SOT23 Power-Supply Sequencers

Power Supply Sequencers for Dual/Multi-Voltage Systems Control Power On/Power Off Characteristics for Higher System Reliability

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The MAX6819/MAX6820 are power-supply sequencers for dual-voltage microprocessors (µPs) and multivoltage systems. These devices monitor a primary supply voltage and enable/disable an external N-channel MOSFET switch for a secondary supply voltage. The MAX6819/MAX6820 control local component voltage sequencing when system power-on/power-off characteristics cannot be guaranteed (supplies come from a multivoltage system bus, silver box, or must be sequenced in different modes for components on the same board). These small power-supply sequencers improve system reliability.

The MAX6819/MAX6820 include an internal voltage reference/comparator with externally adjustable thresholds to monitor the primary power supply. When the primary supply is below the desired threshold, an external secondary supply MOSFET switch is disabled. When the primary supply exceeds the threshold, an internal charge pump is activated and the external MOSFET switch is enabled to connect the secondary supply to the load. The charge pump fully enhances the N-channel MOSFET switch to provide a very low RDS-ON voltage drop. The devices can be connected to support various supply sequencing priorities such as VI/O before VCORE or VCORE before VI/O.

The MAX6819 features a logic-driven EN input to enable/disable the external MOSFET drive and includes an internally fixed 200ms enable timeout period (VPRIMARY GOOD to VSECONDARY ENABLE). The MAX6820 allows the enable timeout period to be adjusted with a single external capacitor. Both devices are specified over the automotive temperature range (-40°C to +125°C) and are available in space-saving 6-pin SOT23 packages.

Key Features

  • Adjustable Primary Supply Voltage Monitor (Monitors Down to 0.62V)
  • Internal Charge Pump to Enhance External Secondary Supply N-Channel MOSFET Switch
  • Delay from Primary Supply Good to Secondary Supply Enabled
    • Factory Fixed 200ms (MAX6819)
    • Capacitor Adjustable (MAX6820)
  • Logic Driven ENABLE Input (MAX6819)
  • Immune to Short Voltage Transients
  • Few External Components
  • -40°C to +125°C Operating Temperature Range
  • Small 6-Pin SOT23 Package


  • Digital Signal Processing
  • Dual-Voltage Microprocessors
  • Multivoltage Systems
  • PowerPC® Series Processors

See parametric specs for Power-Supply Sequencers and Voltage Trackers (43)

Part NumberOptionInterfaceInput ChannelsVIN
Oper. Temp.
maxSee Notes
MAX6819 Sequence
Factory Fixed
R/C Adjustable
-40 to +85
-40 to +125
0 to +70
$2.72 @1k

Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.
Request Reliability Report for: MAX6819 
Device   Fab Process   Technology   Sample size   Rejects   FIT at 25°C   FIT at 55°C   Material Composition  

Note : The failure rates are summarized by technology and mapped to the associated material part numbers. The failure rates are highly dependent on the number of units tested.

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