2.2 Built-in Modes

The OPAMP module includes software configurable internal connections, enabling most common op-amp modes. The different modes are briefly introduced in Table 2-1. For more details related to implementation of the built-in modes, refer to the datasheet.

Table 2-1. Built-in Modes
ModeFigure
Voltage Follower

A unity gain amplifier.

Vout = Vin
Figure 2-2. Voltage Follower
Inverting/Non-Inverting PGA

A software configurable Programmable Gain Amplifier (PGA) using the internal resistor ladder.

Vout = Vin (1 + R2/R1)
Figure 2-3. Non-Inverting PGA
Cascaded Inverting/Non-Inverting PGA

The OPAMPs can be internally connected in cascade to provide a larger varity of gains.

Vout = Vin (1 + R2/R1)(1 + R2/R1)(1 + R2/R1)
Figure 2-4. Cascaded Non-Inverting PGA
Differential Amplifier

A Voltage Follower and a non-inverting PGA connected in cascade.

Vdiff = (V2 - V1) R2/R1
Figure 2-5. Differential Amplifier
Instrumentation Amplifier

A Differential Amplifier with input buffer amplifiers.

Vout = (V2 - V1) Gain + Ref
Figure 2-6. Instrumentation Amplifier
Transimpedance Amplifier

For converting current to voltage.

Vout = -Iin (R1 + R2)
Figure 2-7. Transimpedance Amplifier
Programmable Hysteresis

Inverting or Non-Inverting comparator with programmable hysteresis.

Threshold = ±Vcc R2/R1 + Ref
Figure 2-8. Non-Inverting Comparator with Programmable Hysteresis