STM1061 datasheet(8/23 Pages) STMICROELECTRONICS

8 / 23 page

Operation

STM1061

8/23

Operation

3.1

Output

The STM1061 Voltage Detector monitors system voltages from 1.6 to 5V in 100mV

increments. The detector is designed to ignore fast transients on VCC and has a voltage

hysteresis (VHYST). The STM1061 asserts an output signal (OUT) whenever VCC goes

below the Voltage Detect Threshold (VTH–). The output signal (OUT) stays asserted until

VCC goes above the Voltage Detect Release (VTH+). Output voltage (VOUT) is guaranteed

valid down to VCC =0.7V at 25°C.

The STM1061has an open drain active-low output which will sink current when output is

asserted. Connect a pull-up resistor from OUT to any supply voltage up to 6V (see Figure 6

on page 6). Select a resistor value large enough to register a logic low, and small enough to

output line are being supplied. A 10k pull-up is sufficient in most applications.

The advantages of open drain output is the ability to connect more open drain outputs in

parallel (wired OR connections) as well as connect the output to a power supply voltage

different from VCC.

3.2

Negative-Going VCC Transients and Undershoot

The STM1061 device is relatively immune to negative-going VCC transients (glitches). The

graph (see Figure 11 on page 11) indicates the maximum pulse width a negative VCC

transient can have without causing a reset pulse. As the magnitude of the transient

increases (further below the threshold), the maximum allowable pulse width decreases. Any

combination of duration and overdrive which lies under the curve will NOT generate a reset

signal.

A 0.1µF bypass capacitor mounted as close as possible to the VCC pin provides additional

transient immunity.

STM1061 Datasheet(PDF) 8 Page - STMicroelectronics