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Infineon Technologies STK12C68-L35
- Part No.:
- STK12C68-L35
- Manufacturer:
- Infineon Technologies
- Category:
- Memory
- Package:
- 28-LCC
- Datasheet:
-
STK12C68-L35.pdf
- Description:
- IC NVSRAM 64KBIT PARALLEL 28LCC
- Quantity:
- Payment:
- Shipping:
Inventory:2,466
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Product details
Overview
STK12C68-L35 from Cypress Semiconductor is a 64 Kbit (8K × 8) nonvolatile SRAM with QuantumTrap technology, delivering 35 ns access time, AutoStore on power loss using a 68 µF VCAP capacitor, and unlimited SRAM read/write cycles. It operates at single 5V ±10%, supports software/hardware STORE/RECALL, and is used in industrial control systems requiring persistent memory without battery backup.
For engineers reviewing the STK12C68-L35 datasheet, STK12C68-L35 pinout, STK12C68-L35 application, or STK12C68-L35 equivalent, key selection criteria include AutoStore timing behavior, HSB-controlled hardware store latency, VCAP capacitor sizing constraints, and compatibility with legacy 28-pin SOIC-based 5V memory interfaces.
Technical Context
The STK12C68-L35 integrates parallel SRAM and QuantumTrap nonvolatile cells per bit, enabling simultaneous STORE/RECALL across all 8,192 bytes. It uses internal charge-pump regulation to drive VCAP to 5V and initiates AutoStore when VCC drops below VSWITCH (~3.6V), completing within 10 ms using stored VCAP energy.
STORE operations are conditional: hardware (HSB) and AutoStore require at least one prior SRAM write since last STORE/RECALL; software STORE bypasses this condition. RECALL occurs automatically on power-up or via six-address sequence (0x0000→0x0F0E), clearing SRAM before loading nonvolatile data.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 64 Kbit (8K × 8) - provides byte-wide interface compatible with legacy 8-bit microcontrollers and FPGA configuration buffers. |
| Access Time | 35 ns - defines maximum clock-to-data valid delay for synchronous read cycles under 5V ±10% supply. |
| Nonvolatile Endurance | 1,000,000 STORE cycles - limits total number of times data can be written to QuantumTrap cells before wear-out. |
| Data Retention | 100 years - guaranteed nonvolatile data retention at ≤85°C, independent of power cycling or SRAM activity. |
| VCAP Capacitor | 68 µF ±20%, 6V rated - minimum capacitance required to sustain full 10 ms STORE operation during VCC collapse. |
| Operating Voltage | 5V ±10% (4.5V–5.5V) - single-supply operation eliminates need for auxiliary voltage rails or level shifters. |
| Temperature Range | Industrial: –40°C to +85°C - validated operation across extended thermal range for factory automation and telecom infrastructure. |
Pinout & Package
STK12C68-L35 is packaged in a 28-pin SOIC (300 mil width), pin-compatible with standard 28-pin DIP footprints. The package supports surface-mount assembly and meets RoHS requirements.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A12 | Address Input | 13-bit address bus selecting one of 8,192 memory locations; latched on CE/WE/OE transitions. |
| DQ0–DQ7 | Bidirectional Data I/O | 8-bit data bus shared for read output and write input; tristated when OE HIGH or during STORE/RECALL. |
| CE | Chip Enable | Active-low chip select; must be LOW with OE LOW and WE HIGH for valid read, or WE LOW for write. |
| WE | Write Enable | Active-low write strobe; controls data capture timing and inhibits writes during STORE/RECALL. |
| OE | Output Enable | Active-low output enable; disables drivers when HIGH to prevent bus contention during writes or standby. |
| HSB | Hardware Store Busy | Open-drain status signal: driven LOW during any STORE (Auto/HW/SW); pulled LOW externally to initiate hardware STORE. |
| VCAP | AutoStore Capacitor Terminal | Internal charge-pump output node; requires external 68 µF capacitor to retain energy for power-loss STORE. |
| VCC | Power Supply | +5V ±10% main supply; disconnects from VCAP when falling below VSWITCH (~3.6V) to trigger AutoStore. |
| VSS | Ground | System reference ground; must be low-impedance connection to minimize noise coupling into STORE timing path. |
Key Features
| Feature | Design Value |
|---|---|
| AutoStore on Power Loss | Eliminates need for external battery or supercapacitor backup by using internal charge pump and VCAP capacitor for autonomous STORE during brownout. |
| Three STORE Initiation Modes | Supports system-level flexibility: automatic (power-down), hardware (HSB pin), or software (6-address sequence), each with distinct timing and dependency rules. |
| Conditional STORE Enforcement | Prevents unnecessary nonvolatile writes by requiring at least one SRAM write since last STORE/RECALL-reducing QuantumTrap wear in idle systems. |
| Unlimited RECALL Cycles | Enables repeated restoration of nonvolatile data to SRAM without degradation, critical for firmware recovery and configuration reload use cases. |
| RoHS-Compliant 28-Pin SOIC | Enables drop-in replacement in legacy 5V memory sockets while meeting environmental compliance for industrial and telecom equipment. |
Applications
| Industrial PLC Data Logging | Medical Device Configuration Storage |
|---|---|
Use Scenario: Storing real-time sensor calibration offsets and operational history in programmable logic controllers during mains power interruption. IC Role / Device Role / Timing Role: Nonvolatile SRAM providing immediate-access scratchpad memory with guaranteed data persistence across uncontrolled power cycles. Use Value: Eliminates battery maintenance and avoids data loss during 10–100 ms brownouts typical in factory floor environments. | Use Scenario: Retaining user-defined therapy parameters and device self-test results in portable infusion pumps between power-on events. IC Role / Device Role / Timing Role: Persistent memory holding safety-critical configuration data that must survive >100,000 power cycles over 10-year product lifetime. Use Value: Achieves 100-year data retention without volatile backup, satisfying IEC 62304 Class C software safety requirements. |
| Telecom Line Card State Backup | Avionics Flight Recorder Buffer |
