OPA863 datasheet(29/52 Pages) TI

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10 Power Supply Recommendations

The OPAx863 devices are intended to operate on supplies ranging from 2.7 V to 12.6 V. The OPAx863 devices

may operate on single-sided supplies, split and balanced bipolar supplies, or unbalanced bipolar supplies.

Operating from a single supply can have numerous advantages. The DC errors, due to the –PSRR term, can

be minimized with the negative supply at ground. Typically, AC performance improves slightly at 10-V operation

with minimal increase in supply current. Minimize the distance (< 0.1 in) from the power supply pins to high-

frequency, 0.01-µF decoupling capacitors. A larger capacitor (2.2 µF typical) is used along with a high-frequency,

0.01-µF supply-decoupling capacitor at the device supply pins. Only the positive supply has these capacitors

for single-supply operation. Use these capacitors from each supply to ground when a split-supply is used. If

necessary, place the larger capacitors further from the device and share these capacitors among several devices

in the same area of the printed circuit board (PCB). An optional supply decoupling capacitor across the two

power supplies (for split-supply operation) reduces second harmonic distortion.

11 Layout

11.1 Layout Guidelines

Achieving optimum performance with a high-frequency amplifier (like the OPAx863 devices) require careful

attention to board layout parasitics and external component types. The OPA2863 DGK Evaluation Module

user's guide can be used as a reference when designing the circuit board. Recommendations that optimize

performance includes the following:

1. Minimize parasitic capacitance to any AC ground for all of the signal I/O pins. Parasitic capacitance on

the output and inverting input pins can cause instability on the noninverting input and can react with the

source impedance to cause unintentional band-limiting. Open a window around the signal I/O pins in all of

the ground and power planes around those pins to reduce unwanted capacitance. Otherwise, ground and

power planes must be unbroken elsewhere on the board.

2. Minimize the distance (< 0.1 in) from the power-supply pins to high-frequency 0.01-µF decoupling

capacitors. Avoid narrow power and ground traces to minimize inductance between the pins and the

decoupling capacitors. The power-supply connections must always be decoupled with these capacitors.

Larger (2.2-µF to 6.8-µF) decoupling capacitors, effective at lower frequency, must also be used on the

supply pins. These can be placed somewhat farther from the device and shared among several devices in

the same area of the PC board.

3. Careful selection and placement of external components preserve the high frequency performance

of the OPAx863 devices. Resistors must be a low reactance type. Surface-mount resistors work best and

allow a tighter overall layout. Other network components, such as noninverting input termination resistors,

must also be placed close to the package. Keep resistor values as low as possible and consistent with

load driving considerations. Lowering the resistor values keep the resistor noise terms low and minimize the

effect of its parasitic capacitance; lower resistor values, however, increase the dynamic power consumption

because RF and RG become part of the amplifiers output load network.

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OPA863, OPA2863, OPA4863

SBOS982I – JUNE 2020 – REVISED DECEMBER 2022

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OPA863 Datasheet(PDF) 29 Page - Texas Instruments