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Infineon Technologies STK12C68-C35I
- Part No.:
- STK12C68-C35I
- Manufacturer:
- Infineon Technologies
- Category:
- Memory
- Package:
- 28-CDIP (0.300", 7.62mm)
- Datasheet:
-
STK12C68-C35I.pdf
- Description:
- IC NVSRAM 64KBIT PARALLEL 28CDIP
- Quantity:
- Payment:
- Shipping:
Inventory:2,111
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Product details
Overview
STK12C68-C35I from Cypress Semiconductor is a 64 Kbit (8K × 8) nonvolatile SRAM with QuantumTrap technology, supporting AutoStore on power loss, software/hardware STORE/RECALL, and single 5V±10% operation. It delivers 35 ns access time, 1,000,000 STORE cycles, and 100-year data retention in industrial temperature range (–40°C to +85°C), deployed in industrial PLCs for real-time parameter backup during brownouts.
For engineers reviewing the STK12C68-C35I datasheet, STK12C68-C35I pinout, STK12C68-C35I application, or STK12C68-C35I equivalent, key selection factors include VCAP capacitor sizing (68 µF), HSB-driven hardware STORE timing (tDELAY), AutoStore inhibit configuration, and compatibility with legacy 5V SRAM bus interfaces.
Technical Context
The STK12C68-C35I integrates parallel SRAM and QuantumTrap nonvolatile cells per bit, enabling simultaneous STORE/RECALL of all 8,192 bytes. Its architecture decouples volatile read/write (unlimited cycles) from nonvolatile endurance (1M STOREs), with automatic power-loss detection triggering VCAP-powered STORE when VCC drops below VSWITCH (~3.6V).
STORE initiation occurs via three independent paths: AutoStore (power-down), HSB pin assertion (hardware), or six-address software sequence (0x0000→0x1555→0x0AAA→0x1FFF→0x10F0→0x0F0F). RECALL supports power-up auto-restore and software-triggered reload (0x0F0E), both preserving nonvolatile cell integrity across unlimited recalls.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Density | 64 Kbit (8K × 8) - provides byte-wide interface compatible with 8-bit microcontrollers and legacy ISA bus systems. |
| Access Time | 35 ns - ensures timing compliance with 25 MHz SRAM bus clocks without wait states. |
| STORE Endurance | 1,000,000 cycles - defines maximum field-replaceable backup events before QuantumTrap wear-out. |
| Data Retention | 100 years at +85°C - guarantees firmware/parameter persistence in sealed industrial enclosures without refresh. |
| Operating Voltage | 5V ±10% - matches standard TTL/CMOS logic rails, eliminating need for voltage translators. |
| Temperature Range | –40°C to +85°C - qualified for deployment in motor control cabinets and outdoor telemetry units. |
| VCAP Capacitor | 68 µF ±20%, 6V rating - minimum capacitance required to sustain tSTORE (10 ms) under worst-case VCC droop rate. |
Pinout & Package
STK12C68-C35I is packaged in a 28-pin 300-mil plastic DIP (PDIP), with through-hole mounting and 2.54 mm pitch. Pin 1 is marked by notch or dot; pin numbering follows standard counter-clockwise layout from top-left corner.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A12 | Address Inputs | 13-bit address bus selecting one of 8,192 memory locations; compatible with Z80, 8051, and 68K family address decoding. |
| DQ0–DQ7 | Bidirectional Data I/O | 8-bit data bus shared for read and write; requires external tristate control coordination with OE/WE timing. |
| CE (E) | Chip Enable | Active-low chip select; enables internal logic only when asserted, reducing standby current during bus arbitration. |
| WE (W) | Write Enable | Active-low write strobe; latches DQ data into SRAM array when CE is low and OE is high. |
| OE (G) | Output Enable | Active-low output driver control; places DQ lines in high-impedance state when deasserted to prevent bus contention. |
| HSB | Hardware Store Busy | Open-drain status/output pin: pulled low during STORE execution; driven low externally to initiate hardware STORE. |
| VCAP | AutoStore Capacitor Terminal | Connects to external 68 µF storage capacitor; internal charge pump maintains 5V bias during VCC collapse. |
| VCC | Power Supply | +5V ±10% main supply; powers SRAM core and QuantumTrap control logic; disconnects from VCAP at VSWITCH threshold. |
| VSS | Ground | System ground reference; must be low-inductance connection to minimize STORE timing jitter during power loss. |
Key Features
| Feature | Design Value |
|---|---|
| AutoStore on Power Loss | Eliminates external supervisor ICs by autonomously initiating STORE using VCAP energy when VCC falls below 3.6V. |
| Software STORE/RECALL | Enables deterministic backup/restore via 6-address read sequence-no dedicated command bus or protocol overhead required. |
| Hardware STORE Trigger | HSB pin allows system-level control of STORE timing, synchronizing backup with critical state transitions (e.g., motion stop). |
| QuantumTrap Nonvolatility | Provides 100-year data retention without battery or EEPROM wear leveling, ideal for unattended infrastructure equipment. |
| Unlimited SRAM Cycles | Supports continuous logging or buffer rotation in real-time OS environments without memory degradation concerns. |
Applications
| Industrial PLC Parameter Backup | Medical Device Configuration Storage |
|---|---|
Use Scenario: Preserves I/O mapping, PID tuning constants, and calibration offsets during AC mains interruption in DIN-rail mounted controllers. IC Role / Device Role / Timing Role: Nonvolatile SRAM acting as drop-in replacement for battery-backed SRAM, providing zero-latency recall on power restoration. Use Value: Eliminates battery replacement service calls and avoids data corruption risks from battery leakage or end-of-life voltage sag. | Use Scenario: Stores device-specific calibration tables and user preferences in portable ultrasound units subject to frequent on/off cycling. IC Role / Device Role / Timing Role: Primary configuration memory with guaranteed recall within 10 ms of power-up, meeting IEC 62304 boot-time requirements. Use Value: Ensures regulatory-compliant startup behavior without firmware-initiated restore delays or external NVM polling. |
