Infineon Technologies STK12C68-5L55M

Overview

STK12C68-5L55M from Cypress Semiconductor is a 64 Kbit (8K × 8) nonvolatile static RAM with QuantumTrap™ technology, delivering 55 ns access time, AutoStore™ on power-down, and 100-year data retention. It operates at single 5V ±10%, supports military temperature range (−55°C to +125°C), and integrates SRAM and nonvolatile storage in each cell for seamless STORE/RECALL operations in industrial control and avionics systems.

For engineers reviewing the STK12C68-5L55M datasheet, STK12C68-5L55M pinout, STK12C68-5L55M application, or STK12C68-5L55M equivalent, key selection criteria include VCAP capacitor sizing (68 µF), HSB-controlled hardware STORE timing (tDELAY), software STORE address sequence (0x0000→0x0F0F), RECALL latency (tHRECALL), and AutoStore inhibit configuration via VCC/VCAP re-routing.

Technical Context

The STK12C68-5L55M implements dual-mode nonvolatility: STORE transfers SRAM contents to QuantumTrap cells either automatically at VCC drop below VSWITCH (with external 68 µF VCAP capacitor) or via HSB assertion or six-step software address sequence (0x0000 → 0x0F0F). RECALL restores data on power-up or via software (0x0000 → 0x0F0E), with tHRECALL = 10 ms typical.

Its architecture enforces STORE/RECALL atomicity: SRAM read/write is inhibited during both operations. Hardware protection blocks STORE and write when VCC < VSWITCH, and AutoStore is disabled only by tying VCC to ground and applying +5V to VCAP - a hardwired configuration change, not runtime toggle.

Key Specifications

Pinout & Package

STK12C68-5L55M uses a 28-pad LCC (Leadless Chip Carrier) package, 300-mil body, RoHS-compliant, with gull-wing-compatible land pattern per JEDEC MO-118AC.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY14B108L-BA25XI and FM24CL64-G, the STK12C68-5L55M uniquely delivers pin-compatible SRAM replacement with hardware-triggered, capacitor-powered STORE - essential for retrofitting legacy systems where bus protocol and board space are fixed.

Availability

STK12C68-5L55M is available at Aetrix Electronics and suitable for avionics data loggers, industrial PLC configuration memory, and railway signaling controllers requiring stable component supply under extended temperature and long-lifecycle programs.

Supply support for STK12C68-5L55M 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 U.S.-based semiconductor company specializing in high-reliability memory, PSoC, and USB solutions for industrial, automotive, and aerospace markets.

The STK12C68-5L55M belongs to Cypress's nvSRAM product line, engineered specifically for mission-critical systems needing battery-free, autonomous nonvolatile storage with deterministic STORE/RECALL timing and extended temperature operation.

FAQ

What is the minimum VCAP capacitor value required for reliable AutoStore operation?

The STK12C68-5L55M requires a minimum 68 µF tantalum or polymer capacitor on VCAP, rated ≥6 V and +20% tolerance. Values below 68 µF risk incomplete STORE under worst-case VCC droop profiles; 100 µF is recommended for margin. The capacitor must be placed within 5 mm of the VCAP pin with low-ESR layout.

Can the STK12C68-5L55M be used without connecting the HSB pin?

Yes - HSB is optional. When unconnected, its internal weak pull-up holds it HIGH, disabling hardware STORE initiation. The pin remains functional as an open-drain busy indicator during AutoStore or software STORE, but external pull-up is unnecessary unless system monitoring of STORE progress is required.

How does the STK12C68-5L55M prevent data corruption during brownout conditions?

The device monitors VCC against VSWITCH (~3.6 V). When VCC drops below this threshold, it inhibits all externally initiated STORE and write operations, disables HSB-driven STORE requests, and prevents SRAM access until VCC recovers above VRESET. This hardware lockout ensures no partial writes occur during unstable supply conditions.

Is the software STORE sequence compatible with standard SRAM read timing?

Yes - the six-address software STORE sequence uses standard CE-controlled read cycles with tAA ≤55 ns. No special timing adjustments are needed beyond normal SRAM access; however, intervening writes or address violations abort the sequence. OE may be HIGH or LOW during the sequence - only CE transitions matter for clocking.