Renesas 72255LA20PFI

Overview

IDT72255LA20PFI from Integrated Device Technology is a high-speed, 8,192 × 18-bit synchronous CMOS FIFO memory with independent read/write clocks, 10 ns clock cycle time, fixed low-latency first-word access, and programmable almost-empty/almost-full flags. It operates across –40°C to +85°C and is used in telecom data buffering where deterministic latency and depth expansion are critical.

For engineers reviewing the IDT72255LA20PFI datasheet, IDT72255LA20PFI pinout, IDT72255LA20PFI application, or IDT72255LA20PFI equivalent, key selection criteria include FWFT/IDT Standard timing mode selection, 18-bit bidirectional data width, TQFP-64 packaging, industrial temperature support, and retransmit functionality for packet replay in networking systems.

Technical Context

This FIFO eliminates inter-clock frequency constraints-RCLK and WCLK operate fully independently (0–100 MHz), with no FS pin required. Its architecture features dual-register-buffered EF/FF in IDT Standard mode and triple-buffered OR/IR in FWFT mode, enabling deterministic flag timing.

The device integrates input/output registers, RAM array, flag logic, and offset registers for PAE/PAF. Retransmit (RT) resets the read pointer without disturbing write state or programmable settings, while auto power-down reduces ICC2 to 20 mA during idle cycles.

Key Specifications

Pinout & Package

Package: 64-pin Thin Quad Flat Pack (TQFP), order code PF, lead-free (green) variant per ordering information.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT72255LA20PFI, the IDT72255LA15PFI trades 33% bandwidth for lower cost and identical compatibility, while the NB3N502DG sacrifices depth, voltage flexibility, and FWFT/retransmit features for compactness and 3.3 V integration-neither is pin- or functionally equivalent.

Availability

IDT72255LA20PFI is available at Aetrix Electronics and suitable for telecom infrastructure, industrial protocol gateways, video synchronization systems, and test equipment requiring stable component supply across extended product lifecycles.

Supply support for IDT72255LA20PFI 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, designs high-performance timing, memory interface, and RF solutions for communications and computing markets.

IDT72255LA20PFI belongs to the SuperSync FIFO™ family, engineered specifically for deterministic, deep-buffer data flow control in multi-clock-domain systems such as networking switches and broadcast video infrastructure.

FAQ

What is the maximum operating frequency of the IDT72255LA20PFI?

The IDT72255LA20PFI supports a maximum clock cycle time of 10 ns, corresponding to a 100 MHz operational frequency for both RCLK and WCLK. This is confirmed in the AC Electrical Characteristics table under fS parameter, with no inter-clock frequency dependency-each clock may run independently up to 100 MHz. The IDT72255LA20PFI achieves this using high-speed submicron CMOS technology and optimized internal register staging.

Does the IDT72255LA20PFI support both IDT Standard and FWFT timing modes?

Yes, the IDT72255LA20PFI supports both timing modes. The mode is selected at Master Reset via the FWFT/SI pin state: LOW selects IDT Standard (using EF/FF flags), HIGH selects First Word Fall Through (using OR/IR flags). Both modes are fully supported in the IDT72255LA20PFI silicon, with distinct flag buffering (dual for EF/FF, triple for OR/IR) and documented timing diagrams for each.

How is the retransmit (RT) function implemented in the IDT72255LA20PFI?

The IDT72255LA20PFI implements retransmit by asserting RT LOW on a rising RCLK edge, which resets the read pointer to zero while preserving the write pointer, timing mode, and all programmable flag settings. This allows immediate rereading of the FIFO's first word without clearing data or altering configuration-critical for packet replay in telecom and test applications. RT does not affect WCLK or write operations.

What are the default programmable flag offset values for the IDT72255LA20PFI?

The IDT72255LA20PFI defaults to PAE = 127 and PAF = 127 when LD is LOW at Master Reset (parallel programming mode), or PAE = 1023 and PAF = 1023 when LD is HIGH (serial programming mode). These values are stored in dedicated offset registers and can be overwritten via serial or parallel programming after reset-no factory fuse or OTP involvement.

Is the IDT72255LA20PFI available in a lead-free package?

Yes, the IDT72255LA20PFI is offered in a green (lead-free) version per the ordering information in the datasheet. The "PFI" suffix denotes industrial temperature range and Pb-free finish. SnPb lead finish was discontinued with Last Time Buy expiring June 15, 2018, confirming that current production IDT72255LA20PFI units are RoHS-compliant and halogen-free.