Infineon Technologies STK22C48-SF45TR

Overview

STK22C48-SF45TR from Cypress Semiconductor is a 16-Kbit (2 K × 8) AutoStore™ nvSRAM with QuantumTrap™ nonvolatile storage, 45 ns access time, single 5 V ±10% supply, and 28-pin SOIC package. It performs automatic STORE on power-down using an external 68 µF capacitor and supports software/hardware-initiated STORE/RECALL for industrial data logging and configuration retention.

For engineers reviewing the STK22C48-SF45TR datasheet, STK22C48-SF45TR pinout, STK22C48-SF45TR application, or STK22C48-SF45TR equivalent, key selection criteria include AutoStore timing behavior, HSB-controlled STORE arbitration, VCAP capacitor sizing, and compatibility with legacy SRAM interfaces requiring nonvolatile backup without battery or EEPROM emulation.

Technical Context

The STK22C48 integrates parallel SRAM and QuantumTrap nonvolatile cells per bit, enabling simultaneous STORE/RECALL of all 2,048 bytes. STORE is triggered by power loss (VCC < VSWITCH), HSB assertion, or software command; RECALL occurs automatically at power-up or via software.

It uses a dedicated VCAP pin to source energy for STORE operations, requires no external voltage supervisor, and inhibits STORE unless at least one write has occurred since the last STORE or RECALL-preventing spurious writes during brown-out conditions.

Key Specifications

Pinout & Package

28-pin 300 mil Small Outline Integrated Circuit (SOIC) package with gull-wing leads, RoHS-compliant, surface-mountable.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY14B101PA-SP25XI and FM24CL16B-G, the STK22C48-SF45TR offers direct SRAM bus compatibility, deterministic 45 ns timing, and hands-off AutoStore-making it optimal for legacy designs where minimal firmware change and guaranteed power-loss capture are required.

Availability

STK22C48-SF45TR is available at Aetrix Electronics and suitable for industrial PLC data logging, medical device configuration storage, and telecom base station control memory requiring stable component supply and long-term lifecycle support.

Supply support for STK22C48-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 (now part of Infineon Technologies) designs high-reliability memory and programmable solutions for industrial, automotive, and communications systems.

The STK22C48 belongs to Cypress's AutoStore nvSRAM product line, engineered to replace battery-backed SRAM and EEPROM in applications demanding instant nonvolatile write capability without firmware intervention.

FAQ

What is the minimum VCAP capacitance required for reliable AutoStore operation?

The STK22C48-SF45TR requires a minimum 68 µF tantalum or polymer capacitor on the VCAP pin, rated ≥6 V and with ≤20% tolerance. Lower values risk incomplete STORE under worst-case voltage droop; values up to 220 µF improve margin but increase board area and cost.

Can STK22C48-SF45TR be used without the VCAP capacitor?

Yes-by configuring AutoStore Inhibit mode: tie VCC to ground and apply +5 V to VCAP. In this mode, STORE is initiated only via HSB or software command, eliminating reliance on capacitor discharge. However, power-loss STORE capability is disabled.

How does the STK22C48 handle concurrent SRAM access and STORE initiation?

When HSB is asserted or power drops, the STK22C48 completes any in-progress SRAM write (within tDELAY) before starting STORE. Ongoing reads continue until completion; new writes are blocked until STORE finishes and HSB returns HIGH.

Is STK22C48-SF45TR suitable for new designs?

No-it is Not Recommended for New Designs per Cypress documentation. It remains in production solely to support ongoing programs. For new designs, Infineon recommends evaluating CY14B101PA or newer nvSRAM families with extended support and enhanced features.