Texas Instruments SN74ACT7205L20NP

Overview

SN74ACT7205L20NP from Texas Instruments is a 8192 × 9-bit asynchronous dual-port FIFO memory IC with independent read/write operations, 15 ns access time, 40 MHz max clock frequency, and TTL-compatible inputs. It implements first-in-first-out buffering for data rate matching between asynchronous buses, supporting retransmit, empty/full/half-full status flags, and bit-width/word-depth expansion.

For engineers reviewing the SN74ACT7205L20NP datasheet, SN74ACT7205L20NP pinout, SN74ACT7205L20NP application, or SN74ACT7205L20NP equivalent, key selection criteria include FIFO depth (8192 words), 9-bit data path with parity support, 28-pin PDIP package compatibility, and dual-port SRAM-based architecture for deterministic latency in real-time data channels.

Technical Context

This device integrates dual-port SRAM with dedicated internal write and read address counters, enabling true asynchronous or coincident read/write cycles without external arbitration logic. Its status flag generation (EF, FF, XO/HF) is fully synchronous with internal pointer arithmetic and supports automatic read/write modes when EF or FF is asserted.

The SN74ACT7205L20NP implements depth-expansion daisy-chaining via XI/XO/HF pins and width-expansion via parallel control signal distribution. Retransmit functionality resets the read pointer independently of the write pointer using FL/RT, while RS performs full pointer initialization - both requiring R and W to be high during assertion.

Key Specifications

Pinout & Package

SN74ACT7205L20NP is supplied in a 28-pin plastic dual in-line package (PDIP), designated "NP" in TI's packaging nomenclature. Pin numbering follows standard DIP top-view orientation with pin 1 in the upper-left corner.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT7205L20P and SN74ACT7204L20NP, the SN74ACT7205L20NP uniquely delivers 8192-word depth in the 28-pin PDIP form factor without sacrificing access speed or flag functionality - making it optimal for high-throughput, latency-constrained data channel applications where depth cannot be compromised.

Availability

SN74ACT7205L20NP is available at Aetrix Electronics and suitable for data acquisition systems, communication protocol buffers, magnetic/optical storage interfaces, and real-time industrial control requiring stable component supply and long-term obsolescence management.

Supply support for SN74ACT7205L20NP 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 founded in 1930, specializing in analog, embedded processing, and logic solutions with broad industrial, automotive, and communications portfolio coverage.

The SN74ACT7205L20NP belongs to TI's ACT-family advanced CMOS FIFO product line, designed specifically for deterministic, low-latency data buffering between asynchronous digital subsystems in commercial-grade embedded systems.

FAQ

What is the exact memory organization of the SN74ACT7205L20NP?

The SN74ACT7205L20NP implements an 8192-word × 9-bit first-in-first-out buffer using dual-port SRAM. Each word holds 9 bits - eight data bits plus one parity or framing bit - and the internal read/write address counters operate independently to support true asynchronous operation without external arbitration logic.

Does the SN74ACT7205L20NP support simultaneous read and write operations?

Yes, the SN74ACT7205L20NP supports fully asynchronous and coincident read/write operations. Its dual-port SRAM architecture allows a write on the falling edge of W and a read on the falling edge of R in the same cycle, provided EF and FF flags permit the respective operations - no external synchronization is required.

How does the retransmit function work on the SN74ACT7205L20NP?

The SN74ACT7205L20NP retransmit function is activated by a low pulse on FL/RT while R and W are held high. This resets the internal read pointer to location zero without altering the write pointer, enabling replay of previously stored data. Retransmit is safe only if fewer than 8192 writes have occurred since the last reset.

Can multiple SN74ACT7205L20NP devices be cascaded for greater depth?

Yes, the SN74ACT7205L20NP supports depth expansion via its XI and XO/HF pins. Devices are daisy-chained with XO/HF of one device connected to XI of the next. The first device has FL/RT grounded; others have FL/RT high. Composite EF/FF signals require external OR gates across all units.

What are the voltage-level requirements for TTL compatibility on the SN74ACT7205L20NP?

The SN74ACT7205L20NP meets TTL input thresholds: VIH ≥ 2.0 V (except XI, which requires ≥2.6 V), VIL ≤ 0.8 V, VOH ≥ 2.4 V at −2 mA, and VOL ≤ 0.4 V at 8 mA. These specifications ensure direct interoperability with standard 5 V TTL and LSTTL logic families without level-shifting circuitry.