0
PRODUCTION
The device includes a real-time clock (RTC), CPU supervisor, watchdog timer, 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, RTC, and tamper-detection circuitry active. The DS3640 provides low-leakage tamper-detection inputs for interface to external sensors, interlocks, and anti-tamper meshes. The DS3640 will also invoke a tamper event if the backup battery drops below a specified threshold, absolute temperature or temperature rate-of-change exceeds programmed limits, or crystal-oscillator frequency falls outside a specified window. The tamper event is latched and time stamped for future debugging purposes.
Access to the RTC, tamper monitoring, key memory, and device configuration is conducted through an I²C-compatible interface. The DS3640 is assembled in a Pb-free BGA package, which enhances key security in that the leads are not exposed to the outer edges of the package.
Applications