ADM809-5S/L

–5–

REV. 0

INTERFACING TO OTHER DEVICES OUTPUT

The ADM809-5S/L is designed to integrate with as many devices

Because of this design approach, interfacing this device to other

devices is simplified.

sinks current. A high impedance CMOS logic input connected

to

RESET may, therefore, drift to undetermined logic levels. To

eliminate this problem a 100 k

Ω resistor should be connected

from

RESET to ground.

GND

RESET

ADM809-5S/L

100k

Figure 3. Ensuring a Valid

RESET Output Down to

THE BENEFITS OF A VERY ACCURATE

RESET

THRESHOLD

In other microprocessor supervisory circuits, tolerances in supply

voltages lead to an overall increase in

RESET tolerance levels

due to the deterioration of the microprocessor

RESET circuit’s

power supply. The possibility of a malfunction during a power

failure is greatly reduced because the ADM809-5S/L series can

operate effectively even when there are large degradations of the

supply voltages. Another advantage of the ADM809-5S/L series

is its very accurate internal voltage reference circuit. These

benefits combine to produce an exceptionally reliable Voltage

Monitor Circuit.

INTERFACING TO MICROPROCESSORS WITH

MULTIPLE INTERRUPTS

In a number of cases it is necessary to interface many interrupts

from different devices (i.e., thermal, attitude, and velocity sen-

sors). The ADM809-5S/L can easily be integrated into existing

interrupt-handling circuits (Figure 6) or used as a stand-alone

device.

PRIORITY ENCODER

74LS147

4 LINE BCD

TO µP

ADM809

GND

RESET

OTHER SENSING

DEVICES

Figure 4. Interfacing to

µPs with Multiple Interrupts

47k

47k

100nF

3.3V

GND

RESET

ADM809-5S/L

Figure 5. Alternative Application Circuit with Extra

Decoupling

22k

100nF

3.3V

GND

RESET

ADM809-5S/L

Figure 6. Additional Decoupling Can Be Achieved