Texas Instruments SN74V3640-15PEU

Overview

SN74V3640-15PEU from Texas Instruments is a 3.3-V CMOS, 1024 × 36-bit synchronous FIFO memory with independent read/write clocks, user-selectable bus sizing (×36/×18/×9), and first-word fall-through (FWFT) or standard timing mode. It delivers 166-MHz operation (6-ns read/write cycle time), zero-latency retransmit capability, and 5-V-tolerant inputs - deployed in high-speed network packet buffering and video data stream alignment.

For engineers reviewing the SN74V3640-15PEU datasheet, SN74V3640-15PEU pinout, SN74V3640-15PEU application, or SN74V3640-15PEU equivalent, key selection considerations include configurable bus-matching width, programmable almost-empty/almost-full flag offsets, big-endian/little-endian byte ordering, dual-clock domain operation, and TQFP-128 packaging for dense PCB layouts.

Technical Context

This FIFO implements a dual-clock, asynchronous read/write architecture with fully independent WCLK and RCLK domains (0–166 MHz), enabling seamless bridging between mismatched data rates in telecom and signal processing systems. Its RAM array supports flexible port sizing via BM/IW/OW control pins during master reset, and its flag logic includes EF/OR, FF/IR, HF, PAE, and PAF with selectable synchronous/asynchronous timing modes.

The device features fixed low-latency first-word access (three RCLK edges in FWFT mode), zero-latency retransmit (enabled by RM pin), and serial/parallel offset programming of PAE/PAF thresholds using LD/FSEL0/FSEL1. Bus-matching configuration preserves data integrity across ×36-to-×9 width conversions while maintaining consistent word alignment via BE-controlled endian selection.

Key Specifications

Pinout & Package

SN74V3640-15PEU is housed in a 128-pin Thin Quad Flat Pack (TQFP) package with 0.4-mm lead pitch and exposed thermal pad. Pin assignments are validated per TI SCAS668A datasheet Figure 2 (PEU top view).

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT72V3640L15PF and NB3N502M, SN74V3640-15PEU uniquely combines 5-V-tolerant I/O, FWFT timing, zero-latency retransmit, and full ×36/×18/×9 bus-matching - making it the only option supporting robust interoperability across legacy and modern voltage domains while enabling latency-optimized streaming architectures.

Availability

SN74V3640-15PEU is available at Aetrix Electronics and suitable for network packet buffering, video stream alignment, telecom line card bridging, signal processing pipelining, and high-speed data acquisition requiring stable component supply across extended production cycles.

Supply support for SN74V3640-15PEU 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 over 50 years of innovation in high-reliability interface and memory products.

SN74V3640-15PEU belongs to TI's high-speed synchronous FIFO product line, engineered specifically for deterministic, low-latency data buffering in multi-clock-domain systems such as networking infrastructure, broadcast video equipment, and telecom base stations.

FAQ

What is the maximum operating frequency of the SN74V3640-15PEU?

The SN74V3640-15PEU supports up to 166 MHz for both read and write operations, corresponding to a 6-ns read/write cycle time. This specification is guaranteed across the commercial temperature range (0°C to 70°C) and applies to both WCLK and RCLK domains independently - enabling high-throughput data transfer in demanding applications like packet switching and real-time video processing. The SN74V3640-15PEU achieves this performance using submicron CMOS technology optimized for speed and low power.

Does the SN74V3640-15PEU support 5-V logic inputs?

Yes, the SN74V3640-15PEU features 5-V-tolerant inputs on all control and data pins (D0–D35, WEN, REN, MRS, etc.), allowing direct connection to 5-V TTL or CMOS logic without external level shifters. This tolerance holds across the full operating voltage range (3.0 V to 3.6 V VCC) and is specified in the absolute maximum ratings and DC characteristics sections of the TI SCAS668A datasheet. The SN74V3640-15PEU maintains full functionality and timing compliance under 5-V input conditions.

How does the first-word fall-through (FWFT) mode work on the SN74V3640-15PEU?

In FWFT mode - selected by asserting FWFT/SI high during master reset - the first word written to an empty SN74V3640-15PEU appears on Q0–Q35 after exactly three rising edges of RCLK, without requiring REN to be asserted. Subsequent words still require REN activation. This behavior eliminates initial read latency in streaming applications. The SN74V3640-15PEU uses OR and IR flags instead of EF/FF in FWFT mode to indicate output readiness and input space availability.

Can the SN74V3640-15PEU be configured for different input and output bus widths?

Yes, the SN74V3640-15PEU supports five bus-matching configurations (e.g., ×36-in to ×9-out) via BM, IW, and OW pins sampled during master reset. These pins define write-port and read-port widths independently, enabling seamless interface translation between mismatched subsystems. The SN74V3640-15PEU maintains data coherency across width changes using BE-controlled endian selection and automatic bit alignment - no external multiplexing logic is needed.

What is the purpose of the programmable almost-empty (PAE) and almost-full (PAF) flags on the SN74V3640-15PEU?

The PAE and PAF flags on the SN74V3640-15PEU provide early warning signals at user-defined buffer occupancy thresholds - configurable via eight factory defaults or custom values loaded serially (FWFT/SI) or in parallel (Dn). PAE asserts when word count falls below a set value; PAF asserts when free space drops below a threshold. These flags enable proactive DMA triggering, flow control negotiation, or resource allocation in real-time systems - a capability not available in basic FIFOs. The SN74V3640-15PEU supports synchronous or asynchronous timing modes for these flags via the PFM pin.