Infineon Technologies CY7C144-55JC

Overview

CY7C144-55JC from Cypress Semiconductor is an 8K × 8 true dual-port static RAM with independent left/right address, data, and control buses, 55 ns maximum access time, TTL-compatible I/O, and integrated semaphore, interrupt, and busy arbitration logic - used in interprocessor communication buffers and dual-port video frame memory.

For engineers reviewing the CY7C144-55JC datasheet, CY7C144-55JC pinout, CY7C144-55JC application, or CY7C144-55JC equivalent, key selection criteria include asynchronous dual-port timing, M/S-configurable bus width expansion, on-chip semaphore latches for resource locking, and 68-pin PLCC packaging with push-pull INT/BUSY outputs.

Technical Context

The CY7C144-55JC implements fully asynchronous dual-port operation with separate CE/R/W/OE controls per port, enabling concurrent read/write access to any memory location. Its arbitration logic resolves contention via BUSY flag assertion within 15 ns (tBLA) and supports master/slave cascading via the M/S pin.

Interrupt signaling uses fixed addresses (1FFE/1FFF) with push-pull INTL/INTR outputs requiring no pull-up resistors; semaphores consist of eight dedicated latches accessed via SEML/SEMR with A0–A2 addressing and I/O0 data path - all controlled without external logic.

Key Specifications

Pinout & Package

68-pin Plastic Leaded Chip Carrier (PLCC), JEDEC MO-047AA, body size 24.2 mm × 24.2 mm, lead pitch 0.05 inch. Pin 1 index located at corner adjacent to notch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT70V25L25PF and CY7C146-55JC, the CY7C144-55JC uniquely delivers 5 V TTL compatibility, integrated M/S-expandable bus width, and on-die semaphores in a 68-pin PLCC - making it optimal for legacy industrial and embedded dual-processor designs where pin count, voltage, and hardware arbitration are constrained.

Availability

CY7C144-55JC is available at Aetrix Electronics and suitable for interprocessor communication buffers, dual-port video frame memory, and industrial PLC shared memory modules requiring stable component supply across extended lifecycle programs.

Supply support for CY7C144-55JC 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 systems.

The CY7C144 series belongs to Cypress's legacy dual-port SRAM product line, engineered specifically for deterministic, low-latency shared memory in multiprocessor architectures without external arbitration components.

FAQ

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

The M/S (Master/Slave Select) pin configures the device's BUSY signal behavior: when HIGH, BUSYL/BUSYR operate as push-pull outputs indicating local port arbitration status (master mode); when LOW, they become inputs accepting BUSY signals from a master device (slave mode). This enables seamless 16-bit or wider memory expansion using multiple CY7C144 devices without external logic.

How do the semaphore latches work, and what address space do they occupy?

The CY7C144-55JC includes eight dedicated semaphore latches accessed only when SEML or SEMR is asserted LOW. A0–A2 select the latch (0–7); I/O0 writes the value (0 = request, 1 = release); all eight I/O lines reflect the latch state on read. Semaphores reside outside main memory - no address decoding is needed beyond A0–A2, and they require explicit initialization to '1' at power-up.

Can INTL and INTR be used simultaneously for bidirectional messaging?

Yes - INTL is set when the right port writes to address 1FFE and cleared when the left port reads it; INTR is set when the left port writes to 1FFF and cleared when the right port reads it. This creates two independent, hardware-synchronized mailboxes: one for left-initiated messages (1FFF), one for right-initiated (1FFE), enabling full-duplex port-to-port signaling without polling.

What are the power-down current specifications under different standby conditions?

In industrial temperature range (−40°C to +85°C), ISB1 (both ports disabled with TTL-level CE inputs) is ≤30 mA; ISB2 (one port disabled) is ≤120 mA; ISB3 (both ports disabled with CMOS-level inputs) is ≤30 mA; ISB4 (one port active, other disabled with CMOS inputs) is ≤115 mA. These values assume VCC = 5 V ±10% and f = 0 or fMAX as defined in the datasheet.