Description

AN2504 - Application note

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Description

STMicroelectronics offers e.g. the STM1061 voltage detector. One of its typical uses is

shown in the Figure 2.

The STM1061N open drain output voltage detector is monitoring the 3.6V battery. This

allows the voltage detector to detect a voltage drop early, assert the output signal (OUT) so

the MCU can start safeguard routines even before the regulated supply voltage for the MCU

starts to fall.

The voltage detector open drain output sinks current when the output is asserted. It is

necessary to connect a pull-up resistor from OUT to any supply voltage (see Figure 2). The

resistor value must be large enough to register a logic low and small enough to register a

logic high while all of the input current and leakage paths connected to the reset output line

are being supplied. A10k

Ω pull-up is sufficient in most applications.

Figure 2.

STM1061N Active-Low, Open Drain typical Hardware Hookup

AI10484a

VCC

VIN

+

VSS

VCC

MCU

STM1061N

(Open Drain)

DC/DC

Converter

OUT

3.6V

VOUT

VSS

VSS

Suspend

Regulated 3V

R

VOUT