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Infineon Technologies STK12C68-SF25I
- Part No.:
- STK12C68-SF25I
- Manufacturer:
- Infineon Technologies
- Category:
- Memory
- Package:
- 28-SOIC (0.342", 8.69mm Width)
- Datasheet:
-
STK12C68-SF25I.pdf
- Description:
- IC NVSRAM 64KBIT PARALLEL 28SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,780
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Product details
Overview
STK12C68-SF25I from Cypress Semiconductor is a 64 Kbit (8 K × 8) nonvolatile static RAM (nvSRAM) with QuantumTrap technology, supporting 25 ns access time, AutoStore on power-down (with 68 µF VCAP capacitor), and software/hardware-controlled STORE/RECALL. It operates at single 5 V ±10%, delivers 1,000,000 STORE cycles and 100-year data retention, and is used in industrial control systems requiring deterministic nonvolatile write-back without battery backup.
For engineers reviewing the STK12C68-SF25I datasheet, STK12C68-SF25I pinout, STK12C68-SF25I application, or STK12C68-SF25I equivalent, key selection criteria include AutoStore timing behavior, HSB pin handshake logic, VCAP capacitor sizing constraints, SRAM-compatible interface timing (tAA = 25 ns), and compatibility with legacy 28-pin SOIC footprint designs.
Technical Context
The STK12C68-SF25I integrates parallel SRAM and QuantumTrap nonvolatile storage per cell, enabling simultaneous STORE (SRAM → nv) and RECALL (nv → SRAM) operations. It supports three STORE triggers: AutoStore on VCC drop below VSWITCH (~3.6 V), hardware STORE via HSB pin assertion, and software STORE via 6-cycle CE-controlled address sequence (0x0000 → 0x0F0F).
RECALL occurs automatically on power-up when VCC exceeds VSWITCH, or via software sequence (0x0000 → 0x0F0E). During STORE/RECALL, SRAM read/write is inhibited; HSB pin signals busy state as open-drain output; VCAP supplies energy for STORE using internal charge pump to 5 V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 64 Kbit (8 K × 8), directly replaceable for standard 8K×8 SRAMs in existing PCB layouts |
| Access Time | 25 ns - ensures compatibility with high-speed microcontroller bus timing without wait states |
| STORE Endurance | 1,000,000 cycles - defines maximum field-replaceable write-to-nv lifetime under frequent power-loss events |
| Data Retention | 100 years at T ≤ 85°C - guarantees long-term data integrity without refresh or external power |
| VCAP Requirement | 68 µF ±20%, 6 V rated - sets minimum bulk capacitance needed to sustain full STORE operation during VCC collapse |
| Operating Voltage | 5.0 V ±10% - mandates compatible LDO regulation; no 3.3 V support |
| Temperature Range | –40°C to +85°C - qualified for industrial ambient environments without derating |
Pinout & Package
STK12C68-SF25I is housed in a 28-pin SOIC package (330 mil width), pin-compatible with industry-standard 28-pin SRAM footprints. The package supports surface-mount reflow and meets RoHS requirements.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A12 | Address Inputs | 13-bit address bus for 8,192-byte addressing; TTL-compatible input thresholds |
| DQ0–DQ7 | Bidirectional Data I/O | 8-bit data bus shared for read/write; tristated when OE HIGH or during STORE/RECALL |
| WE | Write Enable (Active LOW) | Controls write latching; must be held HIGH during AutoStore to prevent bus contention |
| CE | Chip Enable (Active LOW) | Primary chip select; required LOW for all memory operations including software STORE sequence |
| OE | Output Enable (Active LOW) | Enables DQ outputs during reads; must be HIGH during writes to avoid contention |
| HSB | Hardware Store Busy | Open-drain status signal: LOW during any STORE/RECALL; also initiates STORE when externally pulled LOW |
| VCAP | AutoStore Capacitor Supply | Internal charge pump node; requires external 68 µF capacitor to sustain STORE energy delivery |
| VCC | Power Supply | +5 V ±10% main supply; disconnects from VCAP at VSWITCH (~3.6 V) to trigger AutoStore |
| VSS | Ground | System ground reference; must be low-impedance for reliable STORE timing |
Key Features
| Feature | Design Value |
|---|---|
| AutoStore on Power Loss | Self-triggered STORE when VCC drops below 3.6 V, using energy from external VCAP capacitor - eliminates need for battery or supercap backup |
| Software STORE/RECALL | 6-cycle CE-controlled read sequence (no special commands or registers) - enables deterministic nonvolatile save from firmware without hardware modification |
| Hardware STORE Trigger | HSB pin double-function: request STORE by pulling LOW, and monitor progress via open-drain busy signal - supports real-time system coordination |
| QuantumTrap Nonvolatile Cell | Embedded per-cell nv element enabling parallel STORE/RECALL across all 8K bytes - avoids serial EEPROM-style bottlenecks |
| Unlimited SRAM Cycles | Standard SRAM interface with unlimited reads/writes - preserves legacy software and timing models while adding nv capability |
Applications
| Industrial PLC Data Logging | Medical Device Parameter Storage |
|---|---|
Use Scenario: Storing runtime configuration and alarm history in programmable logic controllers during unexpected AC mains loss. IC Role / Device Role / Timing Role: Nonvolatile SRAM buffer that captures last valid state before power collapse, recalled on next boot. Use Value: Eliminates battery replacement service intervals and avoids data loss during brownouts shorter than supercap hold-up time. | Use Scenario: Preserving calibration coefficients and patient treatment settings in portable infusion pumps between power cycles. IC Role / Device Role / Timing Role: Zero-maintenance nonvolatile memory with guaranteed 100-year retention, compliant with IEC 62304 Class B software safety requirements. Use Value: Meets regulatory requirement for persistent parameter storage without volatile backup components or periodic refresh routines. |
| Avionics Black Box Buffer | Smart Meter Firmware State Save |
