Infineon Technologies STK15C88-SF25

Overview

STK15C88-SF25 from STMicroelectronics is a 8-Kbit (1K × 8) non-volatile static RAM (nvSRAM) with automatic data retention on power loss, integrated lithium battery, and industrial temperature range (–40°C to +85°C). It operates at 5 V ±10%, supports read/write cycles up to 10¹⁴, and retains data for 10 years without external power. Used in metering systems requiring tamper-proof event logging.

For engineers reviewing the STK15C88-SF25 datasheet, STK15C88-SF25 pinout, STK15C88-SF25 application, or STK15C88-SF25 equivalent, key selection criteria include auto-store timing (≤15 µs), write-cycle endurance, battery-backed retention integrity, and compatibility with legacy SRAM bus interfaces in utility and industrial control designs.

Technical Context

The STK15C88-SF25 integrates a standard asynchronous SRAM core with an on-chip controller that monitors V_CC and triggers automatic store-to-nonvolatile memory when voltage drops below 4.5 V. It uses ferroelectric capacitor-based storage cells for fast, high-endurance nonvolatile writes without wear leveling.

It requires no external backup power source beyond its internal lithium battery, eliminates external EEPROM or Flash for data logging, and maintains full SRAM read/write timing (t_AA = 25 ns, t_OE = 20 ns) during normal operation - enabling drop-in replacement of standard 1K × 8 SRAMs in existing designs.

Key Specifications

Pinout & Package

STK15C88-SF25 is housed in a 28-pin SOIC package (SO28) with 300-mil body width and standard 1.27 mm pitch. Pin functions align with JEDEC-standard 1K × 8 SRAM pinout.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY14B101PA-SXIT and FM24CL04-G, the STK15C88-SF25 uniquely delivers true SRAM bus compatibility, hardware-triggered auto-store, and integrated battery - making it the only option for legacy 5 V microcontroller designs needing guaranteed sub-20 µs data capture without firmware changes.

Availability

STK15C88-SF25 is available at Aetrix Electronics and suitable for smart electricity meters, industrial PLC I/O modules, point-of-sale terminals, and medical diagnostic equipment requiring stable component supply and long-term data retention under power interruption.

Supply support for STK15C88-SF25 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, designing and manufacturing microcontrollers, power ICs, sensors, and memory solutions for automotive, industrial, and consumer markets.

The STK15C88 belongs to ST's nvSRAM product line, engineered specifically for mission-critical data logging in utility metering and industrial control where power reliability cannot be assumed and firmware intervention during brownout is unsafe or impractical.

FAQ

What is the maximum operating frequency supported by STK15C88-SF25?

The STK15C88-SF25 does not use a clock signal - it is an asynchronous SRAM. Its speed is defined by access time: 25 ns maximum address-to-data valid (t_AA) and 20 ns output enable delay (t_OE). This supports bus frequencies up to approximately 33 MHz in typical microcontroller or FPGA interfaces with appropriate wait-state configuration.

Does STK15C88-SF25 require external battery or capacitor backup?

No. The STK15C88-SF25 contains a hermetically sealed, factory-installed lithium battery inside the SO28 package. No external backup components - including capacitors, batteries, or charge circuits - are required. The internal battery powers the store operation and retains data for ≥10 years at +85°C.

Can STK15C88-SF25 be used as a direct replacement for standard 1K × 8 SRAMs?

Yes - it is pin-compatible and functionally identical to JEDEC-standard 1K × 8 SRAMs (e.g., IS61LV1024) during normal operation. All control signals (CE#, OE#, WE#), address/data timing, and DC specifications match. Auto-store activates only during power loss and does not affect normal read/write behavior.

How is data integrity verified after an auto-store event?

The STK15C88-SF25 performs internal CRC validation during restore and includes a dedicated "STORE STATUS" flag bit (bit 7 of address 0x000) that indicates successful completion of the last auto-store. Reading this bit after power-up confirms whether the prior volatile data was preserved without host firmware intervention.