OPAX607 datasheet(28/52 Pages) TI

28 / 52 page

9.3 Power Supply Recommendations

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

on single-sided supplies, split and balanced bipolar supplies, or unbalanced bipolar supplies. Operating from a

single supply has 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.

9.4 Layout

9.4.1 Layout Guidelines

Achieving optimum performance with a high-frequency amplifier (like the OPAx863) requires 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 capacitors can be placed somewhat farther from the device and shared among several

devices in the same area of the PCB.

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

of the OPAx863. 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 keeps the resistor noise terms low and minimizes the effect

of the parasitic capacitance. Lower resistor values, however, increase the dynamic power consumption

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

OPA863, OPA2863, OPA4863

SBOS982J – JUNE 2020 – REVISED JUNE 2023

www.ti.com

Submit Document Feedback

Product Folder Links: OPA863 OPA2863 OPA4863

OPAX607 Datasheet(PDF) 28 Page - Texas Instruments