Texas Instruments SN74ACT72231L35RJ

Overview

SN74ACT72231L35RJ from Texas Instruments is a synchronous 2048 × 9-bit first-in, first-out (FIFO) memory IC with dual-port CMOS SRAM architecture, 15 ns write/read cycle time, TTL-compatible inputs, and programmable almost-empty/almost-full flags. It serves as a high-speed data channel between asynchronous or synchronous buses in communication and graphics systems.

For engineers reviewing the SN74ACT72231L35RJ datasheet, SN74ACT72231L35RJ pinout, SN74ACT72231L35RJ application, or SN74ACT72231L35RJ equivalent, key selection criteria include its 2048-word depth, 9-bit bus width with parity support, independent read/write clocks, flag synchronization logic, and RJ-package compatibility with IDT72231.

Technical Context

The SN74ACT72231L35RJ implements a synchronous FIFO using dual-port SRAM with internal read/write address counters. Its control logic supports independent RCLK and WCLK operation-either asynchronous or coincident-with status flags (EF, FF, PAE, PAF) synchronized to respective clocks via single-stage flip-flops.

Flag behavior is determined by pointer arithmetic: EF asserts low when read/write pointers match; FF asserts low after exactly 2048 writes; PAE and PAF default to offsets of empty+7 and full–7, respectively, and are programmable via WEN2/LD-controlled register writes during reset configuration.

Key Specifications

Pinout & Package

SN74ACT72231L35RJ is housed in a 32-pin plastic J-leaded chip carrier (RJ package), with 0.4-inch body width and gull-wing leads. Pin numbering follows standard top-view orientation with pin 1 at bottom-left corner.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT72231L15JI and SN74ACT72231L25RJ, the SN74ACT72231L35RJ delivers optimal balance of speed (66.7 MHz), commercial-temperature reliability, and direct drop-in compatibility with TI's ACT-family timing and drive strength specifications.

Availability

SN74ACT72231L35RJ is available at Aetrix Electronics and suitable for graphics subsystems, high-speed communication queues, industrial bus bridges, and byte-plus-parity data channels requiring stable component supply and long-term obsolescence management.

Supply support for SN74ACT72231L35RJ 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 timing and interface ICs.

The SN74ACT72231L35RJ belongs to TI's ACT-family synchronous FIFO product line, engineered specifically for deterministic, low-latency data buffering between mismatched clock domains in communications and graphics infrastructure.

FAQ

What is the memory organization of the SN74ACT72231L35RJ?

The SN74ACT72231L35RJ is organized as 2048 words × 9 bits, providing 18,432 bits of synchronous FIFO storage. This structure supports 8-bit data plus one parity or framing bit per word, making it ideal for applications requiring error detection or protocol header embedding. The memory is implemented using dual-port CMOS SRAM with independent read and write address counters.

How does the SN74ACT72231L35RJ handle flag synchronization?

The SN74ACT72231L35RJ synchronizes EF and PAE to the rising edge of RCLK, and FF and PAF to the rising edge of WCLK, each through a single flip-flop stage. This ensures deterministic setup/hold timing relative to their respective clock domains and prevents metastability in handshaking logic. Propagation delays are specified as tpd(R-EF), tpd(W-FF), etc., with maximum values of 12 ns (15 ns speed grade).

Can the SN74ACT72231L35RJ operate with a single clock for both read and write functions?

Yes, the SN74ACT72231L35RJ supports single-clock operation: RCLK and WCLK may be tied together. Its architecture permits coincident clocking without conflict, provided WEN1/REN1 controls remain independently asserted. This mode simplifies timing design in systems where read and write rates are matched, while retaining full flag functionality and boundary protection.

What is the function of the WEN2/LD pin on the SN74ACT72231L35RJ?

The WEN2/LD pin on the SN74ACT72231L35RJ is a dual-function terminal whose role is determined at reset: if held high during RS assertion, it acts as a second write-enable input; if held low, it becomes the load (LD) signal for programming the PAE/PAF offset registers. This hardware-selectable configuration eliminates need for external mode pins or configuration registers.

Is the SN74ACT72231L35RJ pin-compatible with IDT72231 devices?

Yes, the SN74ACT72231L35RJ is fully pin-compatible and functionally equivalent to the IDT72231L15JI in the same RJ package. Both share identical pinout, flag behavior, timing parameters, and programming model. This allows direct substitution in existing designs targeting IDT's 72231 family, with no PCB or firmware changes required.