Infineon Technologies STK14D88-NF45

Overview

STK14D88-NF45 from Cypress Semiconductor is a 32K × 8 (256 Kb) nonvolatile static RAM with integrated Quantum Trap storage, delivering 45 ns read/write cycle time, automatic STORE on power loss, and automatic RECALL at power-up. It operates from a single 3.0V ±10% supply, supports industrial temperature range (–40°C to +85°C), and uses a 32-pin SOIC package. It is deployed in industrial PLCs for real-time data logging during unexpected power interruptions.

For engineers reviewing the STK14D88-NF45 datasheet, STK14D88-NF45 pinout, STK14D88-NF45 application, or STK14D88-NF45 equivalent, key selection criteria include AutoStore timing (12.5 ms), VCAP capacitor requirement (17–120 µF), HSB hardware store control, unlimited SRAM endurance, and compatibility with legacy 32-pin parallel memory interfaces.

Technical Context

The STK14D88-NF45 integrates volatile SRAM and nonvolatile Quantum Trap cells monolithically, enabling atomic STORE/RECALL without external controllers. Its dual-cycle architecture separates SRAM access (25/35/45 ns variants) from nonvolatile operations: AutoStore triggers below 2.65 V (VSWITCH), while RECALL initiates after VCC rises above that threshold within 150 µs.

It supports three STORE modes: automatic (power-loss detection), hardware (HSB pin assertion), and software (command sequence). All modes execute a deterministic 12.5 ms STORE cycle with ≤3 mA average VCC current and require external VCAP capacitance (17–120 µF) tied between VCAP and VSS to sustain internal charge during voltage collapse.

Key Specifications

Pinout & Package

STK14D88-NF45 is housed in a 32-pin Small Outline Integrated Circuit (SOIC) package with 0.3 inch body width and standard JEDEC MS-012AC footprint. Pin 1 is marked by a notch or dot; pin numbering proceeds counterclockwise.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STK14D88-NF45, STK14C88-35I offers tighter timing at lower cost but reduced margin for marginal bus setups; FM1808-40-SG provides superior write speed and no VCAP dependency but requires firmware adaptation and lacks automatic power-loss detection.

Availability

STK14D88-NF45 is available at Aetrix Electronics and suitable for industrial automation, point-of-sale systems, and railway signaling equipment requiring stable component supply and long-term obsolescence support.

Supply support for STK14D88-NF45 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 and automotive markets.

The STK14D88 belongs to Cypress's nvSRAM product line, designed specifically to replace battery-backed SRAM in mission-critical systems where maintenance-free, long-life nonvolatility is mandatory.

FAQ

What is the purpose of the VCAP pin and how is it used?

The VCAP pin connects to an external capacitor (17–120 µF) that stores charge to power the internal Quantum Trap STORE operation during VCC collapse. When VCC drops below 2.65 V, the stored energy sustains the 12.5 ms STORE cycle, ensuring data transfer from SRAM to nonvolatile cells completes reliably. Tantalum or low-ESR ceramic capacitors are recommended; placement must minimize trace inductance.

Can STK14D88-NF45 be used as a direct replacement for standard SRAM?

Yes, in read/write functionality - it is pin-compatible and timing-compatible with standard 32K×8 SRAMs like IS61LV256AL. However, VCAP must be added, HSB should be monitored or left unconnected, and software must avoid issuing STORE commands unless nonvolatility is required. No changes to address/data/control timing are needed for basic SRAM operation.

How does the AutoStore feature activate without external circuitry?

AutoStore activates autonomously when the internal voltage monitor detects VCC falling below 2.65 V (VSWITCH). No external supervisor IC, resistor divider, or GPIO is required. The device immediately suspends SRAM access, initiates the 12.5 ms STORE sequence using VCAP-supplied energy, and asserts HSB low to signal ongoing operation - all without firmware intervention.

Is STK14D88-NF45 suitable for new designs despite "Not Recommended for New Designs" in its datasheet?

The "Not Recommended for New Designs" note reflects Cypress's strategic shift toward newer nvSRAM families (e.g., CY14B108) and F-RAM alternatives - not reliability or obsolescence risk. STK14D88-NF45 remains fully supported, in active production, and widely used in long-lifecycle industrial programs where proven stability and qualification outweigh incremental feature gains.