adcmp356 Analog Devices, Inc., adcmp356 Datasheet - Page 9

• Manufacturer Part Number: adcmp356
• Description: Comparator And Reference Circuits
• Manufacturer: Analog Devices, Inc.

APPLICATIONS
ADDING HYSTERESIS
To prevent oscillations at the output caused by noise or slowly
moving signals passing the switching threshold, positive
feedback can be used to add hysteresis to the noninverting parts
(ADCMP354 and ADCMP356).
For the noninverting configuration shown in Figure 19, two
resistors are used to create different switching thresholds,
depending on whether the input signal is increasing or
decreasing in magnitude. When the input voltage is increasing,
the threshold is above V
threshold is below V
The upper input threshold level is given by
where V
The lower input threshold level is given by
The hysteresis is the difference between these voltage levels and
is given by
V
IN
Figure 19. Noninverting Comparator Configuration with Hysteresis
REF
R1
= 0.6 V.
V
V
IN
IN_HI
ADCMP354
V
V
ADM331
REF
REF
IN_LO
=
.
= 0.6V
REF
∆
V
V
, and when it’s decreasing, the
REF
=
IN
V
V
CC
(
=
R2
R1
REF
= 5V
V
+
(
CC
R2
R1
R2
R2
R2
R1
+
)
−
R2
V
)
CC
R1
OUT
R
PULLUP
R
LOAD
Rev. 0 | Page 9 of 12
ADCMP350/ADCMP352/ADCMP354/ADCMP356
VOLTAGE DETECTOR
The ADCMP35x parts can be used to monitor voltages, such as
battery monitoring or threshold detectors. Using a resistor
divider at the input to select the appropriate trip voltage, the
comparator can be configured to give a logic output when the
input passes that threshold. Figure 20 shows the typical
configuration of the ADCMP354 for monitoring a supply to
indicate that the voltage is above a certain level.
V
IN
R1
R1
V
IN
Figure 20. Voltage Detector Application
ADCMP354
V
ADM331
REF
= 0.6V
V
CC
= 5V
OUT
R
PULLUP