Renesas 72251L15PF

Overview

72251L15PF from Integrated Device Technology (IDT) is a high-speed CMOS synchronous FIFO memory with 8,192 × 9-bit depth, 10 ns read/write cycle time, dual independent clocks (WCLK/RCLK), and programmable Almost-Empty/Almost-Full flags. It serves as a data buffering interface in interprocessor communication, LAN controllers, and graphics subsystems requiring deterministic latency and clock domain bridging.

For engineers reviewing the 72251L15PF datasheet, 72251L15PF pinout, 72251L15PF application, or 72251L15PF equivalent, this device delivers zero fall-through time architecture, industrial temperature support (–40°C to +85°C), and TQFP-32 packaging - critical for real-time embedded buffering where timing predictability and flag configurability are essential.

Technical Context

The 72251L15PF implements a dual-ported, clocked FIFO with separate write and read control logic, RAM array, and synchronized status flag generation. Its architecture supports both single-clock (RCLK = WCLK) and asynchronous dual-clock operation, with EF/FF flags synchronized to RCLK/WCLK respectively, and PAE/PAF flags configurable via offset registers loaded through WEN2/LD.

Flag behavior is precisely timed: tWFF ≤ 15 ns (WCLK → FF), tREF ≤ 15 ns (RCLK → EF), tPAF ≤ 15 ns (WCLK → PAF), and tPAE ≤ 15 ns (RCLK → PAE). The device defaults to Empty+7/Full−7 programmable offsets and supports depth expansion via dual write enables when WEN2/LD is asserted HIGH at reset.

Key Specifications

Pinout & Package

72251L15PF is housed in a 32-pin Thin Quad Flat Pack (TQFP) package with 0.8 mm lead pitch, JEDEC MS-026 compliant, and RoHS-compliant lead finish (Pb-free).

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT72251L10PF and CY7C4255V-15AC, the 72251L15PF offers optimal balance of speed, industrial temperature compliance, and flexible flag configuration - making it the preferred choice for cost-sensitive, 5 V-only industrial buffering where 66.7 MHz throughput suffices.

Availability

72251L15PF is available at Aetrix Electronics and suitable for interprocessor communication, LAN controller buffering, and graphics frame alignment requiring stable component supply across long-lifecycle industrial programs.

Supply support for 72251L15PF 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 sensor signal conditioning ICs, now part of Renesas Electronics.

The IDT72xx SyncFIFO™ family was designed specifically for high-reliability, low-latency data buffering in real-time embedded systems - emphasizing deterministic timing, industrial-grade robustness, and seamless clock domain bridging.

FAQ

What is the memory organization of the 72251L15PF?

The 72251L15PF features an 8,192 × 9-bit synchronous FIFO memory array - meaning it stores up to 8,192 words, each 9 bits wide. This organization supports byte-plus-parity or 8-bit data with dedicated parity bit handling, commonly used in legacy industrial and telecom interfaces where error detection is critical. The 72251L15PF does not support word-width reconfiguration or partial-word access.

Does the 72251L15PF support asynchronous clock domains?

Yes, the 72251L15PF explicitly supports asynchronous operation: its read clock (RCLK) and write clock (WCLK) may run at different frequencies and phases. EF and PAE flags are synchronized to RCLK; FF and PAF flags to WCLK. This eliminates need for external CDC logic in applications like CPU-to-DSP data transfer or FPGA-to-ASIC bridging - a core design intent confirmed in the functional block diagram and AC timing tables of the 72251L15PF datasheet.

How are the programmable Almost-Empty and Almost-Full flags configured on the 72251L15PF?

The 72251L15PF uses the WEN2/LD pin in conjunction with WEN1 and WCLK to load four 8-bit offset registers (Empty LSB/MSB, Full LSB/MSB). When WEN2/LD is held LOW at reset, it enters flag-load mode: four consecutive WCLK edges write offset values. Default values are 007H (7 decimal) for all registers, yielding PAE = Empty+7 and PAF = Full−7. This configuration is verified in Figure 3 and Signal Descriptions section of the 72251L15PF documentation.

What is the function of the RS (Reset) pin on the 72251L15PF?

The RS pin on the 72251L15PF is an asynchronous active-LOW reset that initializes internal read/write pointers to address zero, forces FF and PAF HIGH, and EF and PAE LOW. It also resets output register contents to zero and loads default offset values (007H) into flag registers. A valid reset pulse ≥15 ns is required before first write after power-up - a mandatory initialization step specified in the 72251L15PF datasheet's Signal Descriptions and Reset Timing diagrams.

Is the 72251L15PF compatible with depth expansion configurations?

Yes, the 72251L15PF supports depth expansion by configuring WEN2/LD as a second write enable (asserted HIGH at reset). In this mode, WEN1 and WEN2 jointly control write gating, enabling cascaded FIFO stacks for capacities beyond 8,192 words. The device's dual read enables (REN1/REN2) similarly support expanded read paths. This capability is documented in the "DEPTH EXPANSION" section and Figure 2 of the 72251L15PF datasheet, with timing validated for tSKEW1 ≥ 6 ns.