Infineon Technologies CY62256LL-55ZXIT

Overview

CY62256LL-55ZXIT from Cypress Semiconductor is a 256K-bit (32K × 8) CMOS static RAM with 55 ns access time, 4.5–5.5 V operation, and industrial temperature range (–40°C to +85°C). It features TTL-compatible I/O, automatic CE-controlled power-down (28 µW max standby), and three-state outputs for bus sharing in embedded microcontroller systems.

For engineers reviewing the CY62256LL-55ZXIT datasheet, CY62256LL-55ZXIT pinout, CY62256LL-55ZXIT application, or CY62256LL-55ZXIT equivalent, key selection criteria include guaranteed 55 ns read cycle time, low 28 µW standby current at 85°C, CE/OE/WE control logic compatibility with 8-bit microcontrollers, and narrow SOIC-28 packaging for space-constrained PCB layouts.

Technical Context

The CY62256LL-55ZXIT implements a full CMOS 32K × 8 SRAM array with dual-decode architecture (512 × 512), supporting asynchronous random access via address pins A0–A14. Its CE/OE/WE control scheme enables seamless integration into 8-bit data bus systems without external latching.

Power management relies on automatic CE-driven power-down mode, reducing ICC to ≤28 µW when CE is HIGH - a feature validated across –40°C to +85°C with CMOS input thresholds (VIH ≥ 2.2 V, VIL ≤ 0.8 V) and 6 pF input capacitance.

Key Specifications

Pinout & Package

Package: 28-pin narrow SOIC (450-mil width, 300-mil body), RoHS-compliant, JEDEC MS-012AC compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IS62C256AL-55QLI and AS6C4008-55TIN, the CY62256LL-55ZXIT delivers the lowest standby power (28 µW) in a pin-compatible narrow SOIC package, making it optimal for thermally sensitive or battery-dependent industrial systems where footprint and power are co-constrained.

Availability

CY62256LL-55ZXIT is available at Aetrix Electronics and suitable for industrial PLCs, medical data loggers, automotive body controllers, and legacy HMI retrofits requiring stable component supply and long-term obsolescence mitigation.

Supply support for CY62256LL-55ZXIT 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 mixed-signal ICs for industrial, automotive, and computing applications.

The CY62256 family was engineered specifically for drop-in replacement of legacy 256K SRAMs in 8-bit microcontroller systems, emphasizing low-power standby, industrial temperature resilience, and pin-for-pin compatibility with industry-standard footprints.

FAQ

Is CY62256LL-55ZXIT pin-compatible with the original CY62256-55ZI in DIP package?

Yes - the CY62256LL-55ZXIT uses the identical 28-pin SOIC pinout as defined in the datasheet for address (A0–A14), data (I/O0–I/O7), and control signals (CE, OE, WE, VCC, GND). No logic or timing changes are required when migrating from DIP to SOIC, though PCB layout must accommodate surface-mount soldering and thermal relief.

Does this SRAM retain data during VCC brown-out below 4.5 V?

Data retention is guaranteed down to VCC = 2.0 V per the datasheet's VDR specification. Below 4.5 V, the device remains functional until VCC drops to 2.0 V, after which it enters data retention mode with ICCDR ≤5 µA (LL version), preserving contents as long as VCC stays ≥2.0 V.

Can OE and WE be tied together for simplified control in microcontroller systems?

No - OE and WE serve distinct functions: OE controls output driver enable/disable (three-state), while WE determines read/write direction. Tying them violates timing requirements (tHZOE ≠ tHZWE) and risks bus contention. The datasheet mandates independent control for reliable operation across all temperature ranges.

What is the maximum clock frequency supported for burst reads using this SRAM?

This is an asynchronous SRAM with no internal clock - it supports continuous read cycles at up to 18.2 MHz (1/55 ns), provided address setup/hold and CE/OE timing margins are met. Microcontroller GPIO timing must satisfy tAA = 55 ns, tOHA = 5 ns, and tHZOE = 25 ns to avoid read corruption.