Infineon Technologies STK14CA8-RF25

Overview

STK14CA8-RF25 from Cypress Semiconductor is a 128K × 8 (1 Mb) nonvolatile static RAM with integrated QuantumTrap storage, delivering 25 ns read access 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 48-pin SSOP package. It is deployed in mission-critical data logging systems where SRAM volatility must be eliminated without sacrificing speed or endurance.

For engineers reviewing the STK14CA8-RF25 datasheet, STK14CA8-RF25 pinout, STK14CA8-RF25 application, or STK14CA8-RF25 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 bus protocols (E/G/W control).

Technical Context

The STK14CA8-RF25 integrates a 1024 × 1024 SRAM array with per-cell QuantumTrap nonvolatile storage, enabling true monolithic nvSRAM operation. Its dual-mode STORE-hardware-triggered via HSB pin or software-initiated via command sequence-ensures deterministic data preservation during brownouts.

RECALL occurs automatically when VCC rises above 2.65 V (VSWITCH), completing within 20 ms. The device maintains full SRAM timing compliance (tAVAV = 25 ns, tRC = 25 ns) during normal operation while isolating nonvolatile cycles from active memory access-no wait states or bus arbitration required.

Key Specifications

Pinout & Package

STK14CA8-RF25 is housed in a 48-pin SSOP (Shrink Small Outline Package) with 0.5 mm pitch, RoHS-compliant, footprint-optimized for space-constrained industrial PCBs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY14B108L-ZSP25XI and FM1808-250, STK14CA8-RF25 uniquely preserves full parallel SRAM compatibility, deterministic 12.5 ms STORE duration, and industrial-grade VCAP-based power-loss handling-making it irreplaceable in retrofit or timing-critical brownout recovery designs.

Availability

STK14CA8-RF25 is available at Aetrix Electronics and suitable for industrial data loggers, programmable logic controllers, smart energy meters, and railway signaling controllers requiring stable component supply and long-term lifecycle support.

Supply support for STK14CA8-RF25 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 belongs to Cypress's nvSRAM product line, engineered to eliminate battery dependency in SRAM-based systems while maintaining pin- and timing-compatibility with standard asynchronous SRAMs.

FAQ

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

The STK14CA8-RF25 requires a minimum 17 µF capacitor rated for 5 V between VCAP and VSS. This value ensures sufficient energy delivery over the 12.5 ms STORE duration when VCC collapses from 3.0 V to 2.65 V. Lower values risk incomplete STORE and data corruption; higher values (up to 120 µF) improve margin but increase board area and cost.

Can STK14CA8-RF25 be used as a direct replacement for standard 128K×8 SRAMs?

Yes-STK14CA8-RF25 is pin-compatible and timing-compatible with industry-standard 128K×8 SRAMs (e.g., IS61LV1024) in 48-pin SSOP. All control signals (E, G, W), address/data buses, and DC operating conditions match. The only design additions are the VCAP capacitor and optional HSB pull-up; no firmware or timing changes are needed for basic SRAM operation.

How does the HSB pin function during STORE and RECALL operations?

HSB is an open-drain output that goes low during STORE (hardware or software-initiated) and remains low until completion (~12.5 ms). During RECALL at power-up, HSB stays high-no activity is indicated. If left unconnected, its internal weak pull-up holds it high; pulling it low externally triggers a manual STORE, making it useful for controlled save-on-command scenarios.

Is STK14CA8-RF25 recommended for new designs?

No-Cypress explicitly marks STK14CA8 as "Not Recommended for New Designs" in its datasheet (Rev. *A, Dec 2009). While fully functional and supported, newer alternatives like CY14B108L offer SPI interfaces, lower power, and extended lifecycle. STK14CA8-RF25 remains appropriate for legacy system repair, obsolescence mitigation, or applications requiring proven 25 ns parallel nvSRAM behavior.