Texas Instruments SN74ACT7201LA15RJ

Overview

SN74ACT7201LA15RJ from Texas Instruments is a 512 × 9 asynchronous first-in, first-out (FIFO) memory IC with dual-port SRAM architecture, 15 ns data access time, 40 MHz read/write frequency support, TTL-compatible inputs, and integrated empty/full/half-full status flags. It serves as a rate-matching buffer between asynchronous buses in data-acquisition systems.

For engineers reviewing the SN74ACT7201LA15RJ datasheet, SN74ACT7201LA15RJ pinout, SN74ACT7201LA15RJ application, or SN74ACT7201LA15RJ equivalent, key selection criteria include its 512-word depth, 9-bit width with parity support, retransmit capability, depth/width expansion logic, and PLCC-32 package compatibility with industrial temperature range (0°C to 70°C).

Technical Context

The SN74ACT7201LA15RJ implements independent write and read address counters driving dual-port SRAM, enabling fully asynchronous or coincident read/write operations. Its internal status-flag logic generates EF (empty), FF (full), and XO/HF (half-full/expansion-out) signals based on pointer comparison.

Depth expansion is supported via daisy-chained XI/XO interfaces with FL/RT-controlled device ordering, while width expansion uses parallel control lines across multiple devices. Retransmit functionality resets the read pointer without affecting the write pointer, enabling data replay in communication queues.

Key Specifications

Pinout & Package

SN74ACT7201LA15RJ is housed in a 32-pin plastic J-leaded chip-carrier (PLCC-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 IDT7201LA15J, SN74ACT7201LA15RJ offers identical electrical and functional behavior with TI-specific process optimization; compared with SN74ACT7201LA15DV, it provides full expansion capability and mechanical robustness via the 32-pin PLCC package, making it preferred for industrial FIFO applications requiring daisy-chaining.

Availability

SN74ACT7201LA15RJ is available at Aetrix Electronics and suitable for data-acquisition systems, communication protocol stacks, magnetic/optical storage interfaces, and bus-bridging applications requiring stable component supply across extended production lifecycles.

Supply support for SN74ACT7201LA15RJ 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 technologies with over 50 years of innovation in high-reliability IC design.

The SN74ACT7201LA15RJ belongs to TI's ACT advanced CMOS FIFO family, engineered specifically for high-speed, low-latency data buffering in mixed-rate digital systems where deterministic flow control and hardware-managed queuing are critical.

FAQ

What is the memory depth and width of the SN74ACT7201LA15RJ?

The SN74ACT7201LA15RJ provides 512 words of storage, each word being 9 bits wide. This configuration supports byte-wide data plus a parity bit or packet-framing information. The 9-bit width is fixed and cannot be reduced or expanded without external logic, and the 512-word depth is implemented in silicon-no configuration registers or mode pins alter this value. SN74ACT7201LA15RJ delivers this capacity in a single monolithic device using dual-port SRAM and dedicated address counters.

Does the SN74ACT7201LA15RJ support depth expansion with other FIFOs?

Yes, the SN74ACT7201LA15RJ supports depth expansion via its XI (expansion-in) and XO/HF (expansion-out/half-full) pins. When cascading multiple devices, XO/HF of one device connects to XI of the next, and FL/RT is grounded on the first device and pulled high on subsequent ones. This daisy-chain method scales total FIFO depth linearly (e.g., three devices yield 1536 × 9). SN74ACT7201LA15RJ's internal expansion logic handles pointer rollover and flag generation automatically across the chain.

What is the purpose of the FL/RT pin on the SN74ACT7201LA15RJ?

The FL/RT pin on the SN74ACT7201LA15RJ serves dual roles: in depth expansion, it selects first-load (grounded) or cascade (high) behavior; when XI is grounded (standalone operation), FL/RT enables retransmit-pulsing it low resets the read pointer to zero without altering the write pointer. This allows repeated reading of buffered data, essential for protocol retries. SN74ACT7201LA15RJ requires R and W to remain high during the FL/RT pulse to ensure reliable pointer reset.

Can the SN74ACT7201LA15RJ operate with a 3.3 V supply?

No, the SN74ACT7201LA15RJ is specified only for 4.5 V to 5.5 V operation per its recommended conditions and absolute maximum ratings. Its TTL-compatible inputs require VIH ≥ 2.0 V, but the internal ACT logic core and output drive strength are optimized for 5 V. Using 3.3 V risks undefined behavior, insufficient noise margin, and failure to meet timing specs like the 15 ns access time. For 3.3 V systems, consider newer low-voltage FIFO families-not SN74ACT7201LA15RJ.

How does the half-full flag (XO/HF) function on the SN74ACT7201LA15RJ?

When XI is grounded (non-expanded mode), XO/HF acts as a half-full flag: it transitions low on the falling edge of W after exactly 256 words are written (half of 512), and returns high on the rising edge of R after the count drops back to 256. This provides early flow-control signaling before full/empty conditions occur. SN74ACT7201LA15RJ does not offer programmable threshold-XO/HF is fixed at 50% depth and cannot be disabled or repurposed in standalone use.