Quad Voltage µP Supervisory Circuit in SOT Package

Industry's Smallest Quad Voltage Reset IC

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The MAX6339 is a precision quad voltage monitor with microprocessor (µP) supervisory reset timing. The device can monitor up to four system supply voltages without any external components and asserts a single reset if any supply voltage drops below its preset threshold. The device significantly reduces system size and component count while improving reliability compared to separate ICs or discrete components.

A variety of factory-trimmed threshold voltages are available to accommodate different supply voltages and tolerances with minimal external component requirements. The selection includes internally fixed options for monitoring +5.0V, +3.3V, +3.0V, +2.5V, +1.8V, and -5.0V supplies with -5% and/or -10% tolerances. The device is also available with one or two user-adjustable threshold options if non-standard thresholds are desired (use external resistor-divider network).

The quad monitor provides a single active-low reset output that is asserted when any monitored input is below its associated threshold. The output is open drain with a weak internal pullup (10µA) to IN2. Reset remains low for a reset timeout period (140ms min) after all voltages are above the selected thresholds. The output is valid as long as either the IN1 or IN2 input voltage remains > 1V.

The MAX6339 is available in a small 6-pin SOT23 package and operates over the extended (-40°C to +85°C) temperature range.
MAX6339: Typical Operating Circuit MAX6339: Typical Operating Circuit Enlarge+

Key Features

  • Monitors Four Power-Supply Voltages
  • Precision Factory-Set Reset Threshold Options for +5.0V, +3.3V, +3.0, +2.5V, +1.8V, and -5.0V Supplies
  • User-Adjustable Voltage Monitoring Threshold Options
  • Low 55µA Supply Current
  • Open-Drain active-low RESET Output with 10µA Internal Pullup
  • 140ms (min) Reset Timeout Period
  • Active-low RESET Valid to IN1 = 1V or IN2 = 1V
  • Immune to Short Monitored Supply Transients
  • No External Components Required
  • Guaranteed from -40°C to +85°C
  • Small 6-Pin SOT23 Package


  • Computers: Desktop, Workstation, Server
  • Data Storage Equipment
  • High-End Printers
  • Industrial Equipment
  • Network Equipment
  • Set-Top Boxes
  • Telecommunications

See parametric specs for Supervisors (4 Monitored Voltages) (22)

Part NumberInterfaceReset Thresh.
Reset OuttRESETWatchdog FeatureSupervisor FeaturesICC
(min)(max)(See Notes)
Factory Fixed
R/C Adjustable
1.2 to 1.8
1.8 to 2.5
2.5 to 3.3
3.3 to 5.5
Active Low
Open Drain
85ms to 300msNo Watchdog
Adjustable Reset Input
Negative Voltage
$2.11 @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.

Technical Documents

App Note 2853 Supervisors in Multivoltage Systems
Product Reliability Reports: MAX6339.pdf 
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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