Texas Instruments SN74ACT7807-40FN

Overview

SN74ACT7807-40FN from Texas Instruments is a 2048-word × 9-bit clocked FIFO memory IC with independent asynchronous read/write clocks, 12 ns access time (50-pF load), 67 MHz max data rate, and programmable almost-full/almost-empty flags. It serves as a high-speed data buffering interface between mismatched clock domains in digital communication subsystems.

For engineers reviewing the SN74ACT7807-40FN datasheet, SN74ACT7807-40FN pinout, SN74ACT7807-40FN application, or SN74ACT7807-40FN equivalent, key selection criteria include its dual-clock synchronization architecture, 44-pin PLCC (FN) package, 0°C to 70°C operating range, and support for word-width/depth cascading in embedded data-path designs.

Technical Context

The SN74ACT7807-40FN implements a synchronous dual-port FIFO using a 2048 × 9-bit RAM core with independent write-pointer and read-pointer logic. Its IR flag is synchronized to WRTCLK rising edge; OR flag is synchronized to RDCLK rising edge; both RESET and PEN inputs operate asynchronously relative to clock domains.

Flag generation uses dedicated status-flag logic: HF asserts at ≥1024 words; AF/AE supports programmable offsets (X/Y up to 1023) or defaults to 256; all flags are edge-synchronized and initialized on power-up reset requiring four WRTCLK and four RDCLK cycles under active RESET.

Key Specifications

Pinout & Package

SN74ACT7807-40FN is housed in a 44-pin plastic leaded chip carrier (PLCC, FN package), surface-mountable with J-lead geometry and 1.27 mm pitch. The package supports reflow soldering and provides mechanical stability for high-reliability board assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT7203L15TPG, SN74ACT7807-40FN offers programmable flow-control thresholds and cascading capability; compared with SN74ACT7809-40FN, it provides optimal 2048-word depth for latency-sensitive applications where excess buffer introduces unacceptable delay.

Availability

SN74ACT7807-40FN is available at Aetrix Electronics and suitable for high-speed data acquisition, asynchronous protocol translation, video frame buffering, and industrial PLC I/O expansion requiring stable component supply and long-term manufacturability.

Supply support for SN74ACT7807-40FN 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 delivering analog, embedded processing, and logic solutions for industrial, automotive, and communications markets.

The SN74ACT7807-40FN belongs to TI's Advanced CMOS FIFO memory product line, engineered for deterministic, low-latency data buffering in multi-clock digital systems with strict timing requirements.

FAQ

What is the maximum supported clock frequency for SN74ACT7807-40FN?

The SN74ACT7807-40FN is rated for a maximum clock frequency of 40 MHz per clock domain (WRTCLK or RDCLK), corresponding to a 25 ns minimum clock period. This rating ensures guaranteed timing compliance including setup/hold margins and propagation delays under worst-case voltage and temperature conditions specified in the SCAS200D datasheet.

How does the programmable AF/AE flag work in SN74ACT7807-40FN?

The SN74ACT7807-40FN allows separate programming of almost-empty (X) and almost-full (Y) thresholds via PEN, D0–D8, and WRTEN1/DP9 during reset initialization. After reset and before first write, a low PEN pulse captures D0–D8 + WRTEN1/DP9 as X; a second pulse captures Y. Default values are X = Y = 256 if PEN remains high.

Can SN74ACT7807-40FN be used in word-width expansion configurations?

Yes, SN74ACT7807-40FN supports word-width expansion to 2048 × 18 bits using two devices. Connect shared WRTCLK, RDCLK, RESET, PEN, WRTEN2, RDEN1, RDEN2, OE, IR, OR, HF, and AF/AE signals; cascade D0–D8 and Q0–Q8 buses to form 18-bit paths while maintaining independent flag synchronization per device.

What is the purpose of the input-ready (IR) and output-ready (OR) flags in SN74ACT7807-40FN?

The IR flag in SN74ACT7807-40FN synchronizes to WRTCLK rising edge and goes low when the FIFO is full, preventing overwrites. The OR flag synchronizes to RDCLK rising edge and goes low when the FIFO is empty, preventing invalid reads. Both flags eliminate metastability and simplify handshaking in multi-clock systems.

Does SN74ACT7807-40FN require power-on reset sequencing?

Yes, SN74ACT7807-40FN must be reset upon power-up. RESET must be held low while at least four rising edges occur on both WRTCLK and RDCLK to properly initialize internal pointers and flags (IR, OR, HF low; AF/AE high). Failure to meet this requirement results in undefined buffer state and unreliable flag behavior.