Datasheet

V+
OUT
GND
IN-
IN+
C
BYPASS
0.01 Fm
to
0.1 Fm
+2.7V to +26V
REF
Reference
Voltage
Supply Load
R
SHUNT
Output
R
1
R
3
R
2
R
4
INA199A1, INA199B1
INA199A2, INA199B2
INA199A3, INA199B3
www.ti.com SBOS469D –MAY 2009–REVISED NOVEMBER 2012
APPLICATION INFORMATION
BASIC CONNECTIONS
Figure 20 shows the basic connections for the INA199. The input pins, IN+ and IN–, should be connected as
closely as possible to the shunt resistor to minimize any resistance in series with the shunt resistance.
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 should be tied together (that is, tie IN+ to
IN+ and tie IN– to IN–).
POWER SUPPLY
The input circuitry of the INA199 can accurately measure beyond its power-supply voltage, V+. For example, the
V+ power supply can be 5V, whereas the load power-supply voltage can be as high as +26V. However, the
output voltage range of the OUT terminal is limited by the voltages on the power-supply pin. Note also that the
INA199 can withstand the full –0.3V to +26V range in the input pins, regardless of whether the device has power
applied or not.
SELECTING R
S
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 100mV.
The INA199 series of current-shunt monitors give equivalent accuracy at a full-scale range on the order of 10mV.
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 3.3V supply could easily handle a full-scale shunt drop of 60mV, with only 150μV of offset.
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Product Folder Links: INA199A1 INA199B1 INA199A2 INA199B2 INA199A3 INA199B3