Infineon Technologies STK14CA8-RF45

Overview

STK14CA8-RF45 from Cypress Semiconductor is a 128K × 8 (1 Mb) nonvolatile static RAM with integrated QuantumTrap storage, delivering 45 ns read/write cycle 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) in 48-pin SSOP package. Used in industrial controllers requiring persistent memory without battery backup.

For engineers reviewing the STK14CA8-RF45 datasheet, STK14CA8-RF45 pinout, STK14CA8-RF45 application, or STK14CA8-RF45 equivalent, key selection criteria include AutoStore timing (12.5 ms), VCAP capacitor requirement (17–120 µF), HSB hardware store busy signaling, software-controlled STORE/RECALL command support, and compatibility with standard SRAM bus protocols.

Technical Context

The STK14CA8-RF45 implements monolithic nvSRAM architecture where each SRAM cell integrates a QuantumTrap nonvolatile storage element. STORE is triggered automatically when VCC drops below 2.65 V or via HSB pin assertion or software command; RECALL occurs automatically at power-up once VCC exceeds 2.65 V.

It supports standard asynchronous SRAM timing modes: E/G-controlled reads, W-controlled writes, and full compatibility with existing 8-bit parallel memory interfaces. The device requires external VCAP capacitor (17–120 µF, 5V-rated) connected between VCAP and VSS to sustain STORE operation during power loss.

Key Specifications

Pinout & Package

STK14CA8-RF45 is packaged in a 48-pin SSOP (RF package), RoHS-compliant, with 0.635 mm pitch and 12.0 mm × 7.5 mm footprint. Pinout supports standard parallel SRAM interface plus dedicated HSB and VCAP terminals for nonvolatile control and energy storage.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STK14CA8-35I, the RF45 offers tighter timing for high-speed control loops; versus FM1808-45-SG, it preserves legacy parallel bus compatibility but occupies larger PCB area and requires more GPIOs.

Availability

STK14CA8-RF45 is available at Aetrix Electronics and suitable for industrial data loggers, PLC memory backup systems, medical infusion pumps, and smart meter firmware storage requiring stable component supply and long-term lifecycle support.

Supply support for STK14CA8-RF45 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 STK14CA8 series was designed as a pin-compatible, drop-in replacement for standard SRAMs while adding battery-free nonvolatility - targeting applications where data persistence must survive frequent power loss without maintenance.

FAQ

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

The datasheet specifies a minimum VCAP capacitance of 17 µF (5V-rated) between VCAP and VSS. This value ensures sufficient energy to complete the 12.5 ms STORE cycle under worst-case VCC droop conditions. Using less than 17 µF risks incomplete STORE and data loss; higher values (up to 120 µF) extend hold-up time margin but increase board area and cost.

Can STK14CA8-RF45 be used in place of a standard 128K×8 SRAM without circuit modification?

Yes - it is pin- and timing-compatible with standard parallel SRAMs, requiring only addition of the VCAP capacitor and optional HSB pull-up. No changes to address/data/control bus wiring or timing logic are needed. However, software must avoid writing to reserved addresses used for soft-store commands unless nonvolatile control is intended.

Does the device perform STORE during a controlled system shutdown?

Yes - STORE can be initiated via software command (writing to specific address sequences) or by pulling HSB low externally. This allows deterministic nonvolatile save prior to intentional power-down, ensuring critical state (e.g., encoder position, fault history) is preserved even if VCC remains above 2.65 V during shutdown.

Is STK14CA8-RF45 recommended for new designs?

No - Cypress documentation explicitly marks STK14CA8 as "Not Recommended for New Designs." While fully functional and supported, Infineon recommends newer alternatives such as the SEMPER™ HyperFlash or Excelon™ FRAM families for new projects due to improved density, speed, and long-term supply assurance.