Infineon Technologies STK14C88-NF45I

Overview

STK14C88-NF45I from Cypress Semiconductor is a 32K × 8 (256 Kb) nonvolatile static RAM with AutoStore functionality, operating at 45 ns read/write cycle time, single 5V ±10% supply, and industrial temperature range (–40°C to +85°C). It integrates Quantum Trap nonvolatile storage per cell, enabling automatic STORE on power loss and RECALL on power-up, and is packaged in 32-pin 300 mil SOIC.

For engineers reviewing the STK14C88-NF45I datasheet, STK14C88-NF45I pinout, STK14C88-NF45I application, or STK14C88-NF45I equivalent, key selection criteria include guaranteed 45 ns access timing, hardware/software-controlled STORE/RECALL, HSB status signaling, VCAP-backed power-loss data retention, and compatibility with legacy SRAM interfaces requiring nonvolatility without external backup circuitry.

Technical Context

The STK14C88-NF45I implements monolithic nvSRAM architecture where each SRAM cell embeds a Quantum Trap nonvolatile element. STORE transfers data from volatile SRAM to nonvolatile storage upon power failure detection or software/hardware trigger; RECALL restores data unidirectionally on power-up.

It supports three operational modes: standard SRAM read/write (E/G/W controlled), hardware STORE (HSB low pulse), and software STORE/RECALL (via address/command sequences). The HSB pin provides real-time STORE progress indication, and VCAP supplies hold-up energy for reliable STORE completion during brownout.

Key Specifications

Pinout & Package

Package: 32-pin 300 mil SOIC (RoHS-compliant), surface-mount, JEDEC MS-012AC.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STK14C88-NF45I, STK14CA8-45I offers superior endurance and thermal margin but requires redesign for VCAP handling, while FM24CL64-G reduces write latency and power but increases system-level design effort for STORE control and voltage domain management.

Availability

STK14C88-NF45I is available at Aetrix Electronics and suitable for industrial PLCs, medical diagnostics equipment, and avionics data recorders requiring stable component supply with long-lifecycle support and guaranteed obsolescence management.

Supply support for STK14C88-NF45I 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 connectivity solutions for industrial, automotive, and consumer markets.

The STK14C88 belongs to Cypress's nvSRAM product line, designed specifically to replace battery-backed SRAM and EEPROM in mission-critical systems where data persistence, speed, and reliability cannot be compromised.

FAQ

What is the role of the VCAP pin and what capacitor value is required?

The VCAP pin connects to an external capacitor that supplies energy during VCC collapse to complete the nonvolatile STORE operation. Cypress specifies a minimum 4.7 µF tantalum capacitor with ≤ 1 Ω ESR; typical layouts use 10 µF to ensure margin across temperature and aging. Incorrect VCAP sizing causes STORE failure under fast power-down conditions.

How does hardware STORE differ from software STORE in terms of timing and control?

Hardware STORE is initiated by pulling HSB low for ≥15 ns, triggering immediate STORE after current SRAM cycle completes (tDELAY = 1 µs). Software STORE requires writing to specific address locations (0x0000–0x000F) with defined data patterns and takes ~10 ms (tSTORE). Hardware mode is preferred for unscheduled power loss; software mode enables controlled, deterministic updates.

Is the STK14C88-NF45I pin-compatible with standard 32-pin SOIC SRAMs?

Yes - it uses identical 32-pin SOIC footprint and signal mapping (A0–A14, DQ0–DQ7, E, W, G, VCC, VSS), with HSB and VCAP added as dedicated pins. Standard SRAM interfaces operate unchanged; HSB and VCAP require minor board modifications (pull-up on HSB, capacitor on VCAP) to enable nonvolatile features.

Why does the datasheet state "Not Recommended for New Designs"?

Cypress issued this notice because the STK14C88 has been superseded by the STK14CA8 series, which offers enhanced endurance (10M vs. 1M STORE cycles), lower power, and extended temperature range. However, STK14C88-NF45I remains fully supported for existing designs and legacy program continuity, with no announced end-of-life date.