Infineon Technologies STK14CA8-NF25

Overview

STK14CA8-NF25 from Cypress Semiconductor is a 128K × 8 (1 Mb) nonvolatile static RAM with integrated QuantumTrap storage, delivering 25 ns read access time, single 3.0V ±10% operation, and automatic STORE/RECALL on power loss/power-up. It provides unlimited SRAM read/write endurance, 20-year data retention at 55°C, and operates across industrial temperature range (–40°C to +85°C). Used in industrial controllers for real-time parameter backup during brownout events.

For engineers reviewing the STK14CA8-NF25 datasheet, STK14CA8-NF25 pinout, STK14CA8-NF25 application, or STK14CA8-NF25 equivalent, key selection criteria include AutoStore timing (12.5 ms), VCAP capacitor requirement (17–120 μF), HSB hardware store busy signaling, and compatibility with standard SRAM interface protocols without external control logic.

Technical Context

The STK14CA8-NF25 integrates a 1024 × 1024 SRAM array with per-cell QuantumTrap nonvolatile storage, enabling monolithic, byte-level nonvolatility without external EEPROM or battery. Its dual-cycle architecture separates volatile SRAM operation from nonvolatile STORE/RECALL phases, triggered either autonomously at VCC < 2.65 V or via software command or HSB pin assertion.

STORE execution draws 3 mA average current from VCC over 12.5 ms while transferring data using internal charge stored on the external VCAP capacitor; RECALL restores full 131,072-byte contents within 20 ms after VCC exceeds 2.65 V. The device supports both address-controlled and E/G-controlled read cycles and W/E-controlled write cycles compliant with JEDEC SRAM timing conventions.

Key Specifications

Pinout & Package

STK14CA8-NF25 is packaged in a 32-pin SOIC (Small Outline Integrated Circuit) with 0.4-inch body width and standard 1.27 mm pitch. Pin functions are validated per Cypress Document 001-51592 Rev. *A, Page 3.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STK14CA8-NF25, the RF45I trades speed and package size for legacy compatibility, while the FM16W08-SG removes the external capacitor dependency and extends voltage range but mandates PCB redesign - making NF25 optimal for cost-sensitive, volume-manufactured industrial replacements where VCAP integration is already validated.

Availability

STK14CA8-NF25 is available at Aetrix Electronics and suitable for industrial PLCs, smart meters, medical infusion pumps, and railway signaling systems requiring stable component supply with guaranteed long-term availability and traceable sourcing.

Supply support for STK14CA8-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) is a fabless semiconductor company specializing in high-reliability memory, PSoC, and USB solutions for industrial and automotive markets.

The STK14CA8 belongs to Cypress's nvSRAM product line, designed specifically to replace battery-backed SRAM and EEPROM in mission-critical systems where data integrity during power failure is non-negotiable.

FAQ

What is the required VCAP capacitor value for STK14CA8-NF25?

The VCAP capacitor must be 17 μF minimum to 120 μF maximum, rated for 5 V, and placed between the VCAP pin and VSS with low-ESR characteristics. A 47 μF tantalum or polymer capacitor is commonly used to ensure sufficient charge for the 12.5 ms STORE cycle under worst-case VCC droop conditions.

Can STK14CA8-NF25 operate without an external VCAP capacitor?

No. The VCAP capacitor is mandatory: it supplies energy to complete the STORE operation when VCC collapses. Omitting it results in incomplete or failed STORE cycles and potential data loss. The device will power up and function as SRAM, but nonvolatile capability is disabled.

Is STK14CA8-NF25 pin-compatible with standard 32-pin SOIC SRAMs?

Yes - it uses identical pinout and timing for SRAM read/write operations. However, the HSB and VCAP pins are unique to nvSRAM functionality and must be properly terminated (HSB pulled high via 10 kΩ; VCAP connected to capacitor). Standard SRAMs lack these pins and cannot perform STORE/RECALL.

Does STK14CA8-NF25 support software STORE/RECALL without external hardware control?

Yes. Software STORE and RECALL are executed via specific address/data command sequences defined in the datasheet (e.g., writing 0x0000–0x0007 to address 0x0000). These commands require no external signals - only valid E, W, and G timing - and are fully supported in the NF25 variant.