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The TPS3306 family is a series of supervisory circuits designed for circuit initialization which require two supply voltages, primarily in DSP and processor-based systems.

The product spectrum of the TPS3306-xx is designed for monitoring two independent supply voltages of 3.3 V/1.5 V, 3.3 V/1.8 V, 3.3 V/2 V, 3.3 V/2.5 V, or 3.3 V/5 V.

The various supervisory circuits are designed to monitor the nominal supply voltage.

During power-on, RESET is asserted when the supply voltage V_DD becomes higher than 1.1 V. Thereafter, the supervisory circuits monitor the SENSEn inputs and keep RESET active as long as SENSEn remains below the threshold voltage V_IT.

An internal timer delays the return of the RESET output to the inactive state (high) to ensure proper system reset. The delay time, t_d(typ) = 100 ms, starts after SENSE1 and SENSE2 inputs have risen above the threshold voltage V_IT. When the voltage at SENSE1 or SENSE2 input drops below the threshold voltage V_IT, the output becomes active (low) again.

The integrated power-fail (PFI) comparator with separate open-drain (PFO) output can be used for low-battery detection, power-fail warning, or for monitoring a power supply other than the main supply.

The TPS3306-xx devices integrate a watchdog timer that is periodically triggered by a positive or negative transition of WDI. When the supervising system fails to retrigger the watchdog circuit within the time-out interval, t_t(out) = 0.50 s, RESET becomes active for the time period t_d. This event also reinitializes the watchdog timer. Leaving WDI unconnected disables the watchdog.

The TPS3306-xx devices are available in either 8-pin MSOP or standard 8-pin SO packages, and are characterized for operation over a temperature range of -40°C to +85°C.