The ADM6339 is a high accuracy supervisory circuit capable of monitoring up to four system supply voltages. The ADM6339 incorporates a variety of internally pretrimmed undervoltage threshold options for monitoring ?5.0 V， +1.8 V， +2.5 V， +3.0 V， +3.3 V， and +5.0 V supply voltages. Tolerance levels of ±5% and ±10% are available. The device is also available with one to three adjustable threshold options. The adjustable voltage threshold options are +1.23 V， +0.62 V， and ?0.5 V. See the Ordering Guide section for a list and description of all available options. If a monitored power supply voltage decreases below the minimum voltage threshold （or rises above the maximum voltage threshold for the ?0.5 V and ?5.0 V input options）， a single active low output asserts， triggering a system reset. The output is open drain with a weak internal pull-up to the monitored IN2 supply of typically 10 μA. After all voltages exceed the selected threshold level， the reset signal remains low for the reset timeout period （200 ms typical）。 The ADM6339 output remains valid as long as IN1 or IN2 exceeds 1 V. Unused monitored inputs should not be allowed to float or to be grounded; instead， they should be connected to a supply voltage greater than their specified threshold voltages. The ADM6339 is available in a 6-lead SOT-23 package. The device operates over the extended temperature range of ?40°C to +85°C.