Use Scenario: Capturing flight-critical sensor snapshots in aircraft health monitoring units during engine shutdown or electrical fault. IC Role / Device Role / Timing Role: Deterministic STORE triggered by monitored VCC decay, completing within 10 ms before voltage falls below functional threshold. Use Value: Provides certified, timestamped pre-failure data capture independent of host processor intervention or watchdog timers. | Use Scenario: Saving metering register values and tariff schedules during grid disconnection in ANSI C12.22-compliant smart meters. IC Role / Device Role / Timing Role: High-reliability nvSRAM interfaced directly to metrology SoC's parallel bus, eliminating SPI flash wear-out concerns. Use Value: Supports >1 million STORE cycles over 20-year field life, exceeding ANSI 12.22 data persistence requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar nonvolatile SRAM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| STK12C68-SF35I | 45 ns access time; same pinout, package, and feature set | Lower speed grade suitable for cost-sensitive industrial controllers with relaxed timing margins | Select when tAA ≤ 35 ns satisfies system bus timing and lower cost is prioritized over 25 ns performance |
| FM1808-250 | 4 Mbit density, 55 ns access, 3.3 V operation, different pinout (32-pin TSOP) | Higher density for extended logging buffers; requires PCB redesign and voltage translation | Choose only if migrating to 3.3 V architecture and needing >64 Kbit capacity; not drop-in compatible |
Compared with STK12C68-SF35I and FM1808-250, the STK12C68-SF25I uniquely delivers 25 ns SRAM speed with AutoStore in a legacy 28-pin SOIC footprint - making it the only option for retrofitting high-speed industrial systems without layout change or voltage redesign.
Availability
STK12C68-SF25I is available at Aetrix Electronics and suitable for industrial PLCs, medical infusion devices, avionics black box recorders, and smart metering systems requiring stable component supply with guaranteed long-term manufacturability.
Supply support for STK12C68-SF25I 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 memory, microcontrollers, and programmable solutions for industrial, automotive, and consumer markets.
The STK12C68 belongs to Cypress's QuantumTrap nvSRAM product line, designed specifically for mission-critical applications where battery-free, fast, and highly reliable nonvolatile data capture is required during power interruption.
FAQ
What is the minimum VCAP capacitance required for reliable AutoStore operation?
The STK12C68-SF25I requires a minimum 68 µF capacitor on the VCAP pin, rated at 6 V with ±20% tolerance. This value ensures sufficient stored energy to complete the full 10 ms STORE cycle when VCC collapses. Using less capacitance risks incomplete STORE and data corruption; values up to 220 µF are supported but offer no functional benefit beyond margin.
Can STK12C68-SF25I be operated at 3.3 V?
No. The STK12C68-SF25I is specified exclusively for 5.0 V ±10% operation. Its internal charge pump, QuantumTrap programming voltage, and logic thresholds are designed for 5 V. Attempting 3.3 V operation results in failed STORE/RECALL, invalid timing, and potential data loss. For 3.3 V systems, consider Infineon's newer nvSRAM families like the CY14B108.
How does the HSB pin behave during software-initiated STORE?
The HSB pin goes LOW during software-initiated STORE, exactly as during AutoStore or hardware STORE. It remains LOW for the full tSTORE duration (≤10 ms), providing a hardware-synchronized busy signal usable by the host system to gate further memory accesses or initiate fail-safe actions.
Is the STK12C68-SF25I still recommended for new designs?
No - Cypress explicitly marks the STK12C68 family as "Not Recommended for New Designs" in its official documentation (Rev. *H, Nov 2014). While fully supported for existing production and repair, new designs should evaluate Infineon's CY14B series or alternative nvSRAM solutions offering enhanced density, 3.3 V support, and extended lifecycle assurance.
STK12C68-SF25I Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Infineon Technologies
- Series:
- -
- Package/Case:
- 28-SOIC (0.342", 8.69mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Memory Type:
- Non-Volatile
- Memory Format:
- NVSRAM
- Technology:
- NVSRAM (Non-Volatile SRAM)
- Memory Size:
- 64Kbit
- Memory Organization:
- 8K x 8
- Memory Interface:
- Parallel
- Clock Frequency:
- -
- Write Cycle Time - Word, Page:
- 25ns
- Access Time:
- 25 ns
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-SOIC
STK12C68-SF25I FAQ
1.How can I place an order for STK12C68-SF25I through Aetrix?
Please submit a Request for Quotation (RFQ) for STK12C68-SF25I on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for STK12C68-SF25I reliable?
The price and inventory of STK12C68-SF25I are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STK12C68-SF25I is usually 5 days.
3.What payment methods are accepted for STK12C68-SF25I?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STK12C68-SF25I transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for STK12C68-SF25I?
STK12C68-SF25I orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your STK12C68-SF25I order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for STK12C68-SF25I?
For technical support, including STK12C68-SF25I datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STK12C68-SF25I requirements.
6.How does Aetrix verify that STK12C68-SF25I is sourced from the original manufacturer or authorized distributors?
All STK12C68-SF25I products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that STK12C68-SF25I meets industry standards.
7.What is the process for return or replacement of STK12C68-SF25I?
All STK12C68-SF25I units undergo pre-shipment inspection (PSI). If there is an issue with STK12C68-SF25I, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The STK12C68-SF25I part is unused and in its original packaging.
Return procedure for STK12C68-SF25I:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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