Use Scenario: Capturing port status, link negotiation state, and error counters in carrier-grade Ethernet line cards during hot-swap or power fail events. IC Role / Device Role / Timing Role: Fast-access memory with deterministic 10 ms STORE latency, synchronized to power-fail detection circuitry via VCAP monitoring. Use Value: Ensures zero packet loss visibility and enables rapid service restoration after brief AC interruptions. | Use Scenario: Acting as pre-crash buffer for flight data acquisition systems, capturing last-second telemetry before emergency power shutdown. IC Role / Device Role / Timing Role: High-reliability nvSRAM storing time-stamped sensor samples with guaranteed write completion under rapid VCC decay (≥20 V/ms). Use Value: Meets DO-160 Section 22 induced transient immunity requirements via robust VCAP-based STORE initiation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar nonvolatile SRAM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| CY14B108L-ZSP25XI | 8 Mbit density, 25 ns access, SPI interface, no HSB pin, requires external STORE command via SPI register write. | Lacks hardware STORE trigger and AutoStore analog sensing; relies on host MCU to detect power loss and issue STORE. | Select when migrating to higher density and serial interface; avoid if system lacks SPI-capable controller or needs autonomous power-loss response. |
| FM24CL64-G | 64 Kbit, I²C interface, 1 MHz max clock, no VCAP pin, uses internal energy harvesting for STORE, 1M STORE endurance. | No parallel bus support; incompatible with existing 28-pin SOIC footprint and 5V-only systems; requires I²C pull-ups and clock stretching support. | Choose for low-pin-count designs where I²C is already present and 5V tolerance is not required; unsuitable for direct STK12C68-L35 replacement. |
Compared with CY14B108L-ZSP25XI and FM24CL64-G, STK12C68-L35 offers unique value in legacy 5V parallel-memory systems requiring deterministic, autonomous power-loss STORE without MCU intervention or interface conversion.
Availability
STK12C68-L35 is available at Aetrix Electronics and suitable for industrial PLC data logging, medical device configuration storage, and telecom line card state backup requiring stable component supply and long-term obsolescence management.
Supply support for STK12C68-L35 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 connectivity solutions for industrial, automotive, and consumer markets.
The STK12C68 belongs to Cypress's QuantumTrap nvSRAM product line, designed specifically for systems needing battery-free, fast-access nonvolatile memory with guaranteed data retention during unpredictable power failures.
FAQ
What is the minimum VCAP capacitance required for reliable AutoStore operation?
The STK12C68-L35 requires a minimum 68 µF capacitor (±20%, 6V rating) on the VCAP pin to guarantee successful STORE completion within 10 ms during VCC collapse. Using less capacitance risks incomplete STORE and data corruption. The internal charge pump drives VCAP to 5V during normal operation, and the capacitor must retain sufficient charge to sustain the quantum tunneling process across all 8K cells.
Can STK12C68-L35 be used in systems with 3.3V logic interfaces?
No - STK12C68-L35 is strictly a 5V ±10% device (4.5V–5.5V). Its inputs are not 5V-tolerant when powered at 3.3V, and its outputs swing rail-to-rail around VCC. Interfacing with 3.3V controllers requires level-shifting on all address, data, and control lines (A0–A12, DQ0–DQ7, CE, WE, OE, HSB), which adds propagation delay and complexity not accounted for in the 35 ns access specification.
How does the HSB pin function during a software-initiated STORE?
During software-initiated STORE, the HSB pin is actively driven LOW by the STK12C68-L35 for the entire tSTORE duration (typ. 10 ms), identical to AutoStore or hardware STORE. This provides a hardware-synchronized busy signal usable by the host system to gate further memory accesses or trigger watchdog timeouts. HSB returns HIGH only after STORE completion and SRAM functionality resumes.
Is STK12C68-L35 suitable for new designs?
Cypress explicitly labels STK12C68 as "Not Recommended for New Designs" - it remains in production solely to support ongoing manufacturing programs. For new designs, Infineon recommends migration to the CY14B series (e.g., CY14B108L) with SPI interface and enhanced density, or evaluation of FRAM alternatives where lower STORE latency and higher endurance are required.
STK12C68-L35 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Infineon Technologies
- Series:
- -
- Package/Case:
- 28-LCC
- 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:
- 35ns
- Access Time:
- 35 ns
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-LCC (13.97x8.89)
STK12C68-L35 FAQ
1.How can I place an order for STK12C68-L35 through Aetrix?
Please submit a Request for Quotation (RFQ) for STK12C68-L35 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-L35 reliable?
The price and inventory of STK12C68-L35 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STK12C68-L35 is usually 5 days.
3.What payment methods are accepted for STK12C68-L35?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STK12C68-L35 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for STK12C68-L35?
STK12C68-L35 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your STK12C68-L35 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-L35?
For technical support, including STK12C68-L35 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STK12C68-L35 requirements.
6.How does Aetrix verify that STK12C68-L35 is sourced from the original manufacturer or authorized distributors?
All STK12C68-L35 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-L35 meets industry standards.
7.What is the process for return or replacement of STK12C68-L35?
All STK12C68-L35 units undergo pre-shipment inspection (PSI). If there is an issue with STK12C68-L35, 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-L35 part is unused and in its original packaging.
Return procedure for STK12C68-L35:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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