| Avionics Black Box Buffer | Energy Meter Firmware Patch Storage |
Use Scenario: Captures flight-critical sensor snapshots during transient power faults in UAV flight controllers. IC Role / Device Role / Timing Role: High-reliability data buffer with AutoStore triggered by monitored VCC droop, synchronized to inertial measurement unit sampling. Use Value: Achieves DO-160 Section 22 Category A transient immunity without supplemental hold-up capacitors or watchdog supervision. | Use Scenario: Holds field-upgradable firmware patches in smart electricity meters operating in utility substations with unstable grid voltage. IC Role / Device Role / Timing Role: Secure patch staging area with hardware-protected STORE inhibition during active firmware execution. Use Value: Prevents partial patch writes during grid sags, ensuring atomic update success and avoiding bricking due to interrupted flash programming. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar nonvolatile SRAM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| STK12C68-C25I | 25 ns access time, same pinout and QuantumTrap architecture; requires tighter VCAP regulation due to shorter tSTORE window. | Suitable for high-speed data acquisition systems where <25 ns latency is mandatory. | Select when system clock exceeds 33 MHz and board layout supports reduced VCAP ESR. |
| FM1808-55-TG | 4-Mbit density, 55 ns access, 3.3V operation; uses ferroelectric RAM instead of QuantumTrap; no VCAP capacitor required. | Fits space-constrained designs needing higher density but accepting slower access and different voltage domain. | Choose for new 3.3V designs prioritizing density over legacy 5V compatibility and capacitor-free BOM. |
Compared with STK12C68-C25I and FM1808-55-TG, the STK12C68-C35I balances proven industrial reliability, 5V bus compatibility, and predictable 35 ns timing-making it optimal for cost-sensitive upgrades of existing battery-SRAM systems where VCAP integration is already validated.
Availability
STK12C68-C35I is available at Aetrix Electronics and suitable for industrial PLCs, medical diagnostic instruments, and avionics black box recorders requiring stable component supply amid long product lifecycles and infrequent design revisions.
Supply support for STK12C68-C35I 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 logic solutions for industrial, automotive, and communications markets.
The STK12C68 belongs to Cypress's nvSRAM product line, engineered specifically to replace battery-backed SRAM in mission-critical systems where maintenance-free, long-term data retention is mandatory.
FAQ
What capacitor value is required for reliable AutoStore operation?
A 68 µF ±20%, 6V-rated tantalum or low-ESR electrolytic capacitor must be connected between VCAP and VSS. This value ensures sufficient energy to complete the 10 ms STORE cycle even when VCC collapses at 20 µs/V. Derating below 68 µF risks incomplete STOREs and data loss during rapid power failure.
Can STK12C68-C35I operate without the VCAP capacitor?
Yes-but only in AutoStore Inhibit mode: tie VCC to ground and apply +5V directly to VCAP. In this configuration, AutoStore is disabled and STORE must be initiated exclusively via software sequence or HSB assertion. The device retains full SRAM functionality and RECALL capability.
How does the HSB pin function during STORE execution?
HSB acts as an open-drain busy indicator: it is driven LOW internally for the entire STORE duration (tSTORE ≈ 10 ms), then released HIGH upon completion. When used as input, pulling HSB LOW initiates conditional STORE only if a write occurred since last STORE/RECALL-preventing spurious backups during idle periods.
Is STK12C68-C35I RoHS compliant?
Yes. Per Cypress Document Number 001-51027 Rev. *C, the STK12C68-C35I meets RoHS Directive 2011/65/EU requirements, with lead-free terminations and halogen-free molding compound. The 28-pin PDIP package contains no restricted substances above threshold limits.
STK12C68-C35I Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Infineon Technologies
- Series:
- -
- Package/Case:
- 28-CDIP (0.300", 7.62mm)
- 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:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 28-CDIP
STK12C68-C35I FAQ
1.How can I place an order for STK12C68-C35I through Aetrix?
Please submit a Request for Quotation (RFQ) for STK12C68-C35I 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-C35I reliable?
The price and inventory of STK12C68-C35I are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STK12C68-C35I is usually 5 days.
3.What payment methods are accepted for STK12C68-C35I?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STK12C68-C35I transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for STK12C68-C35I?
STK12C68-C35I orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your STK12C68-C35I 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-C35I?
For technical support, including STK12C68-C35I datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STK12C68-C35I requirements.
6.How does Aetrix verify that STK12C68-C35I is sourced from the original manufacturer or authorized distributors?
All STK12C68-C35I 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-C35I meets industry standards.
7.What is the process for return or replacement of STK12C68-C35I?
All STK12C68-C35I units undergo pre-shipment inspection (PSI). If there is an issue with STK12C68-C35I, 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-C35I part is unused and in its original packaging.
Return procedure for STK12C68-C35I:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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