CC1

+

VOUT

+

-

-

CF

VIN

+

-

RB1

V

+

RB2

CC2

R2

R1

AV = -

R2

100 k:

R1

1 k:

= -100

Copyright © 2016, Texas Instruments Incorporated

17

LMV641

www.ti.com

SNOSAW3D – SEPTEMBER 2007 – REVISED AUGUST 2016

Product Folder Links: LMV641

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Copyright © 2007–2016, Texas Instruments Incorporated

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. Customers should

validate and test their design implementation to confirm system functionality.

8.1 Application Information

The LMV641 is a low-power, low noise, wide-bandwidth operational amplifier with an extended power supply

voltage range of 2.7 V to 12 V. With 10 MHz of gain bandwidth, 14 nV/

√Hz input referred noise, and supply

current of 138 μA, the LMV641 is well suited for portable applications that require precision while amplifying at

high gains.

8.2 Typical Applications

8.2.1 High-Gain, Low-Power Inverting Amplifiers

Figure 39. High-Gain Inverting Amplifier

8.2.1.1 Design Requirements

The wide unity-gain bandwidth allows these parts to provide large gain over a wide frequency range, while

driving loads as low as 2 kΩ with less than 0.003% distortion.

8.2.1.2 Detailed Design Procedure

Figure 39 is an inverting amplifier, with a 100-kΩ feedback resistor, R2, and a 1-kΩ input resistor, R1, and

provides a gain of

−100. With the LMV641, these circuits can provide gain of −100 with a −3-dB bandwidth of

120 kHz, for a quiescent current as low as 116 µA. Coupling capacitors CC1 and CC2 can be added to isolate the

circuit from DC voltages, while RB1 and RB2 provide DC biasing. A feedback capacitor CF can also be added to

improve compensation.