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LT1490/LT1491

Dual and Quad

Micropower Rail-to-Rail

Input and Output Op Amps

FEATURES

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Rail-to-Rail Input and Output

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Single Supply Input Range: – 0.4V to 44V

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Micropower: 50

µA/Amplifier Max

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Specified on 3V, 5V and

±15V Supplies

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High Output Current: 20mA

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Output Drives 10,000pF with Output Compensation

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Reverse Battery Protection to 18V

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No Supply Sequencing Problems

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High Voltage Gain: 1500V/mV

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High CMRR: 98dB

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No Phase Reversal

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Gain Bandwidth Product: 200kHz

The dual LT

single and split supplies with a total voltage of 2V to 44V

drawing only 40

µA of quiescent current per amplifier. These

amplifiers are reverse supply protected; they draw no current

for reverse supply up to 18V. The input range of the LT1490/

LT1491 includes both supplies and the output swings to both

supplies. Unlike most micropower op amps, the LT1490/

LT1491 can drive heavy loads; their rail-to-rail outputs drive

20mA. The LT1490/LT1491 are unity-gain stable and drive all

capacitive loads up to 10,000pF when optional 0.22

µF and

150

Ω compensation is used.

The LT1490/LT1491 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 resis-

tors protect the inputs for faults below the negative supply

up to 22V. There is no phase reversal of the output for inputs

The LT1490 dual op amp is available in the 8-pin SO and

PDIP packages. The quad LT1491 is available in the 14-pin

SO and PDIP packages.

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Battery- or Solar-Powered Systems

Portable Instrumentation

Sensor Conditioning

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Supply Current Sensing

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Battery Monitoring

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Micropower Active Filters

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4mA to 20mA Transmitters

–

+

–

+

RA

2k

Q2

2N3904

S1

S1 = OPEN, GAIN = 1

S1 = CLOSED, GAIN = 10

10k

90.9k

LOGIC

1490/91 TA01

LOGIC HIGH (5V) = CHARGING

LOGIC LOW (0V) = DISCHARGING

10k

Q1

2N3904

0.2

Ω

CHARGER

VOLTAGE

A

1/4 LT1491

B

1/4 LT1491

2k

2k

+

2k

LOAD

–

+

–

+

C

1/4 LT1491

D

1/4 LT1491

GAIN

=

AMPS

Battery Monitor

, LTC and LT are registered trademarks of Linear Technology Corporation.