Send an Inquiry

To receive a quote for your project, please fill in the following information, and we’ll get back to you promptly.

Submit Inventory List

Please fill in the following information, and we’ll get back to you promptly.

Home > Products > Integrated Circuits (ICs) > Logic > FIFOs Memory

Texas Instruments SN74ACT7811-15FN

Name: SN74ACT7811-15FN
Brand: Texas Instruments
SKU: SN74ACT7811-15FN
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

Compare

Part No.:: SN74ACT7811-15FN

Manufacturer:: Texas Instruments

Category:: FIFOs Memory

Package:: 68-LCC (J-Lead)

Datasheet:: SN74ACT7811-15FN.pdf

Description:: IC FIFO SYNC 1KX18 15NS 68PLCC

Quantity:: RFQ Add To RFQ list

Payment:

Shipping:

Inventory:2,915

Please send an inquiry. Send us your inquiry, and we will respond immediately.

Product details

Overview

SN74ACT7811-15FN from Texas Instruments is a 1024 × 18-bit clocked first-in, first-out (FIFO) memory IC with independent asynchronous read/write ports, 15 ns access time at 50-pF load, pin-to-pin compatibility with SN74ACT7881/7882/7884, and programmable almost-full/almost-empty flag logic. It serves as a high-speed data buffering interface between mismatched clock domains in digital communication subsystems.

For engineers reviewing the SN74ACT7811-15FN datasheet, SN74ACT7811-15FN pinout, SN74ACT7811-15FN application, or SN74ACT7811-15FN equivalent, key selection criteria include its 40 MHz maximum clock frequency, dual-clock synchronization capability, 68-pin PLCC (FN) package, status flag architecture (IR/OR/HF/AF-AE), and word-width/depth cascadability for system-level FIFO expansion.

Technical Context

The SN74ACT7811-15FN implements a synchronous FIFO core with separate write and read pointer control logic, each synchronized to its respective free-running clock (WRTCLK/RDCLK). Its status flags - input-ready (IR), output-ready (OR), half-full (HF), and programmable almost-full/almost-empty (AF/AE) - are generated by dedicated comparator logic tied to internal pointer positions.

Flag behavior is deterministic: IR asserts low when FIFO is full (1024 words), OR asserts low when empty, HF asserts high at ≥513 words, and AF/AE toggles based on user-defined offset X (default 256) programmed via DAF/D0–D8 during reset. All timing parameters are specified under VCC = 4.5–5.5 V and TA = 0°C to 70°C.

Key Specifications

Parameter	Value and Actual Design Meaning
Memory Depth × Width	1024 × 18 bits - supports 18-bit parallel data buffering with full depth visibility for protocol framing and burst alignment.
Access Time	15 ns at 50-pF load - enables reliable operation at up to 40 MHz clock rate in high-speed digital interfaces.
Supply Voltage	4.5 V to 5.5 V - compatible with standard 5-V TTL/CMOS logic families and industrial power rails.
Operating Temperature	0°C to 70°C - rated for commercial-grade embedded systems and communications equipment.
Output Drive	–8 mA / +16 mA - provides sufficient current to directly drive 50-Ω transmission lines or multiple TTL inputs without external buffers.
Power Dissipation Cap.	65 pF per 1K bits at 5 V/5 MHz - enables accurate dynamic power estimation for thermal design and PCB layout.

Pinout & Package

SN74ACT7811-15FN is housed in a 68-pin Plastic Leaded Chip Carrier (PLCC) package (FN), with gull-wing J-leads, JEDEC MS-018 compliant footprint, and 0.050-inch lead pitch. The package measures 1.158 inches × 0.958 inches (29.41 mm × 24.33 mm) with 0.219-inch body height.

