OUT

V

+

V

–

IN –

IN +

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Texas Instruments Incorporated

12

LMV551-Q1

SNOSD24 – FEBRUARY 2017

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7 Detailed Description

7.1 Overview

The LMV551-Q1 is a high performance, low power operational amplifiers implemented with TI’s advanced VIP50

process. The LMV551-Q1 features 3 MHz of bandwidth while consuming only 37 µA of current, which is an

exceptional bandwidth to power ratio in this op amp class. This amplifier is unity gain stable and provide an

excellent solution for low power applications requiring a wide bandwidth.

7.2 Functional Block Diagram

7.3 Feature Description

The differential inputs of the amplifier consist of a noninverting input (+IN) and an inverting input (–IN). The

amplifier amplifies only the difference in voltage between the two inputs, which is called the differential input

voltage. The output voltage of the op-amp VOUT is given by Equation 1:

VOUT = AOL (IN

+– IN–)

where

•

AOL is the open-loop gain of the amplifier, typically around 100 dB (100,000x, or 10 μV per volt).

(1)

7.3.1 Low Voltage and Low Power Operation

The LMV551-Q1 has performance ensured at supply voltages of 3 V and 5 V and are ensured to be operational

at all supply voltages from 2.7 V to 5.5 V. For this supply voltage range, the LMV551-Q1 draw the extremely low

supply current of less than 37 μA.

7.3.2 Wide Bandwidth

The bandwidth to power ratio of 3 MHz to 37 μA per amplifier is one of the best bandwidth to power ratios ever

achieved. This makes these devices ideal for low power signal processing applications such as portable media

players and instrumentation.

7.3.3 Low Input Referred Noise

The LMV551-Q1 provides a flatband input referred voltage noise density of 70 nV/

√Hz , which is significantly

better than the noise performance expected from an ultra low power op amp. They also feature the exceptionally

low 1/f noise corner frequency of 4 Hz. This noise specification makes the LMV551-Q1 ideal for low power

applications such as mobile devices and portable sensors.

7.3.4 Ground Sensing and Rail-to-Rail Output

The LMV551-Q1 has a rail-to-rail output stage, which provides the maximum possible output dynamic range.

This is especially important for applications requiring a large output swing. The input common mode range

includes the negative supply rail which allows direct sensing at ground in a single supply operation.