Infineon Technologies STK11C68-SF45I

Overview

STK11C68-SF45I from STMicroelectronics is a non-volatile static RAM (nvSRAM) with 64 Kbit capacity, 8-bit parallel interface, and automatic STORE/RECALL on power loss. It operates from 4.5 V to 5.5 V, retains data for 20 years without battery, and features a 45 ns access time. It is used in industrial control systems requiring instant non-volatility during unexpected power interruption.

For engineers reviewing the STK11C68-SF45I datasheet, STK11C68-SF45I pinout, STK11C68-SF45I application, or STK11C68-SF45I equivalent, key selection criteria include guaranteed STORE/RECALL timing, zero-battery reliability, industrial temperature range (–40°C to +85°C), and compatibility with legacy SRAM-based microcontroller buses.

Technical Context

The STK11C68-SF45I integrates an SRAM core with on-chip lithium battery and auto-store circuitry. It uses a capacitor-assisted STORE operation triggered by V_CC drop below V_POR (4.25 V typical), completing data transfer to internal EEPROM within 10 ms.

RECALL occurs automatically at power-up when V_CC exceeds V_PU (3.0 V), restoring contents to SRAM in ≤15 ms. The device supports standard read/write cycles identical to fast SRAM, with no software overhead or external control signals required for non-volatility.

Key Specifications

Pinout & Package

STK11C68-SF45I is housed in a 28-pin SOIC (Small Outline Integrated Circuit) package with 300 mil body width and standard 1.27 mm pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STK11C68-SF45I, the SF55I offers identical functionality at reduced speed and cost, while FM1808 requires interface redesign and sacrifices SRAM-like timing transparency for density and serial footprint savings.

Availability

STK11C68-SF45I is available at Aetrix Electronics and suitable for industrial PLCs, point-of-sale terminals, smart metering systems, and medical diagnostics equipment requiring stable component supply and long-term lifecycle assurance.

Supply support for STK11C68-SF45I 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, delivering intelligent power, sensing, and control solutions across automotive, industrial, and consumer markets.

This device belongs to ST's nvSRAM product line, engineered specifically to replace battery-backed SRAM in mission-critical industrial systems where maintenance-free, long-life non-volatility is mandatory.

FAQ

What happens during a rapid power interruption lasting less than 10 ms?

The STK11C68-SF45I detects V_CC drop below its power-on reset threshold (4.25 V) and initiates STORE within 1 µs. If V_CC recovers above 4.25 V before STORE completes, the operation aborts cleanly and SRAM remains fully operational-no data corruption occurs.

Can this part be used in place of a standard 64 Kbit SRAM without hardware changes?

Yes-STK11C68-SF45I uses identical pinout, timing, and electrical signaling as industry-standard 8K×8 SRAMs. No PCB layout, voltage regulator, or bus controller modifications are required for drop-in replacement.

Does RECALL overwrite SRAM contents if power is applied while writes are active?

No. RECALL only executes during initial power-up, before any write cycle begins. Once V_CC stabilizes and the device enters normal operation, RECALL is disabled until next cold start-ensuring no conflict with live memory updates.

How is data integrity verified after STORE completion?

The device asserts the READY signal low during STORE and returns it high upon successful EEPROM write verification. External logic can monitor READY to confirm completion before initiating safe shutdown sequences.