Infineon Technologies CY7C025-55JXC

Overview

CY7C025-55JXC from Cypress Semiconductor is an 8K × 16-bit true dual-port static RAM with on-chip arbitration, semaphores, and INT/BUSY flags. It enables simultaneous asynchronous access from two independent processors or data paths to shared memory, supports master/slave expansion to 32-bit bus width, and delivers 55 ns access time at 5 V. Used in interprocessor communication buffers and real-time video frame stores.

For engineers reviewing the CY7C025-55JXC datasheet, CY7C025-55JXC pinout, CY7C025-55JXC application, or CY7C025-55JXC equivalent, key selection criteria include dual-port arbitration timing (tPS = 15 ns), semaphore latch count (8), BUSY/INT flag behavior in master vs. slave mode, and compatibility with 5 V TTL logic levels.

Technical Context

The CY7C025-55JXC implements fully asynchronous dual-port operation with independent CE/R/W/OE controls per port, enabling concurrent read/write access to any memory location. Its on-chip arbitration resolves contention via deterministic BUSY assertion (tBLA = 15 ns) and supports mailbox-style inter-port messaging using upper two memory addresses (1FFEh/1FFFh).

Semaphore logic comprises eight dedicated latches accessible via SEM pin activation, where write-to-zero grants exclusive resource ownership; the latch state is mirrored across ports but writable only by the side holding the token. The M/S pin configures BUSY as output (master) or input (slave), enabling daisy-chained expansion without external logic.

Key Specifications

Pinout & Package

Package: 84-pin PLCC (Plastic Leaded Chip Carrier), Pb-free, body size 29.31 mm × 29.31 mm, JEDEC MS-026AC.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT70V25L25PF and CY7C028-55JC, CY7C025-55JXC uniquely balances 5 V TTL compatibility, 55 ns latency, and full feature parity (semaphores, INT/BUSY, M/S) in a mature, widely supported PLCC package - making it optimal for legacy industrial and communications designs requiring drop-in reliability over voltage or speed upgrades.

Availability

CY7C025-55JXC is available at Aetrix Electronics and suitable for interprocessor communication buffers, dual-port video frame stores, and industrial PLC data exchange modules requiring stable component supply across extended production lifecycles.

Supply support for CY7C025-55JXC 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 programmable solutions for industrial, automotive, and communications infrastructure.

CY7C025 belongs to Cypress's dual-port SRAM product line, engineered specifically for deterministic, contention-free memory sharing between heterogeneous processors in real-time embedded systems.

FAQ

What is the function of the M/S pin on CY7C025-55JXC?

The M/S pin configures the device as master (M/S = HIGH) or slave (M/S = LOW). In master mode, BUSY pins act as outputs signaling arbitration results to downstream slaves; in slave mode, BUSY pins become inputs accepting arbitration signals from a master. This enables scalable 32-bit+ memory expansion without external logic.

How do the semaphore latches operate in CY7C025-55JXC?

Semaphores are eight dedicated latches accessed via SEM pin activation (CE held HIGH). Writing 0 to a semaphore grants exclusive ownership; the value appears as 0 on the owning port and 1 on the other. Only the owner may write to that semaphore. Reading returns the current latch state, enabling atomic resource allocation without software race conditions.

Can CY7C025-55JXC operate at 3.3 V?

No. CY7C025-55JXC is specified only for 5 V ±10% operation (4.5 V to 5.5 V). Its input thresholds, output drive strength, and internal timing are optimized for 5 V TTL/CMOS logic families. Operation outside this range violates electrical specifications and risks data corruption or latch-up.

What memory addresses are used for interrupt mailbox functionality?

The CY7C025-55JXC uses address 1FFFh as the right-port mailbox and 1FFEh as the left-port mailbox. Writing to the opposite port's mailbox asserts its INT pin. The interrupt clears only when the owning port reads that address; reading the opposite port's mailbox does not reset the interrupt.