LTC1444 LINER [Linear Technology], LTC1444 Datasheet - Page 12

• Manufacturer Part Number: LTC1444
• Description: Ultralow Power Single/Dual Comparator with Reference
• Manufacturer: LINER [Linear Technology]

APPLICATIONS
LTC1440/LTC1441/LTC1442
2. Calculate the required resistive divider ratio.
3. Choose the required hysteresis voltage band at the
4. Choose the values for R3 and R4 to set the hysteresis.
5. Choose the values for R1 and R2 to set the trip point.
12
Ratio = V
Ratio = 1.182V/4.65V = 0.254
input V
esis voltage band referred to the comparator input V
V
V
V
R4 = 2.4M
R3(kΩ) = V
R
R
HB
HB
HB
1
2
=
=
= (V
= (60mV)(0.254)
= 15.24mV
I
V
R
BIAS
HBIN
REF
1
⎡
⎢
⎢
⎢
⎢
⎣
HBIN
REF
V
REF
, in this example 60mV. Calculate the hyster-
=
HB
/ V
)(Ratio)
1 182
V
= 15k
.
+
IN
1
IN
µ
U
V
A
HB
2
V
=
INFORMATION
−
U
1 18
1
⎤
⎥
⎥
⎥
⎥
⎦
.
M
W
U
HB
.
Low Voltage Operation
The guaranteed minimum operating voltage is 2V or
(±1V). As the total supply voltage is reduced below 2V, the
performance degrades and the supply current falls. Both
the reference and the comparator are still functioning with
supply voltage down to 1.5V. The reference will have
slightly worse temperature coefficient. While the com-
parator would have less output drive and the propagation
delay increases. The useful input voltage range extends
from the negative supply to a little under 1V below the
positive supply, which is slightly closer to the positive rail
than the device operating from higher supply voltages.
R
R
2 1 18
2 3 40
=
=
.
.
M
M
⎡
⎢
⎢
⎢
⎢
⎣
1 182
.
4 65
V
.
+
V
15
2
mV
−
1
⎤
⎥
⎥
⎥
⎥
⎦
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