9 Power Supply Recommendations

The OPAx388-Q1 family of operational amplifiers can be used with single or dual supplies from an operating

temperature range are shown in Section 6.7.

CAUTION

Supply voltages greater than 7 V can permanently damage the device (see Section 6.1).

10 Layout

10.1 Layout Guidelines

Pay attention to good layout practice. Keep traces short and, if possible, use a printed-circuit board (PCB)

ground plane with surface-mount components placed as close as possible to the device pins. Place a 0.1-µF

capacitor closely across the supply pins. Apply these guidelines throughout the analog circuit to improve

performance and provide benefits, such as reducing the electromagnetic interference (EMI) susceptibility.

For lowest offset voltage and precision performance, optimize the circuit layout and mechanical conditions. Avoid

temperature gradients that create thermoelectric (Seebeck) effects in the thermocouple junctions formed from

connecting dissimilar conductors. These thermally-generated potentials can be made to cancel by making sure

these potentials are equal on both input terminals. Other layout and design considerations include:

• Use low thermoelectric-coefficient conditions (avoid dissimilar metals).

• Thermally isolate components from power supplies or other heat sources.

• Shield operational amplifier and input circuitry from air currents, such as cooling fans.

Follow these guidelines to reduce the likelihood of junctions being at different temperatures, which can cause

thermoelectric voltage drift of 0.1 µV/°C or greater, depending on the materials used.

10.2 Layout Example

+

VIN

VOUT

RG

RF

Figure 10-1. Schematic Representation

N/C

±IN

+IN

V±

V+

OUTPUT

N/C

N/C

VS+

GND

Ground (GND) plane on another layer

VOUT

VIN

GND

Run the input traces

as far away from

the supply lines

as possible

RF

RG

Place components close

to device and to each

other to reduce parasitic

errors

Use low-ESR,

ceramic bypass

capacitors

GND

Figure 10-2. Layout Example

OPA388-Q1, OPA2388-Q1

SBOS989A – AUGUST 2020 – REVISED NOVEMBER 2021

www.ti.com

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