Infineon Technologies CY7C136-25JXI

Overview

CY7C136-25JXI from Cypress Semiconductor is a 2K × 8 true dual-port static RAM with independent left/right ports, 25 ns maximum access time, 5 V ±10% supply, and industrial temperature range (–40 °C to +85 °C). It supports simultaneous read/write operations on separate ports, features BUSY arbitration and INT flags for inter-port communication, and is used in multiprocessor cache buffers and DSP memory subsystems.

For engineers reviewing the CY7C136-25JXI datasheet, CY7C136-25JXI pinout, CY7C136-25JXI application, or CY7C136-25JXI equivalent, key selection criteria include dual-port arbitration timing (tBLA = 20 ns), standby current (ISB1 = 65 mA), open-drain BUSY output requiring pull-up, and compatibility with CY7C146 slave devices for 16-bit expansion.

Technical Context

The CY7C136-25JXI implements fully asynchronous dual-port architecture with independent CE, R/W, and OE controls per port, enabling concurrent access without external synchronization. Its arbitration logic resolves contention via open-drain BUSY outputs (active-low) that signal address collision between ports.

It includes dedicated interrupt logic (INTL/INTR) on 52-pin PLCC/PQFP packages, where writes to fixed addresses (7FFH left, 7FEH right) trigger interrupts. Automatic power-down is controlled per port via CE, supporting ISB2 = 115 mA (one port active) and ISB3 = 15 mA (CMOS-input deep standby).

Key Specifications

Pinout & Package

Package: 52-pin Plastic Leaded Chip Carrier (PLCC), JEDEC MS-026AC compliant, lead-free (Pb-free) variant available.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C136-25ZXC, the JXI variant offers socket-compatible PLCC packaging for prototyping and field-replaceable designs; versus CY7C146-25JXI, it provides full master functionality including BUSY arbitration and interrupt generation - essential for standalone dual-processor systems.

Availability

CY7C136-25JXI is available at Aetrix Electronics and suitable for DSP cache buffers, multiprocessor shared memory, bit-slice computing systems, and legacy bus interface bridges requiring stable component supply and long-term industrial-grade support.

Supply support for CY7C136-25JXI 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 fabless semiconductor company specializing in memory, microcontrollers, and programmable logic solutions for industrial, automotive, and communications markets.

The CY7C13x/CY7C14x dual-port SRAM product line was designed specifically for high-speed inter-processor communication and real-time shared memory applications in embedded control and signal processing systems.

FAQ

What is the function of the BUSY pin on CY7C136-25JXI?

The BUSY pin is an open-drain output that goes low when the associated port attempts to access a memory location currently being accessed by the opposite port. It requires an external pull-up resistor to VCC. This hardware arbitration signal prevents data corruption during simultaneous access and eliminates the need for software polling or wait-state insertion in real-time systems.

Can CY7C136-25JXI operate as a standalone 8-bit memory without a slave device?

Yes, CY7C136-25JXI functions as a complete standalone dual-port SRAM with full read/write capability on both ports. It does not require a CY7C146 slave unless expanding the data bus beyond 8 bits. The device includes all necessary control logic, BUSY arbitration, and interrupt generation internally - no external coordination logic is needed for basic dual-port operation.

What is the purpose of the INTL and INTR pins?

INTL and INTR are dedicated interrupt output pins tied to fixed internal addresses: writing to 7FFH triggers INTL, and writing to 7FEH triggers INTR. These signals provide hardware-level inter-port notification without polling, enabling efficient synchronization in multiprocessor systems. They are available only on 52-pin PLCC and PQFP packages, not smaller variants.

How does power-down work on CY7C136-25JXI?

Power-down is controlled independently per port via the CEL and CER pins: asserting either CE high disables its respective port, reducing current draw. With both CEs high, ISB1 = 65 mA (industrial grade); with one CE high, ISB2 = 115 mA. Deep standby (ISB3 = 15 mA) occurs when CMOS-level inputs are applied and f = 0, making it suitable for battery-backed or ultra-low-power modes in embedded controllers.