Texas Instruments SN74V3650-6PEU

Overview

SN74V3650 from Texas Instruments is a 2048 × 36-bit, 3.3-V CMOS synchronous FIFO memory with independent read/write clocks, user-selectable ×36/×18/×9 bus matching, and 166-MHz operation (6-ns read/write cycle time). It serves as a high-speed data buffer in network packet alignment, video frame rate conversion, and telecom line-card buffering where depth, low latency, and flexible port sizing are critical.

For engineers reviewing the SN74V3650 datasheet, SN74V3650 pinout, SN74V3650 application, or SN74V3650 equivalent, key selection criteria include its fixed first-word latency, zero-latency retransmit capability, programmable almost-empty/almost-full flags with eight default offsets, and 5-V-tolerant inputs for mixed-voltage system interfacing.

Technical Context

This FIFO implements dual-clock architecture with fully asynchronous RCLK and WCLK domains-each operable from DC to 166 MHz-with no frequency ratio constraints. Its internal RAM array supports configurable bus widths via BM/IW/OW control pins during master reset, enabling ×36-to-×36, ×36-to-×18, ×36-to-×9, ×18-to-×36, or ×9-to-×36 data path mapping.

Timing behavior is determined by FWFT/SI state at master reset: standard mode requires REN assertion for all reads including first word; FWFT mode delivers first word after three RCLK edges without REN. PAE/PAF flag timing (synchronous vs. asynchronous) and retransmit latency (zero vs. normal) are configured via PFM and RM pins during the same reset cycle.

Key Specifications

Pinout & Package

SN74V3650 is housed in a 128-pin Thin Quad Flat Pack (TQFP) package with 0.4-mm lead pitch and exposed thermal pad. Pin functions are validated per TI SCAS668A datasheet (Rev. March 2003), with all I/O assigned per terminal function table and top-view pinout diagram.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT72V3650 and NB3N3020B, SN74V3650 uniquely combines deep 2048-word storage, true dual-clock independence, ×36/×18/×9 bus matching, and zero-latency retransmit-making it optimal for high-jitter, asymmetric-data-path applications where deterministic latency and configurability are mandatory.

Availability

SN74V3650 is available at Aetrix Electronics and suitable for network packet buffering, video frame rate conversion, telecom line-card interfacing, DSP-to-MCU bridging, and industrial protocol gateways requiring stable component supply across extended production lifecycles.

Supply support for SN74V3650 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.

SN74V3650 belongs to TI's high-performance FIFO memory product line, designed specifically for demanding data buffering in telecommunications infrastructure, broadcast video systems, and real-time embedded networking equipment.

FAQ

What is the maximum operating frequency of the SN74V3650?

The SN74V3650 supports up to 166 MHz on both WCLK and RCLK inputs, delivering a 6-ns read/write cycle time. This specification is guaranteed over the commercial temperature range (0°C to 70°C) and applies independently to each clock domain-no frequency ratio constraints exist between WCLK and RCLK. The SN74V3650 achieves this performance using high-speed submicron CMOS technology as documented in TI SCAS668A.

Does the SN74V3650 support bus width conversion between different data path sizes?

Yes, the SN74V3650 supports five bus-matching configurations via BM, IW, and OW pins during master reset: ×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. This eliminates external multiplexing logic when interfacing processors, FPGAs, or ASICs with mismatched parallel bus widths. The SN74V3650 maintains full functionality-including flag generation and endian control-in all modes.

How does the zero-latency retransmit feature work in the SN74V3650?

When RM is held low during master reset, the SN74V3650 enables zero-latency retransmit: asserting RT low on a rising RCLK edge causes the read pointer to reset to zero and the first word to appear on Qn within the same RCLK edge-no additional clock cycles required. This differs from normal-latency mode (RM = high), which inserts one-cycle delay. The SN74V3650 retains all other settings (mode, offsets, bus width) during retransmit.

Can the SN74V3650 be used in systems with mixed 3.3-V and 5-V logic levels?

Yes, the SN74V3650 features 5-V-tolerant control inputs (WEN, REN, OE, MRS, PRS, FWFT/SI, BM, IW, OW, LD, FSEL0/1, PFM, RM, IP), allowing direct connection to 5-V logic without level shifters. However, data I/O pins D0–D35 and Q0–Q35 operate strictly at 3.3-V LVTTL levels and are not 5-V tolerant. The SN74V3650 thus bridges voltage domains safely for control signaling while maintaining clean 3.3-V data paths.

What is the difference between master reset (MRS) and partial reset (PRS) in the SN74V3650?

Master reset (MRS) initializes read/write pointers, clears the output register, and reconfigures all programmable settings-including FWFT/standard mode, bus width, flag defaults, and timing modes-based on pin states at reset. Partial reset (PRS) only resets pointers and output register while preserving all configuration settings (mode, offsets, programming method, endian, etc.). The SN74V3650 uses PRS for runtime recovery without losing custom flag thresholds or bus-matching setup.