Pin/Terminal	Circuit Role	Design Meaning
1 (RESET)	Asynchronous reset input	Drives internal read/write pointers and status flags to known state; requires ≥4 WRTCLK/RDCLK cycles for full initialization.
2 (OE)	Output enable input	Controls three-state output drivers Q0–Q17; must be high before RDCLK rising edge to avoid bus contention.
3–4 (RDEN1, RDEN2)	Read enable inputs	Both must be high prior to RDCLK rising edge to gate data readout; not required for first-word read after reset.
5 (RDCLK)	Read clock input	Free-running clock synchronizing all read operations and OR/HF/AF-AE flag updates; low-to-high transition triggers read.
26–19,17,15–7 (D0–D17)	Data input bus	18-bit parallel input port; D0–D8 also carry AF/AE offset value X during DAF-controlled programming sequence.
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 port; outputs valid on third RDCLK rising edge after first write, then on each qualified RDCLK edge.
27 (DAF)	Define almost-full input	High-to-low transition latches D0–D8 as AF/AE offset X; held low during RESET pulse to program custom boundary.
33 (AF/AE)	Status flag output	Open-drain output indicating FIFO occupancy near full (≤X+1 words) or near empty (≥1025−X words); default X=256.
35 (IR)	Input-ready flag	Indicates FIFO not full; driven low on second WRTCLK after RESET, then high on second WRTCLK after first read post-fill.
36 (HF)	Half-full flag	Asserts high when ≥513 words stored; used for flow-control throttling in real-time streaming applications.
66 (OR)	Output-ready flag	Indicates FIFO not empty; set low on third RDCLK after RESET, then high on third RDCLK after first write.
29 (WRTCLK)	Write clock input	Free-running clock synchronizing all write operations and IR flag updates; low-to-high transition stores data if IR/WRTEN1/WRTEN2 high.
30–31 (WRTEN1, WRTEN2)	Write enable inputs	Both must be high before WRTCLK rising edge to qualify write; no effect on AF/AE programming cycle.

Key Features

Feature	Design Value
Independent asynchronous clocks	Enables seamless bridging between 20-MHz microcontroller and 33-MHz DSP without glue logic or clock domain crossing FIFOs.
Programmable AF/AE boundary	Allows tuning of flow-control thresholds (e.g., X=64 for low-latency audio buffering or X=512 for jitter-tolerant video packet handling).
Cascadable architecture	Supports 2048×18 depth expansion (N=2) or 1024×36 width expansion using shared clocks and daisy-chained flags.
Fast 15-ns access time	Meets timing closure requirements for 40-MHz backplane interfaces and high-throughput serial link receivers.
High-output drive (16 mA sink)	Eliminates need for external bus transceivers when interfacing to legacy 5-V TTL peripherals or FPGA I/O banks.

Applications

Telecom Line Card Buffering	Digital Signal Processor Interface
Use Scenario: Buffering ATM cell payloads between OC-3 framer and line interface ASIC operating at different clock rates. IC Role / Device Role / Timing Role: Clock-domain isolation FIFO with IR/OR handshaking to prevent overrun/underrun during SONET frame alignment. Use Value: Eliminates packet loss during clock drift events; 1024-word depth accommodates worst-case jitter accumulation over 125 µs.	Use Scenario: Interfacing ADC data stream (20 MSPS) to TI C6000 DSP running at 100 MHz with non-aligned sampling clocks. IC Role / Device Role / Timing Role: Synchronizing data capture and processing pipelines using independent WRTCLK (ADC clock) and RDCLK (DSP clock). Use Value: Enables continuous acquisition without CPU polling; HF flag triggers DMA request at 513-sample threshold for optimal buffer utilization.
Industrial PLC Communication Module	Legacy Bus Bridge Adapter
Use Scenario: Isolating Modbus RTU master (9.6 kbps) from EtherNet/IP scanner (100 Mbps) in factory automation gateway. IC Role / Device Role / Timing Role: Protocol translation buffer with programmable AF/AE to adapt to variable message lengths and retry intervals. Use Value: Prevents Modbus timeout errors during Ethernet congestion; X=128 setting ensures rapid response to short command bursts.	Use Scenario: Adapting ISA-bus peripheral (8-MHz I/O cycle) to PCI Express endpoint (100-MHz reference clock) in test equipment retrofit. IC Role / Device Role / Timing Role: Asynchronous bridge FIFO with OE-controlled tristate outputs enabling direct connection to multiplexed ISA data bus. Use Value: Removes need for discrete address decoders and latch logic; 18-bit width supports ISA's 16-bit data + parity extension.

Telecom Line Card Buffering

Digital Signal Processor Interface

Use Scenario: Buffering ATM cell payloads between OC-3 framer and line interface ASIC operating at different clock rates.

IC Role / Device Role / Timing Role: Clock-domain isolation FIFO with IR/OR handshaking to prevent overrun/underrun during SONET frame alignment.

