5

Application information

5.1

Driving resistive and capacitive loads

These products are low-voltage, low-power operational amplifiers optimized to drive rather large resistive loads

above 2 kΩ.

In a follower configuration, these operational amplifiers can drive capacitive loads up to 100 pF with no

oscillations. When driving larger capacitive loads, adding a small in-series resistor at the output can improve the

stability of the device (figure below shows the recommended in-series resistor values). Once the in-series resistor

value has been selected, the stability of the circuit should be tested on bench and simulated with the simulation

model.

Figure 19. In-series resistor vs. capacitive load

5.2

PCB layouts

For correct operation, it is advised to add 10 nF decoupling capacitors as close as possible to the power supply

pins.

5.3

Macromodel

An accurate macromodel of the TSV91x is available on STMicroelectronics’ web site at: www.st.com . This

model is a trade-off between accuracy and complexity (that is, time simulation) of the TSV91x operational

amplifiers. It emulates the nominal performances of a typical device within the specified operating conditions

mentioned in the datasheet. It helps to validate a design approach and to select the right operational amplifier, but

it does not replace on-board measurements.

TSV91x, TSV91xA

Application information

DS4899 - Rev 13

page 14/30