Infineon Technologies CY7C131-55JXI

Overview

CY7C131-55JXI from Cypress Semiconductor is a 1 K × 8 true dual-port static RAM with independent left/right ports, 55 ns maximum access time, 5 V ±10% supply, and 52-pin PLCC package. It supports simultaneous reads of the same memory location and features BUSY arbitration and INT port-to-port interrupt flags. Used in multi-processor cache buffers and DSP shared-memory subsystems.

For engineers reviewing the CY7C131-55JXI datasheet, CY7C131-55JXI pinout, CY7C131-55JXI application, or CY7C131-55JXI equivalent, key selection criteria include dual-port arbitration timing (tBLA ≤20 ns), standby current (ISB1 = 35 mA), open-drain BUSY output requiring pull-up, and compatibility with CY7C141 for 16-bit expansion.

Technical Context

This device implements fully asynchronous dual-port SRAM architecture with separate address, data, and control buses per port (A0L–A9L/I/O0L–I/O7L/CEL/R/WL/OEL on left; A0R–A9R/I/O0R–I/O7R/CER/R/WR/OER on right). Arbitration logic resolves contention via open-drain BUSYL/BUSYR outputs and priority-based access resolution.

It includes dedicated INTL/INTR flags tied to fixed addresses (3FFH left, 3FEH right) for inter-port signaling, automatic power-down controlled independently per port via CE pins, and CMOS-compatible input thresholds (VIH = 2.2 V, VIL = 0.8 V) with 15 pF input capacitance.

Key Specifications

Pinout & Package

52-pin Plastic Leaded Chip Carrier (PLCC) package with J-lead geometry, lead-free (Pb-free) compliant, body size 19.13 mm × 19.13 mm, 1.78 mm height. Pin 1 marked by notch orientation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-port SRAM applications.

Compared with CY7C131-55JC and IDT70V25L25PF, CY7C131-55JXI uniquely combines Pb-free compliance, 52-pin PLCC surface-mount compatibility, and integrated BUSY/INT arbitration-enabling drop-in replacement in industrial control modules requiring RoHS adherence and deterministic inter-processor signaling.

Availability

CY7C131-55JXI is available at Aetrix Electronics and suitable for DSP shared-memory buffers, multi-processor cache coherence systems, and industrial PLC data exchange modules requiring stable component supply across extended temperature ranges (–40°C to +85°C).

Supply support for CY7C131-55JXI 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 solutions for embedded systems, with headquarters in San Jose, CA.

The CY7C13x series targets deterministic real-time shared-memory architectures in digital signal processing, bit-slice computing, and multi-processor systems where hardware arbitration and low-latency inter-port signaling are essential.

FAQ

What is the function of the BUSY pin on CY7C131-55JXI?

BUSYL and BUSYR are open-drain outputs indicating port contention: BUSY goes LOW when one port attempts to access an address currently being accessed by the other port. External 4.7 kΩ pull-up resistors to VCC are mandatory. The signal remains asserted until the contending port releases the address or changes its address, enabling hardware flow control without software intervention.

Can CY7C131-55JXI operate at 3.3 V?

No. CY7C131-55JXI is specified only for 5 V ±10% operation (4.5–5.5 V). Its VIH minimum is 2.2 V and VOL maximum is 0.4 V at 4 mA, but internal circuitry-including the 0.65 µm CMOS process and output drivers-is designed for 5 V logic levels. Attempting 3.3 V operation results in undefined behavior, failed arbitration, and potential data corruption.

How does the INT flag work in port-to-port communication?

INTL asserts when data is written to address 3FFH (1023 decimal) on the left port; INTR asserts when data is written to 3FEH (1022 decimal) on the right port. Both are open-drain outputs requiring pull-up resistors. This hardwired address mapping eliminates polling and provides sub-25 ns interrupt latency, enabling real-time synchronization in tightly coupled multi-processor systems.

Is CY7C131-55JXI pin-compatible with CY7C130-55JXI?

No. CY7C131-55JXI uses a 52-pin PLCC package, while CY7C130-55JXI uses a 48-pin DIP package. Although both share identical pin functions (e.g., CEL, R/WL, A0L–A9L), the physical layout, pin count, and package type differ fundamentally. Migration requires PCB redesign and cannot be achieved via socket replacement or adapter.