Infineon Technologies CY7C4221-15JXC

Overview

CY7C4221-15JXC from Cypress Semiconductor is a 1K × 9-bit synchronous FIFO memory with TTL-compatible interfaces, 10 ns read/write cycle time, programmable Almost Empty/Almost Full flags (default offset = 7), and dual-clock asynchronous operation capability. It serves as a high-speed data buffer in multiprocessor interconnects and serial communications interfaces where deterministic latency and clock domain bridging are required.

For engineers reviewing the CY7C4221-15JXC datasheet, CY7C4221-15JXC pinout, CY7C4221-15JXC application, or CY7C4221-15JXC equivalent, key selection criteria include its 100 MHz max clock frequency, independent RCLK/WCLK domains, programmable flag offsets, 32-pin TQFP package, and compatibility with IDT72221-based designs.

Technical Context

The CY7C4221-15JXC implements a dual-port SRAM-based FIFO architecture with separate read and write pointer logic, synchronized status flags (EF/FF updated on RCLK/WCLK respectively), and programmable PAE/PAF flags controlled via dedicated 8-bit offset registers. Its WEN2/LD pin supports dual-mode configuration: second write enable or flag register load control.

It operates with fully asynchronous read/write clocks up to 100 MHz, supports width expansion via enable pin chaining, and uses center-power/ground pin layout to minimize switching noise. Reset (RS) initializes the FIFO to empty state and validates all flags within t_RSF (≤15 ns).

Key Specifications

Pinout & Package

32-pin Thin Quad Flat Package (TQFP), 7 mm × 7 mm body, 0.5 mm pitch, exposed pad optional. Pin 1 marked by dot; pins numbered counterclockwise.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT72221L15JGI and MC100E127FN, the CY7C4221-15JXC uniquely combines TTL compatibility, on-chip programmable flag registers accessible via WEN2/LD, and 32-pin TQFP packaging-making it optimal for industrial control and mixed-signal embedded designs requiring robust, field-programmable buffering.

Availability

CY7C4221-15JXC is available at Aetrix Electronics and suitable for industrial data acquisition, multi-processor communication, and serial protocol bridging requiring stable component supply across extended product lifecycles.

Supply support for CY7C4221-15JXC 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 programmable system-on-chip solutions, memory, and interface ICs for industrial, automotive, and consumer applications.

The CY7C42X1 family was designed specifically for high-reliability, clock-domain-isolation buffering in real-time embedded systems-emphasizing deterministic latency, programmable flow control, and robust 5 V TTL interoperability.

FAQ

What is the function of the WEN2/LD pin during normal operation?

During normal operation, WEN2/LD acts as the second write enable when configured at reset (held HIGH during RS assertion). When used as LD, it enables serial loading of the four 8-bit flag offset registers via WCLK edges-allowing runtime adjustment of PAE/PAF thresholds without device reset or external programming hardware.

How does the CY7C4221-15JXC handle simultaneous read and write at full/empty states?

The device prevents invalid operations: writes are blocked when FF = LOW (full), and reads return last valid data when EF = LOW (empty). Overflow/underflow protection circuitry ensures no corruption occurs; status flags remain valid and synchronized to their respective clocks throughout boundary conditions.

Can the CY7C4221-15JXC be used with a single clock for both read and write?

Yes-RCLK and WCLK may be tied together for single-clock operation. In this mode, the FIFO behaves as a synchronous FIFO with guaranteed setup/hold timing; however, the independent clock capability remains unused, and maximum throughput is limited by the slower of the two clock domains' timing margins.

What is the default behavior of the Almost Empty and Almost Full flags after power-on reset?

After reset, PAE and PAF are configured with default offsets of 7 words. PAE asserts LOW when ≤7 unread words remain; PAF asserts LOW when ≥1017 words are stored (1024 − 7). These values are stored in nonvolatile offset registers and persist until explicitly rewritten via WEN2/LD and WCLK sequences.