LTC1841/LTC1842/LTC1843
Ultralow Power Dual
Comparators with Reference
FEATURES
s
s
DESCRIPTION
The LTC
®
1841/LTC1842/LTC1843 are ultralow power dual
comparators with built-in reference (LTC1842/LTC1843).
The comparators feature less than 5.7µA supply current
over temperature, a 1.182V
±1%
reference, program-
mable hysteresis and open-drain outputs that sink cur-
rent. The reference output can drive a bypass capacitor of
up to 0.01µF without oscillation.
The LTC1841 operates from a single 2V to 11V supply or
a dual
±1V
to
±5.5V
supply. The LTC1842/LTC1843
operate from a single 2.5V to 11V supply or a dual
±1.25V
to
±5.5V
supply. The LTC1842/LTC1843 hysteresis is
easily programmed by using two resistors and the HYST
pin. The comparators’ input operates from the negative
supply to within 1.3V of the positive supply. The compara-
tors’ output stage can typically sink greater than 20mA. By
eliminating the cross-conduction current that normally
happens when the comparators change logic states, power
supply glitches are eliminated.
The LTC1841/LTC1842/LTC1843 are available in SO-8
packages.
s
s
s
s
s
s
Ultralow Quiescent Current: 3.5
µ
A Typ
Open-Drain Outputs Typically Sink
Greater Than 20mA
Wide Supply Range: (LTC1841)
Single: 2V to 11V
Dual:
±1V
to
±5.5V
Input Voltage Range Includes the Negative Supply
Reference Output Drives 0.01
µ
F Capacitor
Adjustable Hysteresis
12µs Propagation Delay with 10mV Overdrive
No Current Spike When Switching
APPLICATIONS
s
s
s
s
Battery-Powered System Monitoring
Threshold Detectors
Window Comparators
Oscillator Circuits
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATION
Single Li-Ion Cell to 5V Supply
1-CELL
Li-Ion
BATTERY
R1
1.5M
+
C1
100µF
R6
25k
7
V
CC
LTC1843
OUT B 8
6
L1
10µH
7
D1
SUPPLY CURRENT (µA)
3 IN A
+
R3
1M
6 REF
–
V
2
–
R4
20k
R5
1.1M
+
R2
100k
–
4 IN B
–
V
IN
SW
LT1302-5
Si9924DY
3
SHDN
I
T
8
4
PGND SENSE
V
C
GND
2
R
C
20k
C
C
0.0µF
1
OUTPUT
5V
600mA
+
C2
100µF
+
OUT A 1
R7
500k
LBO
1841/43 TA01
HYST
5
C1, C2: SANYO OS-CON
D1: MOTOROLA MBRS130LT3
L1: COILTRONICS CTX10-3
U
U
U
LTC1843 Supply Current
vs Supply Voltage
5
T
A
= 25°C
4
3
2
1
0
0
2
6
8
4
SUPPLY VOLTAGE (V)
10
12
1841/43 TA02
1
LTC1841/LTC1842/LTC1843
ABSOLUTE
MAXIMUM
RATINGS
(Note 1)
Voltage
V
+
to V
–
................................................12V to – 0.3V
IN
+
, IN
–
, HYST ................. (V
+
+ 0.3V) to (V
–
– 0.3V)
REF ................................... (V
+
+ 0.3V) to (V
–
– 0.3V)
OUT ................................................ 12V to (V
–
– 0.3V)
Current
IN
+
, IN
–
, HYST ................................................. 20mA
REF ................................................................... 20mA
OUT .................................................................. 50mA
PACKAGE/ORDER INFORMATION
TOP VIEW
OUT A 1
V
–
2
IN A
+
3
IN A
–
4
8
7
6
5
OUT B
V
+
IN B
+
IN B
–
OUT A 1
V
–
2
IN A
+
3
IN B
+
4
S8 PACKAGE
8-LEAD PLASTIC SO
S8 PACKAGE
8-LEAD PLASTIC SO
T
JMAX
= 150°C,
θ
JA
= 125°C/ W
T
JMAX
= 150°C,
θ
JA
= 125°C/ W
ORDER PART
NUMBER
LTC1841CS8
LTC1841IS8
S8 PART
MARKING
1841
1841I
ORDER PART
NUMBER
LTC1842CS8
LTC1842IS8
Consult factory for Military grade parts.
ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER
Power Supply
V
+
I
CC
V
OS
I
IN
V
IN
PSRR
CMRR
V
HYST
Supply Voltage Range
Supply Current
Comparator Input Offset Voltage
Input Leakage Current (IN
+
, IN
–
)
Comparator Input Voltage Range
Power Supply Rejection Ratio
Common Mode Rejection Ratio
Hysteresis Input Voltage Range
LTC1841
LTC1842/LTC1843
CONDITIONS
V
+
= 5V, V
–
= 0V, T
A
= 25°C unless otherwise noted.
