Infineon Technologies STK14C88-NF35U

Overview

STK14C88-NF35U from Simtek is a 256Kb (32K × 8) auto-store non-volatile SRAM with monolithic Quantum Trap storage, delivering 35 ns read/write cycle time, unlimited SRAM endurance, and automatic STORE/RECALL on power loss/power-up. It operates across –55°C to +125°C, uses a single 5V ±10% supply, and integrates VCAP-based energy storage for reliable data retention without external backup batteries - deployed in avionics black boxes, industrial PLCs, and medical diagnostic memory buffers.

For engineers reviewing the STK14C88-NF35U datasheet, STK14C88-NF35U pinout, STK14C88-NF35U application, or STK14C88-NF35U equivalent, key selection criteria include guaranteed 10 ms STORE duration, hardware/software-controlled non-volatile operations, HSB status signaling, VCAP capacitor interface, and extended-temperature SOIC-32 packaging for mission-critical embedded systems.

Technical Context

This nvSRAM implements a dual-mode non-volatility architecture: STORE transfers data from SRAM to integrated Quantum Trap cells upon VCC drop below 4.0–4.5 V or via hardware/software trigger; RECALL restores data on power-up within 550 μs. The device supports both E/G/W-controlled SRAM access and dedicated HSB-driven STORE initiation.

It features separate power domains: VCC powers logic and SRAM, while VCAP supplies energy during brownout to complete STORE. Timing is strictly defined for six-cycle software sequences (e.g., 0E38h–0FC0h for STORE), with tSTORE = 10 ms and tRESTORE = 550 μs - all validated under full industrial temperature range and 10-year data retention spec.

Key Specifications

Pinout & Package

32-pin 300-mil SOIC (RoHS-compliant), surface-mount package with standard JEDEC MS-012AC footprint and thermal pad omitted. Pin 1 marked by notch or dot; pin 16 is VSS (ground), pin 32 is VCC (5V supply), pin 29 is VCAP (external storage capacitor connection).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar non-volatile SRAM applications.

Compared with CY14B101PA-SP and DS1248-120+, the STK14C88-NF35U offers faster access, true hardware-triggered STORE, and battery-free operation - making it optimal for safety-critical, maintenance-free, and high-reliability embedded systems.

Availability

STK14C88-NF35U is available at Aetrix Electronics and suitable for avionics flight data recorders, industrial PLCs, and medical diagnostic imaging systems requiring stable component supply, long-term lifecycle support, and extended-temperature qualification.

Supply support for STK14C88-NF35U 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

Simtek Corporation was a fabless semiconductor company specializing in radiation-hardened and high-reliability non-volatile memory solutions before its acquisition by Cypress Semiconductor in 2008.

The STK14C88-NF35U belongs to Simtek's AutoStore™ nvSRAM product line, engineered for fail-safe data retention in environments where power instability, extreme temperatures, or regulatory audit trails demand zero data loss - targeting aerospace, transportation, and industrial control markets.

FAQ

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

The VCAP pin connects to an external capacitor that supplies energy during VCC dropout to complete the 10 ms STORE operation. Simtek specifies a minimum 4.7 μF solid tantalum capacitor with ≤1 Ω ESR; ceramic capacitors are unsuitable due to insufficient energy storage and voltage droop characteristics under load.

Can the STK14C88-NF35U be used without external hardware STORE control?

Yes - AutoStore™ operates autonomously when VCC falls below the 4.0–4.5 V VSWITCH threshold, initiating STORE without HSB intervention. The HSB pin is optional for manual initiation; leaving it unconnected allows default high-impedance behavior with internal weak pull-up.

How does software STORE differ from hardware STORE in timing behavior?

Software STORE requires six precise E-controlled read cycles at specific addresses (e.g., 0E38h–0FC0h) with W held high; total initiation time is 6 × 35 ns = 210 ns. Hardware STORE begins within 300 ns of HSB going low and completes in 10 ms - independent of CPU clock or bus arbitration delays.

Is the STK14C88-NF35U pin-compatible with standard 32K×8 SRAMs?

Yes - it uses industry-standard SOIC-32 pinout with identical A0–A14, DQ0–DQ7, E, W, G, VCC, and VSS assignments. However, VCAP and HSB are additional pins not found on volatile SRAMs; they must be tied per Simtek layout guidelines (VCAP to capacitor, HSB left floating or pulled high).