LT1490A Datasheet, PDF (1/12 Pages) Linear Technology – Dual Over-The-Top Micropower Rail-to-Rail Input and Output Op Amp

LT1490A
Dual Over-The-Top
Micropower Rail-to-Rail
Input and Output Op Amp
FEATURES
s _{Low Input Offset Voltage: 500µV Max}
s _{Output Swings to 10mV Max from V} ^–
s _{Rail-to-Rail Input and Output}
s _{Micropower: 50µA/Amplifier Max}
s _{MSOP Package}
s _Over-The-Top^TM _{Input Common Mode Range Extends}
44V Above V ^–, Independent of V ⁺
s _{Specified on 3V, 5V and ±15V Supplies}
s _{High Output Current: 20mA}
s _{Output Drives 10,000pF with Output Compensation}
s _{Reverse Battery Protection to 18V}
s _{No Supply Sequencing Problems}
s _{High Voltage Gain: 1500V/mV}
s _{High CMRR: 98dB}
s _{No Phase Reversal}
s _{Gain Bandwidth Product: 200kHz}
U
APPLICATIO S
s _{Battery- or Solar-Powered Systems}
Portable Instrumentation
Sensor Conditioning
s _{Supply Current Sensing}
s _{Battery Monitoring}
s _{Micropower Active Filters}
s _{4mA to 20mA Transmitters}
DESCRIPTIO
The LT^®1490A is an enhanced version of the popular LT1490
op amp with improved input offset voltage (500µV max) and
output voltage swing (10mV max from V ^–). It is recom-
mended for all new designs. The LT1490A operates on all
single and split supplies with a total voltage of 2V to 44V,
drawing only 40µA of quiescent current per amplifier. It is
reverse supply protected; it draws virtually no current for
reverse supply up to 18V. The input range of the LT1490A
includes both supplies and the output swings to both sup-
plies. Unlike most micropower op amps, the LT1490A can
drive heavy loads; its rail-to-rail output drives 20mA. The
LT1490A is unity-gain stable and drives all capacitive loads
up to 10,000pF when optional 0.22µF and 150Ω compensa-
tion is used.
The LT1490A has a unique input stage that operates 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.
, LTC and LT are registered trademarks of Linear Technology Corporation.
Over-The-Top is a trademark of Linear Technology Corporation.
TYPICAL APPLICATIO
Battery Monitor
CHARGER
VOLTAGE
R_S
RA
0.2Ω
2k
+
Q1
2N3904
I_BATT
R_A´
2k
1/2 LT1490A
–
–
1/2 LT1490A
LOGIC
+
LOAD
R_B
2k
R_B´
2k
+
V_BATT = 12V
Q2
+
2N3904
1/2 LT1490A
–
S1
R_G
10k
10k
LOGIC HIGH (5V) = CHARGING
LOGIC LOW (0V) = DISCHARGING
+
1/2 LT1490A
–
90.9k
V_OUT
14901A 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
1