描述 Description

The STM690A/692A/703/704/802/805/817/818/819 supervisors are self-contained devices which provide microprocessor supervisory functions with the ability to non-volatize and write-protect external LPSRAM. A precision voltage reference and comparator monitors the VCC input for an out-of-tolerance condition. When an invalid VCC condition occurs, the reset output (RST) is forced low (or high in the case of RST). These devices also offer a watchdog timer (except for STM703/704/819) as well as a power-fail comparator (except for STM818) to provide the system with an early warning of impending power failure.

特性 Features

■ 5 V operating voltage

■ NVRAM supervisor for external LPSRAM

■ Chip-enable gating (STM818 only) for external LPSRAM (7 ns max prop delay)

■ RST and RSToutputs

■ 200 ms (typ) trec

■ Watchdog timer - 1.6 sec (typ)

■ Automatic battery switchover

■ Low battery supply current - 0.4 μA (typ)

■ Power-fail comparator (PFI/PFO)

■ Low supply current - 40 μA (typ)

■ Guaranteed RST(RST) assertion down to VCC = 1.0 V

■ Operating temperature: –40 °C to +85 °C (industrial grade)

■ RoHS compliance

– Lead-free components are compliant with the RoHS directive