Datasheet

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INA199A1-A3EVM Circuit

3.3 R3, R4, C1

R3 and R4 are factory-installed 0Ω resistors. These resistors, in combination with C1, form an input filter.

These locations allow for both through-hole and surface-mount packages that range in size from 0603 to

1206. Additional information regarding the use of input filtering is provided in the INA199A1-A3 product

data sheet.

3.4 Bypass Capacitors and Jumpers

C2 and C3 are 0.1mF supply bypass capacitors.

J1 is intended to be used as measurements points of R1, if necessary.

J2 is used as a test port at the factory but can be used for the corresponding input and output pins, if

desired.

3.5 U1

U1 is the location for the test device. Three device boards are supplied with the INA199A1-A3EVM board.

Each board is populated with one of the available device gains. This interchangeable option allows users

to test the devices and determine the gain setting that is best suited for a given application.

Here is a list of the factors involved in selecting the appropriate device.

• The INA199A1-A3 devices are identical with the exception of different gain settings.

• The differential input voltage is either applied across the inputs or developed based on the load current

that flows through the shunt resistor.

• The limiting factor that requires attention to be given to device selection is the output voltage.

• The selected device must allow the output voltage to remain within the acceptable range after the

developed input voltage is amplified by the respective device gain. The output voltage must remain

with the range of 50mV above ground to 200mV below the supply voltage.

• An output below the minimum allowable output requires the selection of a device with a higher gain.

Likewise, an output above the maximum allowable output requires the selection of a device with a

lower gain.

SBOU085–May 2010 INA199A1-A3EVM