MIN
q
q
q
HYST = REF (Note 2)
(Note 3)
IN
+
= IN
–
= 2.5V (LTC1841),
IN
+
= IN
–
= V
REF
(LTC1842/LTC1843)
V
+
= 2V to 11V (LTC1841),
V
+
= 2.5V to 11V (LTC1842/LTC1843)
V
CM
= V
–
to (V
+
– 1.3V) LTC1841
LTC1842/LTC1843
Comparator
q
q
q
2
U
U
W
W W
U
W
OUT Short-Circuit Duration (V
+
≤
5.5V) ...... Continuous
Power Dissipation ............................................. 500mW
Operating Temperature Range
LTC1841C/LTC1842C/LTC1843C ........... 0°C to 70°C
LTC1841I/LTC1842I/LTC1843I .......... – 40°C to 85°C
Storage Temperature Range ................ – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
TOP VIEW
8
7
6
5
OUT B
V
+
REF
HYST
OUT A 1
V
–
2
IN A
+
3
IN B
–
4
TOP VIEW
8
7
6
5
OUT B
V
+
REF
HYST
S8 PACKAGE
8-LEAD PLASTIC SO
T
JMAX
= 150°C,
θ
JA
= 125°C/ W
S8 PART
MARKING
1842
1842I
ORDER PART
NUMBER
LTC1843CS8
LTC1843IS8
S8 PART
MARKING
1843
1843I
TYP
MAX
11
11
UNITS
V
V
µA
mV
nA
V
mV/V
mV/V
V
2.0
2.5
3.5
±3
±0.01
V
–
0.1
5.7
±10
±1.0
V
+
– 1.3V
1
1
V
REF
q
q
0.1
V
REF
– 50mV
LTC1841/LTC1842/LTC1843
ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER
t
PD
I
LEAK
V
OL
V
REF
Propagation Delay
Output Leakage Current
Output Low Voltage
Reference Voltage
CONDITIONS
V
+
= 5V, V
–
= 0V, T
A
= 25°C unless otherwise noted.
MIN
TYP
12
4
q
q
MAX
UNITS
µs
µs
C
OUT
= 10pF, R
PULL-UP
= 100k Overdrive = 10mV
Overdrive = 100mV
V
OUT
= 12V (Note 2)
I
OUT
= 1.8mA
No Load
25°C
0°C to 70°C
– 40°C to 85°C
q
q
q
q
1
100
V
–
+ 0.4V
nA
V
V
V
V
mV
mV
mV
µV
RMS
Reference (LTC1842/LTC1843)
1.174
1.170
1.164
1
1.75
100
1.182
1.190
1.194
1.200
3
4
6
∆V
REF
Load Regulation
I
SOURCE
= 1mA
I
SINK
=10µA
e
n
Voltage Noise
100Hz to 100kHz
V
+
= 3V, V
–
= 0V, T
A
= 25°C unless otherwise noted.
SYMBOL PARAMETER
Power Supply
V
+
I
CC
V
OS
I
IN
V
IN
PSRR
CMRR
V
HYST
t
PD
I
LEAK
V
OL
V
REF
Supply Voltage Range
Supply Current
Comparator Input Offset Voltage
Input Leakage Current (IN
+
, IN
–
)
Comparator Input Voltage Range
Power Supply Rejection Ratio
Common Mode Rejection Ratio
Hysteresis Input Voltage Range
Propagation Delay
Output Leakage Current
Output Low Voltage
Reference Voltage
V
+
= 2V to 11V (LTC 1841),
V
+
= 2.5V to 11V (LTC1842/LTC1843)
V
CM
= V
–
to (V
+
– 1.3V) LTC1841
LTC1842/LTC1843
C
OUT
= 10pF, R
PULL-UP
= 100k Overdrive = 10mV
Overdrive = 100mV
V
OUT
= 12V (Note 2)
I
O
= 0.8mA
No Load
25°C
0°C to 70°C
– 40°C to 85°C
∆V
REF
Load Regulation
q
q
q
q
q
q
q
q
V
REF
– 50mV
CONDITIONS
LTC1841
LTC1842/LTC1843
HYST = REF (Note 2)
(Note 3)
IN
+
= IN
–
= 1.5V (LTC1841),
IN
+
= IN
–
= V
REF
(LTC1842/LTC1843)
q
q
q
MIN
2.0
2.5
TYP
MAX
11
11
UNITS
V
V
µA
mV
nA
V
mV/V
mV/V
V
µs
µs
3.5
±3
±0.01
V
–
0.1
0.1
14
5
1
5.5
±10
±1
V
+
– 1.3V
1
1
V
REF
Comparator
q
q
q
100
V
–
+ 0.4V
nA
V
V
V
V
mV
mV
mV
µV
RMS
Reference (LTC1842/LTC1843)
1.174
1.170
1.164
2
1.75
100
Note 2:
IN
+
= IN
–
+ 80mV, output is in high impedance state.
