INA199 datasheet(21/42 Pages) TI2

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9 Power Supply Recommendations

The input circuitry of the INA199 can accurately measure beyond its power-supply voltage, V+. For example,

the V+ power supply can be 5 V, whereas the load power-supply voltage can be as high as 26 V. However, the

output voltage range of the OUT pin is limited by the voltages on the power-supply pin. Also, the INA199 can

withstand the full input signal range up to 26-V range in the input pins, regardless of whether the device has

power applied or not.

10 Layout

10.1 Layout Guidelines

• Connect the input pins to the sensing resistor using a kelvin or 4-wire connection. This connection technique

ensures that only the current-sensing resistor impedance is detected between the input pins. Poor routing of

the current-sensing resistor commonly results in additional resistance present between the input pins. Given

the very low ohmic value of the current resistor, any additional high-current carrying impedance can cause

significant measurement errors.

• Place the power-supply bypass capacitor as close as possible to the supply and ground pins. TI recommends

using a bypass capacitor with a value of 0.1 μF. Additional decoupling capacitance can be added to

compensate for noisy or high-impedance power supplies.

10.2 Layout Example

Supply Bypass

Capacitor

VIA to Power or

Ground Plane

VIA to Ground Plane

Supply

Voltage

Output Signal

Trace

Figure 10-1. Recommended Layout

www.ti.com

INA199

SBOS469H – APRIL 2009 – REVISED OCTOBER 2023

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INA199 Datasheet(PDF) 21 Page - Texas Instruments