ADCMP370/ADCMP371 Data Sheet
The hysteresis is the difference between these voltage levels and
is given by
)(
)
()
( R3R2
R1
R2R3
R1
R2
R1V
V
CC
IN
×
+×
+
×
××
=∆
OUT
V
CC
= 5V
ADCMP371
IN+
IN–
04745-019
V
OUT
V
IN
V
IN_LO
= 1.67V
V
IN_HI
= 3.33V
V
CC
V
CC
R3
R1
R2
V
IN_HI
V
IN_LO
R1
R3R2
R
LOAD
R2 = 1M
Ω
R3 = 1M
Ω
R1 = 1M
Ω
V
IN
V
OUT
HIGH:
V
OUT
LOW:
Figure 20. Inverting ADCMP371 Comparator Configuration with Hysteresis
For the ADCMP370 configuration, a pull-up resistor is required
for the open-drain output, which affects the hysteresis calcula-
tion. The noninverting ADCMP370 configuration is shown in
Figure 21. The upper switching threshold is
( )
R2
R2R1+
=
REF
IN_HI
V
V
The lower input threshold level is given by
(
)
PULLUP
CC
PULLUP
RR2
R1
VRR2R1
+
−++
=
REF
IN_LO
V
V
The hysteresis is the difference between these voltage levels
PULLUP
RR2
R1
+
=∆
CC
IN
V
V
ADCMP370
IN+
IN–
04745-031
OUT
R1
R2
V
IN
V
REF
= 2.5V
V
CC
= 5V
R
PULLUP
R
LOAD
Figure 21. Noninverting ADCMP370 Comparator Configuration with
Hysteresis
The inverting ADCMP370 configuration is shown in Figure 22.
The upper and lower switching thresholds are
(
)
R2
RR3R1
R2V
V
PULLUP
CC
IN_HI
++
=
)(
||
( )
))(()())((
)(
PULLUPPULLUP
PULLUP
CC
IN_HI
RR3R2R1R2RR3R1
RR3R1R2V
V
+×+×++×
++×
=
( )
( )
)(||
)(||
PULLUP
PULLUP
CC
IN_LO
RR3R2R1
RR3R2V
V
++
+
=
))(()
())((
)(
PULLUPPULLUP
PULLUP
CC
IN_LO
R
R3R2R1
R2R
R3R1
RR3R2V
V
+
×+×
++×
+××
=
assuming R
LOAD
>> R1, R2, R3, R
PULLUP
.
The hysteresis is the difference between these voltage levels and
is given by
))(()())((
PULLUPPULLUP
CC
IN
RR3R2R1R2RR3R1
R2R1V
V
+×+×++×
××
=∆
ADCMP370
IN+
IN
–
04745-032
OUT
R3
R1
R2
V
IN
V
CC
= 5V
R
PULLUP
R
LOAD
Figure 22. Inverting ADCMP370 Comparator Configuration with Hysteresis
Rev. D | Page 10 of 12
