Infineon Technologies STK14CA8-NF25I

Overview

STK14CA8-NF25I from Cypress Semiconductor is a 128K × 8 (1 Mb) nonvolatile static RAM with integrated QuantumTrap storage, operating at 3.0V ±10%, offering 25 ns read access time, automatic STORE on power loss, and automatic RECALL on power-up. It delivers unlimited SRAM read/write endurance, 20-year data retention at 55°C, and supports industrial temperature range (–40°C to +85°C). Used in industrial PLCs for real-time parameter backup during brownouts.

For engineers reviewing the STK14CA8-NF25I datasheet, STK14CA8-NF25I pinout, STK14CA8-NF25I application, or STK14CA8-NF25I equivalent, key selection criteria include AutoStore timing (12.5 ms), VCAP capacitor requirement (17–120 µF), HSB hardware control interface, and compatibility with standard SRAM bus protocols without external logic.

Technical Context

The STK14CA8-NF25I integrates a 1024 × 1024 SRAM array with per-cell QuantumTrap nonvolatile storage, enabling monolithic STORE/RECALL without external controllers. Its dual-cycle architecture separates volatile SRAM operation from nonvolatile transfer, with dedicated VCAP pin supplying hold-up energy during power failure.

STORE is triggered either automatically when VCC drops below 2.65 V (VSWITCH), via hardware assertion of HSB low, or through software command sequences. RECALL occurs unconditionally at power-up once VCC exceeds VSWITCH, completing within 20 ms - critical for deterministic boot recovery in safety-critical systems.

Key Specifications

Pinout & Package

STK14CA8-NF25I uses a 32-pin SOIC (NF package) with 0.3-inch body width and RoHS-compliant finish. Pin layout matches industry-standard parallel SRAM footprint, enabling drop-in PCB replacement where space and thermal constraints permit.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STK14CA8-RF45I and FM1808-25-SG, the STK14CA8-NF25I offers optimal balance of speed, industrial qualification, and SOIC-32 footprint - making it ideal for cost-sensitive industrial upgrades where automotive qualification or higher thermal margin is unnecessary.

Availability

STK14CA8-NF25I is available at Aetrix Electronics and suitable for industrial PLCs, smart meters, railway signaling systems, and medical infusion pumps requiring stable component supply with guaranteed long-term traceability.

Supply support for STK14CA8-NF25I 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 IoT applications.

The STK14CA8 belongs to Cypress's nvSRAM product line, engineered specifically to replace battery-backed SRAM and EEPROM in systems demanding instant nonvolatile write capability and zero maintenance data retention.

FAQ

What is the minimum VCAP capacitance required for reliable AutoStore operation?

The STK14CA8-NF25I requires a minimum 17 µF capacitor rated for 5 V between VCAP and VSS. This value ensures sufficient energy to complete the 12.5 ms STORE cycle even at VCC = 2.7 V and worst-case temperature (85°C). Lower capacitance risks incomplete STORE and data loss; recommended derating is 2× (≥34 µF) for long-term reliability.

Can the HSB pin be left unconnected in a design?

Yes - HSB has an internal weak pull-up and may be left floating if hardware-initiated STORE is not used. However, leaving it unconnected forfeits real-time STORE status feedback and prevents external hardware-triggered STORE. For robustness in noisy environments, tie HSB to VCC via 10 kΩ resistor instead of floating.

Does STK14CA8-NF25I support byte-level writes like standard SRAM?

Yes - it functions electrically identical to a standard 128K × 8 SRAM for all read/write operations. Address and data lines behave per JEDEC-standard parallel SRAM timing; no special addressing or command protocol is needed for byte writes. STORE/RECALL are background operations transparent to normal access.

Is STK14CA8-NF25I pin-compatible with standard 32-pin SOIC SRAMs such as IS61LV10248AL?

Yes - STK14CA8-NF25I uses identical 32-pin SOIC pinout (NF package) and signal naming (A0–A16, DQ0–DQ7, E, W, G, VCC, VSS). No PCB redesign is needed for drop-in replacement, though VCAP addition and HSB handling must be implemented per application requirements.