Infineon Technologies STK14C88-NF25

Overview

STK14C88-NF25 from Cypress Semiconductor is a 32K × 8 (256 Kb) nonvolatile static RAM with integrated Quantum Trap storage, delivering 25 ns read access time, single 5V ±10% supply operation, and automatic STORE/RECALL on power loss or reset-used in industrial PLCs for real-time data logging without battery backup.

For engineers reviewing the STK14C88-NF25 datasheet, STK14C88-NF25 pinout, STK14C88-NF25 application, or STK14C88-NF25 equivalent, key selection criteria include AutoStore timing (10 ms STORE duration), HSB-controlled hardware STORE initiation, VCAP capacitor interface for energy hold-up, and compatibility with standard SRAM bus protocols in mission-critical control systems.

Technical Context

The STK14C88-NF25 integrates volatile SRAM and nonvolatile Quantum Trap cells monolithically per bit, enabling atomic STORE (SRAM → nonvolatile) and RECALL (nonvolatile → SRAM) operations. It supports both hardware-triggered STORE via HSB pin assertion and software-controlled STORE/RECALL using address-based command sequences.

Its dual-mode operation includes standard SRAM read/write cycles (E/G/W controlled) and dedicated nonvolatile cycles with strict timing constraints: tSTORE = 10 ms, tDELAY = 1 μs, and tRECOVER = 700 ns. The device requires an external VCAP capacitor (typically 4.7 µF tantalum) to sustain STORE during VCC dropout.

Key Specifications

Pinout & Package

STK14C88-NF25 is housed in a 32-pin 300-mil SOIC package (RoHS-compliant), with 15 address inputs (A0–A14), 8 bidirectional data lines (DQ0–DQ7), and dedicated control pins including E (chip enable), W (write enable), G (output enable), HSB (hardware store busy), VCAP (store capacitor connection), and VCC/VSS.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STK14C88-NF25, STK14CA8-35I trades speed for cost in industrial settings, while FM24CL64-G replaces parallel interface and STORE latency with serial simplicity and infinite endurance-making each suitable only where their specific timing, interface, and reliability trade-offs align with system architecture.

Availability

STK14C88-NF25 is available at Aetrix Electronics and suitable for industrial automation, smart metering, and medical diagnostics requiring stable component supply, long-term data retention, and deterministic power-loss recovery.

Supply support for STK14C88-NF25 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 markets.

The STK14C88 belongs to Cypress's nvSRAM product line, engineered specifically to replace battery-backed SRAM in applications demanding maintenance-free, long-life nonvolatile storage with SRAM-speed access.

FAQ

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

The VCAP pin connects to an external capacitor that supplies energy during VCC dropout to complete the AutoStore operation. Cypress specifies a 4.7 µF solid tantalum capacitor with ≤1 Ω ESR; using undersized or high-ESR capacitors risks incomplete STORE and data loss during power failure.

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

Hardware STORE is initiated by pulling HSB low and completes in 10 ms with automatic VCAP discharge management; software STORE uses address-command sequences and requires CPU intervention but allows precise scheduling. Both use identical internal STORE logic and endurance limits.

Is STK14C88-NF25 compatible with standard SRAM timing controllers?

Yes-its 25 ns read/write timing, E/G/W control protocol, and DQ bus behavior match JEDEC-standard fast SRAMs. No additional glue logic or timing adaptation is needed when replacing 25 ns 32K×8 SRAMs in existing designs.

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

Cypress issued this notice because newer nvSRAM generations (e.g., STK14DE8) offer improved speed, lower power, and enhanced reliability. However, STK14C88-NF25 remains fully supported with active inventory and full documentation for legacy design maintenance and long-lifecycle industrial deployments.