Use Value: Eliminates packet loss during clock drift events; 1024-word depth accommodates worst-case jitter accumulation over 125 µs.

Use Scenario: Interfacing ADC data stream (20 MSPS) to TI C6000 DSP running at 100 MHz with non-aligned sampling clocks.

IC Role / Device Role / Timing Role: Synchronizing data capture and processing pipelines using independent WRTCLK (ADC clock) and RDCLK (DSP clock).

Use Value: Enables continuous acquisition without CPU polling; HF flag triggers DMA request at 513-sample threshold for optimal buffer utilization.

Industrial PLC Communication Module

Legacy Bus Bridge Adapter

Use Scenario: Isolating Modbus RTU master (9.6 kbps) from EtherNet/IP scanner (100 Mbps) in factory automation gateway.

IC Role / Device Role / Timing Role: Protocol translation buffer with programmable AF/AE to adapt to variable message lengths and retry intervals.

Use Value: Prevents Modbus timeout errors during Ethernet congestion; X=128 setting ensures rapid response to short command bursts.

Use Scenario: Adapting ISA-bus peripheral (8-MHz I/O cycle) to PCI Express endpoint (100-MHz reference clock) in test equipment retrofit.

IC Role / Device Role / Timing Role: Asynchronous bridge FIFO with OE-controlled tristate outputs enabling direct connection to multiplexed ISA data bus.

Use Value: Removes need for discrete address decoders and latch logic; 18-bit width supports ISA's 16-bit data + parity extension.

Equivalent & Alternatives

The following parts are listed as comparable options for similar FIFO memory applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
SN74ACT7881-15FN	Same 1024×18 architecture and pinout, but lacks programmable AF/AE flag; fixed boundary at 256 words.	Suitable only where static flow-control thresholds suffice; cannot support adaptive latency management.	Select SN74ACT7881-15FN only if AF/AE programmability is unnecessary and cost minimization is critical.
SN74ACT7882-15FN	1024×9-bit configuration; requires two devices for 18-bit width; shares same timing and flag structure as SN74ACT7811-15FN.	Increases PCB area and routing complexity due to dual-device layout; doubles power consumption.	Choose SN74ACT7882-15FN only when existing designs already use 9-bit FIFOs and board space permits duplication.

Compared with SN74ACT7881-15FN and SN74ACT7882-15FN, SN74ACT7811-15FN uniquely delivers programmable AF/AE functionality in a single 18-bit package, reducing component count and enabling dynamic buffer management - essential for real-time audio/video and adaptive networking protocols.

Availability

SN74ACT7811-15FN is available at Aetrix Electronics and suitable for telecom infrastructure, industrial PLCs, digital signal processing subsystems, and legacy bus bridge adapters requiring stable component supply across extended production lifecycles.

Supply support for SN74ACT7811-15FN 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 90 years of innovation in high-reliability electronic components.

The SN74ACT7811-15FN belongs to TI's Widebus™ family of high-speed CMOS FIFOs, designed specifically for clock-domain bridging in data-intensive communication and control systems where deterministic latency and robust flag signaling are critical.

FAQ

What is the maximum clock frequency supported by the SN74ACT7811-15FN?

The SN74ACT7811-15FN supports a maximum clock frequency of 40 MHz for both WRTCLK and RDCLK inputs under recommended operating conditions (VCC = 4.5–5.5 V, TA = 0°C to 70°C). This rating is derived from its 15 ns access time specification with 50-pF load and is validated across the full commercial temperature range. Operation above 40 MHz is not guaranteed and may result in timing violations or metastability in flag generation.

How is the almost-full/almost-empty (AF/AE) flag programmed on the SN74ACT7811-15FN?

The AF/AE flag on the SN74ACT7811-15FN is programmed during reset using the DAF input and D0–D8 data lines. To define a custom offset X, assert DAF low, then apply the 9-bit binary value to D0–D8 before taking RESET low and releasing it. For the default X = 256, hold DAF high during the RESET pulse. The SN74ACT7811-15FN applies this value on every subsequent reset unless reprogrammed, and the AF/AE output reflects occupancy relative to (X+1) and (1025−X) word boundaries.

Can the SN74ACT7811-15FN be used in depth-expansion configurations, and what timing impact does that have?

