Renesas 72235LB10JG

Overview

IDT72235LB10JG from Integrated Device Technology is a 2,048 × 18-bit synchronous FIFO memory IC with dual-clock operation, 10 ns read/write cycle time, and industrial temperature range (–40°C to +85°C). It features programmable Almost-Empty/Almost-Full flags, Half-Full flag, and depth/width expandability-used in LAN controllers, interprocessor communication, and optical disk interfaces.

For engineers reviewing the IDT72235LB10JG datasheet, IDT72235LB10JG pinout, IDT72235LB10JG application, or IDT72235LB10JG equivalent, key selection considerations include its 2,048-word depth, 18-bit bus width, 5 V supply, TQFP-64 package, and dual-port zero fall-through architecture supporting asynchronous clock domains.

Technical Context

This FIFO implements a dual-port, zero fall-through time architecture with independent read and write pointer logic, offset register programming via LD/WEN/REN control, and synchronized status flags (EF/FF) tied to respective clocks. Its expansion logic supports daisy-chained depth scaling using WXI/WXO and RXI/RXO pins.

The device uses high-speed submicron CMOS technology and supports both single-clock (RCLK = WCLK) and dual-clock (asynchronous RCLK/WCLK) operation. Programmable flags (PAE/PAF) default to 127-word offsets, and HF operates as a half-full indicator in single-device mode or expansion pulse generator in daisy-chain mode.

Key Specifications

Pinout & Package

Package: 64-lead thin quad flatpack (TQFP), order code PF, JEDEC MS-026AC, 10 mm × 10 mm body, 0.5 mm lead pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 72235L10JG, IDT72235LB10JG adds guaranteed operation at –40°C to +85°C and tighter AC specs; compared with 72235LB15JG, it delivers 50% higher throughput at the cost of slightly higher power and stricter layout requirements.

Availability

IDT72235LB10JG is available at Aetrix Electronics and suitable for LAN controllers, interprocessor communication links, optical disk interfaces, and digital signal processing pipelines requiring stable component supply across extended temperature ranges.

Supply support for IDT72235LB10JG 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 interconnect solutions.

IDT72235LB10JG belongs to the SyncFIFO™ family-designed specifically for high-speed, low-latency data buffering in communications, storage, and embedded control systems requiring deterministic clock-domain bridging.

FAQ

What is the memory capacity and data width of IDT72235LB10JG?

IDT72235LB10JG provides 2,048 words of storage, each word being 18 bits wide, for a total capacity of 36,864 bits. This configuration supports high-bandwidth data staging in applications such as network controllers and DSP interfaces where wide parallel buses reduce transaction overhead.

Does IDT72235LB10JG support both single-clock and dual-clock operation?

Yes, IDT72235LB10JG supports both configurations: RCLK and WCLK may be tied together for single-clock use, or run asynchronously for clock-domain isolation. The device's flag synchronization (EF to RCLK, FF to WCLK) ensures reliable status reporting regardless of clock relationship.

What is the default offset value for the Programmable Almost-Empty Flag (PAE) in IDT72235LB10JG?

The default PAE offset for IDT72235LB10JG is 127 words from empty, consistent with its 2,048-word depth and the IDT72225LB/72235LB/72245LB family specification. This value is loaded into the Empty Offset register at reset and can be reprogrammed via the LD/WEN interface.

How is depth expansion implemented using IDT72235LB10JG in a daisy-chain configuration?

Depth expansion uses WXO/WXI and RXO/RXI pins: WXO of one device connects to WXI of the next, and RXO to RXI. FL is grounded on the first device and pulled HIGH on subsequent devices. This enables cascaded FIFOs to behave as a single deeper buffer without external address logic.

Is IDT72235LB10JG compatible with 3.3 V logic systems?

No, IDT72235LB10JG is a 5 V-only device with VCC specified from 4.5 V to 5.5 V and input voltage thresholds (VIH = 2.0 V, VIL = 0.8 V) aligned to TTL/5 V CMOS levels. Interfacing with 3.3 V systems requires level-shifting circuitry on all I/O lines.