Texas Instruments SN74ACT72231L20RJ

Overview

SN74ACT72231L20RJ from Texas Instruments is a 2048 × 9-bit synchronous FIFO memory IC with dual-clock architecture, 15 ns write/read cycle time, TTL-compatible inputs, and programmable almost-empty/almost-full flags. It operates from 4.5 V to 5.5 V at 0°C–70°C and is used in high-speed data buffering between asynchronous buses in communication systems.

For engineers reviewing the SN74ACT72231L20RJ datasheet, SN74ACT72231L20RJ pinout, SN74ACT72231L20RJ application, or SN74ACT72231L20RJ equivalent, this page delivers verified timing parameters, flag programming behavior, dual-port SRAM architecture details, and precise pin-level functional mapping for system integration and FIFO depth validation.

Technical Context

This device implements a CMOS dual-port SRAM core with independent synchronous write and read address counters, enabling true first-in-first-out (FIFO) operation. Its internal pointer logic ensures deterministic data flow without external control logic.

Write and read operations are fully decoupled: WCLK and RCLK may run asynchronously or coincidentally, while WEN1/WEN2/LD and REN1/REN2 provide edge-triggered enable control synchronized to their respective clocks. Flag outputs (EF, FF, PAE, PAF) are registered to RCLK or WCLK with one-flip-flop synchronization for metastability immunity.

Key Specifications

Pinout & Package

SN74ACT72231L20RJ is housed in a 32-pin plastic J-leaded chip carrier (RJ) package with gull-wing leads, designed for surface-mount assembly and thermal reliability in dense PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT72231L20JI and SN74ACT72231L25RJ, SN74ACT72231L20RJ delivers the highest clock speed (66.7 MHz) in the family while maintaining pin compatibility and identical flag programming behavior-making it optimal for bandwidth-critical FIFO applications where thermal range is limited to 0°C–70°C.

Availability

SN74ACT72231L20RJ is available at Aetrix Electronics and suitable for graphics subsystems, telecom queuing modules, industrial bus bridges, and legacy system upgrades requiring stable component supply and long-lifecycle support.

Supply support for SN74ACT72231L20RJ 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 and automotive qualification expertise.

The SN74ACT72231L20RJ belongs to TI's ACT-family advanced CMOS FIFO product line, engineered for high-speed, low-power, and robust asynchronous data channel bridging in commercial and industrial systems.

FAQ

What is the memory organization of the SN74ACT72231L20RJ?

The SN74ACT72231L20RJ contains 2048 words of 9-bit synchronous FIFO memory implemented in dual-port CMOS SRAM. This yields 18,432 bits of total storage, supporting byte-wide data plus parity or framing information. The architecture uses independent read and write address counters to maintain strict FIFO ordering without external sequencing logic.

How does the SN74ACT72231L20RJ handle clock domain crossing between write and read paths?

The SN74ACT72231L20RJ handles clock domain crossing by registering all status flags (EF, FF, PAE, PAF) to their respective clock domains-EF and PAE to RCLK, FF and PAF to WCLK-with single-stage flip-flops. This prevents metastability during cross-domain assertions and ensures reliable boundary detection even when WCLK and RCLK operate asynchronously or at different frequencies.

Can the programmable almost-empty and almost-full flags of the SN74ACT72231L20RJ be reconfigured dynamically during operation?

Yes-the SN74ACT72231L20RJ allows dynamic reconfiguration of PAE and PAF offsets via its four 8-bit flag offset registers. When WEN2/LD is held low at reset, the terminal becomes LD, enabling sequential write/read of empty LSB/MSB and full LSB/MSB registers using WCLK or RCLK edges. Values persist until rewritten, supporting runtime adaptation to changing buffer utilization patterns.

What is the required reset sequence before using the SN74ACT72231L20RJ in a system?

The SN74ACT72231L20RJ must undergo an asynchronous reset (RS low) after power-up to initialize internal pointers and flag states. During reset, read/write pointers are set to zero, EF and PAE go low, FF and PAF go high, Q0–Q8 outputs clear to low (if OE is low), and default offset values (empty+7/full−7) are loaded. No write operation is permitted until RS returns high and stabilizes.

Is the SN74ACT72231L20RJ pin-compatible with other members of the SN74ACT722xxL family?

Yes-SN74ACT72231L20RJ shares identical pinout, signal definitions, and package (32-pin RJ) with SN74ACT72211L20RJ, SN74ACT72221L20RJ, and SN74ACT72241L20RJ. Only memory depth differs (512/1024/2048/4096 × 9), so PCBs designed for one variant can accommodate others without layout changes-enabling scalable FIFO sizing in production variants.