LT1490A_1 Datasheet, PDF (1/16 Pages) Linear Technology – Dual/Quad Over-The-Top Micropower Rail-to-Rail Input and Output Op Amps

LT1490A/LT1491A
Dual/Quad Over-The-Top
Micropower Rail-to-Rail
Input and Output Op Amps
FEATURES
■ _{Low Input Offset Voltage: 500µV Max}
■ _{Output Swings to 10mV Max from V} ^–
■ _{Rail-to-Rail Input and Output}
■ _{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 × 3mmU× 0.8mm DFN Package}
APPLICATIO S
■ _{Battery- or Solar-Powered Systems}
Portable Instrumentation
Sensor Conditioning
■ _{Supply Current Sensing}
■ _{Battery Monitoring}
■ _{Micropower Active Filters}
■ _{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.
DESCRIPTIO
The LT^®1490A/LT1491A are dual and quad op amps with a
low input offset voltage of 500µV max. The LT1490A/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
supplies and the output swings to both supplies. Unlike most
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.
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
below V^– or 44V above V^–, independent of V⁺.
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
pitch leadless package (DFN). The quad LT1491A is available
in the 14-pin SO, PDIP and 5mm × 3mm × 0.8mm DFN
packages.
TYPICAL APPLICATIO
Battery Monitor
CHARGER
VOLTAGE
R_S
RA
0.2Ω
2k
I_BATT
R_A´
2k
+
1/4 LT1491A
–
Q1
2N3904
–
1/4 LT1491A
LOGIC
+
LOAD
R_B
2k
R_B´
2k
+
V_BATT = 12V
Q2
+
2N3904
1/4 LT1491A
–
S1
R_G
10k
10k
LOGIC HIGH (5V) = CHARGING
LOGIC LOW (0V) = DISCHARGING
+
1/4 LT1491A
–
90.9k
V_OUT
1490A TA01
I_BATT
=
V_OUT
=
(R_S)(R_G/R_A)(GAIN)
V_{OUT AMPS}
GAIN
S1 = OPEN, GAIN = 1
S1 = CLOSED, GAIN = 10
R_A = R_B
V_S = 5V, 0V
sn1490, 14901afbs
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