Texas Instruments SN74ACT72241L20RJR

Overview

SN74ACT72241L20RJR from Texas Instruments is a 4096 × 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. It operates from 0°C to 70°C and is used in high-speed asynchronous data bridging between mismatched buses in communication systems and graphics rate buffers.

For engineers reviewing the SN74ACT72241L20RJR datasheet, SN74ACT72241L20RJR pinout, SN74ACT72241L20RJR application, or SN74ACT72241L20RJR equivalent, key selection criteria include its 4096-word depth, 9-bit data path with parity support, independent RCLK/WCLK operation, flag synchronization timing, and RJ package compatibility with IDT72241 family devices.

Technical Context

This FIFO implements first-in, first-out data flow using internal synchronous read and write address counters. Data input and output ports are independently clocked via RCLK and WCLK, which may operate asynchronously or coincidentally. Write-enable (WEN1, WEN2/LD) and read-enable (REN1, REN2) signals gate clock-triggered transfers.

Empty (EF) and full (FF) flags are synchronized to RCLK and WCLK respectively; programmable almost-empty (PAE) and almost-full (PAF) flags use offset registers loaded during reset-defaulting to empty+7 and full−7-and are likewise clock-synchronized. Flag behavior depends on pointer difference and configured offsets, not fixed thresholds.

Key Specifications

Pinout & Package

SN74ACT72241L20RJR 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 high-density PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT72241L20JI and SN74ACT72241L25RJR, SN74ACT72241L20RJR delivers the highest clock speed (66.7 MHz) in the family while maintaining pin and functional compatibility-making it optimal for bandwidth-constrained real-time systems requiring minimal latency.

Availability

SN74ACT72241L20RJR is available at Aetrix Electronics and suitable for graphics rate buffering, high-speed communication queuing, and asynchronous bus bridging requiring stable component supply across multi-year production cycles.

Supply support for SN74ACT72241L20RJR 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 communications infrastructure experience.

The SN74ACT72241L20RJR belongs to TI's ACT-family advanced CMOS FIFO product line, engineered specifically for high-reliability, low-latency data buffering in mixed-clock-domain systems such as telecom gateways and real-time imaging subsystems.

FAQ

What is the memory organization of the SN74ACT72241L20RJR?

The SN74ACT72241L20RJR is organized as 4096 words × 9 bits, implemented using CMOS dual-port SRAM. This provides a total capacity of 36,864 bits with independent read and write addressing. The 9-bit width supports byte-plus-parity or framing-bit applications without external expansion logic, and the FIFO operates on strict first-in, first-out data ordering.

How does the SN74ACT72241L20RJR handle clock domain crossing between read and write paths?

The SN74ACT72241L20RJR uses fully synchronous, independent RCLK and WCLK inputs with no internal phase-locking. EF and PAE flags are synchronized to RCLK; FF and PAF flags to WCLK. This eliminates metastability risk at flag outputs while allowing arbitrary clock ratios or phase relationships-provided minimum skew times (tsk1 = 6 ns, tsk2 = 28 ns) are met for flag update integrity.

Can the programmable almost-empty and almost-full flags of the SN74ACT72241L20RJR be customized in-system?

Yes-the SN74ACT72241L20RJR supports in-system programming of PAE and PAF trigger points via its four 8-bit offset registers. When WEN2/LD is held low during reset, it becomes a load (LD) signal. Subsequent WCLK edges write to empty-LSB, empty-MSB, full-LSB, and full-MSB registers sequentially. Default offsets are empty+7 and full−7, but values can be updated dynamically during operation without reset.

What is the function of the WEN2/LD pin on the SN74ACT72241L20RJR?

The WEN2/LD pin on the SN74ACT72241L20RJR is a dual-function terminal whose role is determined at reset: if held high during RS low→high transition, it acts as a second write-enable (WEN2); if held low, it becomes the Load (LD) signal for accessing flag offset registers. This configuration is latched and remains fixed until next reset-enabling either robust dual-enable write gating or full programmable flag control.

Is the SN74ACT72241L20RJR pin-compatible with IDT72241-series FIFOs?

Yes-the SN74ACT72241L20RJR is fully pin-compatible and functionally equivalent to the IDT72241L20JI and other IDT72241 variants. Both share identical RJ package footprint, pin assignments, electrical characteristics, timing parameters, and flag behavior. TI explicitly states "Fully Compatible With the IDT72211/72221/72231/72241" in the datasheet, confirming drop-in replacement capability in existing IDT-based designs.