OPA835IDBVT datasheet(29/53 Pages) NSC

29 / 53 page

OPA 835

Load

SIG

2.5 V

5 V

OUT

OPA 835

Load

SIG

OUT

+2.5 V

-2.5 V

OPA835

OPA2835

www.ti.com

SLOS713E – JANUARY 2011 – REVISED JULY 2013

Figure 61. Split Supply Operation

Single-Supply Operation (2.5V to 5.5V)

Many newer systems use single power supply to improve efficiency and reduce the cost of the power supply.

OPA835 and OPA2835 are designed for use with single-supply power operation and can be used with single-

supply power with no change in performance from split supply as long as the input and output are biased within

the linear operation of the device.

To change the circuit from split supply to single supply, level shift of all voltages by ½ the difference between the

power supply rails. For example, changing from ±2.5 V split supply to 5 V single supply is shown conceptually in

Figure 62.

Figure 62. Single Supply Concept

A more practical circuit will have an amplifier or other circuit before to provide the bias voltage for the input and

the output provides the bias for the next stage.

Figure 63 shows a typical non-inverting amplifier situation. With 5V single supply, a mid supply reference

generator is needed to bias the negative side via RG. To cancel the voltage offset that would otherwise be

caused by the input bias currents, R1 is chosen to be equal to RF in parallel with RG. For example if gain of 2 is

required and RF = 2 kΩ, select RG = 2 kΩ to set the gain and R1 = 1 kΩ for bias current cancellation. The value

for C is dependent on the reference, but at least 0.1µF is recommended to limit noise.

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OPA835IDBVT Datasheet(PDF) 29 Page - National Semiconductor (TI)