10 Power Supply Recommendations

The nominal performance of the INA849 is specified with a supply voltage of ±15 V and midsupply reference

voltage. The device also operates using power supplies from ±4 V (8 V) to ±18 V (36 V) and non-midsupply

reference voltages with excellent performance. Parameters that can vary significantly with operating voltage and

reference voltage are shown in Section 7.6.

11 Layout

11.1 Layout Guidelines

For best operational performance of the device, use good PCB layout practices, including:

• To avoid converting common-mode signals into differential signals and thermal electromotive forces (EMFs),

make sure that both input paths are symmetrical and well-matched for source impedance and capacitance.

• Place the external gain resistor close to the RG pins to keep the loop inductance as low as possible and to

avoid a potential parasitic coupling path, but also so that capacitance mismatch between the RG pins is

minimized.

• Noise can propagate into analog circuitry through the power pins of the circuit as a whole and of the device.

Bypass capacitors reduce the coupled noise by providing low-impedance power sources local to the analog

circuitry.

– Connect low-ESR, 0.1-µF, ceramic bypass capacitors between each supply pin and ground, placed as

close as possible to the device.

– A single bypass capacitor from V+ to ground is applicable for single-supply applications.

• To reduce parasitic coupling, run the input traces as far away as possible from the supply or output traces. If

these traces cannot be kept separate, crossing the sensitive trace perpendicular is much better than in

parallel with the noisy trace.

• Keep traces as short as possible.

• Minimize the number of thermal junctions. Ideally, the signal path is routed within a single layer without vias.

• Keep sufficient distance from major thermal energy sources (circuits with high power dissipation). If not

possible, place the device such that it matches the thermal energy source on the differential signal path.

www.ti.com

INA849

SBOS945A – NOVEMBER 2020 – REVISED DECEMBER 2020

Copyright © 2020 Texas Instruments Incorporated

Submit Document Feedback

25

Product Folder Links: INA849