8 Application and Implementation

Note

Information in the following applications sections is not part of the TI component specification, and TI

does not warrant its accuracy or completeness. TI’s customers are responsible for determining

suitability of components for their purposes, as well as validating and testing their design

implementation to confirm system functionality.

8.1 Application Information

8.1.1 Low Input Voltage Noise

The LMP7704-SP have the very low input voltage noise of 9 nV/√Hz. This input voltage noise can be further

reduced by placing N amplifiers in parallel as shown in Figure 8-1. The total voltage noise on the output of this

circuit is divided by the square root of the number of amplifiers used in this parallel combination. This is because

each individual amplifier acts as an independent noise source, and the average noise of independent sources is

the quadrature sum of the independent sources divided by the number of sources. For N identical amplifiers, this

means:

REDUCED INPUT VOLTAGE NOISE =

2

2

2

=

1

N

1

N

2

=

N

N

=

1

N

(6)

Figure 8-1 shows a schematic of this input voltage noise reduction circuit. Typical resistor values are:

V

-

V

+

V

-

V

+

V

-

V

+

V

-

V

+

+

-

+

-

+

-

+

-

Figure 8-1. Noise Reduction Circuit

LMP7704-SP

SNOSDB6A – DECEMBER 2020 – REVISED JANUARY 2021

www.ti.com

22

Submit Document Feedback

Copyright © 2021 Texas Instruments Incorporated

Product Folder Links: LMP7704-SP