LTC1440IS8 Linear Technology, LTC1440IS8 Datasheet - Page 12

• Manufacturer Part Number: LTC1440IS8
• Description: IC COMP W/REF LP SINGLE 8-SOIC
• Manufacturer: Linear Technology
• Type: with Voltage Referencer

Specifications of LTC1440IS8

• Number Of Elements: 1
• Output Type: CMOS, TTL
• Voltage - Supply: 2 V ~ 11 V, ±1 V ~ 5.5 V
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (0.154", 3.90mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

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
It is important to note that the voltage references internal
to the LTC1440 and LTC1442 can exceed the common
mode range of the comparators at low supply voltages.
The input common mode range of the LTC1440/LTC1441/
LTC1442 comparators is guaranteed to extend up to (V
1.3V). Therefore, if one of the comparator inputs is at the
1.182V reference voltage, the minimum supply voltage is
2.5V for a valid output reading.
The guaranteed minimum operating voltage for the
LTC1440/LTC1441/LTC1442 is 2V (or ±1V). However,
both the reference and comparator(s) will function with a
supply voltage as low as 1.5V, but performance will
degrade as the voltage goes below 2V. The voltage refer-
ence temperature coefficient will degrade slightly, and the
comparators will have less output drive with an increase in
propagation delay. At the reduced supply voltages, the
input common mode range of the comparator(s) will still
typically extend from the negative supply to approximately
1.1V below the positive supply.
R
R
2 1 18
2 3 40
=
=
.
.
M
M
⎡
⎢
⎢
⎢
⎢
⎣
1 182
.
4 65
V
.
+
V
15
2
mV
−
1
⎤
⎥
⎥
⎥
⎥
⎦
144012fd
+
-