Infineon Technologies STK11C88-SF25TR

Overview

STK11C88-SF25TR from Cypress Semiconductor is a 256 Kbit (32K × 8) nonvolatile static RAM with QuantumTrap® nvSRAM technology, delivering 25 ns access time, automatic hardware RECALL on power-up, and software-initiated STORE/RECALL. It operates from a single 5V ±10% supply, supports commercial and industrial temperature ranges, and is packaged in a 28-pin SOIC (300 mil). It serves as drop-in replacement for standard SRAMs in systems requiring persistent data retention without backup batteries or external EEPROM.

For engineers reviewing the STK11C88-SF25TR datasheet, STK11C88-SF25TR pinout, STK11C88-SF25TR application, or STK11C88-SF25TR equivalent, key selection criteria include its 1,000,000 STORE cycles, 100-year data retention, unlimited RECALL endurance, and compatibility with industry-standard 32K × 8 SRAM footprints in embedded control, metering, and industrial PLC designs.

Technical Context

The STK11C88 integrates volatile SRAM and nonvolatile QuantumTrap cells at the bit level, enabling atomic STORE (SRAM → NV) and RECALL (NV → SRAM) operations. Its dual-mode operation-standard SRAM read/write plus nonvolatile control via six-address software sequences-eliminates need for external controllers or battery management circuitry.

Hardware RECALL triggers automatically when VCC exceeds VSWITCH after brownout or power-up, completing in tHRECALL (typ. 20 ms). STORE and RECALL are mutually exclusive; during either cycle, all I/O is disabled, and the device enters a high-impedance state until completion.

Key Specifications

Pinout & Package

Package: 28-pin SOIC (300 mil body width, 0.025" lead pitch), RoHS-compliant, surface-mountable with standard reflow profiles.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STK11C88-SF45TR, the -SF25TR delivers faster deterministic response for real-time control loops; compared with FM24CL64-G, it retains full SRAM compatibility and autonomous hardware RECALL-critical for safety-critical boot integrity.

Availability

STK11C88-SF25TR is available at Aetrix Electronics and suitable for industrial automation, smart metering, and medical diagnostics requiring stable component supply and long-lifecycle support.

Supply support for STK11C88-SF25TR 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 markets.

The STK11C88 belongs to Cypress's SoftStore® nvSRAM product line, engineered specifically to eliminate battery dependencies in mission-critical embedded systems while maintaining full SRAM interface compatibility.

FAQ

What happens if power fails mid-STORE cycle?

If VCC drops below VSWITCH during a STORE operation, the hardware protect feature immediately halts the cycle and preserves the previous nonvolatile state. No partial writes occur-QuantumTrap cells retain their prior value intact. The SRAM contents remain unchanged, and the next successful STORE will overwrite the entire array atomically.

Can STK11C88-SF25TR be used in place of a standard 32K × 8 SRAM without firmware changes?

Yes-pinout, timing, and read/write electrical behavior match JEDEC-standard 32K × 8 SRAMs. Firmware changes are only needed to implement STORE/RECALL sequences; basic SRAM operation requires zero modification. Hardware RECALL ensures functional equivalence at boot without code intervention.

Is the 25 ns access time guaranteed over the full industrial temperature range?

No-the 25 ns access time is specified only for the commercial temperature range (0°C to +70°C). At industrial temperatures (–40°C to +85°C), the maximum access time is 45 ns, as confirmed in the AC switching characteristics table (Document #001-50591 Rev. *A, Page 9).

How does the device prevent accidental STORE during noise events on address lines?

STORE initiation requires six consecutive CE-controlled READs to exact addresses in strict order, with WE held HIGH throughout. Any interrupting write, CE deassertion, or address mismatch aborts the sequence. This multi-step protocol provides robust immunity against glitches, ESD transients, or metastability on address/data buses.