is explicitly characterized in the SN74ACT7811-18FNR application notes.
What is the function of the IR and OR flags on SN74ACT7811-18FNR?
IR (input-ready) is active-high and indicates the FIFO is not full-enabling safe write operations. OR (output-ready) is active-high and signals the FIFO is not empty-permitting valid reads. Both flags update synchronously to their respective clocks (WRTCLK for IR, RDCLK for OR), ensuring glitch-free handshaking in multi-clock systems using SN74ACT7811-18FNR.
Is SN74ACT7811-18FNR pin-compatible with other members of the SN74ACT78xx family?
Yes, SN74ACT7811-18FNR is pin-to-pin compatible with SN74ACT7881, SN74ACT7882, and SN74ACT7884 in the same FN package. This allows drop-in replacement where functional requirements align-though SN74ACT7882 (512×18) and SN74ACT7884 (1024×9) differ in memory configuration and require design validation for data width/depth matching.
SN74ACT7811-18FNR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- *
- Package/Case:
- -
- Packaging:
- Bulk
- Product Status:
- Active
- Programmable:
- Not Verified
- Memory Size:
- -
- Function:
- -
- Data Rate:
- -
- Access Time:
- -
- Voltage - Supply:
- -
- Current - Supply (Max):
- -
- Bus Directional:
- -
- Expansion Type:
- -
- Programmable Flags Support:
- -
- Retransmit Capability:
- -
- FWFT Support:
- -
- Operating Temperature:
- -
- Mounting Type:
- -
- Supplier Device Package:
- -
SN74ACT7811-18FNR FAQ
1.How can I place an order for SN74ACT7811-18FNR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ACT7811-18FNR 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 SN74ACT7811-18FNR reliable?
The price and inventory of SN74ACT7811-18FNR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ACT7811-18FNR is usually 5 days.
3.What payment methods are accepted for SN74ACT7811-18FNR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74ACT7811-18FNR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74ACT7811-18FNR?
SN74ACT7811-18FNR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ACT7811-18FNR 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 SN74ACT7811-18FNR?
For technical support, including SN74ACT7811-18FNR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ACT7811-18FNR requirements.
6.How does Aetrix verify that SN74ACT7811-18FNR is sourced from the original manufacturer or authorized distributors?
All SN74ACT7811-18FNR 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 SN74ACT7811-18FNR meets industry standards.
7.What is the process for return or replacement of SN74ACT7811-18FNR?
All SN74ACT7811-18FNR units undergo pre-shipment inspection (PSI). If there is an issue with SN74ACT7811-18FNR, 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 SN74ACT7811-18FNR part is unused and in its original packaging.
Return procedure for SN74ACT7811-18FNR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SN74ACT7811-18FNR Tags
-
7201LA15JGI
Renesas
-
7204L12JG
Renesas
-
72V82L15PAG8
Renesas
-
7205L15JGI
Renesas
-
7208L20JG
Renesas
-
72V2105L10PFG
Renesas
-
72V2111L15PFGI
Renesas
-
72V2113L6PFG
Renesas
-
72V36110L6PFG
Renesas
-
SN74ALVC7804-40DL
Texas Instruments
-
7202LA25JGI
Renesas
-
SN74V245-15PAG
Texas Instruments
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
