Infineon Technologies CY7C4205-10AXCT

Overview

CY7C4205-10AXCT from Cypress Semiconductor is a 256 × 18-bit synchronous FIFO memory with 10 ns read/write cycle time, 100 MHz clock support, and TTL-compatible I/O. It implements independent read/write clocks (RCLK/WCLK), programmable Almost Empty/Almost Full flags, and retransmit functionality for packet buffering in high-speed data acquisition and multiprocessor interfaces.

For engineers reviewing the CY7C4205-10AXCT datasheet, CY7C4205-10AXCT pinout, CY7C4205-10AXCT application, or CY7C4205-10AXCT equivalent, this device is selected for asynchronous buffer design requiring deterministic flag timing, depth/width expansion capability, and low-latency retransmission control in industrial communications and test equipment.

Technical Context

The CY7C4205-10AXCT uses dual-port SRAM architecture with separate read and write pointers, enabling true simultaneous read/write operation. Its synchronous flag logic ties EF exclusively to RCLK edges and FF exclusively to WCLK edges, ensuring predictable timing behavior across power-up and reset sequences.

Programmable PAE/PAF offset registers (12-bit) allow user-defined trigger thresholds for almost-empty and almost-full conditions. The VCC/SMODE pin selects between asynchronous (VCC) and RCLK/WCLK-synchronized (VSS) flag transitions - a critical configuration for deterministic system-level handshake timing.

Key Specifications

Pinout & Package

Package: 64-pin TQFP (10 mm × 10 mm, 0.5 mm pitch), RoHS-compliant, center power/ground layout for noise reduction.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT72205L10PFI and SN74V293-10PAG, the CY7C4205-10AXCT uniquely combines 5 V operation, hardware retransmit, and configurable flag synchronization - making it optimal for industrial protocol bridges requiring field-upgradeable reliability and multi-FIFO scalability.

Availability

CY7C4205-10AXCT is available at Aetrix Electronics and suitable for high-speed data acquisition, multiprocessor interconnect, and communications protocol buffering requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for CY7C4205-10AXCT 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) designs high-performance memory and programmable logic solutions for industrial, automotive, and communications infrastructure.

The CY7C42X5 family was engineered specifically for deterministic, low-latency data buffering in mixed-clock-domain systems - emphasizing flag timing precision, expansion flexibility, and hardware-assisted flow control.

FAQ

What is the minimum pulse width required on the RS (Reset) pin to ensure reliable initialization?

The RS pin requires a minimum LOW pulse width of 10 ns to guarantee proper reset of internal pointers and flag states. Cypress specifies that RS must be held LOW for at least one full WCLK or RCLK cycle - whichever is longer - and no read/write operations may occur during the LOW period. This ensures the FIFO enters a known Empty state with EF = LOW and all outputs driven LOW if OE is asserted.

How does the VCC/SMODE pin affect timing behavior of the PAE and PAF flags?

When VCC/SMODE is tied to VSS (0 V), PAE transitions are synchronized to RCLK rising edges and PAF transitions to WCLK rising edges - eliminating metastability in clock-domain crossing. When tied to VCC (5 V), both flags operate asynchronously, with propagation delays specified as maximum 20 ns. Synchronous mode is required for systems where flag assertion must align precisely with data availability timing.

Can the CY7C4205-10AXCT be used in depth-expanded configurations with devices of different densities?

No - depth expansion requires identical CY7C42X5 variants (e.g., all CY7C4205-10AXCT). Mixing densities (e.g., CY7C4205 + CY7C4215) causes misalignment of write/read pointer boundaries and invalid flag generation. The FL pin logic and WXO/RXO handshake protocol assume uniform memory depth per stage; Cypress explicitly restricts cascading to same-density parts in the datasheet.

What is the electrical behavior of the Q0–Q17 outputs when OE is HIGH and the FIFO is not empty?

When OE is HIGH, all Q0–Q17 outputs enter high-impedance (Hi-Z) state regardless of FIFO content or REN status. No current flows into or out of these pins, and voltage levels float unless externally terminated. This allows multiple FIFOs or other drivers to share the same data bus without contention - a requirement for bus-multiplexed test equipment and modular backplane architectures.