Then, find the available output swing range greater than the reference voltage available for the measurement:

VSWING=VOUTMAX−VZERO=2.5V−0.3V=2.2V

(4)

where

• VSWING is the expected change in output voltage.

• VOUTMAX is the maximum amplifier output swing.

Finally, calculate the transimpedance resistor (RF) value using the maximum swing and the maximum sensor

current:

RF= VSWING

ISENSMAX= 2.2V20.7μA=106.28kΩ use 110kΩ for a common value

(5)

7.2.1.3 Application Curve

Time (10 ms/div)

0.3 V

2.5 V

20 PA

C012

VTIA

VCE

ISENS

Figure 7-3. Sensor Transient Response to Simulated 300ppm CO Exposure

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OPA396, OPA2396, OPA4396

SBOSA65A – JULY 2021 – REVISED MARCH 2026

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