Linear Tech Single Supervisor With Watchdog Monitors 0.5 to 12V Voltage Range
Linear Technology Corp. introduced the LTC2917, a single voltage supervisor capable of monitoring a 0.5 to 12V input range. The LTC2917 can monitor 27 unique pin-selectable thresholds, ranging from a 1V drained single AA battery up to 12V industrial applications. The company claims that competitive solutions require separate supervisors for each of these different voltage thresholds. The LTC2917 VCC supply also includes a 6.2V shunt regulator for monitoring input voltages greater than 12V. The 27 selectable thresholds are specified with an overall accuracy of ±1.5% without the need of costly 0.1% external resistors to maintain accuracy.
The LTC2917 includes a watchdog input that checks whether the processor has locked up, with the option of monitoring a maximum time or a windowed time. The watchdog timer can be set to a fixed 3.2ms, 1.6s, or is adjustable based on an external capacitor, allowing the system software time to initialize. Offered in the tiny MSOP-10 and 3mm x 2mm DFN-10 packages, with guaranteed specifications across the -40 to +125°C temperature range, the LTC2917 is suitable for automotive monitoring, portable devices, and general purpose voltage monitoring.
The LTC2917 includes two three-state input pins that select one of nine internally programmed thresholds: 12, 5, 3.3, 2.5, 1.8, 1.5, 1.2, 1.0, or an adjustable 0.5V. A third three-state input determines if the input threshold is -5, -10 or -15% below the selected voltage level, allowing for margining. The LTC2918 is a variation on the LTC2917 that offers the same nine input thresholds, but with a fixed -5% tolerance. The LTC2918 also includes a separate manual reset input for a simple push-button interface. Both the LTC2917 and LTC2918 operate from a single 1.5 to 5.5V supply while consuming only 30µA of quiescent current.
The LTC2917 and LTC2918 are available in commercial, industrial, and automotive temperature grades, with pricing beginning at $1.30 each, in 1,000-piece quantities.
