An advantage of this configuration becomes evident for temperature drifts. In traditional instrumentation

amplifiers, the external resistor must match the internal monolithic resistors. Discrete resistors are available

with a ratio temperature coefficient of < 10ppm/°C to achieve excellent gain drift performance.

7.3.2 Linear Input Voltage Range

The indirect current feedback architecture in the INA630 enables a simple design procedure to verify whether

the operating input voltages of the application lie within the linear input and output voltage ranges of the INA630,

given by:

• Maximum input and output voltage is within specified range of VS+ −1.75V and VS−1.5V

• Operating differential input voltage is within specified range of VDM(MAX) = ±125mV

Figure 7-3 and Figure 7-4 show the most common operating conditions and the corresponding linear operating

ranges.

Max/Min Output Voltage (V)

-15

-10

-5

0

5

10

15

-15

-12.5

-10

-7.5

-5

-2.5

0

2.5

5

7.5

10

12.5

15

MAX Operating

MAX Specified

Dual Supply VS = ±15V, G = 100, REF = GND

Figure 7-3. Input Voltage

vs Output Voltage for Dual Supply VS = ±15V

Min/Max Output Voltage (V)

0

1

2

3

4

5

0

1

2

3

4

5

MAX Specified

Single Supply VS = 5V, REF = GND

Figure 7-4. Input Voltage

vs Output Voltage for Single Supply VS = 5V

7.3.3 Input Protection

The maximum differential input voltage of the INA630 is internally limited to ±125mV. Traditionally this is

achieved with a resistor connected to back-to-back diodes. When the differential input voltage exceeds a

threshold, one of the diode starts to conduct and the resistor defines the maximum input current that can be

quite large. There is a trade-off to accept between large input current for small resistors and increased noise and

offset behavior for larger resistance.

The INA630 incorporates a JFET clamping structure provide low series resistance under normal conditions. In

the fault case when the inputs are more than the maximum differential input voltage of ±125mV, the protection

circuitry limits the input current to a value of approximately 40μA.

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INA630

SBOSAI8A – MARCH 2025 – REVISED JULY 2025

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