8.2.3 DC Level-Shifting

Often, applications must level-shift a ground-referenced signal to a non-ground voltage. Configurations in Figure

8-10 and Figure 8-11 show two different ways of level-shifting a signal by using the OPA862 without having to

use external resistors, saving board cost and space. These configurations leverage the fixed noninverting gain-

of-2 configuration of A2 and the summing configuration of A1 to level-shift the signal at VOUT–. The internal

resistors of the OPA862 are extremely well-matched to maintain the gain-of-2 accuracy of A2. Similarly matched

external resistors can add significant cost to the system and often are more expensive than the amplifier itself.

noninverting input of A1 is grounded.

A1

+

±

A2

+

±

700

700

1

8

5

+7 V

3

OPA862

4

0.1 µF

0.1 µF

6

7

2

±2.5 V

±2.5 V

with respect to GND

0 V

0 V

2.5 V

-1.25 V

1.25 V

5 V

Figure 8-10. Level-Shifting With a DC Source of Polarity Opposite to the Desired DC Shift

A1

+

±

A2

+

±

700

700

1

8

5

+7 V

3

OPA862

4

0.1 µF

0.1 µF

6

7

2

with respect to GND

2.5 V

0 V

0 V

2.5 V

±2.5 V

I =

-1.25 V

1.25 V

5 V

Figure 8-11. Level-Shifting With a DC Source of Polarity Same as the Desired DC Shift

OPA862

SBOS919C – AUGUST 2019 – REVISED AUGUST 2020

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