Renesas 72255LA15TF

Overview

IDT72255LA15TF 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 IDT72255LA15TF datasheet, IDT72255LA15TF pinout, IDT72255LA15TF application, or IDT72255LA15TF equivalent, key selection criteria include FWFT/Standard timing mode configurability, programmable almost-empty/almost-full flag offsets, retransmit capability, auto power-down behavior, and TQFP-64 packaging compatibility with depth/width expansion support.

Technical Context

The IDT72255LA15TF uses a dual-clock, fully asynchronous read/write architecture with no frequency ratio constraints between RCLK and WCLK - eliminating the FS pin required in earlier SuperSync FIFOs. Its internal RAM array is paired with separate input/output registers and dedicated flag logic for EF/OR, FF/IR, HF, PAE, and PAF.

It supports two mutually exclusive timing modes selected at Master Reset via FWFT/SI: IDT Standard mode (EF/FF flags, REN-gated reads) and First Word Fall Through (FWFT) mode (OR/IR flags, immediate first-word output after three RCLK edges). Flag offset registers are programmable via serial (26-bit) or parallel load, with default values of 127 (parallel) or 1,023 (serial).

Key Specifications

Pinout & Package

Package: 64-pin Slim Thin Quad Flat Pack (STQFP), order code TF, 10 mm × 10 mm body, 0.5 mm pitch, lead-free (RoHS-compliant) finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT72255LA15PF, the IDT72255LA15TF offers identical functionality in a lower-profile package; compared with NB3N502DG, it adds FWFT latency reduction, retransmit capability, and field-programmable flag thresholds - essential for high-performance, protocol-aware buffering.

Availability

IDT72255LA15TF is available at Aetrix Electronics and suitable for telecom infrastructure, broadcast video equipment, industrial Ethernet gateways, and medical imaging systems requiring stable component supply across extended product lifecycles.

Supply support for IDT72255LA15TF 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) is a fabless semiconductor company specializing in timing, memory interface, RF, and high-performance FIFO solutions for communications and computing markets.

IDT72255LA15TF belongs to the SuperSync FIFO family, engineered specifically for high-throughput, low-latency data buffering in multi-clock-domain systems such as telecom switches, video routers, and real-time industrial controllers.

FAQ

What is the maximum operating frequency of the IDT72255LA15TF?

The IDT72255LA15TF supports up to 66.7 MHz on both RCLK and WCLK simultaneously, derived from its 15 ns clock cycle time specification. This frequency is guaranteed across the full industrial temperature range (–40°C to +85°C) with VCC = 5V ±10%. No clock ratio constraints apply - RCLK and WCLK may run at identical, harmonically related, or completely independent frequencies.

Does the IDT72255LA15TF support both IDT Standard and FWFT timing modes?

Yes, the IDT72255LA15TF supports both timing modes. The mode is selected during Master Reset (MRS) based on the logic level of the FWFT/SI pin: LOW selects IDT Standard mode (EF/FF flags, REN-gated reads), HIGH selects FWFT mode (OR/IR flags, first-word output after three RCLK edges). Mode selection is latched and remains active until next MRS.

How is the programmable almost-empty (PAE) flag configured on the IDT72255LA15TF?

The PAE flag threshold is set via an 18-bit empty offset register. At Master Reset, LD pin state selects default: LD = LOW → 127-word offset; LD = HIGH → 1,023-word offset. Full 18-bit values can be loaded later via parallel (using D0–D17 and WEN/LD) or serial (26-bit shift-in via SI, SEN, WCLK) methods - both supported on IDT72255LA15TF.

Can the IDT72255LA15TF be used in depth-expanded configurations?

Yes, the IDT72255LA15TF supports seamless depth expansion in FWFT mode by connecting Q0–Q17 outputs of one device directly to D0–D17 inputs of the next. No external logic or timing compensation is required - the architecture inherently propagates OR/IR handshaking and maintains fixed latency across chained devices.

What is the function of the RT (Retransmit) pin on the IDT72255LA15TF?

The RT pin initiates a retransmit operation: when asserted LOW on a rising RCLK edge, it resets the read pointer to zero while preserving the write pointer and all flag offset settings. This allows rereading the oldest data word without clearing the FIFO or disrupting ongoing write operations - critical for packet retry protocols and diagnostic replay.