Renesas 72255LA15PFG

Overview

IDT72255LA15PFG from Integrated Device Technology (IDT) is a high-speed, 8,192 × 18-bit synchronous CMOS FIFO memory with independent read/write clocks, 15 ns clock cycle time, fixed 8 ns access time, and industrial temperature support (–40°C to +85°C). It implements SuperSync architecture for low-latency data buffering in telecom and networking interfaces.

For engineers reviewing the IDT72255LA15PFG datasheet, IDT72255LA15PFG pinout, IDT72255LA15PFG application, or IDT72255LA15PFG equivalent, key selection criteria include FWFT/Standard timing mode configurability, programmable almost-empty/almost-full flag offsets, retransmit capability, auto power-down, and TQFP-64 packaging compatibility with depth/width expansion.

Technical Context

This FIFO eliminates inter-clock frequency constraints-RCLK and WCLK operate fully independently from DC to 66.7 MHz without requiring FS pin configuration. Its architecture features dual-register-buffered flags in IDT Standard mode and triple-buffered OR output in FWFT mode to ensure timing robustness across clock domain crossings.

The device integrates dedicated offset registers for PAE and PAF, supporting both serial (26-bit stream) and parallel loading via D0–D17. Retransmit (RT) resets only the read pointer while preserving write pointer state and flag configurations, enabling deterministic replay of buffered data without full reset.

Key Specifications

Pinout & Package

Package: 64-pin Thin Quad Flat Pack (TQFP), PN64 order code PF, 10 mm × 10 mm body, 0.5 mm pitch, lead-free (Green) option available.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT72255LA15PFG, the IDT72255LA20PFG trades 16.7 MHz bandwidth for reduced dynamic power and broader voltage tolerance, while the NB3N502DR2G lacks FWFT, retransmit, and programmable flags-making it unsuitable for telecom or real-time replay use cases.

Availability

IDT72255LA15PFG is available at Aetrix Electronics and suitable for telecom infrastructure, industrial protocol gateways, and video synchronization systems requiring stable component supply, long-lifecycle support, and industrial temperature qualification.

Supply support for IDT72255LA15PFG 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) was a fabless semiconductor company specializing in timing, memory interface, RF, and high-performance FIFO solutions before its acquisition by Renesas Electronics in 2019.

IDT72255LA15PFG belongs to the SuperSync FIFO family-designed specifically for high-throughput, low-latency data buffering in multi-clock-domain systems such as networking equipment, broadcast video, and test instrumentation.

FAQ

What is the maximum operating frequency of IDT72255LA15PFG?

IDT72255LA15PFG supports up to 66.7 MHz clock frequency on both RCLK and WCLK inputs, corresponding to a 15 ns clock cycle time. This specification is guaranteed across the full industrial temperature range (–40°C to +85°C) with VCC = 5.0 V ±10%. The device does not impose frequency ratio constraints between the two clocks, enabling truly asynchronous operation.

Does IDT72255LA15PFG support First Word Fall Through (FWFT) mode?

Yes, IDT72255LA15PFG supports FWFT mode, selected at Master Reset by asserting FWFT/SI HIGH. In this mode, the first word written to an empty FIFO appears on Q0–Q17 after exactly three RCLK rising edges-without requiring REN activation. Subsequent words still require REN assertion, and OR/IR flags replace EF/FF for status reporting.

How is the programmable Almost-Empty flag (PAE) configured on IDT72255LA15PFG?

PAE threshold is set to either 127 or 1,023 words via the LD pin state during Master Reset-LOW selects 127, HIGH selects 1,023. Alternatively, custom offsets can be loaded dynamically using serial (via SI pin and SEN) or parallel (via D0–D17) programming. The register retains its value through Partial Reset and operates independently of timing mode.

Can IDT72255LA15PFG be used in depth-expanded configurations?

Yes, IDT72255LA15PFG supports seamless depth expansion in FWFT mode by cascading multiple devices: Q0–Q17 of one unit connects directly to D0–D17 of the next, with shared RCLK and WCLK. No external logic is needed because FWFT ensures continuous data flow across boundaries-enabling effective 16K×18, 24K×18, or larger buffers.

What is the purpose of the Retransmit (RT) function in IDT72255LA15PFG?

The Retransmit (RT) function resets only the read pointer to zero on the rising edge of RCLK, allowing the same data sequence to be read again from the beginning of the FIFO. Unlike Master Reset, RT preserves write pointer position, flag states, timing mode, and programmable offset settings-making it ideal for packet replay, error recovery, or diagnostic data looping without disrupting ongoing write operations.