Infineon Technologies CY7C4291V-15JC

Overview

CY7C4291V-15JC from Cypress Semiconductor is a 128K × 9-bit, 3.3V asynchronous FIFO memory with programmable Almost Empty/Almost Full flags, 10-ns read/write cycle time, and 32-pin PLCC package - used for high-speed data buffering in multiprocessor interfaces and communications systems.

For engineers reviewing the CY7C4291V-15JC datasheet, CY7C4291V-15JC pinout, CY7C4291V-15JC application, or CY7C4291V-15JC equivalent, key selection criteria include synchronous flag timing (RCLK/WCLK-aligned), dual write-enable configuration capability, programmable flag offset registers, and 3.3V-only operation with 25 mA active current.

Technical Context

The CY7C4291V-15JC implements a dual-clock, fully asynchronous FIFO architecture with independent 9-bit input (D0–D8) and output (Q0–Q8) ports, controlled by separate WCLK/REN1/REN2 and RCLK/WEN1/WEN2/LD signal paths. It uses a 0.35-µm CMOS process and supports both single-clock (WCLK = RCLK) and true asynchronous operation.

Its flag logic is strictly clock-synchronous: EF and PAE update on RCLK edges; FF and PAF update on WCLK edges. The WEN2/LD pin serves dual roles - second write enable or flag-offset register load control - determined at reset by its logic level, enabling flexible depth-expansion or programmable threshold configuration.

Key Specifications

Pinout & Package

Package: 32-pin Plastic Leaded Chip Carrier (PLCC), JEDEC MS-026AC compliant, surface-mount compatible with standard reflow profiles.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT72V2115L15PF and SN74V293-15PAG, the CY7C4291V-15JC uniquely integrates flag-programming capability, dual-mode pin control, and native width-expansion support in a single PLCC package - reducing BOM count and PCB area in multi-channel buffering systems.

Availability

CY7C4291V-15JC is available at Aetrix Electronics and suitable for high-speed data acquisition, multiprocessor interfacing, serial communications buffering, and video frame synchronization requiring stable component supply across extended product lifecycles.

Supply support for CY7C4291V-15JC 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 high-performance memory, microcontrollers, and programmable logic solutions for industrial, automotive, and communications markets.

The CY7C42x1V family was designed specifically for low-voltage, high-throughput asynchronous data buffering - targeting applications where clock domain isolation, deterministic flag timing, and field-programmable thresholds are critical.

FAQ

Is CY7C4291V-15JC pin-compatible with older 5V CY7C4291 devices?

No. The CY7C4291V-15JC is a 3.3V-only device with different DC specifications and absolute maximum ratings. It is pin-compatible only with other CY7C42x1V-series parts (e.g., CY7C4261V/CY7C4271V/CY7C4281V) and not with the original 5V CY7C4291. Direct replacement requires voltage translation or board redesign.

How is the programmable flag offset configured at power-up?

At reset, the WEN2/LD pin's logic level determines mode: if held LOW, the device enters flag-offset programming mode; if HIGH, it defaults to dual-write-enable operation. Default offset values are Empty = 7, Full = 7 - stored in four 9-bit registers accessible only when WEN2/LD = LOW and appropriate clock edges occur.

What happens if RS is asserted during active read/write operations?

Asserting RS asynchronously forces the FIFO into a known empty state: all pointers reset, EF goes LOW after tRSF, Q0–Q8 outputs go LOW, and flag logic reinitializes. Any ongoing read/write is aborted; data in transit is lost. RS must be held active for minimum pulse width (tRS) to ensure reliable reset.

Can WCLK and RCLK be driven from the same oscillator source?

Yes - the CY7C4291V-15JC supports single-clock operation. Tie WCLK and RCLK together with a 50% duty-cycle signal. In this mode, the FIFO behaves as a synchronous FIFO with RCLK-aligned EF/PAE and WCLK-aligned FF/PAF, maintaining correct flag timing as long as clock skew is minimized.