Infineon Technologies CY7C136-25JXCT

Overview

CY7C136-25JXCT 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 52-pin PLCC package. It functions as a master dual-port SRAM in shared-memory systems, enabling simultaneous read/write access to the same memory location-critical for multiprocessor cache coherency and DSP data buffering.

For engineers reviewing the CY7C136-25JXCT datasheet, CY7C136-25JXCT pinout, CY7C136-25JXCT application, or CY7C136-25JXCT equivalent, key selection criteria include BUSY arbitration logic, INT flag support for port-to-port signaling, automatic per-port power-down, and compatibility with CY7C142/CY7C146 slave devices for 16-bit+ bus expansion.

Technical Context

This device implements fully asynchronous dual-port architecture with separate CE, R/W, and OE controls per port, enabling concurrent access without external synchronization. The arbitration logic resolves contention via open-drain BUSY outputs (requiring pull-up resistors) and supports priority-based conflict resolution.

The 52-pin PLCC version includes dedicated INTL/INTR pins for inter-port interrupt signaling at fixed addresses (7FF_L, 7FE_R), while automatic power-down is triggered independently per port via CE high assertion-reducing ISB2 standby current to 75 mA (commercial) or 75 mA (industrial) with one port active.

Key Specifications

Pinout & Package

Package: 52-pin Plastic Leaded Chip Carrier (PLCC), JEDEC MS-026AC, body size 19.1 mm × 19.1 mm, 1.78 mm height, lead pitch 0.635 mm.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C136-25JXC, the PLCC variant offers mechanical robustness and socket compatibility but requires wave soldering; versus CY7C136A-25JXCT, it lacks formal extended-temp qualification despite identical measured performance-making the 'A' version preferable for industrial deployments.

Availability

CY7C136-25JXCT is available at Aetrix Electronics and suitable for DSP data buffering, multiprocessor shared memory, bit-slice processor cache, and legacy system bus bridge applications requiring stable component supply and long-lifecycle support.

Supply support for CY7C136-25JXCT 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-performance memory and programmable solutions for industrial, automotive, and communications markets.

CY7C136 belongs to the legacy dual-port SRAM product line engineered for deterministic, low-latency shared memory in real-time embedded systems-prioritizing timing predictability over density or power efficiency.

FAQ

What is the maximum clock frequency supported by CY7C136-25JXCT?

CY7C136-25JXCT has no internal clock-it operates asynchronously. Its 25 ns access time supports read cycles up to 40 MHz (1/25 ns), but actual system frequency depends on external controller timing margins, PCB trace lengths, and load capacitance. Measured tRC = 25 ns under standard AC test conditions (CL = 30 pF, VIH/VIL = 2.2/0.8 V).

Can CY7C136-25JXCT operate with mixed voltage supplies (e.g., 3.3 V I/O, 5 V VCC)?

No. CY7C136-25JXCT requires 5 V ±10% on VCC (Pin 48) and uses TTL-compatible input thresholds (VIH = 2.2 V, VIL = 0.8 V). Driving inputs from 3.3 V logic violates VOH/VOL specifications and risks unreliable operation; level shifters are mandatory for 3.3 V controller interfaces.

How does the BUSY arbitration logic resolve simultaneous access to the same address?

When both ports attempt access to the same address, the internal arbitration logic asserts BUSYL and BUSYR LOW simultaneously. The port that asserted CE first gains priority; the contending port sees BUSY LOW and must wait until BUSY returns HIGH (after tBHA = 20 ns min) before retrying-ensuring deterministic, hardware-enforced serialization.

Is the INT flag latched or edge-triggered?

The INT flag is level-sensitive and self-clearing: it goes LOW when data is written to address 7FF_L (left port) or 7FE_R (right port), and returns HIGH automatically upon reading that location. No external reset is needed, enabling simple handshake protocols without register programming overhead.