ADC

Power

Supply

Load

0.1µF

5V Supply

-

+

IN-

IN+

GND

V+

OUT

REF

Micro-

controller

INA199

www.ti.com

SBOS469E – APRIL 2009 – REVISED DECEMBER 2015

8.3 Feature Description

8.3.1 Basic Connections

Figure 20 shows the basic connections for the INA199. The input pins, IN+ and IN–, must be connected as close

as possible to the shunt resistor to minimize any resistance in series with the shunt resistor.

Figure 20. Typical Application

Power-supply bypass capacitors are required for stability. Applications with noisy or high-impedance power

supplies may require additional decoupling capacitors to reject power-supply noise. Connect bypass capacitors

close to the device pins.

On the RSW package, two pins are provided for each input. These pins must be tied together (that is, tie IN+ to

IN+ and tie IN– to IN–).

The zero-drift offset performance of the INA199 offers several benefits. Most often, the primary advantage of the

low offset characteristic enables lower full-scale drops across the shunt. For example, non-zero-drift current

shunt monitors typically require a full-scale range of 100 mV.

The INA199 series gives equivalent accuracy at a full-scale range on the order of 10 mV. This accuracy reduces

shunt dissipation by an order of magnitude with many additional benefits.

Alternatively, there are applications that must measure current over a wide dynamic range that can take

advantage of the low offset on the low end of the measurement. Most often, these applications can use the lower

gain of 50 or 100 to accommodate larger shunt drops on the upper end of the scale. For instance, an INA199A1

operating on a 3.3-V supply could easily handle a full-scale shunt drop of 60 mV, with only 150

μV of offset.

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