Texas Instruments SN74V3690-7PEU

Overview

SN74V3690-7PEU from Texas Instruments is a 32,768 × 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 packet buffering and video frame synchronization systems.

For engineers reviewing the SN74V3690-7PEU datasheet, SN74V3690-7PEU pinout, SN74V3690-7PEU application, or SN74V3690-7PEU equivalent, key selection considerations include its 128-pin TQFP package, 5-V-tolerant inputs, fixed low first-word latency, big/little-endian byte configuration, and dual-mode flag timing (synchronous/asynchronous).

Technical Context

This FIFO implements a dual-clock architecture with fully asynchronous WCLK and RCLK domains, supporting independent frequency operation up to 166 MHz. Its RAM array is organized as 32,768 words × 36 bits, with configurable input/output port widths via BM/IW/OW control pins during master reset.

The device supports two distinct timing modes: FWFT mode enables immediate output of the first word after three RCLK edges without REN assertion, while standard mode requires explicit REN activation for all reads. Flag logic includes EF/OR, FF/IR, HF, PAE, and PAF - with PAE/PAF programmable via serial or parallel loading and configurable timing (synchronous/asynchronous) via PFM.

Key Specifications

Pinout & Package

SN74V3690-7PEU is housed in a 128-pin Thin Quad Flat Pack (TQFP) with 0.4-mm lead pitch, JEDEC MO-220 standard footprint, and exposed thermal pad for enhanced power dissipation in sustained high-speed operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT72V3690L15PF and NB3N3020B, SN74V3690-7PEU uniquely combines 32K×36 depth, 6-ns cycle time, 5-V-tolerant inputs, FWFT timing, and full bus-matching - making it irreplaceable in high-throughput, mixed-voltage, multi-width buffering applications where latency predictability and interface flexibility are non-negotiable.

Availability

SN74V3690-7PEU is available at Aetrix Electronics and suitable for network packet buffering, video frame synchronization, and telecom line card data aggregation requiring stable component supply across extended production lifecycles.

Supply support for SN74V3690-7PEU 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 leadership in high-speed interface and memory products.

SN74V3690-7PEU belongs to TI's high-performance FIFO memory product line, engineered specifically for deterministic, low-latency data buffering in multi-clock-domain systems such as networking infrastructure, broadcast video, and telecom equipment.

FAQ

What is the maximum operating frequency of the SN74V3690-7PEU?

The SN74V3690-7PEU supports up to 166 MHz for both read and write operations, corresponding to a 6-ns read/write cycle time. This specification is guaranteed over the full commercial temperature range (0°C to +70°C) and applies to all supported bus configurations (×36/×18/×9) and timing modes (FWFT or standard). The SN74V3690-7PEU achieves this performance using high-speed submicron CMOS technology.

Does the SN74V3690-7PEU support 5-V logic inputs?

Yes, the SN74V3690-7PEU features 5-V-tolerant inputs on all control and data pins (including WEN, REN, WCLK, RCLK, D0–D35, and configuration pins), allowing direct connection to 5-V TTL or CMOS logic without external level shifters. The core operates from a 3.3-V supply, and output drivers are not 5-V tolerant - Q0–Q35 outputs swing rail-to-rail with VCC = 3.3 V.

How does the first-word fall-through (FWFT) mode work in the SN74V3690-7PEU?

In FWFT mode, the first word written to an empty SN74V3690-7PEU appears on Q0–Q35 after exactly three rising edges of RCLK - no REN assertion is required. Subsequent words still require REN activation. This mode is selected by holding FWFT/SI high during master reset (MRS low). FWFT enables immediate data availability critical for burst-start protocols like PCIe transaction layer handshaking or video line sync.

Can the SN74V3690-7PEU be used to expand memory depth beyond 32,768 words?

Yes, the SN74V3690-7PEU supports depth expansion via daisy-chaining in FWFT mode: the Q outputs of one device connect directly to the D inputs of the next, with shared RCLK/WCLK and cascaded flag signals. No external logic is needed because FWFT ensures seamless handoff - the second device begins accepting data as soon as the first asserts IR (input ready). Standard mode requires additional control logic for depth expansion.

What packaging and thermal characteristics apply to the SN74V3690-7PEU?

The SN74V3690-7PEU is supplied in a 128-pin TQFP (PEU) package with 14 mm × 14 mm body size, 0.4-mm lead pitch, and JEDEC MO-220 compliant footprint. It includes an exposed thermal pad for soldering to PCB ground plane, enabling effective heat dissipation during sustained 166-MHz operation. Thermal resistance (θ_JA) is 32°C/W under standard JEDEC 2-layer board conditions.