Texas Instruments SN74V3670-6PEU

Overview

SN74V3670 from Texas Instruments is a 8192 × 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 - deployed in high-throughput network buffering and video data alignment applications.

For engineers reviewing the SN74V3670 datasheet, SN74V3670 pinout, SN74V3670 application, or SN74V3670 equivalent, key selection criteria include its 166-MHz operation (6-ns cycle time), zero-latency retransmit capability, programmable almost-empty/almost-full flags, 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 WCLK and RCLK domains (0–166 MHz), enabling simultaneous write/read operations without clock domain crossing logic. Its RAM array supports flexible bus-width configuration via BM/IW/OW 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 flow paths.

Flag logic includes EF/OR, FF/IR, HF, PAE, and PAF outputs - with PAE/PAF programmable via serial or parallel loading of 8-bit offset registers. Timing mode (FWFT vs. standard) and flag synchronization (synchronous/asynchronous) are configured at master reset using FWFT/SI and PFM pins, directly determining first-word latency and flag update behavior.

Key Specifications

Pinout & Package

SN74V3670 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 industrial operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT72V3680 and NB3N502, SN74V3670 uniquely delivers full 8192-word depth with zero-latency retransmit, dual-mode flags (EF/OR, FF/IR), and synchronized/asynchronous flag timing selection - making it optimal for deterministic real-time buffering where latency predictability and configurability are critical.

Availability

SN74V3670 is available at Aetrix Electronics and suitable for network packet buffering, video frame alignment, telecom line card buffering, DSP data pipeline interfaces, and high-speed bus bridging applications requiring stable component supply and long-term industrial lifecycle support.

Supply support for SN74V3670 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-performance memory and interface ICs.

SN74V3670 belongs to TI's high-speed synchronous FIFO product line, engineered for deterministic data buffering in telecom infrastructure, broadcast video, and industrial real-time systems where clock domain isolation and programmable flow control are essential.

FAQ

What is the maximum operating frequency of the SN74V3670?

The SN74V3670 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 industrial temperature range (0°C to 70°C) and 3.3-V ±0.3-V supply. The device maintains timing integrity even with asynchronous WCLK and RCLK frequencies - no ratio constraints apply. SN74V3670 achieves this performance using submicron CMOS process technology optimized for low skew and high-speed register-to-register transfer.

Does the SN74V3670 support 5-V logic inputs?

Yes, the SN74V3670 features 5-V-tolerant inputs on all control and data pins (D0–D35, WEN, REN, MRS, PRS, etc.), allowing direct interfacing with 5-V microcontrollers, FPGAs, or legacy logic without level-shifting circuitry. This tolerance applies regardless of VCC being 3.3 V. However, output pins Q0–Q35 are not 5-V tolerant and must connect only to 3.3-V–compatible receivers. SN74V3670 maintains full functionality and timing compliance under 5-V input conditions per TI SCAS668A datasheet Section 6.1.

How does the first-word fall-through (FWFT) mode work in the SN74V3670?

In FWFT mode, the first word written to an empty SN74V3670 appears on Q0–Q35 after exactly three rising edges of RCLK - no REN assertion required. Subsequent words still require REN = low. This mode is selected by holding FWFT/SI high during master reset. The SN74V3670 uses OR (output ready) instead of EF and IR (input ready) instead of FF in FWFT mode. FWFT enables immediate data availability in streaming applications like video frame capture, eliminating initial read-enable latency that would otherwise stall the pipeline.

Can the SN74V3670 be expanded in depth or width?

Yes, the SN74V3670 supports both depth and width expansion without external logic. For depth expansion, multiple SN74V3670 devices can be chained in series using FWFT mode: Qn of one device connects directly to Dn of the next, with shared RCLK/WCLK and synchronized flag propagation. For width expansion, parallel SN74V3670 units operate with common clocks and enable signals, while data buses are concatenated. The 128-pin TQFP package and consistent pinout across the SN74V36xx family simplify board-level scalability. SN74V3670's architecture explicitly supports these configurations per TI SCAS668A Section 1.4.

What is the difference between master reset (MRS) and partial reset (PRS) on the SN74V3670?

Master reset (MRS) initializes all internal state: read/write pointers go to zero, output register clears to all zeros, and all configuration pins (FWFT/SI, BM, IW, OW, BE, RM, PFM, IP, FSEL0/FSEL1, LD) are sampled to set timing mode, bus width, endianness, retransmit latency, flag timing, parity mode, and default flag offsets. Partial reset (PRS) only resets read/write pointers and output register - all configuration settings, flag offsets, and programming method (serial/parallel) remain unchanged. SN74V3670 uses PRS for mid-operation recovery without disrupting established buffer thresholds or timing behavior.