Application information

TSV99x, TSV99xA

12/25

Doc ID 12833 Rev 9

3

Application information

3.1

Driving resistive and capacitive loads

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

large resistive loads above 2 k

Ω..

TSV99x products are not unity gain stable. To ensure proper stability they must be used in a

gain configuration, with a minimum gain of -3 or +4.

However, they can be used in a “follower“ configuration by adding a small, in-series resistor

at the output, which drastically improves the stability of the device (Figure 15 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 the bench and simulated with the

simulation model.

Another way to improve stability and reduce peaking is to add a capacitor in parallel with the

feedback resistor. As shown in Figure 16, the feedback capacitor drastically reduces the

peaking versus capacitive load (inverting gain configuration, gain = -2).

3.2

PCB layouts

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

to the power supply pins.

Figure 15.

In-series resistor vs. capacitive

load when TSV99x used in follower

configuration

Figure 16.

Peaking versus capacitive load,

with or without feedback capacitor

in inverting gain configuration