Infineon Technologies CY7C4245-15ASXC

Overview

CY7C4245-15ASXC from Cypress Semiconductor is a 4K × 18-bit synchronous FIFO memory with TTL-compatible interfaces, 10 ns read/write cycle time at 100 MHz, 45 mA ICC (20 MHz), and programmable Almost Empty/Almost Full flags. It supports independent read/write clocks, retransmit functionality, and depth/width expansion for high-speed data buffering in communications and multiprocessor systems.

For engineers reviewing the CY7C4245-15ASXC datasheet, CY7C4245-15ASXC pinout, CY7C4245-15ASXC application, or CY7C4245-15ASXC equivalent, key selection criteria include its 4096-word depth, dual-clock asynchronous operation, synchronous flag architecture tied to RCLK/WCLK, and PLCC/TQFP package compatibility for legacy board designs.

Technical Context

The CY7C4245-15ASXC implements a dual-port SRAM array with independent read and write pointers, controlled by free-running RCLK and WCLK signals. Its flag logic delivers five synchronized status outputs-EF, FF, PAE, PAF, and WXO/HF-with EF updated exclusively on RCLK edges and FF on WCLK edges.

Programmable offset registers (12-bit) configure PAE and PAF thresholds; VCC/SMODE pin selects between asynchronous (VCC) or RCLK/WCLK-synchronized (VSS) flag behavior. Retransmit (RT) resets the read pointer to enable packet replay without external controller intervention.

Key Specifications

Pinout & Package

Available in 68-pin PLCC (10 × 10 mm) and 64-pin TQFP (14 × 14 mm and 10 × 10 mm) packages. The -15ASXC suffix denotes the 10 ns speed grade in 68-pin PLCC configuration.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT72245L15PF and SN74V293-15PAG, the CY7C4245-15ASXC uniquely delivers hardware retransmit and full 5 V TTL compatibility in PLCC-68, making it irreplaceable in legacy industrial controllers requiring packet replay and direct bus interfacing.

Availability

CY7C4245-15ASXC is available at Aetrix Electronics and suitable for high-speed data acquisition, multiprocessor interfacing, and serial communications buffering requiring stable component supply across extended product lifecycles.

Supply support for CY7C4245-15ASXC 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-reliability memory and interface ICs for industrial, automotive, and communications markets.

The CY7C42X5 family was engineered specifically for deterministic, low-latency data buffering in mixed-clock-domain systems - emphasizing pin compatibility, expandability, and hardware-assisted flow control over software-managed alternatives.

FAQ

What is the purpose of the VCC/SMODE pin on CY7C4245-15ASXC?

The VCC/SMODE pin selects synchronization mode for the Programmable Almost Empty (PAE) and Programmable Almost Full (PAF) flags. When tied to VSS, PAE becomes synchronized to RCLK and PAF to WCLK - ensuring deterministic timing relative to respective clock domains. When tied to VCC, both flags operate asynchronously, reducing latency but introducing potential metastability in critical handshaking paths.

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

In standalone mode, a HIGH pulse on the FL/RT pin (with FL inactive) triggers retransmit: the internal read pointer resets to the first physical location, enabling repeated reading of all previously written data. WCLK and RCLK must be halted during the pulse and for tRTR (≥20 ns) afterward. Subsequent reads deliver the original data sequence until the write pointer is reached again.

Can CY7C4245-15ASXC be used in single-clock mode?

Yes - RCLK and WCLK may be tied together for single-clock operation. In this configuration, the device behaves as a standard synchronous FIFO with shared timing, while retaining independent REN/WEN enables and all status flags. Setup/hold timing requirements remain unchanged, and EF/FF flags retain their respective clock-domain synchronization (EF→RCLK, FF→WCLK).

What is the default Almost Empty offset value for CY7C4245-15ASXC?

The default Almost Empty offset is 127 words. This means the PAE flag asserts LOW when 127 or fewer words remain in the FIFO. The offset is stored in a 12-bit register and can be reprogrammed via the LD/WEN/WCLK sequence; unprogrammed devices automatically use this factory-set value for immediate plug-and-play operation.