Features and Benefits

  • 4096-Byte Nonimprinting Key Memory with High-Speed Erase
  • Optional External SRAM Clear Upon Qualified Tamper Event
  • 64-Byte General-Purpose RAM (Not Cleared)
  • 32-Bit Seconds Counter
  • Watchdog Timer
  • CPU Supervisor
  • Four General-Purpose Tamper-Detect Comparators
  • Four Window Comparators with On-Chip Reference Voltages
  • Two Tamper-Detect Logic Inputs
  • On-Chip, Programmable Temperature Sensing with Proprietary Rate-of-Change Detector
  • On-Chip Random-Number Generator (RNG)
  • Latching and Timestamping of Tamper Events
  • Crystal Oscillator Tamper Monitoring
  • Low-Power Consumption
  • Wide Temperature Range: -55°C to +95°C
  • CSBGA Package (7mm x 7mm x 0.8mm) with No Horizontally Exposed Leads
  • I²C-Compatible Interface

Product Details

The DS3645 is a secure supervisor with 4096 bytes of SRAM for applications requiring the secure storage of sensitive data and the physical tamper-sensing response functions required in cryptographic processors and data security equipment.

One of the DS3645's primary features is the on-chip encryption key memory, consisting of 32 128-byte banks incorporating a high-speed, direct-clearing function. The 4KB key memory is constantly complemented in the background to prevent memory imprinting. In the event of a qualified tamper event, the key memory is rapidly cleared and a negative bias is applied to clear SRAM external to the DS3645.

The device includes a real-time seconds counter, watchdog timer, CPU supervisor, nonvolatile (NV) SRAM controller, and on-chip temperature sensor. In the event of a primary power failure, an external battery source is automatically switched in to keep the key memory, seconds counter, and tamper-detection circuitry active. The DS3645 provides low-leakage tamper-detection inputs for interface to external sensors, interlocks, and antitamper meshes. The DS3645 also invokes a tamper event if the backup battery drops below a specified threshold or absolute temperature, if the temperature rate-of-change exceeds programmed limits, or if the crystal oscillator frequency falls outside a specified window. The tamper event is latched and timestamped for future debugging purposes.

Access to the seconds counter, tamper monitoring, key memory, and device configuration is conducted through an I2-C-compatible interface. The DS3645 is assembled in a CSBGA package, which enhances key security because the leads are not exposed to the outer edges of the package.


  • Alarm Systems
  • Gaming
  • IT Security
  • Point-of-Sale Terminals
  • Routers/Switches
Complete documentation is available upon completion of a Non-Disclosure Agreement (NDA). To request an NDA, click here.

Product Lifecycle icon-recommended Production

At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.

Design Resources

ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well.  "Zero defects" for shipped products is always our goal.

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