Supply Bypass

Capacitor

Via to Power or Ground Plane

Via to Internal Layer

Supply Voltage

Shunt Resistor

Pull-ups

Vs

CMP1 IN-

/0.6V Ref

CMP1

IN+

CMP2

DELAY

CMP2 OUT

V

IN-

V

IN+

CMP1 OUT

CMP2

IN+

CMP2 IN-

/0.6V Ref

GND

CMP1

RESET

1.2V REF

OUT

OUT

21

INA203-Q1

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SBOS539A – DECEMBER 2010 – REVISED APRIL 2016

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10 Power Supply Recommendations

The input circuitry of the INA203-Q1 can accurately measure beyond the power-supply voltage, VS. For example,

the VS power supply can be 5 V, whereas the load power-supply voltage is up to 80 V. The output voltage range

of the OUT terminal, however, is limited by the voltages on the power-supply pin.

11 Layout

11.1 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.

•

The power-supply bypass capacitor should be placed as closely as possible to the supply and ground pins. TI

recommends the value of this bypass capacitor is 0.1

μF. Additional decoupling capacitance can be added to

compensate for noisy or high-impedance power supplies.

11.2 Layout Example

Figure 38. Layout Recommendation