LTC1443IS#TR Linear Technology, LTC1443IS#TR Datasheet - Page 9

• Manufacturer Part Number: LTC1443IS#TR
• Description: IC COMP QUAD LP 1.182VREF 16SOIC
• Manufacturer: Linear Technology
• Type: with Voltage Referencer

Specifications of LTC1443IS#TR

• Number Of Elements: 4
• Output Type: CMOS, TTL
• Voltage - Supply: 2 V ~ 11 V, ±1 V ~ 5.5 V
• Mounting Type: Surface Mount
• Package / Case: 16-SOIC (0.154", 3.90mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

APPLICATIO S I FOR ATIO
producing a maximum hysteresis voltage band of 100mV. If
hysteresis is not wanted, the HYST pin should be shorted to
REF. Acceptable values for I
2.4M is chosen for R2, then R1(kΩ) = V
Level Detector
The LTC1444 is ideal for use as a multisupply micropower
level detector as shown in Figure 5.
R1 and R2 form a voltage divider from V1 to the noninverting
comparator A input. R6 and R7 are used to divide down V2,
while R8 is the output pull-up resistor for the comparator
outputs. R3 and R4 set the hysteresis voltage and R5 and C1
bypass the reference output. The following design procedure
can be used to select the component values:
V2
R6
1.82M
1%
R7
1.21M
1%
Figure 5. Glitch-Free Level Detector with Hysteresis
V1
R2
3.40M
1%
R1
1.21M
1%
15k, 1%
R4
2.4M
1%
R3
U
R5
430Ω
5%
C1
1.0µF
14
U
7
6
5
4
8
REF
IN B
IN A
IN B
IN A
HYST
REF
range from 0.1µA to 5µA. If
–
–
+
+
+
–
+
–
W
5V
V
+
3
9
1/2LTC1444
LTC1443/44/45 • F05
V
HB
–
(mV).
OUT B
OUT A
U
1
2
R8
2M
1%
1. Choose the V1 voltage trip level, in this example 4.65V.
2. Calculate the required resistive divider ratio.
3. Choose the required hysteresis voltage band at the input,
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.
Using the same equations, R6 and R7 are 1.82M and 1.21M
respectfully to set the trip level at 3V for V2.
V
voltage band referred to the comparator input V
HBIN
Ratio = V
Ratio = 1.221V/4.65V = 0.263
, in this example 60mV. Calculate the hysteresis
V
V
V
R4 = 2.4M
R3(kΩ) = V
R1 = V
R
R
R
LTC1443/LTC1444/LTC1445
HB
HB
HB
2
2
2 3 40
=
=
=
= (V
= (60mV)(0.263)
= 15.78mV
( )
(
1 21
REF
R
.
.
1
HBIN
REF
/I
⎡
⎢
⎢
⎢
⎣
M
BIAS
M
HB
V
/V
REF
)(Ratio)
)
⎡
⎢
⎢
⎢
⎣
= 15k
IN
1 221
= 1.221V/1µA ≈ 1.21M
V
.
IN
+
V
HB
2
4 65
V
.
+
−
V
15
1
⎤
⎥
⎥
⎥
⎦
mV
2
−
1
⎤
⎥
⎥
⎥
⎦
HB
.
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