Texas Instruments SN74ACT7807-25PAG

Overview

SN74ACT7807-25PAG from Texas Instruments is a 2048-word × 9-bit clocked FIFO memory IC with independent asynchronous read/write clocks, 12 ns access time at 50-pF load, 40 MHz maximum clock frequency, 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 SN74ACT7807-25PAG datasheet, SN74ACT7807-25PAG pinout, SN74ACT7807-25PAG application, or SN74ACT7807-25PAG equivalent, key selection criteria include its 64-pin TQFP (PAG) package, synchronous flag timing referenced to RDCLK/WRTCLK edges, cascading capability for depth/width expansion, and support for 0°C to 70°C industrial operation.

Technical Context

The SN74ACT7807-25PAG implements a dual-clock FIFO architecture with fully independent read and write pointer control logic, status-flag synchronization to respective clock domains, and reset-initiated initialization of IR, OR, and HF flags. Its internal 2048 × 9 RAM core supports bit-parallel data transfer with noninverting outputs.

Flag generation uses dedicated status logic: IR synchronized to WRTCLK rising edge, OR and HF synchronized to RDCLK rising edge, and AF/AE programmable via PEN-controlled latching of D0–D8 and WRTEN1/DP9 during reset recovery. The device requires four WRTCLK and four RDCLK cycles under RESET low to clear synchronizers.

Key Specifications

Pinout & Package

SN74ACT7807-25PAG uses a 64-pin Thin Quad Flat Package (PAG) with 0.5-mm lead pitch and exposed thermal pad. Pin numbering follows standard TQFP top-view convention with corner pin 1 marked.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT7203L15TPG, SN74ACT7807-25PAG offers native 5-V operation and programmable AF/AE offsets; versus SN74ACT7804-25PAG, it doubles buffer depth for longer burst absorption while retaining pin compatibility and timing behavior.

Availability

SN74ACT7807-25PAG is available at Aetrix Electronics and suitable for network packet buffering, digital signal processing interfaces, industrial PLC I/O expansion, and video frame synchronization requiring stable component supply across production lifecycles.

Supply support for SN74ACT7807-25PAG 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 50 years of innovation in high-reliability interface ICs.

The SN74ACT7807-25PAG belongs to TI's ACT advanced CMOS logic family, designed specifically for high-speed, low-power asynchronous data buffering in industrial and communications equipment where clock domain isolation is critical.

FAQ

What is the maximum clock frequency supported by the SN74ACT7807-25PAG?

The SN74ACT7807-25PAG supports a maximum clock frequency of 40 MHz for both read and write operations, as specified in the timing requirements table for the -25 speed grade. This corresponds to a minimum clock period of 25 ns and enables sustained data transfer rates up to 360 Mbps (9 bits × 40 MHz). The device achieves this performance using low-power advanced CMOS technology with 12 ns access time at 50-pF load.

How does the SN74ACT7807-25PAG handle reset initialization?

The SN74ACT7807-25PAG requires an asynchronous reset pulse held low for at least four rising edges of WRTCLK and four rising edges of RDCLK to fully initialize internal pointers and flags. During reset, IR, OR, and HF flags are driven low, while AF/AE is driven high. The FIFO must be reset at power-up to ensure predictable operation; failure to do so may result in undefined flag states and pointer misalignment.

Can the SN74ACT7807-25PAG be used in cascaded configurations?

Yes, the SN74ACT7807-25PAG supports both word-width and word-depth cascading. For depth expansion (e.g., 4096 × 9), multiple devices share RDCLK, WRTCLK, and control signals while connecting IR/OR flags in daisy-chain fashion. For width expansion (e.g., 2048 × 18), devices share clocks and enables while concatenating D0–D8 and Q0–Q8 buses. All cascading uses standard pins-no additional logic or glue components are required.

What is the function of the PEN pin on the SN74ACT7807-25PAG?

The PEN (Program Enable) pin on the SN74ACT7807-25PAG controls programming of the almost-full/almost-empty (AF/AE) flag thresholds. After reset and before the first write, asserting PEN low during a WRTCLK rising edge latches D0–D8 and WRTEN1/DP9 as the almost-empty offset (X); a second PEN assertion latches the same bus as the almost-full offset (Y). While PEN is active, writes to memory are inhibited regardless of WRTEN states.

Does the SN74ACT7807-25PAG support 3.3-V operation?

No, the SN74ACT7807-25PAG is specified only for 4.5 V to 5.5 V supply operation and is not rated for 3.3-V use. Its input thresholds (VIH = 2.0 V, VIL = 0.8 V) and output drive strength are optimized for 5-V TTL/CMOS compatibility. Attempting 3.3-V operation risks unreliable flag assertion, increased propagation delay, and potential damage due to underspecified internal biasing-TI explicitly defines VCC min as 4.5 V in recommended operating conditions.