Texas Instruments SN74ACT7807-40PAG

Overview

SN74ACT7807-40PAG from Texas Instruments is a 2048-word × 9-bit clocked FIFO memory IC with asynchronous read/write clocks, 12 ns access time, 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 and control systems.

For engineers reviewing the SN74ACT7807-40PAG datasheet, SN74ACT7807-40PAG pinout, SN74ACT7807-40PAG application, or SN74ACT7807-40PAG equivalent, key selection criteria include its 64-pin TQFP (PAG) package, synchronous flag outputs tied to respective clocks, 3-state outputs, and support for word-width/depth cascading in embedded data pipelines.

Technical Context

The SN74ACT7807-40PAG implements a dual-clock FIFO architecture with independent WRTCLK and RDCLK inputs, enabling true asynchronous operation between write and read subsystems. Its internal 2048 × 9 RAM core is managed by synchronized write and read pointer logic, with IR flag latched on WRTCLK rising edge and OR flag latched on RDCLK rising edge.

Status flag generation is fully synchronous: HF indicates ≥1024 words stored; AF/AE supports programmable thresholds (X/Y up to 1023) via PEN-controlled offset loading before first write; RESET requires four cycles of each clock to clear all pointers and initialize flags. All I/Os use Advanced CMOS logic with TTL-compatible thresholds and 3-state output drivers.

Key Specifications

Pinout & Package

SN74ACT7807-40PAG is housed in a 64-pin Thin Quad Flat Package (PAG) with 0.5-mm lead pitch and exposed thermal pad. Pin numbering follows standard counter-clockwise orientation starting from pin 1 (top-left corner when notch is oriented upward).

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT7203L15TPG and SN74ACT7805-40PAG, the SN74ACT7807-40PAG uniquely supports user-defined AF/AE thresholds via PEN-controlled programming and delivers maximum 2048-word depth in the same 64-pin footprint-enabling flexible flow control and higher throughput in space-constrained designs.

Availability

SN74ACT7807-40PAG is available at Aetrix Electronics and suitable for high-speed data acquisition, asynchronous bus bridging, and industrial PLC communication requiring stable component supply and long-term production continuity.

Supply support for SN74ACT7807-40PAG 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 over 90 years of innovation in high-reliability components.

The SN74ACT7807-40PAG belongs to TI's ACT advanced CMOS logic family, designed specifically for high-speed, low-power FIFO buffering in mixed-clock-domain digital systems requiring deterministic latency and robust flow control.

FAQ

What is the maximum guaranteed clock frequency for SN74ACT7807-40PAG?

The SN74ACT7807-40PAG is rated for a maximum clock frequency of 25 MHz under recommended operating conditions (VCC = 4.5 V to 5.5 V, TA = 0°C to 70°C). This specification corresponds to its -40 speed grade, with timing parameters validated at this rate including setup/hold times and propagation delays. Higher nominal rates (e.g., 67 MHz) apply only to faster speed grades like -15.

How does the PEN pin function during AF/AE programming on SN74ACT7807-40PAG?

On SN74ACT7807-40PAG, the PEN pin enables loading of programmable AF/AE offset values. After reset and before the first write, holding PEN low during a WRTCLK rising edge captures D0–D8 and WRTEN1/DP9 as the almost-empty offset X; a second low PEN pulse captures the same bus as the almost-full offset Y. During programming, writes to memory are inhibited regardless of WRTEN states.

Can SN74ACT7807-40PAG be used in cascaded configurations, and what are the limitations?

Yes, SN74ACT7807-40PAG supports both word-width and word-depth cascading. For depth expansion (e.g., 4096 × 9), connect RDCLK/WRTCLK in parallel and daisy-chain IR/OR/HF/AF-AE flags. For width expansion (e.g., 2048 × 18), align clocks and enables while fanning out D/Q buses. No additional glue logic is needed, but PEN must be controlled per device if programming offsets individually.

What is the power-up requirement for SN74ACT7807-40PAG, and why is RESET mandatory?

SN74ACT7807-40PAG must be reset upon power-up because its internal pointers and flags are in undefined states. The RESET signal must be asserted for at least four WRTCLK and four RDCLK cycles to initialize IR, OR, and HF low and AF/AE high. Failure to perform this reset may result in incorrect flag behavior and unpredictable data flow, as the FIFO cannot self-synchronize without explicit initialization.

Does SN74ACT7807-40PAG support 3.3-V operation, and what are the implications of using it outside its specified voltage range?

No, SN74ACT7807-40PAG is specified only for 4.5 V to 5.5 V operation. Its Advanced CMOS process and TTL-compatible input thresholds require minimum 4.5 V for guaranteed VIH/VIL margins and output drive strength. Operating below 4.5 V risks timing violations, reduced noise immunity, and potential failure to meet AC specifications-including the 25 MHz clock limit and 12 ns access time-making 3.3-V use unsupported and unreliable.