Infineon Technologies CY7C135-25JXC

Overview

CY7C135-25JXC from Cypress Semiconductor is a 4K × 8 true dual-port static RAM with fully asynchronous operation, 25 ns maximum access time, 5 V ±10% supply, and 52-pin PLCC package. It enables simultaneous independent read access to the same memory location on left and right ports, supporting interprocessor communication and video buffer sharing in real-time embedded systems.

For engineers reviewing the CY7C135-25JXC datasheet, CY7C135-25JXC pinout, CY7C135-25JXC application, or CY7C135-25JXC equivalent, key selection criteria include dual-port arbitration requirements (semaphore-free vs. semaphore-enabled variants), port-level power-down control via CE pins, TTL/CMOS standby current trade-offs, and compatibility with legacy 52-pin PLCC PCB footprints.

Technical Context

The CY7C135-25JXC implements a fully asynchronous dual-port architecture with independent CE, OE, and R/W controls per port-no wait states or external arbitration logic required. Its 0.65 µm CMOS process delivers deterministic timing across commercial temperature range (0°C to +70°C) with guaranteed tRC = 25 ns and tAA = 25 ns.

All I/Os are TTL-compatible with VIH = 2.2 V, VIL = 0.8 V, VOH = 2.4 V, and VOL = 0.4 V at IOH/IOL = ±4.0 mA. Standby modes support four distinct current profiles (ISB1–ISB4), enabling fine-grained power management per port based on CE assertion level and input voltage thresholds.

Key Specifications

Pinout & Package

Package: 52-pin Plastic Leaded Chip Carrier (PLCC), JEDEC MS-018AC compliant, lead-free option available. Pin 1 marked by corner notch; top view orientation shown in Figure 1 of datasheet Rev. *D.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C1342-25JXC, this part omits semaphores-reducing complexity and cost where hardware arbitration suffices. Versus IDT7132SA25YG, it retains field-serviceable PLCC packaging but requires larger PCB area and different thermal profile.

Availability

CY7C135-25JXC is available at Aetrix Electronics and suitable for interprocessor communication, video buffering, communications protocol stacks, and multiprocessor control systems requiring stable component supply over extended production lifecycles.

Supply support for CY7C135-25JXC 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 system-on-chip solutions for industrial, automotive, and communications markets.

CY7C135 belongs to Cypress's legacy dual-port SRAM product line, engineered specifically for deterministic, low-latency shared-memory architectures in real-time embedded systems.

FAQ

Is CY7C135-25JXC pin-compatible with CY7C1342-25JXC?

Yes-both devices share identical 52-pin PLCC pinouts, address/data mappings, and control signal assignments. The only functional difference is the presence of semaphore logic in CY7C1342, which uses dedicated SEM pins instead of NC pins on CY7C135. No PCB redesign is needed for substitution.

Can CY7C135-25JXC operate at 3.3 V?

No-this device requires 5 V ±10% (4.5–5.5 V) and is not rated for 3.3 V operation. Attempting to power it at 3.3 V will result in undefined behavior, failed reads/writes, and potential damage due to violated absolute maximum ratings on VCC.

What happens during simultaneous write to the same address on both ports?

The datasheet explicitly states that simultaneous writes to the same location produce undefined data. Unlike simultaneous reads, which are guaranteed safe, concurrent writes create bus contention and may corrupt memory contents-software must prevent this via external coordination or use of CY7C1342 semaphores.

Does CY7C135-25JXC support partial write masking?

No-it lacks byte-write enable or mask inputs. All eight bits on each port are written simultaneously when R/W = LOW and CE = LOW. To modify individual bytes, full 8-bit reads-modify-writes are required, increasing latency and bus utilization.