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Home > Products > Integrated Circuits (ICs) > Logic > FIFOs Memory

Texas Instruments SN74ACT3622-15PQ

Name: SN74ACT3622-15PQ
Brand: Texas Instruments
SKU: SN74ACT3622-15PQ
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SN74ACT3622-15PQ

Manufacturer:: Texas Instruments

Category:: FIFOs Memory

Package:: 132-BQFP Bumpered

Datasheet:: SN74ACT3622-15PQ.pdf

Description:: IC FIFO SYNC 256X36X2 132BQFP

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Product details

Overview

SN74ACT3622-15PQ from Texas Instruments is a clocked bidirectional FIFO memory IC with dual 256 × 36 × 2 SRAM buffers, supporting asynchronous or coincident CLKA/CLKB up to 67 MHz, 11 ns access time, and programmable almost-full/empty flags synchronized per port. It enables high-speed data bridging between microprocessor buses operating at different clock domains, such as in PCI-to-PCIe bridge interface logic.

For engineers reviewing the SN74ACT3622-15PQ datasheet, SN74ACT3622-15PQ pinout, SN74ACT3622-15PQ application, or SN74ACT3622-15PQ equivalent, key selection criteria include dual-port flag synchronization timing, mailbox-bypass register behavior, FIFO reset sequencing requirements, and PQ-package thermal/power derating for industrial temperature operation.

Technical Context

The SN74ACT3622-15PQ integrates two independent clocked FIFOs (FIFO1 and FIFO2), each with 256 words × 36 bits, using low-power 0.8 µm Advanced CMOS. Port-A (CLKA-synchronized) and Port-B (CLKB-synchronized) operate fully asynchronously, with all status flags (IRA/ORA/AFA/AEA and IRB/ORB/AFB/AEB) two-stage synchronized to their respective clocks to suppress metastability.

Each FIFO features programmable almost-full (Y1/Y2) and almost-empty (X1/X2) offset registers loaded either via FS0/FS1 during reset or dynamically from Port-A, enabling configurable buffer watermarking. The integrated mailbox registers (Mail1/Mail2) provide non-queued 36-bit command transfer paths, controlled by MBA/MBB and flagged by MBF1/MBF2.

Key Specifications

Parameter	Value and Actual Design Meaning
Memory depth × width × ports	256 × 36 × 2 - Two independent FIFOs, each storing 256 words of 36-bit data, enabling full-duplex buffering without shared memory contention.
Max clock frequency	67 MHz - Supports high-throughput interconnects such as legacy PCI bus bridging or DSP-to-FPGA data streaming.
Access time	11 ns - Enables sub-15 ns read/write cycles, critical for meeting tight setup/hold timing in synchronous bus interfaces.
Flag synchronization	Two-stage flip-flop sync per port - Reduces metastability risk when CLKA and CLKB are asynchronous; ORA/IRA tied to CLKA, ORB/IRB to CLKB.
Operating temperature	0°C to +70°C - Qualified for commercial-grade embedded systems including industrial controllers and test equipment.
Technology node	0.8 µm Advanced CMOS - Delivers low static power consumption while maintaining TTL-compatible voltage thresholds (V_IH = 2.0 V, V_IL = 0.8 V).
Programmable offsets	X1/X2/Y1/Y2 registers - Allow runtime configuration of almost-empty/almost-full thresholds (1–252 words) via Port-A writes, enabling adaptive flow control.

Pinout & Package

SN74ACT3622-15PQ uses a 132-pin Plastic Quad Flat (PQ) package with 0.65 mm lead pitch, designed for surface-mount assembly and thermal dissipation in high-density PCB layouts. Pin numbering follows standard PQ top-view orientation with corner pin #1 marked.

