LM6211MF National Semiconductor, LM6211MF Datasheet - Page 18

• Manufacturer Part Number: LM6211MF
• Description: IC,Operational Amplifier,SINGLE,CMOS,TSOP,5PIN,PLASTIC
• Manufacturer: National Semiconductor

Specifications of LM6211MF

• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Typical Applications
(Continued)
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FIGURE 16. Method for C
selection
F
SENSOR INTERFACES
The low input bias current and low input referred noise of the
LM6211 make it ideal for sensor interfaces. These circuits
are required to sense voltages of the order of a few µV, and
currents amounting to less than a nA, and hence the op amp
needs to have low voltage noise and low input bias current.
Typical applications include infra-red (IR) thermometry, ther-
mocouple amplifiers and pH electrode buffers. Figure 17 is
an example of a typical circuit used for measuring IR radia-
tion intensity, often used for estimating the temperature of an
object from a distance. The IR sensor generates a voltage
proportional to I, which is the intensity of the IR radiation
falling on it. As shown in Figure 17, K is the constant of
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proportionality relating the voltage across the IR sensor (V
)
IN
to the radiation intensity, I. The resistances R
and R
are
A
B
FIGURE 17. IR Radiation Sensor
selected to provide a high gain to amplify this voltage, while
C
is added to filter out the high frequency noise.
F
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