Infineon Technologies STK14C88-5C45M

Overview

STK14C88-5C45M from Cypress Semiconductor is a 32K × 8 (256 Kb) nonvolatile static RAM with AutoStore functionality, operating at 5 V ±10%, 45 ns read/write cycle time, and featuring automatic STORE on power loss and RECALL on power-up. It delivers unlimited SRAM read/write endurance, 100-year data retention, and integrates Quantum Trap nonvolatile storage per cell for mission-critical data logging in industrial controllers.

For engineers reviewing the STK14C88-5C45M datasheet, STK14C88-5C45M pinout, STK14C88-5C45M application, or STK14C88-5C45M equivalent, key selection criteria include AutoStore timing (10 ms), HSB-controlled hardware STORE initiation, VCAP capacitor interface, and compatibility with legacy 5 V parallel bus systems requiring guaranteed nonvolatile write persistence without external controllers.

Technical Context

The STK14C88-5C45M implements monolithic nvSRAM architecture with integrated Quantum Trap storage cells co-located with each SRAM bit. Its STORE/RECALL control logic operates autonomously during power transitions and supports both hardware-triggered (via HSB low pulse) and software-initiated nonvolatile operations.

It uses standard asynchronous parallel interface timing with E, G, W controls and supports three operating modes: SRAM read (E=L, G=L, W=H), SRAM write (E=L, W=L), and hardware STORE (HSB=L). The device requires external VCAP capacitor (typically 4.7 µF tantalum) connected to VCAP pin to sustain STORE operation during VCC collapse.

Key Specifications

Pinout & Package

32-pin 300 mil SOIC (RoHS-compliant) package with standard parallel memory footprint and dedicated VCAP and HSB pins for AutoStore management.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STK14C88-5C45M, the -35M variant improves speed and reduces active current, while the -5I45M extends thermal reliability-neither alters AutoStore latency, VCAP requirements, or pin compatibility, making them direct drop-in alternatives for specific environmental or performance needs.

Availability

STK14C88-5C45M is available at Aetrix Electronics and suitable for industrial PLC data logging, medical device event buffering, and avionics black box recorders requiring stable component supply and long-term obsolescence support.

Supply support for STK14C88-5C45M 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 infrastructure markets.

The STK14C88 belongs to Cypress's nvSRAM product line, engineered specifically to replace battery-backed SRAM and EEPROM in systems demanding zero-maintenance, deterministic nonvolatile storage with true SRAM performance.

FAQ

What capacitor value and type is required on the VCAP pin?

A 4.7 µF solid tantalum capacitor with ≤1 Ω ESR is required between VCAP and VSS. This capacitor must be placed within 10 mm of the package and rated for ≥10 V. It supplies energy during VCC dropout to complete the 10 ms STORE operation-using ceramic or aluminum electrolytic capacitors violates specification and risks data loss.

Can STK14C88-5C45M operate without connecting the HSB pin?

Yes-HSB has an internal weak pull-up and may be left unconnected if only power-loss-triggered AutoStore is needed. However, leaving HSB unconnected disables hardware-initiated STORE. For controlled nonvolatile writes (e.g., after critical data update), HSB must be actively driven low for ≥15 ns with proper slew rate control.

Does RECALL occur automatically even if the device was in the middle of a write cycle when power failed?

Yes-RECALL always restores the last fully STORED image from Quantum Trap cells on power-up, regardless of SRAM state at power loss. If a STORE was incomplete due to insufficient VCAP energy, RECALL returns the most recent successfully completed STORE image-not the corrupted partial write.

Is software STORE supported, and what is the register interface?

Yes-software STORE is implemented via a specific 3-cycle write sequence to address 0x0000 with data values 0x00, 0x01, then 0x00. No internal registers or configuration bits exist; the sequence is detected by on-die state machine. This method avoids bus contention and requires no additional address decoding or control lines beyond standard E/W/G.