Pin/Terminal	Circuit Role	Design Meaning
A0–A35	Port-A bidirectional data bus	36-bit I/O path for FIFO2 read/FIFO1 write; high-impedance when CSA or W/RA high; requires external bus termination for signal integrity.
B0–B35	Port-B bidirectional data bus	36-bit I/O path for FIFO1 read/FIFO2 write; active only when CSB low and W/RB high; inverted W/RB logic simplifies microcontroller GPIO mapping.
CLKA / CLKB	Independent port clocks	Continuous synchronous clocks; support asynchronous operation (no phase alignment required); all transfers edge-triggered on low-to-high transition.
CSA / CSB	Port chip select inputs	Active-low enables; disable port I/O drivers and suspend flag updates when deasserted; essential for multi-device bus sharing.
ENA / ENB	Port enable inputs	High-level enables; gate clock-triggered transfers; allow dynamic port gating without clock stopping, reducing power in idle states.
MBA / MBB	Mailbox select inputs	Select between FIFO output register (low) or mailbox register (high); enable zero-latency command handshaking alongside buffered data flow.
RST1 / RST2	Independent FIFO resets	Asynchronous active-high; require ≥4 CLKA+CLKB transitions while low; initialize pointers, flags, and mailbox flags; mandatory after power-up before first write.
IRA / ORA / AFA / AEA	Port-A status flags	Synchronized to CLKA; IRA=low = FIFO1 full, ORA=high = valid data in FIFO2 output register, AFA/AEA indicate programmable fill thresholds.
IRB / ORB / AFB / AEB	Port-B status flags	Synchronized to CLKB; IRB=low = FIFO2 full, ORB=high = valid data in FIFO1 output register; AFB/AEB reflect FIFO2 fill level against Y2/X2 offsets.
MBF1 / MBF2	Mailbox full flags	MBF1=low = Mail1 written and unread; MBF2=low = Mail2 written and unread; both auto-clear on corresponding port read with mailbox select asserted.

Key Features

Feature	Design Value
Dual independent clock domains	Enables seamless data transfer between subsystems with unrelated clocks (e.g., 50 MHz CPU bus ↔ 66 MHz peripheral bus) without external clock domain crossing logic.
Mailbox-bypass registers	Two dedicated 36-bit registers (Mail1/Mail2) provide immediate command/control exchange-bypassing FIFO latency-critical for handshake protocols and interrupt signaling.
Programmable almost-full/empty flags	Four offset registers (X1/X2/Y1/Y2) configurable via FS0/FS1 pins or Port-A writes allow dynamic tuning of flow-control thresholds to match real-time bandwidth demands.
Metastability-hardened flag synchronization	Two-stage synchronizers on all status flags reduce probability of metastable failure to <10⁻¹²/hour under worst-case async clock skew, meeting industrial reliability requirements.
Microprocessor interface logic	Integrated CSA/CSB, W/RA/W/RB, ENA/ENB decoding eliminates need for external address decoders or glue logic in 80x86 or ARM-based host designs.

Applications

PCI-to-PCI Bridge Interface	DSP-to-FPGA Data Streaming
Use Scenario: Bridging two PCI buses with mismatched timing specifications and arbitration schemes. IC Role / Device Role / Timing Role: Dual-clock FIFO acts as elastic buffer and protocol translator, absorbing burst traffic while isolating clock domains. Use Value: Eliminates need for custom ASIC or FPGA-based bridging logic; supports 67 MHz PCI clock rates with deterministic 11 ns latency per transfer.	Use Scenario: Real-time sensor data ingestion from high-speed ADCs into FPGA-based digital signal processing pipelines. IC Role / Device Role / Timing Role: SN74ACT3622-15PQ serves as a jitter-tolerant, clock-domain-crossing FIFO between DSP's system clock and FPGA's sampling clock. Use Value: Prevents data loss during clock rate mismatches; mailbox registers deliver trigger commands (e.g., start/stop acquisition) with zero FIFO delay.
Industrial PLC Backplane Interconnect	Legacy Bus Protocol Converter
Use Scenario: Connecting modular I/O cards to a central controller over a deterministic backplane with variable slot timing. IC Role / Device Role / Timing Role: Bidirectional FIFO buffers command packets (from controller) and status responses (from I/O modules), decoupling timing across slots. Use Value: Ensures reliable communication despite ±5% clock tolerance between modules; programmable AF/AE flags enable adaptive backpressure signaling.	Use Scenario: Converting between ISA and VMEbus protocols in test instrumentation rack systems. IC Role / Device Role / Timing Role: SN74ACT3622-15PQ provides synchronous, width-matched buffering (36-bit) between buses with incompatible handshaking and clocking. Use Value: Replaces discrete logic and CPLDs; mailbox registers handle bus-specific control signals (e.g., VME BERR#, ISA IRQ), reducing firmware complexity.

