Application Notes

The propagation delay time for the LM8364 is measured

using a 470k

Ω pull-up resistor connected to from the RESET

output pin to 5V in addition to a 10pF capacitive load con-

nected from the same pin to GND. Figure 1 shows the timing

diagram for the measurement for the propagation delay.

V

and the built in hysteresis, V

The LM8364 ultra-low current voltage detector was designed

to monitor voltages and to provide an indication when the

monitored voltage, V

threshold voltage. This characteristic is displayed in the typi-

cal operating timing diagram below. V

being monitored and a pull up resistor is connected from the

RESET output pin to V

and then begins to decrease. Since this is an Active Low

device the RESET output is pulled High through the pull-up

resistor and tracks V

old V

now in a fault condition and the output immediately changes

to the Logic Low State. The RESET output will remain in this

low state until V

V

This built-in hysteresis has been added to the design to help

prevent erratic reset operation when the input voltage

crosses the threshold.

The LM8364 has a wide variety of applications that can take

advantage of its precision and low current consumption to

monitor Input voltages even though it was designed as a

reset controller in portable microprocessor based systems. It

is a very cost effective and space saving device that will

protect your more expensive investments of microproces-

sors and other devices that need a guaranteed supply volt-

age for proper operation.

20065909

FIGURE 1. Propagation Delay Timing Diagrams

20065910

FIGURE 2. Timing Waveforms

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