Texas Instruments SN74ACT72211L35RJ

Overview

SN74ACT72211L35RJ from Texas Instruments is a 512 × 9-bit synchronous FIFO memory IC designed for high-speed data buffering between asynchronous or synchronous buses. It features independent read/write clocks (RCLK/WCLK), 15 ns cycle time, TTL-compatible inputs, and programmable almost-empty/almost-full flags with default offsets of empty+7 and full–7. It is used in graphics rate buffers and communication system queues.

For engineers reviewing the SN74ACT72211L35RJ datasheet, SN74ACT72211L35RJ pinout, SN74ACT72211L35RJ application, or SN74ACT72211L35RJ equivalent, key selection criteria include its 512-word depth, 9-bit data width, 32-pin RJ package, synchronous dual-clock operation, and flag programmability via WEN2/LD configuration at reset.

Technical Context

This device implements a CMOS dual-port SRAM-based FIFO with internal write/read address counters and synchronized status flags: EF (RCLK-synchronized) and FF (WCLK-synchronized). It supports both single-clock (coincident RCLK/WCLK) and fully asynchronous clocking modes.

Flag behavior is determined by offset registers programmed via WEN2/LD during reset - when held low, it enables access to four 8-bit registers (empty LSB/MSB, full LSB/MSB); when held high, it functions as a second write enable. Default flag offsets are fixed at 7, yielding PAE active at ≤7 unread words and PAF active at ≥505 unread words (512 – 7).

Key Specifications

Pinout & Package

SN74ACT72211L35RJ is housed in a 32-pin plastic J-leaded chip carrier (RJ) package, top-view layout with pins 1–16 on bottom row (left-to-right), pins 17–32 on top row (right-to-left), and pin 1 marked by notch or dot.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT72211L and SN74ACT72211L-20, SN74ACT72211L35RJ delivers the highest speed grade (15 ns), lowest propagation delays (e.g., ta = 2–10 ns), and optimal power efficiency at 66.7 MHz - making it the preferred choice for bandwidth-critical FIFO applications requiring minimal latency.

Availability

SN74ACT72211L35RJ is available at Aetrix Electronics and suitable for graphics subsystems, telecom infrastructure, industrial bus bridges, and legacy-to-modern interface designs requiring stable component supply and long-term obsolescence management.

Supply support for SN74ACT72211L35RJ 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 validation.

SN74ACT72211L35RJ belongs to TI's ACT-family advanced CMOS FIFO product line, engineered for high-speed, low-power data buffering in mixed-clock-domain systems such as video pipelines and protocol translators.

FAQ

What is the memory depth and data width of the SN74ACT72211L35RJ?

The SN74ACT72211L35RJ provides a 512 × 9-bit memory organization - meaning it stores 512 words, each 9 bits wide. This supports byte-plus-parity transmission or packet-framing applications. The 9-bit width is fixed and not configurable; expansion to wider paths requires cascading multiple units.

How does the SN74ACT72211L35RJ handle clock domain crossing between read and write interfaces?

The SN74ACT72211L35RJ uses independent RCLK and WCLK inputs that may operate asynchronously or coincidentally. Status flags EF and FF are synchronized to their respective clocks (RCLK and WCLK), preventing metastability. This allows safe, lock-free data transfer between unrelated clock domains without external handshaking logic.

Can the almost-empty and almost-full flags of the SN74ACT72211L35RJ be customized, and how?

Yes - the SN74ACT72211L35RJ supports programmable PAE and PAF thresholds via four 8-bit offset registers. During reset, holding WEN2/LD low configures it as LD (load) input. Subsequent WCLK edges write to empty LSB/MSB and full LSB/MSB registers. Default offsets are 7, but values can be set to any integer within device limits.

What is the function of the RS (reset) pin on the SN74ACT72211L35RJ, and is it required before operation?

The RS pin is an active-low hardware reset that initializes read/write pointers, clears the output register, and sets FF/PAF high and EF/PAE low. A valid reset is mandatory after power-up before any write operation - failure to do so results in undefined pointer states and potential data corruption.

Does the SN74ACT72211L35RJ support 3.3 V operation, or is it strictly 5 V?

The SN74ACT72211L35RJ is specified only for 4.5 V to 5.5 V operation per its recommended conditions and absolute maximum ratings. It is not 3.3 V tolerant - applying 3.3 V to VCC will result in noncompliant timing, reduced noise margin, and possible functional failure. Level-shifting is required for interfacing with 3.3 V systems.