Infineon Technologies STK22C48-NF45ITR

Overview

STK22C48-NF45ITR from Cypress Semiconductor is a 16-Kbit (2 K × 8) nonvolatile SRAM with AutoStore™ functionality, integrating QuantumTrap™ nonvolatile elements in each memory cell. It operates at 5 V ±10%, delivers 45 ns access time, supports unlimited SRAM read/write cycles, and guarantees 1,000,000 STORE cycles and 100-year data retention. Used in industrial control modules where power-loss resilience and deterministic recall timing are critical.

For engineers reviewing the STK22C48-NF45ITR datasheet, STK22C48-NF45ITR pinout, STK22C48-NF45ITR application, or STK22C48-NF45ITR equivalent, key selection factors include AutoStore activation method (VCAP capacitor vs. HSB pin), STORE cycle inhibition logic, RECALL timing on power-up, and compatibility with 28-pin SOIC footprint in legacy 5 V systems.

Technical Context

The STK22C48-NF45ITR implements a dual-cell architecture: a standard fast SRAM array (32 × 512) paired with parallel QuantumTrap nonvolatile storage. STORE transfers data from SRAM to nonvolatile cells either automatically on VCC drop below VSWITCH (using external 68 µF VCAP capacitor) or via hardware trigger on HSB pin.

RECALL restores data from QuantumTrap to SRAM on power-up when VCC exceeds VSWITCH, completing in tHRECALL ≤ 10 ms. During STORE/RECALL, SRAM read/write is inhibited; HSB serves as both initiation input and open-drain busy indicator, pulled low for duration of operation.

Key Specifications

Pinout & Package

STK22C48-NF45ITR uses a 28-pin 300-mil Small Outline Integrated Circuit (SOIC) package with standard pin pitch and lead finish compliant with RoHS.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STK12C68-AB55I, STK22C48-NF45ITR offers faster 45 ns access and lower VCAP requirement (68 µF vs. 100 µF), making it preferable in space-constrained 5 V industrial controllers. Versus FM24CL64-G, it maintains 5 V compatibility and deterministic STORE timing but trades off F-RAM's instant-write capability for higher temperature tolerance and legacy bus alignment.

Availability

STK22C48-NF45ITR is available at Aetrix Electronics and suitable for industrial PLC data logging, medical device configuration backup, and avionics black box recorders requiring stable component supply and long-lifecycle support.

Supply support for STK22C48-NF45ITR 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) is a fabless semiconductor company specializing in memory, microcontrollers, and programmable solutions for industrial, automotive, and communications markets.

The STK22C48 belongs to Cypress's AutoStore nvSRAM product line, designed specifically for systems needing deterministic, capacitor-backed nonvolatile storage without firmware intervention or external controllers.

FAQ

What is the minimum VCAP capacitor value required for reliable AutoStore operation?

The STK22C48-NF45ITR requires a minimum 68 µF tantalum or aluminum electrolytic capacitor rated at ≥6 V on the VCAP pin. Values below this threshold may cause incomplete STORE cycles during rapid VCC collapse. The capacitor must be placed within 10 mm of the VCAP pin with low-ESR construction to ensure sufficient energy delivery within the 10 ms STORE window.

Can STK22C48-NF45ITR operate without the VCAP capacitor?

Yes-when configured in AutoStore Inhibit mode (VCC tied to ground, +5 V applied to VCAP), the device disables automatic STORE and relies solely on HSB-triggered hardware STORE. In this mode, VCAP functions as the primary supply, and no external capacitor is needed. However, all STORE operations become explicit and require system-level coordination.

How does the STK22C48-NF45ITR handle power-up RECALL timing?

Upon VCC rising above VSWITCH (~3.6 V), the STK22C48-NF45ITR initiates an automatic RECALL cycle that completes within tHRECALL ≤ 10 ms. During this period, SRAM outputs are invalid and all control pins (CE/OE/WE) are ignored. The HSB pin remains HIGH until RECALL finishes, signaling readiness for normal access.

Is STK22C48-NF45ITR pin-compatible with standard 28-pin SOIC SRAMs?

Yes-the STK22C48-NF45ITR uses industry-standard 28-pin SOIC pinout (300 mil width) matching JEDEC MS-012AC. Address, data, and control signals align directly with common 2 K × 8 SRAMs like IS61LV256AL. The addition of HSB and VCAP pins replaces two NC pins, preserving functional compatibility for drop-in replacement in existing 5 V board layouts.