Infineon Technologies CY7C4231-15AXC

Overview

CY7C4231-15AXC from Cypress Semiconductor is a 2K × 9-bit synchronous FIFO memory with TTL-compatible interfaces, 10 ns read/write cycle time, programmable Almost Empty/Almost Full flags, and dual-clock asynchronous operation. It serves as a high-speed data buffer in multiprocessor interconnects and serial communication gateways where deterministic latency and clock domain bridging are required.

For engineers reviewing the CY7C4231-15AXC datasheet, CY7C4231-15AXC pinout, CY7C4231-15AXC application, or CY7C4231-15AXC equivalent, key selection criteria include its 2048-word depth, 100 MHz max clock frequency, programmable flag offsets, independent RCLK/WCLK domains, and TQFP-32 package compatibility with IDT72231.

Technical Context

The CY7C4231-15AXC 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 thresholds set via four 8-bit offset registers. Its WEN2/LD pin operates in dual mode-either as second write enable or flag register load control-determined at reset.

It supports both single-clock (RCLK = WCLK) and fully asynchronous operation, with three-state output control via OE, independent REN1/REN2 and WEN1/WEN2 enable logic, and center-ground/power pin layout to minimize switching noise. Reset (RS) initializes the FIFO to empty state and validates all flags within tRSF.

Key Specifications

Pinout & Package

Package: 32-pin Thin Quad Flat Package (TQFP), 7 mm × 7 mm, 0.5 mm pitch, lead-free (RoHS compliant).

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT72231L15PF, CY7C4231-15AXC offers runtime flag reconfiguration via WEN2/LD, while NB3N502M trades parallel interface support for higher speed and differential signaling - making CY7C4231-15AXC optimal for flexible, TTL-based buffering where adaptability matters.

Availability

CY7C4231-15AXC is available at Aetrix Electronics and suitable for high-speed data acquisition, multiprocessor interconnect, and serial communication gateway applications requiring stable component supply and long-term industrial availability.

Supply support for CY7C4231-15AXC 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 fabless semiconductor company specializing in programmable system-on-chip solutions, memory, and interface ICs for industrial, automotive, and communications markets.

The CY7C42X1 family was designed specifically for high-reliability, low-latency data buffering in mixed-clock-domain systems - emphasizing deterministic flag behavior, expandability, and robust noise immunity in dense PCB environments.

FAQ

What is the function of the WEN2/LD pin, and how does its behavior change after reset?

The WEN2/LD pin is dual-mode: its function is determined by its logic state during reset (RS active). If held HIGH at reset, it acts as a second write enable (WEN2); if held LOW, it becomes the Load (LD) control for accessing the four 8-bit flag offset registers. This configuration is latched and remains fixed until next power cycle or reset.

How are the Almost Empty and Almost Full flags synchronized, and why does this matter for system design?

PAE and EF are synchronized to RCLK; PAF and FF are synchronized to WCLK. This ensures each flag's assertion/deassertion is aligned with the clock domain governing the corresponding operation - eliminating metastability risks and guaranteeing stable flag states for at least one full clock cycle, which simplifies timing-critical handshaking logic.

Can CY7C4231-15AXC be used in a single-clock configuration, and what pins must be tied together?

Yes - tie RCLK and WCLK together for single-clock operation. All other controls remain independent: REN1/REN2 manage reads, WEN1/WEN2 manage writes, and OE controls output drivers. This configuration simplifies clock tree design while retaining full flag functionality and three-state output control.

What is the default Almost Empty/Almost Full offset, and how is it modified?

The default offset is 7 words for both Almost Empty and Almost Full. To modify it, hold WEN2/LD LOW and WEN1 LOW, then apply four consecutive rising edges on WCLK to write LSB/MSB of empty offset and LSB/MSB of full offset into internal registers. Subsequent reads use RCLK with WEN2/LD LOW and REN1/REN2 LOW.