Renesas 72235LB15PFGI

Overview

IDT72235LB15PFGI 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 industrial temperature support (–40°C to +85°C). It serves as a high-speed data buffer in optical disk controllers, LAN interfaces, and interprocessor communication systems requiring deterministic latency and depth-expandable buffering.

For engineers reviewing the IDT72235LB15PFGI datasheet, IDT72235LB15PFGI pinout, IDT72235LB15PFGI application, or IDT72235LB15PFGI equivalent, key selection considerations include its 2,048-word depth, 18-bit bus width, TQFP-64 package, 5 V supply compatibility, and dual-port zero fall-through architecture - all critical for clock domain bridging and burst-mode data staging.

Technical Context

This device implements a dual-port, clocked FIFO architecture with independent read and write pointers synchronized to RCLK and WCLK respectively. It supports both asynchronous (dual-clock) and coincident (single-clock) operation modes, with flag logic fully synchronized to their respective clocks: EF and HF to RCLK, FF and PAF to WCLK.

The FIFO includes dedicated offset registers for PAE/PAF configuration, loaded via LD/WEN/RCLK sequences, and supports depth expansion via daisy-chained WXO/WXI and RXO/RXI signals. Its submicron CMOS process enables 100 MHz maximum clock frequency (tCLK = 10 ns) with low active current (ICC1 ≤ 60 mA) and 5 mA standby draw.

Key Specifications

Pinout & Package

Package: 64-lead thin quad flatpack (TQFP), Pb-free (RoHS-compliant), body size 10 mm × 10 mm × 1.4 mm.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 72235L15TF8 and 72235LB15JG, IDT72235LB15PFGI offers optimal balance of compact TQFP packaging, industrial temperature rating, and drop-in compatibility with existing 5 V system designs - making it preferred for space-constrained, high-reliability embedded deployments.

Availability

IDT72235LB15PFGI is available at Aetrix Electronics and suitable for optical disk controllers, LAN interface modules, and interprocessor communication links requiring stable component supply and long-term industrial lifecycle support.

Supply support for IDT72235LB15PFGI 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, and high-performance interconnect solutions.

IDT72235LB15PFGI belongs to the SyncFIFO™ family - designed specifically for deterministic, low-latency data buffering in mixed-clock-domain systems such as storage controllers, networking equipment, and real-time industrial controllers.

FAQ

What is the memory organization and maximum operating frequency of IDT72235LB15PFGI?

IDT72235LB15PFGI features a 2,048 × 18-bit synchronous FIFO memory array, supporting up to 100 MHz operation (10 ns cycle time). This configuration delivers 36,864 bits of deterministic buffering with zero fall-through latency, optimized for high-speed data staging between asynchronous subsystems. The IDT72235LB15PFGI maintains full functionality across its industrial temperature range (–40°C to +85°C) without derating.

How does the programmable Almost-Empty and Almost-Full flag logic work in IDT72235LB15PFGI?

IDT72235LB15PFGI implements asynchronous PAE and PAF flags with default offsets of 127 words from empty/full states. These offsets are stored in dedicated 12-bit registers and can be reprogrammed via LD/WEN/RCLK sequences. PAE asserts LOW when (write pointer − read pointer) ≤ offset + 1; PAF asserts LOW when (write pointer − read pointer) ≥ depth − offset. The IDT72235LB15PFGI guarantees tPAE/tPAF ≤ 26 ns for 25 ns speed grade parts.

Can IDT72235LB15PFGI operate in single-clock mode, and what are the requirements?

Yes, IDT72235LB15PFGI supports single-clock operation by tying WCLK and RCLK together. In this mode, read and write operations share the same clock edge, eliminating skew concerns. WEN and REN must remain independently controlled to prevent bus contention. The IDT72235LB15PFGI retains full flag functionality and timing compliance (tSKEW1/tSKEW2 not applicable) in single-clock configuration.

What is the purpose of the FL, WXI, and RXI pins on IDT72235LB15PFGI, and how should they be configured?

In single-device mode, FL, WXI, and RXI must all be grounded - this disables depth expansion and enables HF flag functionality. For daisy-chain expansion, FL is grounded only on the first device; WXI connects to WXO of the prior device, and RXI connects to RXO of the prior device. The IDT72235LB15PFGI's expansion logic automatically handles pointer coordination across chained devices without external control logic.

Does IDT72235LB15PFGI support 3.3 V operation, or is it strictly 5 V compatible?

IDT72235LB15PFGI is specified for 4.5 V to 5.5 V operation only and is not 3.3 V tolerant. Its input thresholds (VIH = 2.0 V min, VIL = 0.8 V max) and output drive levels (VOH ≥ 2.4 V, VOL ≤ 0.4 V) align with 5 V TTL/CMOS logic families. Interfacing with 3.3 V systems requires level-shifting circuitry. The IDT72235LB15PFGI does not support mixed-voltage I/O or internal voltage regulation.