MAX6819-MAX6820: SOT23 Power-Supply Sequencers Data Sheet (Rev. 3)6/7/2006521K
Features and Benefits
- 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
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.
- Digital Signal Processing
- Dual-Voltage Microprocessors
- Multivoltage Systems
- PowerPC® Series Processors
Product Lifecycle Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Documentation & Resources
MAX6820 Reliability Data1/12/202361K
Reduce the Chances of Human Error: Part 1, Power and Ground3/8/2011
Simple Devices for Meeting Voltage Tracking Requirements6/20/2006
System-Management IC Meets Monitoring and Sequencing Requirements in Multivoltage Systems5/11/2005
Programmable System-Management IC Monitors and Sequences Requirements in Complex, Multivoltage Systems1/17/2005
Supervisors in Multivoltage Systems11/17/2003
Dual Voltage Tracking Circuit for I/O, Microprocessor, and DSP Core Voltages9/29/2003
Multiple Voltage Systems Need Supply-Voltage Sequencing6/27/2002
MAX6820 Companion Parts
Recommended Related Parts
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