Analog Devices

TheADM8690–ADM8695 family of supervisory circuits offers complete single chip solutions for power supply monitoring and battery control functions in microprocessor systems. These functions include mP reset, backup battery switchover, watchdog timer, CMOS RAM write protection and power failure warning. The complete family provides a variety of configurations to satisfy most microprocessor system requirements.The ADM8690, ADM8692 and ADM8694 are available in 8-pin DIP packages and provide:Power-on reset output during power-up, power-down and brownout conditions. The RESET output remains operational with VCCas low as 1 V.Battery backup switching for CMOS RAM, CMOS microprocessor or other low power logic.A reset pulse if the optional watchdog timer has not been toggled within a specified time.A 1.3 V threshold detector for power fail warning, low battery detection or to monitor a power supply other than +5 V.TheADM8691, ADM8693 and ADM8695 are available in 16-pin DIP and small outline packages (including TSSOP) and provide three additional functions:Write protection of CMOS RAM or EEPROM.Adjustable reset and watchdog timeout periods.Separate watchdog timeout, backup battery switchover, and low VCCstatus outputs.

The ADM8828/ADM8829 is a charge-pump voltage inverter which may be used to generate a negative supply from a positive input. Input voltages ranging from +1.5 V to +5.5 V can be inverted into a negative –1.5 V to –5.5 V output supply. This inverting scheme is ideal for generating a negative rail in single power-supply systems. Only two small external capacitors are needed for the charge pump. Output currents up to 25 mA with greater than 99% efficiency are achievable.The ADM8828 also features a low power shutdown (SHDN) pin. This can be used to disable the device and reduce the quiescent current to 20 nA.The ADM8828/ADM8829 is available in a 6-lead SOT-23 package.ApplicationsHandheld InstrumentsLCD PanelsCellular PhonesPDAsRemote Data AcquisitionOp Amp Power Supplies