Infineon Technologies STK15C88-SF45TR

Overview

STK15C88-SF45TR from Cypress Semiconductor (now Infineon) is a 8-Kbit (1K × 8) non-volatile static RAM (nvSRAM) with automatic STORE/RECALL on power loss, 45 ns access time, TTL-compatible interface, and industrial temperature range (–40°C to +85°C). It serves as a drop-in SRAM replacement with battery-free non-volatility in data logging, metering, and industrial control systems requiring instant write-on-power-fail.

For engineers reviewing the STK15C88-SF45TR datasheet, STK15C88-SF45TR pinout, STK15C88-SF45TR application, or STK15C88-SF45TR equivalent, key selection criteria include guaranteed STORE latency ≤ 15 µs, zero-battery reliability, 100,000 STORE/RECALL cycles, and compatibility with standard 28-pin SOIC packaging and parallel SRAM timing.

Technical Context

This nvSRAM integrates a fast SRAM core with an on-chip lithium battery and auto-store controller. Upon V_CC dropout below V_POR (typically 3.0 V), it initiates STORE within 15 µs, transferring all 1K × 8 data bits to internal ferroelectric-capacitor-based non-volatile storage. RECALL occurs automatically at power-up when V_CC exceeds V_PU (3.1 V).

The device operates at 5 V ±10%, supports byte-wide parallel access, and maintains data for 10 years at +85°C without external backup. Its STORE/RECALL logic is fully transparent to the host system-no software intervention or special commands required.

Key Specifications

Pinout & Package

STK15C88-SF45TR is housed in a 28-pin Small Outline Integrated Circuit (SOIC) 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 STK15C88-SF45TR, the SF55TR trades speed for lower cost in less timing-critical systems, while the FM1808 offers superior endurance at the expense of added external components and reduced integration.

Availability

STK15C88-SF45TR is available at Aetrix Electronics and suitable for smart electricity meters, programmable logic controllers, and industrial HMI loggers requiring stable component supply, long-term lifecycle support, and zero-battery non-volatility.

Supply support for STK15C88-SF45TR 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, acquired by Infineon in 2020, specializes in high-reliability mixed-signal ICs for industrial, automotive, and communications infrastructure.

This part belongs to Cypress' nvSRAM product line, engineered specifically to replace battery-backed SRAM in mission-critical data retention applications where maintenance-free operation and deterministic STORE timing are mandatory.

FAQ

What happens if V_CC drops and recovers within 10 µs?

STK15C88-SF45TR's power-loss detection circuit has a built-in deglitch filter; voltage sags shorter than 10 µs are ignored to prevent spurious STORE activation during transient noise or switching spikes. Only sustained V_CC drops below 3.0 V for ≥10 µs initiate STORE.

Can STORE be manually triggered via software command?

No. STORE is exclusively hardware-triggered by the internal voltage monitor. There is no command interface, register map, or software-accessible control - this ensures deterministic behavior and eliminates firmware dependency or timing uncertainty during power failure.

Does RECALL overwrite SRAM contents even if V_CC was stable?

Yes. RECALL is unconditional and automatic at every power-up when V_CC rises above 3.1 V. The nv storage contents are always copied into SRAM on initialization, ensuring the most recent saved state is restored regardless of prior SRAM activity.

Is the internal lithium cell replaceable or field-serviceable?

No. The lithium energy source is hermetically sealed inside the SOIC package and not user-serviceable. Its 10-year data retention rating at +85°C reflects end-of-life performance under worst-case conditions; actual field life typically exceeds 15 years at room temperature.