Texas Instruments SN74ACT72211L20RJ

Overview

SN74ACT72211L20RJ from Texas Instruments is a 512 × 9-bit synchronous dual-clock FIFO memory IC with CMOS dual-port SRAM architecture, 15 ns write/read cycle time, TTL-compatible inputs, and programmable almost-empty/almost-full flags (default offsets: empty+7 / full−7). It operates from 0°C to 70°C and is used in high-speed data buffering between asynchronous buses in graphics and communication systems.

For engineers reviewing the SN74ACT72211L20RJ datasheet, SN74ACT72211L20RJ pinout, SN74ACT72211L20RJ application, or SN74ACT72211L20RJ equivalent, key selection criteria include its 32-pin RJ package, synchronous dual-clock operation (WCLK/RCLK), 9-bit data path with parity support, flag synchronization logic, and compatibility with IDT72211 family designs.

Technical Context

This FIFO implements first-in, first-out data flow using independent synchronous write and read address counters. Write operations are enabled by WEN1 and WEN2/LD on WCLK rising edges; reads are controlled by REN1/REN2 on RCLK rising edges. The device supports both asynchronous clock domains and single-clock operation when WCLK and RCLK are tied.

Flag logic includes EF (synchronized to RCLK) and FF (synchronized to WCLK) for absolute boundary detection, plus PAE and PAF (each synchronized to their respective clocks) with programmable offsets stored in four 8-bit registers. Reset initializes pointers and loads default offset values (007h for both empty and full LSB registers).

Key Specifications

Pinout & Package

Package: 32-pin plastic J-leaded chip carrier (RJ), top-view layout with 0.025-inch lead pitch and 0.500-inch body size.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT72211LA15J and SN74ACT72211L25RJ, the SN74ACT72211L20RJ delivers optimal balance of 66.7 MHz performance, TI's long-term product continuity, and full compatibility with legacy IDT72211-based layouts-making it ideal for new designs requiring proven reliability and supply assurance.

Availability

SN74ACT72211L20RJ is available at Aetrix Electronics and suitable for graphics subsystems, telecom protocol stacks, industrial bus bridges, and test equipment data capture requiring stable component supply and long-lifecycle support.

Supply support for SN74ACT72211L20RJ 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 decades of industrial-grade reliability and broad distribution infrastructure.

The SN74ACT72211L20RJ belongs to TI's ACT-family advanced CMOS FIFO product line, designed specifically for high-speed, low-latency data buffering in mixed-clock-domain systems such as graphics pipelines and communications infrastructure.

FAQ

What is the memory organization of the SN74ACT72211L20RJ?

The SN74ACT72211L20RJ implements a 512 × 9-bit synchronous FIFO structure, delivering 4,608 bits of dual-port SRAM storage. This configuration supports 9-bit-wide data transfers-ideal for 8-bit byte plus parity bit or packet header/framing information-within a single monolithic IC. Its fixed depth distinguishes it from larger variants like SN74ACT72221L (1024 × 9) and SN74ACT72241L (4096 × 9).

How does the SN74ACT72211L20RJ handle clock domain crossing?

The SN74ACT72211L20RJ handles clock domain crossing through fully independent WCLK and RCLK inputs with status flags synchronized to their respective clocks: EF and PAE to RCLK, FF and PAF to WCLK. This architecture eliminates metastability risk during inter-domain handshaking and allows true asynchronous operation-verified by tsk1/tsky timing parameters-without external synchronizers or FIFO controllers.

Can the SN74ACT72211L20RJ be configured for programmable flag offsets?

Yes, the SN74ACT72211L20RJ supports programmable almost-empty and almost-full flag offsets via four 8-bit internal registers. When WEN2/LD is held low during reset, it functions as LD to access these registers. Default values are 007h for both empty and full LSB registers, yielding empty+7 and full−7 thresholds. Offset values are written sequentially using WCLK edges and read back via RCLK for verification.

What is the role of the RS (reset) pin on the SN74ACT72211L20RJ?

The RS pin on the SN74ACT72211L20RJ performs asynchronous hardware reset: it initializes both read and write pointers to the first memory location, sets FF and PAF high, EF and PAE low, clears Q0–Q8 outputs, and loads default flag offset values (007h). A reset is mandatory after power-up before any write operation, and RS must meet minimum pulse width (15 ns) and setup/hold timing relative to other controls.

Is the SN74ACT72211L20RJ compatible with IDT72211 devices?

Yes, the SN74ACT72211L20RJ is fully compatible with the IDT72211 family per datasheet SCAS222. It matches pinout, electrical characteristics, timing parameters, flag behavior, and functional operation-including identical 512 × 9 organization, 15 ns cycle time, and programmable flag architecture. This enables direct substitution in existing IDT72211-based designs without PCB or firmware changes.