Infineon Technologies STK14C88-NF35

Overview

STK14C88-NF35 from Cypress Semiconductor is a 32K × 8 (256 Kb) nonvolatile static RAM with integrated Quantum Trap storage, delivering 35 ns read/write cycle time, automatic STORE on power loss, and automatic RECALL on power-up. It operates from a single 5V ±10% supply, supports commercial temperature range (0°C to 70°C), and uses a 32-pin 300-mil SOIC package - deployed in industrial control data logging where persistent memory retention without external backup is required.

For engineers reviewing the STK14C88-NF35 datasheet, STK14C88-NF35 pinout, STK14C88-NF35 application, or STK14C88-NF35 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 while ensuring 100-year data retention.

Technical Context

The STK14C88-NF35 integrates volatile SRAM and nonvolatile Quantum Trap cells monolithically per bit, enabling true byte-level nonvolatility without external EEPROM or battery. Its STORE/RECALL control logic operates independently of host timing, triggered either by power-fail detection or explicit HSB assertion.

Hardware STORE is initiated by pulling HSB low for ≥15 ns, followed by 10 ms internal STORE execution during which DQ lines go high-impedance and HSB remains low. RECALL occurs automatically at power-up, restoring full 32K×8 contents to SRAM within microseconds before bus access is enabled.

Key Specifications

Pinout & Package

Package: 32-pin 300-mil SOIC (RoHS-compliant), surface-mount, gull-wing lead form.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STK14CA8-NF35, the STK14C88-NF35 offers proven reliability in commercial-temperature legacy systems but lacks industrial-grade thermal margin; versus FM1808-35-SG, it provides tighter timing control and simpler VCAP design at the cost of lower density and finite STORE endurance.

Availability

STK14C88-NF35 is available at Aetrix Electronics and suitable for industrial data loggers, POS terminal memory backup, medical device configuration storage, and network router boot parameter retention requiring stable component supply and long-lifecycle support.

Supply support for STK14C88-NF35 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 to replace battery-backed SRAM in mission-critical systems where data persistence, timing predictability, and zero-maintenance operation are mandatory.

FAQ

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

The VCAP pin connects to an external 4.7 µF tantalum capacitor that supplies energy during power loss to complete the 10 ms STORE operation. Cypress specifies 4.7 µF ±20%, 10 V rating, with ESR < 1 Ω; deviation risks incomplete STORE and data loss. The capacitor must be placed within 5 mm of VCAP/VSS pins with low-inductance routing.

Can STK14C88-NF35 be used in place of a standard 32K×8 SRAM without hardware changes?

Yes - it is pin-compatible and timing-compatible with standard 35 ns SRAMs (e.g., AS6C4008), provided the VCAP capacitor is added and HSB is either pulled up via 10 kΩ or left unconnected. No firmware or address/data bus modifications are needed for basic SRAM operation; STORE/RECALL features remain transparent unless explicitly used.

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

Hardware STORE (via HSB low pulse) initiates immediately upon detection and guarantees STORE execution regardless of SRAM bus activity, making it ideal for uncontrolled power loss. Software STORE requires two back-to-back writes to specific addresses and depends on clean bus timing - it is less robust during brownout but allows precise application-level control over save points.

Is STK14C88-NF35 recommended for new designs?

No - Cypress marks STK14C88 as "Not Recommended for New Designs" (NRND) in its official documentation. While fully functional and supported, newer alternatives like STK14CA8 or Infineon's nvSRAM portfolio offer enhanced specs and longer-term availability. Aetrix recommends evaluating STK14CA8-NF35 for new projects requiring drop-in compatibility.