Note 3:
V
CM
= 1/2(V
+
– V
–
) for LTC1841, V
CM
= V
REF
for LTC1842/
LTC1843.
1.182
1.190
1.194
1.200
6
4
6
I
SOURCE
= 1mA
I
SINK
=10µA
e
n
Voltage Noise
100Hz to 100kHz
The
q
denotes specifications which apply over the full operating
temperature range.
Note 1:
Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
3
LTC1841/LTC1842/LTC1843
TYPICAL PERFORMANCE CHARACTERISTICS
Comparator Response Time vs
Input Overdrive, with R
PULL-UP
= 5k
INPUT VOLTAGE (mV) OUTPUT VOLTAGE (V)
4
3
2
1
0
T
A
= 25°C
OUTPUT VOLTAGE (V)
5
100mV
50mV
10mV
20mV
INPUT VOLTAGE (mV)
0
100
–1
0
2
4
6
RESPONSE TIME (µs)
8
10
Comparator Short-Circuit Sink
Current vs Supply Voltage
200
180
160
140
120
100
80
60
40
20
0
OUT CONNECTED TO V
+
T
A
= 25°C
RESPONSE TIME (µs)
SINK CURRENT (mA)
0
1
2
3 4 5 6 7 8
SUPPLY VOLTAGE (V)
Comparator Response Time at
Low Supply Voltage
10000
2.5
OUTPUT VOLTAGE HIGH (V)
RESPONSE TIME (µs)
1000
20mV OVERDRIVE
100
10
100mV OVERDRIVE
1
1.0
1.1
1.2
1.3
1.4
SUPPLY VOLTAGE (V)
1.5
1.6
4
U W
Comparator Response Time vs
Input Overdrive, with R
PULL-UP
= 5k
5
4
3
2
1
0
T
A
= 25°C
100mV
50mV
20mV
10mV
100
0
–1
0
2
4 6 8 10 12 14 16 18
RESPONSE TIME (µs)
1440/1/2/3 G02
1440/1/2/3 G01
Comparator Response Time vs
Load Capacitance with 100mV
Input Overdrive
12
10
t
PHL
8
6
t
PLH
4
2
9
10
0
20
60
80
40
LOAD CAPACITANCE (nF)
100
1440/1/2/3 G03
1440/1/2/3 G04
Comparator Output Voltage Low
vs Load Current
T
A
= 25°C
2.0
V
+
= 2V
V
+
= 5V
1.0
V
+
= 3V
1.5
0.5
0
0
10
50 60
20 30 40
LOAD CURRENT (mA)
70
80
1440/1/2/3 G05
1440/1/2/3 G06
LTC1841/LTC1842/LTC1843
TYPICAL PERFORMANCE CHARACTERISTICS
LTC1842/LTC1843
Hysteresis Control
POSITIVE-TO-NEGATIVE INPUT VOLTAGE (mV)
80
60
OUTPUT HIGH
SUPPLY CURRENT (µA)
40
20
0
–20
–40
–60
–80
0
10
30
V
REF
– V
HYST
(mV)
20
40
50
OUTPUT LOW
Reference Output Voltage vs
Output Load Current
1.190
V
CC
= 5V
REFERENCE OUTPUT VOLTAGE (V)
REFERENCE OUTPUT VOLTAGE (V)
1.185
SOURCE
1.180
1.175
1.170
1.165
1.160
1.155
0
0.5 1.0 1.5 2.0 2.5 3.0
OUTPUT LOAD CURRENT (mA)
3.5
REFERENCE VOLTAGE (V)
U W
LTC1842/LTC1843
Supply Current vs Temperature
4.5
4.0
V
+
= 5V
V
–
= –5V
3.5
3.0
V
+
= 5V
V
–
= 0V
V
+
= 3V
V
–
= 0V
2.5
2.0
–60 –40 –20 0 20 40 60 80 100 120 140
TEMPERATURE (°C)
1440/1/2/3 G08
1440/1/2/3 G07
Reference Output Voltage vs Output
Load Current (Sink)
1.200
V
CC
= 2V
1.195
V
CC
= 5V
1.190
1.185
SINK
1.180
1.175
1.170
0
25
10
15
20
5
OUTPUT LOAD CURRENT (µA)
30
1841/2/3 G09
1440/1/2/3 G10
Reference Voltage vs
Temperature
1.186
1.184
1.182
1.180
1.178
1.176
1.174
1.172
1.170
–60 –40 –20 0 20 40 60 80 100 120 140
TEMPERATURE (°C)
1440/1/2/3 G11
5
Embedded System
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