Texas Instruments SN74ACT3632-15PCB

Overview

SN74ACT3632-15PCB from Texas Instruments is a clocked bidirectional FIFO memory IC with two independent 512 × 36 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 buffering between mismatched microprocessor buses in industrial control and communications interfaces.

For engineers reviewing the SN74ACT3632-15PCB datasheet, SN74ACT3632-15PCB pinout, SN74ACT3632-15PCB application, or SN74ACT3632-15PCB equivalent, key selection criteria include dual-port flag synchronization timing, mailbox-bypass register behavior, FIFO reset sequencing, and PCB-package pin compatibility with SN74ACT3622/SN74ACT3642.

Technical Context

This device integrates two independent 512-word × 36-bit clocked FIFOs with separate read/write pointers, input-ready (IRA/IRB) and output-ready (ORA/ORB) flags synchronized to their respective clocks, and two-stage metastability-hardened flag logic for reliable operation across asynchronous clock domains. Each FIFO supports programmable almost-empty (AEA/AEB) and almost-full (AFA/AFB) thresholds via offset registers loaded during reset or programmed from Port A.

The chip includes dual 36-bit mailbox-bypass registers (Mail1/Mail2) with dedicated flags (MBF1/MBF2), enabling direct command handshaking without queuing. Control logic implements microprocessor-compatible interface timing with CSA/CSB, W/RA/W/RB, ENA/ENB, and RST1/RST2 signals, all operating under 5-V TTL-compatible CMOS levels with 0.8-µm process technology.

Key Specifications

Pinout & Package

SN74ACT3632-15PCB uses a 120-pin Thin Quad Flat Package (TQFP) with 0.4 mm lead pitch, designated "PCB" in TI documentation. The package is RoHS-compliant and designed for surface-mount assembly on high-density PCBs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74ACT3622-15PCB and SN74ACT3642-15PCB, SN74ACT3632-15PCB provides optimal balance of buffer depth, pin compatibility, and timing margin for mid-range industrial and communications interfaces requiring deterministic 512-word queuing without layout changes.

Availability

SN74ACT3632-15PCB is available at Aetrix Electronics and suitable for industrial PLC backplane interfaces, DSP-to-microcontroller data bridges, and test equipment pattern generators requiring stable component supply and long-term lifecycle support.

Supply support for SN74ACT3632-15PCB 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 timing and interface ICs.

The SN74ACT3632-15PCB belongs to TI's ACT-family clocked FIFO product line, engineered for robust clock-domain crossing in industrial automation, test instrumentation, and digital signal processing subsystems.

FAQ

What is the memory organization of the SN74ACT3632-15PCB?

The SN74ACT3632-15PCB contains two independent 512-word × 36-bit FIFO memories: FIFO1 accepts writes from Port B and supplies reads to Port B, while FIFO2 accepts writes from Port A and supplies reads to Port A. Each FIFO has dedicated status flags and pointer logic, enabling true bidirectional buffering without internal contention.

How are the almost-full and almost-empty flags configured on the SN74ACT3632-15PCB?

The SN74ACT3632-15PCB supports two configuration methods for AFA/AEA/AEB/AFB flags: preset offsets (8, 16, or 64) selected via FS0/FS1 during RST1/RST2 assertion, or user-programmed values (1–508) written to offset registers Y1/X1/Y2/X2 through four consecutive writes to FIFO1 after simultaneous reset with FS0=FS1=L. All offsets are stored in on-chip registers and applied per-FIFO.

Does the SN74ACT3632-15PCB support asynchronous clock operation between Port A and Port B?

Yes, the SN74ACT3632-15PCB explicitly supports asynchronous CLKA and CLKB operation. All status flags (IRA/IRB, ORA/ORB, AFA/AFB, AEA/AEB) are synchronized to their respective port clocks using two-stage flip-flop chains, minimizing metastability risk and enabling reliable handshaking across unrelated clock domains.

What is the function of the mailbox registers in the SN74ACT3632-15PCB?

The SN74ACT3632-15PCB includes two 36-bit mailbox registers (Mail1 and Mail2) that operate independently of the FIFOs. Mail1 is written via Port B and read via Port A; Mail2 is written via Port A and read via Port B. Each has a dedicated flag (MBF1/MBF2) that goes low on write and high on corresponding port read, enabling interrupt-driven command exchange without consuming FIFO storage.

Is the SN74ACT3632-15PCB pin-compatible with other devices in the same family?

Yes, the SN74ACT3632-15PCB is pin-to-pin compatible with SN74ACT3622-15PCB (256×36×2) and SN74ACT3642-15PCB (1024×36×2) in the same 120-pin PCB package. This allows direct substitution to scale buffer depth without modifying PCB layout, provided timing margins accommodate the different memory depths.