Infineon Technologies STK14C88-3WF45I

Overview

STK14C88-3WF45I from Cypress Semiconductor is a 256 Kbit (32K × 8) nonvolatile SRAM with AutoStore functionality, integrating QuantumTrap nonvolatile storage in each memory cell. It operates on a single 3.3V ±0.3V supply, delivers 45 ns access time, supports unlimited SRAM read/write cycles, and guarantees 100-year data retention after STORE. It is used in industrial control systems requiring persistent memory across power cycles without external backup.

For engineers reviewing the STK14C88-3WF45I datasheet, STK14C88-3WF45I pinout, STK14C88-3WF45I application, or STK14C88-3WF45I equivalent, key selection criteria include AutoStore timing behavior, VCAP capacitor sizing (68–220 µF), HSB-controlled hardware STORE synchronization, and software STORE/RECALL address sequence integrity.

Technical Context

The STK14C88-3WF45I combines a standard fast SRAM array (512 × 512) with parallel QuantumTrap nonvolatile cells per bit. STORE transfers data from SRAM to nonvolatile elements using charge stored on the external VCAP capacitor; RECALL restores data on power-up or via software. Both operations inhibit concurrent SRAM access.

It implements three STORE initiation modes: automatic (on VCC drop below VSWITCH), hardware (via HSB pin pull-down), and software (six-address CE-controlled READ sequence). The HSB pin serves dual roles - as an open-drain busy indicator and as a hardware trigger - with tDELAY (≥20 µs) allowing pending writes to complete before STORE begins.

Key Specifications

Pinout & Package

STK14C88-3WF45I is housed in a 32-pin SOIC (300 mil width) package with standard JEDEC pinout and RoHS-compliant finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AS1C32K8P-35TIN and FM24V01A-G, the STK14C88-3WF45I uniquely provides hardware-triggered STORE, VCAP-backed autonomous power-loss response, and true parallel SRAM timing - making it optimal for real-time systems needing deterministic, zero-software-overhead persistence.

Availability

STK14C88-3WF45I is available at Aetrix Electronics and suitable for industrial PLCs, medical diagnostics equipment, telecom infrastructure, and avionics subsystems requiring stable component supply and long-term lifecycle support.

Supply support for STK14C88-3WF45I 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 U.S.-based semiconductor company specializing in memory, microcontrollers, and programmable solutions for industrial and automotive markets.

The STK14C88-3 series belongs to Cypress's nvSRAM product line, designed specifically to replace battery-backed SRAM in mission-critical systems where maintenance-free, high-endurance, and deterministic nonvolatile storage are essential.

FAQ

What is the purpose of the VCAP pin and how is the capacitor selected?

The VCAP pin connects to an external 68–220 µF electrolytic capacitor (±20%, 4.7V rating) that stores energy to power the STORE operation during VCC collapse. Capacitor ESR must be ≤1 Ω to ensure sufficient current delivery within tSTORE (≤20 ms). A 100 µF/4.7V part is commonly used for single-device configurations.

Can STK14C88-3WF45I be used without the AutoStore function?

Yes - AutoStore can be disabled by connecting VCC to ground and applying +3.3V directly to VCAP (AutoStore Inhibit mode). In this configuration, STORE is software-only, VCAP becomes the primary supply, and all references to VCC in timing specs shift to VCAP. Mode change requires power cycle; dynamic switching is prohibited.

How does the HSB pin behave during multi-device STORE synchronization?

When multiple STK14C88-3WF45I devices share a common VCAP and have HSB pins tied together with a single 10 kΩ pull-up to VCAP, any device detecting power loss pulls HSB LOW, triggering STORE across all devices. Only those devices with recent SRAM writes (since last STORE/RECALL) execute STORE; others remain idle.

Is the software STORE sequence sensitive to bus timing or interrupt interference?

Yes - the six-address CE-controlled READ sequence must execute consecutively without intervening reads/writes or interrupts. Any interruption aborts the sequence. To ensure reliability, disable interrupts during the sequence and use CE-controlled (not OE-controlled) reads with stable address setup/hold times per datasheet tACS/tACH.