Infineon Technologies CY7C144-55AXC

Overview

CY7C144-55AXC from Cypress Semiconductor is an 8K × 8 true dual-port static RAM with independent asynchronous access on left and right ports, 55 ns maximum access time, TTL-compatible I/O, and integrated semaphore/INT/BUSY arbitration logic - used in interprocessor communication buffers and dual-port video frame stores.

For engineers reviewing the CY7C144-55AXC datasheet, CY7C144-55AXC pinout, CY7C144-55AXC application, or CY7C144-55AXC equivalent, key selection criteria include dual-port contention handling (BUSY arbitration), software handshake capability via eight semaphores, port-to-port interrupt signaling (INTL/INTR), and master/slave expansion support via M/S pin for 16-bit+ bus width.

Technical Context

The CY7C144-55AXC implements fully asynchronous dual-port operation with separate CE/R/W/OE controls per port, enabling concurrent read/write to distinct addresses without synchronization overhead. Its on-chip arbitration resolves simultaneous access to the same memory location using BUSY flag assertion with tBLA/tBLC timing.

Semaphore logic consists of eight dedicated latches accessed via SEML/SEMR and A0–A2, allowing atomic resource reservation between ports; INTL/INTR flags support mailbox-style communication by triggering on writes to fixed addresses (1FFE/1FFF). The M/S pin configures BUSY as output (master) or input (slave) for cascaded width expansion.

Key Specifications

Pinout & Package

Package: 68-pin PLCC (Plastic Leaded Chip Carrier), body size 24.2 mm × 24.2 mm, lead pitch 1.27 mm, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT70V25L25PF and CY7C146-55AXC, the CY7C144-55AXC uniquely integrates BUSY arbitration, semaphores, and M/S expansion in a 55 ns 8K × 8 footprint - making it optimal for cost-sensitive, software-handshake-driven multiprocessor designs where external logic minimization is critical.

Availability

CY7C144-55AXC is available at Aetrix Electronics and suitable for interprocessor communication buffers, dual-port video frame stores, industrial PLC data exchange, and communications protocol stack buffers requiring stable component supply across extended product lifecycles.

Supply support for CY7C144-55AXC 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 U.S.-based semiconductor company specializing in programmable solutions for embedded systems, connectivity, and memory.

The CY7C144 series belongs to Cypress's legacy dual-port SRAM product line, designed specifically for deterministic, low-latency interprocessor communication in real-time control and graphics subsystems.

FAQ

What is the function of the M/S pin on CY7C144-55AXC?

The M/S (Master/Slave Select) pin configures the device's BUSY pin behavior: when HIGH, BUSY pins act as outputs for master-mode arbitration signaling; when LOW, they become inputs for slave-mode operation. This enables seamless 16-bit or wider memory expansion using multiple CY7C144 devices without external logic, as the master's BUSY output directly drives the slave's BUSY input.

How do the semaphore latches operate in CY7C144-55AXC?

The eight semaphore latches are accessed via SEML/SEMR and A0–A2, with only I/O0 used during write. Writing 0 reserves a resource; reading returns 0 if successfully acquired or 1 if contested. Semaphores must be initialized to 1 at power-up from both ports. The read value is latched to prevent corruption during cross-port writes, ensuring atomic resource ownership transfer.

Can CY7C144-55AXC operate with mixed voltage interfaces?

No - CY7C144-55AXC is strictly a 5V ±10% device with TTL-compatible thresholds (VIH = 2.2 V, VIL = 0.8 V). It does not support mixed-voltage I/O or level-shifting internally. Interfacing with 3.3V logic requires external translators; connecting directly risks violating input voltage limits and may cause unreliable operation or damage.

What happens during simultaneous access to the same memory location?

When both ports attempt access within tPS (15 ns for -55 variant), on-chip arbitration asserts BUSYL/BUSYR to indicate contention. One port gains guaranteed access; the other sees high-Z data and must retry. If tPS is violated, access priority is undefined. Data flowthrough delay (tDDD) applies when one port reads data written by the other - critical for synchronizing cross-port operations.