Yes, the SN74ACT7811-15FN supports depth expansion (e.g., 2048×18) by cascading multiple devices. In such configurations, the output-ready flag (OR) goes high after (N × 3) RDCLK cycles following the first write, and the input-ready flag (IR) recovers after (N × 2) WRTCLK cycles post-fill, where N is the number of cascaded devices. These linear delays must be accounted for in system-level timing budgets and handshake logic design.

What are the voltage and current specifications for the SN74ACT7811-15FN's I/O pins?

The SN74ACT7811-15FN operates with VCC = 4.5 V to 5.5 V. Input high-level voltage (VIH) is minimum 2.0 V, and input low-level voltage (VIL) is maximum 0.8 V. Output drive capability is –8 mA (source) and +16 mA (sink) at VOH = 2.4 V and VOL = 0.5 V, respectively. These values ensure compatibility with standard 5-V TTL and CMOS logic families and support direct connection to 50-Ω transmission lines without level-shifting circuitry.

Is the SN74ACT7811-15FN pin-compatible with other members of the SN74ACT78xx family?

Yes, the SN74ACT7811-15FN is explicitly pin-to-pin compatible with SN74ACT7881, SN74ACT7882, and SN74ACT7884 in the same FN package. This allows drop-in replacement in existing designs where functional differences - such as memory width (9-bit vs. 18-bit), AF/AE programmability, or flag set - are acceptable or can be accommodated in firmware. No PCB layout changes are required for mechanical or electrical interconnection.

SN74ACT7811-15FN Specifications

Product attributes: Attribute value

Manufacturer:: Texas Instruments

Series:: 74ACT

Package/Case:: 68-LCC (J-Lead)

Packaging:: Tube

Product Status:: Obsolete

Programmable:: Not Verified

Memory Size:: 18K (1K x 18)

Function:: Synchronous

Data Rate:: 40MHz

Access Time:: 15ns

Voltage - Supply:: 4.5 V ~ 5.5 V

Current - Supply (Max):: 1mA

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:: 68-PLCC (24.23x24.23)

SN74ACT7811-15FN FAQ

1.How can I place an order for SN74ACT7811-15FN through Aetrix?

Please submit a Request for Quotation (RFQ) for SN74ACT7811-15FN 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 SN74ACT7811-15FN reliable?

The price and inventory of SN74ACT7811-15FN are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ACT7811-15FN is usually 5 days.

3.What payment methods are accepted for SN74ACT7811-15FN?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74ACT7811-15FN transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SN74ACT7811-15FN?

SN74ACT7811-15FN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SN74ACT7811-15FN 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 SN74ACT7811-15FN?

For technical support, including SN74ACT7811-15FN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ACT7811-15FN requirements.

6.How does Aetrix verify that SN74ACT7811-15FN is sourced from the original manufacturer or authorized distributors?

All SN74ACT7811-15FN 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 SN74ACT7811-15FN meets industry standards.

7.What is the process for return or replacement of SN74ACT7811-15FN?

All SN74ACT7811-15FN units undergo pre-shipment inspection (PSI). If there is an issue with SN74ACT7811-15FN, 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 SN74ACT7811-15FN part is unused and in its original packaging.

Return procedure for SN74ACT7811-15FN:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

Tech Hub

2026-09-03 Logic Level Shifter: How to Connect 3.3V and 5V Logic Safely

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.

2026-09-03 74HC595 vs TPIC6B595: Output Drive, Pinout, Current, and Load Selection

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…

2026-09-01 74HC595 Pinout, Timing, Output Current, and Applications

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…

2026-09-01 Latch vs Flip-Flop: Timing, Differences and Design Choices

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…

2026-08-30 D Latch Circuit: Truth Table, Timing, ICs and Applications

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 …

2026-08-28 SR Latch Explained: NOR and NAND Circuits, Truth Tables, and Applications

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…

2026-08-27 Latch Circuit: SR and D Latches, Truth Tables, Timing, and Applications

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…

2026-08-21 What Is an LED Driver? Types, Circuits, Dimming, and Selection

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…

2026-08-18 Operational Amplifier (Op Amp): Basics, Configurations, Feedback and Applications

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…

2026-08-14 Jumper Cables: How to Use, Connect and Choose Them Safely

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…