LT1490A/LT1491A
Dual/Quad Over-The-Top
Micropower Rail-to-Rail
Input and Output Op Amps
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FEATURES
DESCRIPTIO
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®
Low Input Offset Voltage: 500µV Max
The LT 1490A/LT1491A are dual and quad op amps with a
Output Swings to 10mV Max from V–
Rail-to-Rail Input and Output
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lowinputoffsetvoltageof500µVmax.TheLT1490A/LT1491A
operate on all single and split supplies with a total voltage of
2V to 44V, drawing only 40µA of quiescent current per
amplifier. These amplifiers are reverse supply protected;
they draw virtually no current for reverse supply up to 18V.
The input range of the LT1490A/LT1491A includes both
suppliesandtheoutputswingstobothsupplies. Unlikemost
micropower op amps, the LT1490A/LT1491A can drive
heavy loads; their rail-to-rail outputs drive 20mA. The
LT1490A/LT1491A are unity-gain stable and drive all capaci-
tive loads up to 10,000pF when optional 0.22µF and 150Ω
compensation is used.
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Micropower: 50µA/Amplifier Max
Over-The-Top® Input Common Mode Range Extends
44V Above V–, Independent of V+
Specified on 3V, 5V and ±15V Supplies
High Output Current: 20mA
Output Drives 10,000pF with Output Compensation
Reverse Battery Protection to 18V
No Supply Sequencing Problems
High Voltage Gain: 1500V/mV
High CMRR: 98dB
No Phase Reversal
Gain Bandwidth Product: 200kHz
Tiny 3mm × 3mm × 0.8mm DFN Package
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The LT1490A/LT1491A have a unique input stage that oper-
ates and remains high impedance when above the positive
supply. The inputs take 44V both differential and common
mode even when operating on a 3V supply. Built-in resistors
protect the inputs for faults below the negative supply up to
15V. There is no phase reversal of the output for inputs 15V
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APPLICATIO S
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Battery- or Solar-Powered Systems
Portable Instrumentation
Sensor Conditioning
–
–
+
below V or 44V above V , independent of V .
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Supply Current Sensing
The LT1490A dual op amp is available in the 8-pin MSOP,
PDIP and SO packages. For space limited applications
LT1490A is available in a 3mm × 3mm × 0.8mm, dual fine
pitchleadlesspackage(DFN). ThequadLT1491Aisavailable
in the 14-pin SO, PDIP and 5mm × 3mm × 0.8mm DFN
packages.
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Battery Monitoring
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Micropower Active Filters
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4mA to 20mA Transmitters
, LTC and LT are registered trademarks of Linear Technology Corporation.
Over-The-Top is a registered trademark of Linear Technology Corporation.
Protected by U.S. Patents including 5825228.
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Battery Monitor
TYPICAL APPLICATIO
R
R
S
A
0.2Ω
2k
Q1
2N3904
CHARGER
VOLTAGE
+
R
A
I
´
1/4 LT1491A
BATT
–
2k
1/4 LT1491A
LOGIC
–
+
R
B
Q2
2N3904
2k
LOGIC HIGH (5V) = CHARGING
LOGIC LOW (0V) = DISCHARGING
+
R
B
´
1/4 LT1491A
2k
–
LOAD
+
+
R
G
1/4 LT1491A
V
OUT
10k
V
BATT
= 12V
–
S1
10k
90.9k
1490A TA01
V
V
=
OUT
OUT
S1 = OPEN, GAIN = 1
S1 = CLOSED, GAIN = 10
R
= R
A
S
B
I
=
AMPS
BATT
(R )(R /R )(GAIN) GAIN
V
= 5V, 0V
S
G
A
sn1490, 14901afbs
1