The CAT809 is a µP supervisory circuits that monitor power supplies in digital systems. The CAT809 is a direct replacements for the MAX809 in applications operating over the industrial temperature range.
This device generates a reset signal, which is asserted while the power supply voltage is below a preset threshold level and for at least 140 ms after the power supply level has risen above that level. The underlying floating gate technology, AE²™ used by ON Semiconductor, makes it possible to offer any custom reset threshold value. Seven industry standard threshold levels are offered to support +5.0 V, +3.3 V, +3.0 V and +2.5 V systems.
The CAT809 features a push-pull
output (active LOW) and the CAT810 features a push-pull RESET output (active HIGH).
Fast transients on the power supply are ignored and the output is guaranteed to be in the correct state at Vcc levels as low as 1.0 V.
The CAT809 is available in both the compact 3-pin SOT-23 and SC70 packages.

• Precision monitoring of
• +5.0V (-5%, -10%, -20%),
• +3.3V (-5%, -10%),
• +3.0V (-10%) and
• +2.5V (-5%) power supplies
• Offered in three output configurations:
• - CAT809: Push-Pull Active LOW reset
• Direct replacements for the MAX809 in applications operating over the industrial temperature range
• Reset valid down to V
• = 1.0 V
• 6 μA power supply current
• Power supply transient immunity
• Industrial temperature range: -40˚C to +85˚C
• Available in RoHS-compliant SOT-23 and SC70 packages