CY7C421-25PC

Overview

The CY7C421-25PC is an asynchronous FIFO memory device manufactured by Cypress Semiconductor Corp. It features a storage capacity of 512 x 9 bits and operates with a maximum access time of 25ns, supporting data rates up to 28.5MHz. The component utilizes a 28-pin PDIP package for through-hole mounting. It functions as a uni-directional bus device with programmable status flags. The supply voltage range is specified between 4.5V and 5.5V, with a maximum supply current of 35mA. The operational temperature range extends from 0°C to 70°C.

Feature Summary

• Uni-directional data transfer capability for single-path communication applications
• Programmable status flags indicating full, empty, and almost full conditions
• Asynchronous clock domains allowing independent read and write operations
• Standard TTL-compatible logic levels for interface integration

Applications

• Buffering data streams between microprocessors and peripheral devices
• Clock domain crossing in digital signal processing systems
• Interface bridging between components operating at different speeds
• Data acquisition systems requiring temporary storage before processing

Procurement Notes

Verify the specific suffix 'PC' confirms the 28-pin PDIP package and 25ns speed grade, as the CY7C421 series includes multiple variants with different packages and timings. Confirm RoHS compliance status, as older Cypress parts may not meet current environmental directives. Check for lead-free plating requirements if used in regulated manufacturing environments. Ensure the supplier provides original manufacturer documentation to verify authenticity and traceability.

Selection Notes

Select this part when uni-directional asynchronous buffering is required with a 9-bit word width. The 25ns access time suits moderate-speed interfaces where higher performance parts are unnecessary. Consider the PDIP package only for prototyping or through-hole designs; surface-mount alternatives exist within the same family. Verify that the 512-word depth meets system buffer requirements without excessive cost or board space usage.

Part Context

The CY7C421 belongs to Cypress's CY7C421 family of asynchronous FIFOs, offering various depths and widths. This specific model represents the 512x9 configuration. The family is designed for general-purpose data buffering in embedded systems. Other variants include different bit widths and organization sizes, sharing similar control logic and pinouts for design flexibility across product lines.

Replacement Considerations

Direct replacements include other CY7C421 variants with compatible pinouts but verify speed and package differences. Cross-reference with equivalent asynchronous FIFOs from manufacturers like IDT or Xilinx if Cypress parts are unavailable. Ensure substitute parts match the 9-bit width and uni-directional requirement.