PCI-to-PCI Bridge Interface

DSP-to-FPGA Data Streaming

Use Scenario: Bridging two PCI buses with mismatched timing specifications and arbitration schemes.

IC Role / Device Role / Timing Role: Dual-clock FIFO acts as elastic buffer and protocol translator, absorbing burst traffic while isolating clock domains.

Use Value: Eliminates need for custom ASIC or FPGA-based bridging logic; supports 67 MHz PCI clock rates with deterministic 11 ns latency per transfer.

Use Scenario: Real-time sensor data ingestion from high-speed ADCs into FPGA-based digital signal processing pipelines.

IC Role / Device Role / Timing Role: SN74ACT3622-15PQ serves as a jitter-tolerant, clock-domain-crossing FIFO between DSP's system clock and FPGA's sampling clock.

Use Value: Prevents data loss during clock rate mismatches; mailbox registers deliver trigger commands (e.g., start/stop acquisition) with zero FIFO delay.

Industrial PLC Backplane Interconnect

Legacy Bus Protocol Converter

Use Scenario: Connecting modular I/O cards to a central controller over a deterministic backplane with variable slot timing.

IC Role / Device Role / Timing Role: Bidirectional FIFO buffers command packets (from controller) and status responses (from I/O modules), decoupling timing across slots.

Use Value: Ensures reliable communication despite ±5% clock tolerance between modules; programmable AF/AE flags enable adaptive backpressure signaling.

Use Scenario: Converting between ISA and VMEbus protocols in test instrumentation rack systems.

IC Role / Device Role / Timing Role: SN74ACT3622-15PQ provides synchronous, width-matched buffering (36-bit) between buses with incompatible handshaking and clocking.

Use Value: Replaces discrete logic and CPLDs; mailbox registers handle bus-specific control signals (e.g., VME BERR#, ISA IRQ), reducing firmware complexity.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
SN74ACT3632-15PQ	Same pinout, identical 256×36×2 architecture, but lacks mailbox registers and bypass functionality.	Suitable only for pure FIFO buffering without sideband command channel; cannot replace SN74ACT3622-15PQ where mailbox handshaking is required.	Choose when cost reduction is prioritized and mailbox functionality is unused; verify absence of MBA/MBB/MBF1/MBF2 dependencies in existing firmware.
SN74ACT3642-15PQ	Pin-compatible, adds separate reset control per flag group and enhanced power-down mode, but retains same mailbox and FIFO structure.	Offers lower standby current and finer-grained reset control; functionally superset for new designs requiring extended power management.	Select for new designs targeting reduced system power; backward-compatible drop-in replacement if existing layout accommodates identical PQ footprint and no reliance on deprecated features.

Compared with SN74ACT3632-15PQ and SN74ACT3642-15PQ, the SN74ACT3622-15PQ uniquely delivers mailbox-bypass capability in a mature, widely documented implementation-making it optimal for legacy protocol bridges where command/data separation is mandatory and power optimization is secondary.

Availability

SN74ACT3622-15PQ is available at Aetrix Electronics and suitable for PCI bridge interfaces, DSP-to-FPGA streaming links, and industrial PLC backplane interconnects requiring stable component supply and long-term obsolescence mitigation.

Supply support for SN74ACT3622-15PQ 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 SN74ACT3622-15PQ belongs to TI's ACT-family advanced CMOS logic portfolio, engineered specifically for high-speed, low-power bidirectional data buffering in mixed-clock-domain systems such as industrial automation and communications infrastructure.

FAQ

What is the maximum supported clock frequency for SN74ACT3622-15PQ?

The SN74ACT3622-15PQ supports clock frequencies up to 67 MHz on both CLKA and CLKB inputs. This rating is validated across the full 0°C to +70°C operating range and reflects guaranteed timing margins for setup/hold compliance in synchronous bus interfaces. Exceeding 67 MHz may violate internal register timing and cause metastability or data corruption in flag outputs.

