The MAX6819/MAX6820 Power Sequencing Dual-Voltage Microprocessors (µPs) and Multi-Voltage Systems. These devices monitor the main supply voltage and enable/disable external N-channel MOSFET switches for the auxiliary supply voltage. The MAX6819/MAX6820 control local component voltages when system power-on/power-off feature sequencing is not guaranteed (from supplying multi-voltage system buses, silver boxes, or components that must be sequenced in different modes on the same board). These small power sequencers improve system reliability. The MAX6819/MAX6820 include an internal voltage reference/comparison with an externally adjustable threshold to monitor the mains supply. When the primary power supply falls below the desired threshold, the external secondary power MOSFET switch will be disabled. When the main supply exceeds the threshold, the internal charge pump is activated and the external MOSFET switch is enabled to connect the secondary supply load. The charge pump fully enhances the N-channel MOSFET switch to provide a very low RDSON voltage drop. The device can be connected to support different supplies, such as sorting prioritization of VI/O before VCORE or VCORE before VI/O. The MAX6819 has a logic drive EN input to enable/disable the external MOSFET driver, including an internal fixed 200ms enable timeout (VPRIMARY and VSECONDARY enable). The MAX6820 allows an external capacitor adjustment of the timeout period. Both devices are specified over the automotive temperature range (-40°C to +125°C) and in a space-saving 6-pin SOT23 package.