ina219 datasheet

Supply bypass
capacitor
A0
A1
SDA
IN+
IN±
GND
SCL VS
I
2
C - /
SMBUS -
compatible
interface
Via to Ground Plane
Via to Power Plane
Sense/Shunt
Resistor
INA219
www.ti.com SBOS448G –AUGUST 2008–REVISED DECEMBER 2015
10 Power Supply Recommendations
The input circuitry of the device can accurately measure signals on common-mode voltages beyond its power
supply voltage, V
S
. For example, the voltage applied to the V
S
power supply terminal can be 5 V, whereas the
load power-supply voltage being monitored (the common-mode voltage) can be as high as 26 V. Note also that
the device can withstand the full 0-V to 26-V range at the input terminals, regardless of whether the device has
power applied or not.
Place the required power-supply bypass capacitors as close as possible to the supply and ground terminals of
the device to ensure stability. A typical value for this supply bypass capacitor is 0.1 μF. Applications with noisy or
high-impedance power supplies may require additional decoupling capacitors to reject power-supply noise.
11 Layout
11.1 Layout Guidelines
Connect the input pins (IN+ and IN –) to the sensing resistor using a Kelvin connection or a 4-wire connection.
These connection techniques ensure 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-sensing resistor, any additional high-current carrying
impedance causes significant measurement errors. Place the power-supply bypass capacitor as close as
possible to the supply and ground pins.
11.2 Layout Example
Figure 30. Recommended Layout
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