How does the mailbox-bypass functionality work in SN74ACT3622-15PQ?

The SN74ACT3622-15PQ implements two independent 36-bit mailbox registers (Mail1 and Mail2). Writing to Mail1 occurs on CLKA edge with MBA high; reading occurs on CLKB edge with MBB high. Each mailbox has a dedicated flag (MBF1/MBF2) that goes low on write and high on read. This enables zero-latency command exchange alongside FIFO-buffered data streams.

Can SN74ACT3622-15PQ operate with completely asynchronous CLKA and CLKB?

Yes - SN74ACT3622-15PQ is explicitly designed for asynchronous clock operation. All status flags (IRA/ORA/AFA/AEA and IRB/ORB/AFB/AEB) are two-stage synchronized to their respective port clocks, suppressing metastability. Functional operation is guaranteed even when CLKA and CLKB have arbitrary phase relationships or frequency ratios.

What are the reset requirements for SN74ACT3622-15PQ before normal operation?

Both RST1 and RST2 must be asserted (high) for at least four low-to-high transitions of CLKA and CLKB while held active. After release, IRA and ORA go high after two CLKA cycles; IRB and ORB go high after two CLKB cycles. Reset is mandatory after power-up; failure to reset results in undefined pointer states and unreliable flag behavior in SN74ACT3622-15PQ.

How are the almost-full and almost-empty flag offsets programmed in SN74ACT3622-15PQ?

Offsets for AFA/AEA/AFB/AEB are stored in X1/X2/Y1/Y2 registers. They can be loaded with preset values (8, 16, or 64) by setting FS0/FS1 during RST1/RST2 assertion, or programmed dynamically from Port-A: after simultaneous RST1+RST2 with FS0=FS1=low, the first four writes to FIFO1 load Y1→X1→Y2→X2 using A7–A0 bits. Valid values range from 1 to 252.

SN74ACT3622-15PQ Specifications

Product attributes: Attribute value

Manufacturer:: Texas Instruments

Series:: 74ACT

Package/Case:: 132-BQFP Bumpered

Packaging:: Tray

Product Status:: Obsolete

Programmable:: Not Verified

Memory Size:: 18K (256 x 36 x 2)

Function:: Synchronous

Data Rate:: 66.7MHz

Access Time:: 11ns

Voltage - Supply:: 4.5 V ~ 5.5 V

Current - Supply (Max):: 400µA

Bus Directional:: Bi-Directional

Expansion Type:: Width

Programmable Flags Support:: Yes

Retransmit Capability:: No

FWFT Support:: No

Operating Temperature:: 0°C ~ 70°C

Mounting Type:: Surface Mount

Supplier Device Package:: 132-BQFP (24.13x24.13)

SN74ACT3622-15PQ FAQ

1.How can I place an order for SN74ACT3622-15PQ through Aetrix?

Please submit a Request for Quotation (RFQ) for SN74ACT3622-15PQ on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for SN74ACT3622-15PQ reliable?

The price and inventory of SN74ACT3622-15PQ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ACT3622-15PQ is usually 5 days.

3.What payment methods are accepted for SN74ACT3622-15PQ?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74ACT3622-15PQ transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SN74ACT3622-15PQ?

SN74ACT3622-15PQ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SN74ACT3622-15PQ order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for SN74ACT3622-15PQ?

For technical support, including SN74ACT3622-15PQ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ACT3622-15PQ requirements.

6.How does Aetrix verify that SN74ACT3622-15PQ is sourced from the original manufacturer or authorized distributors?

All SN74ACT3622-15PQ products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that SN74ACT3622-15PQ meets industry standards.

7.What is the process for return or replacement of SN74ACT3622-15PQ?

All SN74ACT3622-15PQ units undergo pre-shipment inspection (PSI). If there is an issue with SN74ACT3622-15PQ, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The SN74ACT3622-15PQ part is unused and in its original packaging.

Return procedure for SN74ACT3622-15PQ:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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