Texas Instruments SN74V235-15PAG

Overview

SN74V235-15PAG from Texas Instruments is a 2048 × 18-bit synchronous FIFO memory IC with 7.5-ns read/write cycle time, 3.3-V V_CC, and 5-V input-tolerant I/O. It supports both first-word fall-through (FWFT) and standard timing modes, features programmable almost-empty/almost-full flags, and is optimized for DSP-to-processor and DSP-to-AFE buffering in high-speed digital signal processing systems.

For engineers reviewing the SN74V235-15PAG datasheet, SN74V235-15PAG pinout, SN74V235-15PAG application, or SN74V235-15PAG equivalent, key selection considerations include its 2048-word depth, dual-clock asynchronous/synchronous operation, 64-pin TQFP package, FWFT mode latency behavior, and TI TMS320 DSP glueless interface capability.

Technical Context

This is a synchronous, clocked FIFO with independent read and write ports, each gated to the low-to-high transition of continuous free-running clocks (RCLK/WCLK). All flag outputs - EF/OR, FF/IR, PAE, PAF, HF - are synchronous and updated on respective clock edges, with configurable timing modes determined at reset via FL/RXI/WXI pin states.

The device implements a 2048 × 18-bit SRAM array with dual-register buffering for empty/full flags, programmable offset registers (12-bit), and expansion logic supporting daisy-chain depth expansion or width expansion. It uses high-performance submicron CMOS and operates over 0°C to 70°C.

Key Specifications

Pinout & Package

Packaged in a 64-pin thin quad flat package (TQFP), the SN74V235-15PAG provides full 18-bit bidirectional data paths (D0–D17, Q0–Q17), dual independent clocks (WCLK, RCLK), enable controls (WEN, REN, OE), flag outputs (EF/OR, FF/IR, PAE, PAF, WXO/HF, RXO), configuration pins (FL, LD, RS, WXI, RXI), and distributed power/ground (5× V_CC, 7× GND).

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT72V2105L15PF and NB3N204, the SN74V235-15PAG uniquely delivers FWFT timing, 5-V-tolerant I/O, and user-programmable flag offsets - making it optimal for TI DSP-centric designs demanding minimal latency and flexible flow control without external logic.

Availability

SN74V235-15PAG is available at Aetrix Electronics and suitable for DSP interface design, real-time signal processing, and high-speed data buffering applications requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for SN74V235-15PAG 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 digital signal processing technologies, with decades of leadership in high-performance timing and interface solutions.

The SN74V235-15PAG belongs to TI's DSP-SYNC™ FIFO family, designed specifically to eliminate glue logic between TMS320 DSPs and peripheral subsystems while delivering deterministic, low-latency data buffering in demanding real-time applications.

FAQ

What is the memory organization and total capacity of the SN74V235-15PAG?

The SN74V235-15PAG implements a 2048 × 18-bit synchronous FIFO memory array, providing 36,864 bits (2048 words × 18 bits) of buffer storage. This capacity supports full-line buffering for HD video pixels, multi-channel audio sample streams, or burst-mode packet payloads in communications systems - all with deterministic read/write timing governed by WCLK and RCLK.

Does the SN74V235-15PAG support both FWFT and standard timing modes, and how is the mode selected?

Yes, the SN74V235-15PAG supports both first-word fall-through (FWFT) and standard timing modes. Mode selection occurs during power-up reset (RS) based on the logic states of FL, RXI, and WXI pins per Table 5 in the datasheet. FWFT mode enables immediate data visibility on Q outputs after three RCLK transitions, while standard mode requires explicit REN assertion for every read - giving designers flexibility for latency-sensitive or protocol-constrained applications.

What are the default offset values for the programmable almost-empty and almost-full flags in the SN74V235-15PAG?

The SN74V235-15PAG defaults to an empty offset of 127 and a full offset of 127 - meaning PAE asserts when ≤127 words remain, and PAF asserts when ≥1921 words are stored (2048 − 127). These 12-bit offsets are loaded via the LD pin and D0–D11 inputs, and can be reprogrammed dynamically during operation to adapt to varying buffer management policies in the SN74V235-15PAG.

Can the SN74V235-15PAG be used in depth-expansion configurations, and what pins enable this?

Yes, the SN74V235-15PAG supports daisy-chain depth expansion using WXI/WXO and RXI/RXO pins. In expansion mode, FL is grounded on the first device and high on subsequent devices. WXO pulses on last write, driving WXI of the next device; similarly, RXO pulses on last read to drive RXI. This allows stacking multiple SN74V235-15PAG units to achieve >2048-word depth without external control logic.

Is the SN74V235-15PAG compatible with 5-V logic systems despite its 3.3-V supply?

Yes, the SN74V235-15PAG features 5-V input-tolerant I/O on all control and data pins (D0–D17, WEN, REN, OE, RS, LD, FL, WXI, RXI, etc.), allowing direct connection to 5-V TTL/CMOS sources without level shifters. Its V_CC remains at 3.3 V, ensuring low-power operation while maintaining interoperability with legacy 5-V peripherals - a key advantage in mixed-voltage DSP subsystems using the SN74V235-15PAG.