OPA830 datasheet(28/66 Pages) TI2

28 / 66 page

8.4 Device Functional Modes

8.4.1 Split-Supply Operation (±1.25 V to ±2.75 V)

To facilitate testing with common lab equipment, the OPA836 EVM (see OPA835DBV, OPA836DBV EVM,

SLOU314) is built to allow for split-supply operation. This configuration eases lab testing because the mid-point

between the power rails is ground, and most signal generators, network analyzers, oscilloscopes, spectrum

analyzers and other lab equipment have inputs and outputs with a ground reference.

Figure 8-6 shows a simple noninverting configuration analogous to Figure 8-1 with ±2.5-V supply and VREF equal

to ground. The input and output will swing symmetrically around ground. For ease of use, split supplies are

preferred in systems where signals swing around ground.

OPA 836

Load

SIG

OUT

+2.5 V

-2.5 V

Figure 8-6. Split-Supply Operation

8.4.2 Single-Supply Operation (2.5 V to 5.5 V)

Often, newer systems use a single power supply to improve efficiency and reduce the cost of the power supply.

The OPA836 and OPA2836 devices are designed for use with a single supply with no change in performance

compared to a 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 half the difference between

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

8-7.

OPA 836

Load

SIG

2.5 V

5 V

OUT

Figure 8-7. Single-Supply Concept

A practical circuit will have an amplifier or other circuit providing the bias voltage for the input, and the output of

this amplifier stage provides the bias for the next stage.

Figure 8-8 shows a typical noninverting amplifiercircuit. With 5-V single-supply, a mid-supply reference generator

is needed to bias the negative side through RG. To cancel the voltage offset that would otherwise be caused by

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

and RF = 1 kΩ, select RG = 1 kΩ to set the gain and R1 = 499 Ω for bias-current cancellation. The value for C

depends on the reference; TI recommends a value of at least 0.1 µF to limit noise.

OPA836, OPA2836

SLOS712J – JANUARY 2011 – REVISED MARCH 2021

www.ti.com

Submit Document Feedback

Product Folder Links: OPA836 OPA2836

OPA830 Datasheet(PDF) 28 Page - Texas Instruments

OPA830 Datasheet(HTML) 28 Page - Texas Instruments

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66

Datasheet Download

Link URL