Infineon Technologies CY7C4225-15AC

Overview

CY7C4225-15AC from Cypress Semiconductor is a 1K × 18-bit synchronous FIFO memory with TTL-compatible interfaces, 66.7 MHz maximum clock frequency (15 ns cycle time), 45 mA operating current at 20 MHz, and programmable Almost Empty/Almost Full flags. It supports independent read/write clocks, retransmit function, and depth/width expansion for high-speed data buffering in communications interfaces and multiprocessor systems.

For engineers reviewing the CY7C4225-15AC datasheet, CY7C4225-15AC pinout, CY7C4225-15AC application, or CY7C4225-15AC equivalent, key selection considerations include synchronous flag timing behavior (VCC/SMODE-controlled), cascading capability via WXO/RXO/FL pins, OE-controlled three-state outputs, and compatibility with IDT722x5-series designs requiring 1K-depth, 18-bit-wide buffering.

Technical Context

The CY7C4225-15AC implements a dual-clock, synchronous FIFO architecture with separate WCLK/REN and RCLK/WEN control paths, enabling true asynchronous read/write operation. Its status flags (EF, FF, PAE, PAF, WXO/HF) are decoded from internal read/write pointer logic and support both asynchronous and RCLK/WCLK-synchronized assertion depending on VCC/SMODE configuration.

Depth expansion uses daisy-chained WXO→WXI and RXO→RXI signals with FL pin hierarchy (first device FL=VSS, others FL=VCC); width expansion connects multiple devices in parallel with shared clocks and enables. The retransmit function is activated by pulsing FL/RT while OE=LOW, allowing repeat output of the last valid word without advancing the read pointer.

Key Specifications

Pinout & Package

Package: 64-pin Thin Quad Flat Package (TQFP), 10 mm × 10 mm body, 0.5 mm pitch, lead-free (Pb-free) compliant per J-STD-020.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT72205L15PF, CY7C4225-15AC offers integrated retransmit and selectable flag synchronization - critical for protocol-aware buffering - while NB3N502DR2G serves an entirely different clock-domain function and is not a viable alternative.

Availability

CY7C4225-15AC is available at Aetrix Electronics and suitable for high-speed data acquisition, multiprocessor interconnect, serial-to-parallel conversion, and industrial Ethernet gateway buffering requiring stable component supply and long-term obsolescence management.

Supply support for CY7C4225-15AC 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

Cypress Semiconductor (now part of Infineon Technologies) is a U.S.-based semiconductor company specializing in memory, microcontrollers, and programmable solutions for industrial, automotive, and communications markets.

The CY7C42X5 family was designed specifically for high-reliability, low-latency data buffering in mixed-clock-domain systems where deterministic flag timing and expandable depth/width are essential - targeting test equipment, telecom infrastructure, and real-time control applications.

FAQ

What is the function of the VCC/SMODE pin on CY7C4225-15AC?

The VCC/SMODE pin configures the synchronization behavior of the Programmable Almost Empty (PAE) and Programmable Almost Full (PAF) flags. When tied to VCC, PAE/PAF operate asynchronously; when tied to VSS, PAE synchronizes to RCLK and PAF to WCLK - enabling precise timing alignment with respective clock domains in deterministic systems.

How does the retransmit function work, and what pins are involved?

Retransmit is activated by pulsing the FL/RT pin LOW while OE is LOW, causing the FIFO to output the last valid word again without advancing the read pointer. This requires no external logic and is electrically identical to a normal read cycle, making it ideal for protocol-level retry mechanisms in serial or packetized interfaces.

Can CY7C4225-15AC be used in depth-expanded configurations with other CY7C42X5 variants?

Yes - all CY7C42X5 devices (CY7C4425 through CY7C4245) share identical pinouts and expansion logic. A CY7C4225-15AC can be cascaded with CY7C4235 or CY7C4245 to achieve composite depths of 3K, 5K, or more words while preserving 18-bit width and synchronous flag behavior across the chain.

Is the CY7C4225-15AC RoHS-compliant and lead-free?

Yes - the "AC" suffix denotes a lead-free, RoHS-compliant 64-pin TQFP package meeting J-STD-020 moisture sensitivity level 3 requirements. The device uses NiPdAu lead finish and is qualified for standard reflow profiles without special handling beyond standard MSL3 precautions.