Texas Instruments SN74ACT3622-30PQ

Overview

SN74ACT3622-30PQ from Texas Instruments is a clocked bidirectional FIFO memory IC with dual 256 × 36 × 2 SRAM buffers, supporting asynchronous or coincident 67 MHz clocks (CLKA/CLKB), 11 ns read access time, and programmable almost-full/empty flags synchronized to respective ports. It enables high-speed data bridging between mismatched microprocessor buses in telecom backplanes and real-time DSP interconnects.

For engineers reviewing the SN74ACT3622-30PQ datasheet, SN74ACT3622-30PQ pinout, SN74ACT3622-30PQ application, or SN74ACT3622-30PQ equivalent, key selection criteria include dual-port flag synchronization timing, mailbox-bypass register behavior, FIFO reset sequencing, and PQ-package pin compatibility with SN74ACT3632/SN74ACT3642 for board-level reuse.

Technical Context

The SN74ACT3622-30PQ integrates two independent clocked FIFOs (FIFO1 and FIFO2), each with 256 × 36-bit SRAM, separate write/read pointers, and two-stage synchronized status flags (IRA/ORA/AEA/AFA for Port A; IRB/ORB/AEB/AFB for Port B). Clock domains CLKA and CLKB operate independently and support asynchronous operation with metastability mitigation.

Each FIFO features programmable almost-empty (X1/X2) and almost-full (Y1/Y2) offset registers loaded either via FS0/FS1 during reset or dynamically from Port A (A7–A0), enabling runtime threshold adjustment. Mailbox registers (Mail1/Mail2) provide 36-bit bypass paths with dedicated MBF1/MBF2 flags for handshaking, decoupling control messaging from FIFO queuing.

Key Specifications

Pinout & Package

SN74ACT3622-30PQ uses a 132-pin Plastic Quad Flat (PQ) package with 0.65 mm pitch, no internal connections on pins 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, and 132.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74ACT3632-30PQ and SN74ACT3642-30PQ, the SN74ACT3622-30PQ uniquely delivers 36-bit-wide dual FIFOs with two-stage synchronized flags and integrated mailbox registers-enabling robust, low-latency bridging in mixed-clock industrial and telecom systems without external synchronization logic.

Availability

SN74ACT3622-30PQ is available at Aetrix Electronics and suitable for telecom backplane interconnect, DSP data pipelines, industrial PLC I/O modules, and legacy bus protocol translators requiring stable component supply across extended production lifecycles.

Supply support for SN74ACT3622-30PQ 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 decades of heritage in high-reliability interface and memory products.

The SN74ACT3622-30PQ belongs to TI's advanced CMOS FIFO family designed for high-speed, low-power bridging between asynchronous digital subsystems in communications infrastructure and real-time control systems.

FAQ

What is the memory configuration of the SN74ACT3622-30PQ?

The SN74ACT3622-30PQ contains two independent 256 × 36-bit SRAM FIFOs (FIFO1 and FIFO2), totaling 256 words of 36-bit depth per FIFO. Each FIFO supports separate read/write pointers, status flags, and programmable almost-full/empty offsets. This configuration enables bidirectional buffering of wide parallel data streams without shared memory contention.

How does the mailbox-bypass functionality work in the SN74ACT3622-30PQ?

The SN74ACT3622-30PQ includes two 36-bit mailbox registers (Mail1 and Mail2) with dedicated flags MBF1 and MBF2. Writing to Mail1 is triggered by CLKA with MBA high; reading is triggered by CLKB with MBB high. The flags indicate register occupancy and are cleared automatically on successful read, enabling non-blocking command handshaking independent of FIFO queuing latency.

What are the reset requirements for SN74ACT3622-30PQ FIFO initialization?

Each FIFO in the SN74ACT3622-30PQ requires separate asynchronous reset: RST1 must be held low for ≥4 CLKA and ≥4 CLKB rising edges to initialize FIFO1; RST2 follows the same sequence for FIFO2. Upon rising edge of RST1/RST2, FS0/FS1 are latched to configure flag offset programming mode. Both FIFOs must be reset after power-up before writing data.

Can SN74ACT3622-30PQ operate with fully asynchronous CLKA and CLKB?

Yes, the SN74ACT3622-30PQ supports fully asynchronous CLKA and CLKB operation. All status flags (IRA/ORA/AEA/AFA and IRB/ORB/AEB/AFB) are two-stage synchronized to their respective clocks, reducing metastability probability to <10⁻⁹ per cycle. This allows reliable handshaking even when clocks have arbitrary phase/frequency relationships.

Is SN74ACT3622-30PQ pin-compatible with other devices in its family?

Yes, the SN74ACT3622-30PQ is pin-to-pin compatible with SN74ACT3632-30PQ and SN74ACT3642-30PQ in the 132-pin PQ package. This allows direct substitution in existing layouts, though functional differences (e.g., FIFO depth, mailbox presence, flag synchronization stages) must be verified in system-level timing and software.