LT1490A_15 Datasheet, PDF (1/18 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
DESCRIPTION
n _{Low Input Offset Voltage: 500μV Max}
n _{Output Swings to 10mV Max from V}^–
n _{Rail-to-Rail Input and Output}
n _{Micropower: 50μA/Amplifier Max}
n _Over-The-Top^® _{Input Common Mode Range Extends}
44V Above V^–, Independent of V⁺
n _{Specified on 3V, 5V and ±15V Supplies}
n _{High Output Current: 20mA}
n _{Output Drives 10,000pF with Output Compensation}
n _{Reverse Battery Protection to 18V}
n _{No Supply Sequencing Problems}
n _{High Voltage Gain: 1500V/mV}
n _{High CMRR: 98dB}
n _{No Phase Reversal}
n _{Gain Bandwidth Product: 200kHz}
n _{Tiny 3mm × 3mm × 0.8mm DFN Package}
APPLICATIONS
n _{Battery- or Solar-Powered Systems}
Portable Instrumentation
Sensor Conditioning
n _{Supply Current Sensing}
n _{Battery Monitoring}
n _{Micropower Active Filters}
n _{4mA to 20mA Transmitters}
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 ampli-
fier. 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 capacitive 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.
L, LT, LTC, LTM, Over-The-Top, Linear Technology and the Linear logo are registered
trademarks of Linear Technology Corporation. All other trademarks are the property of their
respective owners. Protected by U.S. Patents including 5825228.
TYPICAL APPLICATION
Battery Monitor
CHARGER
VOLTAGE
R_S
RA
0.2Ω
2k
+
Q1
2N3904
I_BATT
R_A´
2k
1/4 LT1491A
–
–
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
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