Texas Instruments SN74V3690-15PEU

Overview

SN74V3690-15PEU from Texas Instruments is a 32,768 × 36-bit, 3.3-V CMOS synchronous FIFO memory with independent read/write clocks, 166-MHz operation (6-ns cycle time), user-selectable ×36/×18/×9 bus matching, and FWFT/standard timing modes - deployed in high-throughput network packet buffering and video frame synchronization systems.

For engineers reviewing the SN74V3690-15PEU datasheet, SN74V3690-15PEU pinout, SN74V3690-15PEU application, or SN74V3690-15PEU equivalent, key selection criteria include its zero-latency retransmit capability, programmable almost-empty/almost-full flags with eight default offsets, 5-V-tolerant inputs, and 128-pin TQFP package compatibility with depth/width expansion architectures.

Technical Context

This FIFO implements dual-clock architecture with fully asynchronous RCLK and WCLK domains (0–166 MHz), enabling simultaneous read/write without metastability risk. Its internal RAM array supports flexible bus-matching via BM/IW/OW configuration pins during master reset, allowing ×36-in-to-×36-out, ×36-in-to-×18-out, ×36-in-to-×9-out, ×18-in-to-×36-out, or ×9-in-to-×36-out data path configurations.

Flag logic includes EF/OR, FF/IR, HF, PAE, and PAF outputs, with PAE/PAF programmable via serial or parallel loading of offset registers. Timing mode (FWFT vs. standard) and flag latency (synchronous vs. asynchronous) are set at master reset using FWFT/SI and PFM pins, respectively - directly determining first-word access behavior and flag update edges.

Key Specifications

Pinout & Package

SN74V3690-15PEU 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 (not electrically connected). Pin numbering follows top-view orientation per TI SCAS668A datasheet Figure 2.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT72V3680L15PF and NB3N502DR2G, SN74V3690-15PEU uniquely delivers FWFT timing, zero-latency retransmit, and eight-programmable-flag-offset flexibility - making it irreplaceable in latency-critical video and telecom buffering where deterministic data delivery is mandatory.

Availability

SN74V3690-15PEU is available at Aetrix Electronics and suitable for network packet buffering, video frame synchronization, telecom line card data aggregation, and high-speed test equipment pattern memory requiring stable component supply and long-term obsolescence planning.

Supply support for SN74V3690-15PEU 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.

The SN74V3690-15PEU belongs to TI's high-speed synchronous FIFO product line, designed specifically for deterministic data buffering in multi-clock-domain systems such as networking infrastructure, broadcast video, and industrial automation controllers.

FAQ

What is the maximum operating frequency of the SN74V3690-15PEU?

The SN74V3690-15PEU supports up to 166 MHz for both read and write clocks, corresponding to a 6-ns read/write cycle time. This specification is guaranteed across the full commercial temperature range (0°C to +70°C) and requires compliance with setup/hold timing relative to WCLK and RCLK rising edges as defined in the SCAS668A datasheet.

Does the SN74V3690-15PEU support depth expansion using daisy-chained configuration?

Yes, the SN74V3690-15PEU supports depth expansion in First-Word Fall-Through (FWFT) mode: the Q outputs of one device connect directly to the D inputs of the next, with no external logic required. Standard mode does not support this chaining due to read-enable dependency for first-word access.

How is the bus width configured on the SN74V3690-15PEU?

Bus width is configured at master reset using the BM, IW, and OW pins per Table 1 in the SCAS668A datasheet. Valid combinations include ×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 - all determined solely by static logic levels during MRS assertion.

Can the SN74V3690-15PEU operate with different read and write clock frequencies?

Yes, the SN74V3690-15PEU permits fully independent RCLK and WCLK frequencies from DC to 166 MHz, with no phase or frequency relationship required. This enables robust bridging between unrelated clock domains, such as 100-MHz processor buses and 125-MHz network interfaces.

What is the function of the RM pin on the SN74V3690-15PEU?

The RM (Retransmit Latency Mode) pin selects zero-latency or normal-latency retransmit behavior during master reset. A low RM enables zero-latency mode: the first retransmitted word appears on Qn at the same RCLK edge that samples RT low - critical for minimizing recovery time in protocol error handling.