+

-

+

-

-

+

a

100

1k

10k

100k

600k

FREQUENCY (Hz)

0

20

40

60

80

100

120

140

LMV771, LMV772, LMV774

SNOSA04F – MAY 2004 – REVISED SEPTEMBER 2010

www.ti.com

Typical Performance Characteristics (continued)

Crosstalk Rejection

vs.

Frequency (LMV772/LMV772Q/LMV774)

Application Note

LMV771/LMV772/LMV772Q/LMV774

The LMV771/LMV772LMV772Q/LMV774 are a family of precision amplifiers with very low noise and ultra low

offset voltage. LMV771/LMV772/LMV772Q/LMV774's extended temperature range of

−40°C to 125°C enables

the user to design this family of products into a variety of applications including automotive.

The LMV771 has a maximum offset voltage of 1mV over the extended temperature range. This makes the

LMV771 ideal for applications where precision is important.

The LMV772/LMV772Q/LMV774 have a maximum offset voltage of 1mV at room temperature and 1.2mV over

the extended temperature range of

−40°C to 125°C. Care must be taken when the LMV772/LMV772Q/LMV774

are designed into applications with heavy loads under extreme temperature conditions. As indicated in the DC

tables, the LMV772/LMV772Q/LMV774's gain and output swing may be reduced at temperatures between 85°C

and 125°C with loads heavier than 2k

Ω.

INSTRUMENTATION AMPLIFIER

Measurement of very small signals with an amplifier requires close attention to the input impedance of the

amplifier, gain of the overall signal on the inputs, and the gain on each input since we are only interested in the

difference of the two inputs and the common signal is considered noise. A classic solution is an instrumentation

amplifier. Instrumentation amplifiers have a finite, accurate, and stable gain. Also they have extremely high input

impedances and very low output impedances. Finally they have an extremely high CMRR so that the amplifier

can only respond to the differential signal. A typical instrumentation amplifier is shown in Figure 5.

Figure 5. Instrumentation Amplifier

14

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