Renesas 72255LA15TFI8

Overview

IDT72255LA15TFI8 from Integrated Device Technology 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 range (–40°C to +85°C). It supports both IDT Standard and First Word Fall Through (FWFT) timing modes and is used in telecom data buffering, video streaming interfaces, and network packet aggregation where deterministic latency and depth expansion are critical.

For engineers reviewing the IDT72255LA15TFI8 datasheet, IDT72255LA15TFI8 pinout, IDT72255LA15TFI8 application, or IDT72255LA15TFI8 equivalent, key selection considerations include its 64-pin TQFP/STQFP package, programmable almost-empty/almost-full flags, auto power-down capability, retransmit function for data replay, and compatibility with depth-expansion architectures in high-throughput serial data paths.

Technical Context

The IDT72255LA15TFI8 implements a dual-clock FIFO architecture with fully asynchronous RCLK and WCLK domains-no frequency ratio constraints apply. Its internal RAM array (8,192 × 18) feeds into input/output registers controlled by dedicated read/write logic, enabling simultaneous read and write operations without arbitration.

Flag generation is mode-dependent: in IDT Standard mode, EF/OR and FF/IR operate as double-register-buffered status outputs; in FWFT mode, OR and IR use triple/double buffering respectively, and first-word latency is fixed at three RCLK cycles. Programmable offset registers for PAE and PAF support configurable thresholds (127 or 1,023 words), loaded via parallel (D0–D17) or serial (SI) interface under LD control.

Key Specifications

Pinout & Package

64-pin Slim Thin Quad Flat Pack (STQFP), order code TF, 10 mm × 10 mm body, 0.5 mm lead pitch, exposed pad not present. Pin 1 marked by corner notch; pins numbered counterclockwise.

Key Features

Applications

Equivalent & Alternatives

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

Compared with NB7L14M, IDT72255LA15TFI8 delivers parallel 5 V logic compatibility and FWFT latency optimization for legacy bus systems; compared with Renesas 72V255L15TF, it lacks 3.3 V support and extended temperature rating but remains viable for cost-sensitive industrial replacements where 5 V infrastructure is fixed.

Availability

IDT72255LA15TFI8 is available at Aetrix Electronics and suitable for telecom infrastructure, industrial video processing, embedded test equipment, and network packet buffering requiring stable component supply across long-lifecycle programs.

Supply support for IDT72255LA15TFI8 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, specialized in high-performance timing, memory interface, and RF solutions for communications and computing markets.

IDT72255LA15TFI8 belongs to the SuperSync FIFO™ family-designed specifically for deterministic, low-latency data buffering in multi-clock-domain systems such as telecom line cards, broadcast video gear, and industrial automation controllers.

FAQ

What is the maximum operating frequency of the IDT72255LA15TFI8?

The IDT72255LA15TFI8 supports a maximum clock cycle time of 15 ns, corresponding to a 66.7 MHz operational frequency for both RCLK and WCLK. 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 require synchronized clocks-the two domains operate independently without frequency ratio constraints.

Does the IDT72255LA15TFI8 support both IDT Standard and FWFT timing modes?

Yes, the IDT72255LA15TFI8 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), HIGH selects FWFT mode (OR/IR flags). Once set, the mode persists until next MRS. Both modes are fully supported in the IDT72255LA15TFI8 and documented in its functional description and timing diagrams.

How is the programmable Almost-Empty flag (PAE) configured on the IDT72255LA15TFI8?

The PAE threshold on the IDT72255LA15TFI8 is configured via internal offset registers loaded either in parallel (using D0–D17 and WEN/LD) or serially (via SI, SEN, WCLK, and LD). At Master Reset, LD determines default: LOW → 127-word offset; HIGH → 1,023-word offset. Reprogramming is allowed anytime post-reset, and the current value can be read back in parallel via Q0–Q17 and REN/LD.

What is the purpose of the Retransmit (RT) function on the IDT72255LA15TFI8?

The Retransmit (RT) function on the IDT72255LA15TFI8 allows rereading data from the beginning of the FIFO without resetting write operations or losing configuration. When RT is asserted on a rising RCLK edge, the read pointer resets to zero, EF/OR toggles temporarily, and subsequent reads deliver the earliest stored words again-ideal for packet retransmission, waveform replay, or diagnostic data capture without host intervention.

Is the IDT72255LA15TFI8 available in a lead-free package?

Yes, the IDT72255LA15TFI8 is offered in green (lead-free) versions. The "TF" in the part number denotes the 64-pin Slim Thin Quad Flat Pack (STQFP), and IDT documentation confirms RoHS-compliant variants were made available prior to the SnPb EOL date (June 15, 2018). Aetrix Electronics supplies only lead-free, RoHS-compliant units of IDT72255LA15TFI8 meeting JEDEC J-STD-609A Class 3 marking requirements.