Texas Instruments SN74V3680-15PEU

Overview

SN74V3680-15PEU from Texas Instruments is a 16,384 × 36-bit, 3.3-V CMOS synchronous FIFO memory with independent read/write clocks, user-selectable ×36/×18/×9 bus matching, and first-word fall-through (FWFT) or standard timing modes. It delivers 166-MHz operation (6-ns read/write cycle time), zero-latency retransmit capability, and programmable almost-empty/almost-full flags - deployed in high-throughput network buffering and video data stream alignment.

For engineers reviewing the SN74V3680-15PEU datasheet, SN74V3680-15PEU pinout, SN74V3680-15PEU application, or SN74V3680-15PEU equivalent, key selection criteria include its 16,384-word depth, 36-bit configurable port widths, FWFT vs. standard mode behavior, 5-V-tolerant inputs, and TQFP-128 package compatibility with industrial timing-critical buffer designs.

Technical Context

This FIFO implements dual-clock architecture with fully asynchronous WCLK and RCLK domains (0–166 MHz), enabling simultaneous write/read operations without metastability risk. Its RAM array is paired with dedicated read/write pointer logic, flag generation circuitry, and offset registers for PAE/PAF thresholds.

Bus-matching configuration is determined at master reset via BM/IW/OW pins, supporting five bidirectional width combinations (e.g., ×36-in to ×18-out). Byte ordering (big/little-endian) and programmable-flag timing (synchronous/asynchronous) are also set during initialization and remain static until next MRS.

Key Specifications

Pinout & Package

SN74V3680-15PEU is housed in a 128-pin Thin Quad Flat Pack (TQFP) with 0.4-mm lead pitch, RoHS-compliant, and rated for 0°C to 70°C operation. Pin numbering follows standard top-view orientation with pin 1 marked by corner notch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT72V3680L15PF and NB3N3020B, SN74V3680-15PEU uniquely combines maximum depth, FWFT timing, zero-latency retransmit, and 5-V-tolerant inputs - making it optimal for high-fidelity, low-jitter data bridging in telecom and broadcast infrastructure.

Availability

SN74V3680-15PEU is available at Aetrix Electronics and suitable for network packet buffering, video frame synchronization, telecom line card design, and DSP data flow management requiring stable component supply across extended production lifecycles.

Supply support for SN74V3680-15PEU 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 experience in high-speed interface and memory products.

SN74V3680-15PEU belongs to TI's high-performance FIFO memory family, engineered specifically for deterministic, low-latency data buffering in telecommunications, networking, and digital video systems.

FAQ

What is the memory depth and width of the SN74V3680-15PEU?

The SN74V3680-15PEU provides a fixed memory organization of 16,384 words × 36 bits, totaling 589,824 bits of buffer storage. This depth is explicitly defined in the device part number and confirmed in the SCAS668A datasheet revision March 2003. The SN74V3680-15PEU does not support reconfiguration of total bit count - only input/output bus width scaling via BM/IW/OW pins.

Does the SN74V3680-15PEU support 5-V logic inputs?

Yes, the SN74V3680-15PEU features 5-V-tolerant inputs on all control and data pins (D0–D35, WEN, REN, MRS, etc.), allowing direct connection to 5-V signal sources while operating from a 3.3-V VCC supply. This tolerance is specified in the Absolute Maximum Ratings table and functional description of the SCAS668A datasheet. The SN74V3680-15PEU outputs are not 5-V tolerant and must interface with 3.3-V receivers.

How does the first-word fall-through (FWFT) mode operate in the SN74V3680-15PEU?

In FWFT mode - selected by asserting FWFT/SI high during master reset - the first word written to an empty SN74V3680-15PEU appears on Q0–Q35 after exactly three rising edges of RCLK, without requiring REN assertion. Subsequent words still require REN. This behavior is hardware-implemented and deterministic, reducing latency for time-critical header reads. The SN74V3680-15PEU maintains this mode until next MRS.

Can the SN74V3680-15PEU be used with different input and output bus widths?

Yes, the SN74V3680-15PEU supports five bus-matching configurations set at master reset via BM, IW, and OW pins: ×36-in to ×36-out; ×36-in to ×18-out; ×36-in to ×9-out; ×18-in to ×36-out; and ×9-in to ×36-out. These modes are mutually exclusive per power-on cycle and affect pin usage (e.g., D18–D35 become don't-care in ×18-in mode). The SN74V3680-15PEU does not support dynamic width switching during operation.

What is the purpose of the retransmit (RT) function in the SN74V3680-15PEU?

The RT input enables rereading data from the beginning of the SN74V3680-15PEU's memory array without disturbing the write pointer. When asserted low on a rising RCLK edge, RT resets the read pointer to address zero. With zero-latency mode enabled (RM low at MRS), the first word appears on Qn within that same RCLK edge. This feature is essential for protocol header reinspection and error recovery. The SN74V3680-15PEU retains all flag states and offsets during retransmit.