Renesas 72235LB10TFG8

Overview

IDT72235LB10TFG8 from Integrated Device Technology is a 2,048 × 18-bit synchronous FIFO memory IC with dual-clock operation, 10 ns read/write cycle time, programmable Almost-Empty/Almost-Full flags, and Half-Full flag capability-designed for high-speed data buffering in LAN controllers and interprocessor communication interfaces.

For engineers reviewing the IDT72235LB10TFG8 datasheet, IDT72235LB10TFG8 pinout, IDT72235LB10TFG8 application, or IDT72235LB10TFG8 equivalent, key selection criteria include its 2,048-word depth, 18-bit parallel I/O, industrial temperature range (–40°C to +85°C), TQFP-64 package, and dual-port zero fall-through time architecture.

Technical Context

This FIFO implements a dual-port, clocked RAM array with independent read and write pointer logic, offset register programming via LD/WEN/RCLK/REN control, and asynchronous flag generation (PAE, PAF, HF) synchronized to respective clocks. It supports both single-clock (RCLK = WCLK) and asynchronous dual-clock modes with skew tolerance up to 10 ns.

The device uses high-performance submicron CMOS technology, features output enable (OE) for three-state bus control, and includes dedicated expansion logic (WXI/WXO, RXI/RXO) enabling daisy-chain depth expansion. Reset (RS) initializes pointers and flags, while FL determines single-device vs. depth-expansion configuration.

Key Specifications

Pinout & Package

Package: 64-lead STQFP (Thin Quad Flatpack), order code TF, lead finish SnPb (EOL as of June 2018).

Key Features

Applications

Equivalent & Alternatives

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

Compared with 72235L10TF and 72235LB15TFG8, the IDT72235LB10TFG8 uniquely delivers industrial-temperature operation at 100 MHz performance-making it the only option among the three qualified for continuous use in harsh environments requiring maximum throughput.

Availability

IDT72235LB10TFG8 is available at Aetrix Electronics and suitable for LAN controllers, interprocessor communication links, optical disk interfaces, and legacy bus protocol bridges requiring stable component supply and long-term industrial-grade availability.

Supply support for IDT72235LB10TFG8 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

Integrated Device Technology (IDT), now part of Renesas Electronics, is a fabless semiconductor company specializing in timing, memory interface, RF, and high-performance data path solutions.

IDT72235LB10TFG8 belongs to the SyncFIFO™ family-designed specifically for deterministic, low-latency data buffering in high-speed digital systems where clock domain crossing and burst absorption are critical.

FAQ

What is the memory organization of the IDT72235LB10TFG8?

The IDT72235LB10TFG8 implements a 2,048 × 18-bit synchronous FIFO memory array. This means it stores up to 2,048 words, each 18 bits wide, providing 36,864 bits of total buffer capacity. The organization is fixed and cannot be reconfigured as 1,024 × 36 or other variants-the 18-bit width is inherent to the IDT72235LB10TFG8 silicon design.

Does the IDT72235LB10TFG8 support both single-clock and dual-clock operation?

Yes, the IDT72235LB10TFG8 supports both configurations. When RCLK and WCLK are tied together, it operates in single-clock mode with deterministic timing. When driven independently, it functions in asynchronous dual-clock mode-with tSKEW1 and tSKEW2 specifications ensuring reliable Full/Empty flag updates across clock domain boundaries. This flexibility is intrinsic to the IDT72235LB10TFG8 architecture.

What is the default offset value for the Programmable Almost-Empty Flag (PAE) in the IDT72235LB10TFG8?

The IDT72235LB10TFG8 defaults to a PAE offset of 127 words after reset. This means the PAE flag asserts LOW when 127 words remain before the FIFO becomes empty. The offset is stored in an internal 12-bit Empty Offset register and can be reprogrammed via the LD/WEN sequence using D0–D11 inputs-confirming this behavior is documented for IDT72235LB10TFG8 in the official datasheet.

Is the IDT72235LB10TFG8 RoHS-compliant or green-part qualified?

The IDT72235LB10TFG8 uses SnPb lead finish and was in End-of-Life (EOL) process as of June 15, 2018 per the datasheet. While "green parts" are noted as available for the family, the specific IDT72235LB10TFG8 variant (TF package, SnPb) is not RoHS-compliant. Customers requiring RoHS compliance should verify alternate suffixes or newer-generation replacements directly with Renesas.

How does the Half-Full flag (HF) function on the IDT72235LB10TFG8 in single-device mode?

In single-device mode (FL = GND, WXI = RXI = GND), the WXO/HF pin acts solely as a Half-Full flag. It asserts LOW when exactly 1,024 words (half of 2,048) are stored in the IDT72235LB10TFG8 FIFO. The flag remains LOW until the word count drops to ≤1,023, then resets HIGH on the next RCLK rising edge-providing a precise mid-buffer threshold for DMA or interrupt-driven data management.