Key Specifications

 

The UM805/811/812 are low-power microprocessor (μP) supervisory circuits used to monitor power supplies in μP and digital systems. They provide excellent circuit reliability and low cost by eliminating external components and adjustments when used with 5V-powered or 3V-powered circuits. The UM805/811/812 also provide a debounced manual reset input.

These devices perform a single function: They assert a reset signal whenever the V_CC supply voltage falls below a preset threshold, keeping it asserted for at least 140ms after V_CC has risen above the reset threshold. Reset thresholds are available for operation with a variety of supply voltages.

The UM805 has an open-drain output stage, while the UM811/812 have push-pull outputs. The UM805’s open-drain RESET(_______________) output requires a pull-up resistor that can be connected to a voltage higher than V_CC. The UM805/811 have an active-low RESET(_______________) output, while the UM812 has an active-high RESET output. The reset comparator is designed to ignore fast transients on V_CC, and the outputs are guaranteed to be in the correct logic state for V_CC down to 1V.

Low supply current makes the UM805/811/812 ideal for use in portable equipments. The devices come in a 4-pin SOT143 package.

 

 

- No External Components

- V_CC Transient Immunity

- Correct Logic Output Guaranteed to V_CC=1.0V

- Precision V_CC Monitoring of 3.0V, 3.3V and 5.0V Supplies

- 2μA Supply Current

- 140ms Minimum Power-On Reset Pulse Width

- Guaranteed Over Temperature

- Available in 3 Output Configurations:

  Open-Drain Active-Low RESET(_______________) Output(UM805)

  Push-Pull Active-Low RESET(_______________) Output(UM811)

  Push-Pull Active-High RESET Output(UM812)

- 4-Pin SOT143 Package

- Wide Operation Temperature: -40°C to +85°C

  

 

- Computers

- Controllers

- Portable/Battery-Powered Equipments

- Intelligent Instruments

- Critical μP and μC Power Monitoring

 

Pin Configurations

  
( ) are for UM812

Part Number	RESET Threshold (V)	Timeout Period (ms)	Output Type	Marking Code	Package Type	Shipping Qty
UM805LE	4.63	240	Open-Drain, Active Low	05L	SOT143	3000pcs/7Inch Tape & Reel
UM805ME	4.38	240	Open-Drain, Active Low	05M
UM805JE	4.00	240	Open-Drain, Active Low	05J
UM805TE	3.08	240	Open-Drain, Active Low	05T
UM805SE	2.93	240	Open-Drain, Active Low	05S
UM805RE	2.63	240	Open-Drain, Active Low	05R
UM805ZE	2.32	240	Open-Drain, Active Low	05Z
UM811LE	4.63	240	Push-Pull, Active Low	11L
UM811ME	4.38	240	Push-Pull, Active Low	11M
UM811JE	4.00	240	Push-Pull, Active Low	11J
UM811TE	3.08	240	Push-Pull, Active Low	11T
UM811SE	2.93	240	Push-Pull, Active Low	11S
UM811RE	2.63	240	Push-Pull, Active Low	11R
UM811ZE	2.32	240	Push-Pull, Active Low	11Z
UM812LE	4.63	240	Push-Pull, Active High	12L
UM812ME	4.38	240	Push-Pull, Active High	12M
UM812JE	4.00	240	Push-Pull, Active High	12J
UM812TE	3.08	240	Push-Pull, Active High	12T
UM812SE	2.93	240	Push-Pull, Active High	12S
UM812RE	2.63	240	Push-Pull, Active High	12R
UM812ZE	2.32	240	Push-Pull, Active High	12Z