Texas Instruments SN74ABT3612-15PCB

Overview

SN74ABT3612-15PCB from Texas Instruments is a clocked bidirectional FIFO memory IC with two independent 64 × 36 dual-port SRAM buffers, supporting up to 67 MHz clock frequency, 10 ns read access time, and passive/active parity checking on both 36-bit ports. It enables asynchronous data bridging between microprocessor buses in telecom backplanes and high-speed interconnects.

For engineers reviewing the SN74ABT3612-15PCB datasheet, SN74ABT3612-15PCB pinout, SN74ABT3612-15PCB application, or SN74ABT3612-15PCB equivalent, this device delivers deterministic latency control via synchronized flag logic, mailbox-bypass registers for command injection, and programmable almost-full/empty thresholds - critical for real-time buffer management in synchronous digital systems.

Technical Context

The SN74ABT3612-15PCB implements two independent clock domains (CLKA and CLKB), each driving a dedicated 64-word × 36-bit FIFO with two-stage synchronized status flags (EFA/FFA/AFA/AEA for port A; EFB/FFB/AFB/AEB for port B). Each port supports microprocessor-style control via chip select (CSA/CSB), enable (ENA/ENB), and write/read (W/RA/W/RB) signals.

It integrates dual 36-bit mailbox registers (mail1/mail2) with dedicated flag outputs (MBF1/MBF2), parity generation (PGA/PGB) and checking (PEFA/PEFB) per port using four-byte partitioning (A0–A8, A9–A17, etc.), and selectable odd/even parity via ODD/EVEN input. Flag offset is set by FS0/FS1 at reset to 4, 8, 12, or 16 words.

Key Specifications

Pinout & Package

SN74ABT3612-15PCB uses a 120-pin thin quad flat package (TQFP), designated PCB in TI documentation, with 0.4 mm lead pitch and exposed thermal pad. Pin numbering follows standard TQFP top-view convention (pin 1 at top-left corner, counterclockwise).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74ABT3612-15PCB, IDT72V36120L15PF offers higher speed but removes mailbox and parity features essential for robust command/data coexistence, while SN74ACT2222DW sacrifices depth, width, and clock domain isolation - making SN74ABT3612-15PCB uniquely balanced for complex embedded interconnects requiring both bandwidth and functional safety features.

Availability

SN74ABT3612-15PCB is available at Aetrix Electronics and suitable for telecom infrastructure, industrial automation, and test equipment applications requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for SN74ABT3612-15PCB 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 decades of expertise in high-reliability interface ICs.

The SN74ABT3612-15PCB belongs to TI's ABT-family of advanced BiCMOS FIFOs, designed specifically for high-speed, low-latency data buffering in mixed-clock-domain systems such as network switches, motor drives, and instrumentation platforms.

FAQ

What is the maximum supported clock frequency for SN74ABT3612-15PCB?

The SN74ABT3612-15PCB supports clock frequencies up to 67 MHz on both CLKA and CLKB inputs, as specified in the SCBS129G datasheet. This rating applies across the full commercial temperature range (0°C to 70°C) and is validated with 10 ns read access time under standard loading conditions. Exceeding 67 MHz may result in timing violations or metastability in flag synchronization.

How does the mailbox-bypass functionality work in SN74ABT3612-15PCB?

In SN74ABT3612-15PCB, mailbox-bypass registers (mail1 and mail2) allow direct 36-bit data transfer between ports without queuing. Writing to mail1 occurs on CLKB when CSB, W/RB, and ENB are active and MBB is high; reading occurs when MBB is high and W/RB is low. Each mailbox has a dedicated flag (MBF1/MBF2) that asserts low on write and clears on corresponding read, enabling hardware handshaking.

Can SN74ABT3612-15PCB operate with asynchronous CLKA and CLKB clocks?

Yes, SN74ABT3612-15PCB explicitly supports asynchronous operation of CLKA and CLKB, as confirmed in the functional description and timing diagrams of SCBS129G. All status flags (EFA/FFA/AFA/AEA and EFB/FFB/AFB/AEB) are two-stage synchronized to their respective port clocks, eliminating metastability risks and enabling reliable cross-domain signaling without external synchronizers.

What are the programmable flag offset values for SN74ABT3612-15PCB?

The SN74ABT3612-15PCB supports four programmable almost-full and almost-empty flag offsets: 4, 8, 12, or 16 words. These values are selected by the combination of FS0 and FS1 inputs latched on the rising edge of RST, as defined in Table 1 of the SCBS129G datasheet. The offset register X determines threshold behavior for AFA, AFB, AEA, and AEB flags.

Does SN74ABT3612-15PCB support parity generation and checking simultaneously on both ports?

Yes, SN74ABT3612-15PCB supports independent parity generation (via PGA/PGB) and checking (via PEFA/PEFB) on both ports. Parity is computed over four 9-bit groups per port (e.g., A0–A8, A9–A17), with odd/even selection controlled by the ODD/EVEN input. When parity generation is enabled during a read, the generated bit replaces the MSB of each byte on output, while parity checking remains active on input data.