Texas Instruments SN74V235-10PAG

Overview

SN74V235-10PAG from Texas Instruments is a 2048 × 18-bit synchronous first-in, first-out (FIFO) memory IC designed for high-speed DSP-to-processor and DSP-to-analog front-end buffering. It delivers 7.5-ns read/write cycle time, 3.3-V V_CC with 5-V input tolerance, and supports both standard and first-word fall-through (FWFT) timing modes in industrial temperature range (0°C to 70°C).

For engineers reviewing the SN74V235-10PAG datasheet, SN74V235-10PAG pinout, SN74V235-10PAG application, or SN74V235-10PAG equivalent, key selection criteria include its dual-clock asynchronous/synchronous operation, programmable almost-empty/almost-full flags with default offsets of 127, half-full flag capability, and 64-pin TQFP package compatibility with TI TMS320 DSP glueless interfacing.

Technical Context

This FIFO employs independent synchronous read and write ports gated on low-to-high clock transitions, with RCLK and WCLK supporting coincident or fully asynchronous operation. Its internal architecture includes dual 12-bit offset registers for PAE/PAF configuration, dedicated read/write pointers, and expansion logic enabling depth expansion via daisy-chained XI/XO pins.

Flag behavior is mode-dependent: FWFT mode activates output-ready (OR) after three RCLK edges without REN assertion, while standard mode requires explicit REN activation for first-word access. EF/OR and FF/IR are synchronous, updated on RCLK/WCLK rising edges respectively; HF, PAE, and PAF support configurable synchronous/asynchronous update based on FL/RXI/WXI states.

Key Specifications

Pinout & Package

Packaged in a 64-pin thin quad flat package (TQFP), the SN74V235-10PAG features 18-bit bidirectional data paths (D0–D17, Q0–Q17), dual independent clocks (RCLK, WCLK), and dedicated flag/control pins including EF/OR, FF/IR, PAE, PAF, HF/WXO, RS, LD, OE, REN, WEN, FL, RXI, RXO, WXI, and WXO/HF.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT72V2105L10PF and ICS650G-01LFT, the SN74V235-10PAG uniquely combines 5-V input tolerance with FWFT timing and user-programmable flag offsets-enabling robust glueless integration into mixed-voltage DSP systems without external logic or timing calibration.

Availability

SN74V235-10PAG is available at Aetrix Electronics and suitable for DSP interface design, real-time data acquisition, and industrial communications requiring stable component supply across extended production lifecycles.

Supply support for SN74V235-10PAG 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.

The SN74V235-10PAG belongs to the DSP-SYNC™ family of high-speed synchronous FIFOs, engineered specifically to provide glueless, low-latency buffering between TI TMS320 DSPs and peripheral subsystems such as AFEs, microprocessors, and network interfaces.

FAQ

What is the memory organization of the SN74V235-10PAG?

The SN74V235-10PAG implements a 2048 × 18-bit synchronous FIFO memory array, providing 36,864 bits of buffer storage. This organization supports 18-bit parallel data paths for both input (D0–D17) and output (Q0–Q17), making it ideal for wide-data applications like DSP-to-processor communication and video line buffering. The SN74V235-10PAG is part of the SN74V2xx series, where the '235' explicitly denotes the 2048-word depth.

Does the SN74V235-10PAG support both standard and first-word fall-through (FWFT) timing modes?

Yes, the SN74V235-10PAG supports both timing modes, selected at reset via FL, RXI, and WXI pin states. In FWFT mode, the first word written to an empty FIFO appears on Q0–Q17 after three RCLK transitions without requiring REN assertion-reducing initial read latency. In standard mode, REN must be asserted for every read, including the first word. The SN74V235-10PAG's dual-mode capability makes it adaptable to both latency-critical and deterministic timing applications.

What are the default offset values for the programmable almost-empty (PAE) and almost-full (PAF) flags in the SN74V235-10PAG?

The SN74V235-10PAG defaults to 127-word offsets for both PAE and PAF flags-meaning PAE asserts low when ≤127 words remain, and PAF asserts low when ≥127 words are unused. These values are stored in internal 12-bit offset registers and can be reprogrammed via the LD/WEN sequence using D0–D11. The SN74V235-10PAG shares this default with SN74V225 and SN74V245, distinguishing it from SN74V215 (63-word default).

How does the SN74V235-10PAG handle power supply and I/O voltage compatibility?

The SN74V235-10PAG operates from a 3.3-V V_CC supply but features 5-V tolerant inputs on all control and data pins (D0–D17, REN, WEN, etc.), eliminating the need for external level shifters when interfacing with 5-V microcontrollers or legacy logic. Outputs are 3.3-V CMOS compatible. This dual-voltage capability is intrinsic to the SN74V235-10PAG's design and is confirmed in the SCAS636E datasheet revision September 2002.

Can multiple SN74V235-10PAG devices be cascaded to increase FIFO depth?

Yes, the SN74V235-10PAG supports daisy-chain depth expansion using WXI/WXO and RXI/RXO pins. In this configuration, FL is grounded on the first device and pulled high on subsequent devices. The SN74V235-10PAG's expansion logic automatically coordinates read/write pointers across the chain, enabling seamless scaling to 4096, 6144, or greater word depths without external address decoding or glue logic.