Cypress Semiconductor Corp CY7C144-25AXC

Overview

CY7C144-25AXC from Cypress Semiconductor is an 8K × 8 true dual-port static RAM with independent left/right ports, 25 ns access time, TTL-compatible I/O, and integrated semaphore/INT/BUSY arbitration logic. It enables simultaneous asynchronous reads of the same memory location and supports interprocessor communication in real-time embedded systems requiring deterministic shared-memory access.

For engineers reviewing the CY7C144-25AXC datasheet, CY7C144-25AXC pinout, CY7C144-25AXC application, or CY7C144-25AXC equivalent, key selection criteria include dual-port arbitration behavior, M/S-configurable bus expansion, semaphore latch timing (tSOP, tSWRD), and industrial-grade 5V ±10% operation with 160 mA max ICC.

Technical Context

The CY7C144-25AXC implements fully asynchronous dual-port architecture with separate CE/R/W/OE control per port and on-chip hardware arbitration using BUSY flag assertion within tBLA/tBLC latency. Its semaphore subsystem comprises eight dedicated latches accessed via SEM pin with A0–A2 addressing and I/O0 data path.

Interrupt signaling uses fixed address locations (1FFE for INTL, 1FFF for INTR) with push-pull outputs requiring no pull-up resistors. The M/S pin configures BUSY as output (master) or input (slave), enabling seamless 16-bit+ width expansion without external logic or discrete master/slave pairing.

Key Specifications

Pinout & Package

Available in 68-pin PLCC (CY7C144-25AXC), 64-pin TQFP, and 80-pin TQFP packages. This part uses the 68-pin PLCC variant with lead-free finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT70V25L25PF and IS61LV5128AL-25KLI, CY7C144-25AXC delivers integrated arbitration and 5 V TTL compatibility out-of-box, reducing BOM count by two ICs and eliminating timing-critical FPGA logic for semaphore management.

Availability

CY7C144-25AXC is available at Aetrix Electronics and suitable for interprocessor communication, dual-port video buffering, communications protocol stack buffering, and industrial PLC data exchange requiring stable component supply across extended temperature ranges.

Supply support for CY7C144-25AXC 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 markets.

The CY7C144 series targets deterministic multi-processor systems requiring hardware-managed shared memory, emphasizing arbitration robustness, 5 V interoperability, and minimal external component count.

FAQ

What is the function of the M/S pin on CY7C144-25AXC?

The M/S (Master/Slave Select) pin configures BUSY signal direction: when HIGH, BUSY pins act as outputs for master-mode arbitration; when LOW, they become inputs for slave-mode cascading. This enables 16-bit or wider memory expansion using identical CY7C144 devices without external logic, with the master's BUSY driving the slave's BUSY input to synchronize write cycles.

How do the semaphore latches operate in CY7C144-25AXC?

The eight semaphore latches are accessed by asserting SEML or SEMR LOW while holding CE HIGH, using A0–A2 as address lines and I/O0 as data input. Writing a 0 requests ownership; reading returns 0 if granted, 1 if contested. Each latch is owned exclusively by one port until released by writing 1, preventing race conditions in resource allocation.

Can CY7C144-25AXC operate with mixed voltage interfaces?

No - CY7C144-25AXC is strictly 5 V ±10% tolerant with TTL-compatible thresholds (VIH ≥ 2.2 V, VIL ≤ 0.8 V). It does not support 3.3 V or 2.5 V I/O directly. Interfacing with lower-voltage controllers requires level-shifting circuitry, as internal logic and output drivers are designed for 5 V rail operation and cannot withstand sustained overvoltage on I/O pins.

What timing parameters govern interrupt flag behavior?

INTL is set when the right port writes address 1FFE and cleared when the left port reads that same address; INTR follows the inverse pattern at 1FFF. Both flags are push-pull outputs with no external pull-up needed. The interrupt assertion occurs within tACE (25 ns) of valid address and write strobe, and clearing requires full read cycle completion including tDOE setup.