Application Notes

The propagation delay time for the LM8365 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

from

High-to-Low

and

t

D2

is

the

propagation

from

Low-to-High.

The LM8365 ultra-low current voltage detector was designed

to monitor voltages and to provide an indication when the

monitored voltage, V

threshold voltage. The voltage detector of the LM8365 drives

a time delay generator that may be programmed for fixed

lengths of time depending on the application needs. This

characteristic is displayed in the typical operating timing

diagram in Figure 2.V

tored and as it decreases passed the precisely trimmed

threshold V

Logic Low state and the C

the external capacitor connected to the C

ately discharged by an internal N-Channel MOSFET. When

V

capacitor connected to the C

through an internal pull-up resistor R

has charged up past the internal Delay Pin Threshold, which

is typically 0.675 V

it’s original state. The LM8365 has built-in hysteresis to help

prevent erratic reset operation when the input voltage

crosses the threshold.

The LM8365 has a wide variety of applications that can take

advantage of it’s 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 and time delay for proper operation.

20066016

FIGURE 1. Propagation Delay Timing Diagrams

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