Infineon Technologies CY7C4245V-25ASXC

Overview

CY7C4245V-25ASXC from Cypress Semiconductor is a 4K × 18-bit, 3.3 V synchronous FIFO memory with independent read/write clocks, 67-MHz operation (25 ns cycle time), 5 V-tolerant inputs, and programmable Almost Full/Almost Empty flags. It serves as a high-speed data buffer in multi-clock domain interfaces between FPGAs and DSPs in telecom line cards.

For engineers reviewing the CY7C4245V-25ASXC datasheet, CY7C4245V-25ASXC pinout, CY7C4245V-25ASXC application, or CY7C4245V-25ASXC equivalent, key selection criteria include depth-expansion capability, synchronous flag timing control via VCC/SMODE, retransmit function for packet recovery, and STQFP/TQFP package compatibility with 0.65 µm CMOS process constraints.

Technical Context

The CY7C4245V-25ASXC implements dual-clock FIFO architecture with separate WCLK and RCLK domains, enabling true asynchronous read/write operation up to 66 MHz. Its 4,096-word × 18-bit SRAM array supports depth expansion via WXO/RXO cascade pins and width expansion using parallel device configurations.

Flag logic includes five synchronized status outputs: EF (RCLK-synchronized), FF (WCLK-synchronized), HF (shared with WXO), PAE, and PAF - all configurable for synchronous/asynchronous behavior via VCC/SMODE pin. Retransmit (RT) resets the read pointer to enable deterministic packet replay without external controller intervention.

Key Specifications

Pinout & Package

64-pin STQFP (10 × 10 mm, 0.5 mm pitch) with exposed thermal pad; RoHS-compliant Pb-free construction.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT72V2115L15PF and NB3N502MNG, the CY7C4245V-25ASXC uniquely combines 4K depth, retransmit capability, and VCC/SMODE-configurable flag synchronization - making it optimal for packet-oriented, multi-clock industrial and telecom buffers requiring field-upgradeable reliability features.

Availability

CY7C4245V-25ASXC is available at Aetrix Electronics and suitable for telecom infrastructure, FPGA prototyping, and medical imaging equipment requiring stable component supply across extended production lifecycles.

Supply support for CY7C4245V-25ASXC 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 mixed-signal ICs for embedded control, connectivity, and memory applications.

The CY7C42X5V series was developed specifically for high-speed, low-latency data buffering in multi-clock domain systems requiring deterministic flag timing and hardware-assisted packet recovery.

FAQ

What is the function of the VCC/SMODE pin on CY7C4245V-25ASXC?

The VCC/SMODE pin configures synchronization behavior of the Programmable Almost Empty (PAE) and Almost Full (PAF) flags. When tied to VSS, PAE becomes synchronized to RCLK and PAF to WCLK; when tied to VCC, both operate asynchronously. This allows designers to match flag timing to system clock domain requirements without external logic.

How does the retransmit (RT) feature work in standalone mode?

In standalone mode, a HIGH pulse on the RT pin resets the internal read pointer to the first physical location of the FIFO. After RT deassertion, subsequent reads output previously written data in sequence until the write pointer is reached. WCLK and RCLK must be disabled during and for tRTR (10 ns) after the RT pulse to ensure pointer integrity.

Can CY7C4245V-25ASXC be used in depth-expanded configurations with other CY7C42X5V variants?

Yes - all CY7C42X5V devices (CY7C4425V through CY7C4245V) share identical cascade pin definitions (WXI/WXO, RXI/RXO, FL/RT) and flag logic, enabling mixed-depth expansion. However, total effective depth is limited by the smallest device in the chain due to pointer alignment constraints across differing memory sizes.

What is the purpose of the FL pin in depth-expansion mode?

In depth-expansion mode, the FL pin identifies the first device in the daisy chain: FL is tied to VSS on the first device and to VCC on all subsequent devices. This configuration ensures correct initialization of cascade logic and prevents race conditions during power-up reset sequencing across multiple FIFOs.