The TLV354x series op amps can drive a wide range of capacitive loads. However, all op amps under certain conditions may become unstable. Op amp configuration, gain, and load value are just a few of the factors to consider when determining stability. An op amp in unity-gain configuration is most susceptible to the effects of capacitive loading. The capacitive load reacts with the device output resistance, along with any additional load resistance, to create a pole in the small-signal response that degrades the phase margin. Refer to the typical characteristic curve, Frequency Response for Various C_L (Figure 5-6) for details.

The TLV354x topology enhances the ability to drive capacitive loads. In unity gain, these op amps perform well with large capacitive loads. Refer to the typical characteristic curves, Recommended R_S vs Capacitive Load (Figure 5-7) and Frequency Response vs Capacitive Load (Figure 5-8) for details.

One method of improving capacitive load drive in the unity-gain configuration is to insert a 10Ω to 20Ω resistor in series with the output, as shown in Figure 6-6. This configuration significantly reduces ringing with large capacitive loads. See the typical characteristic curve, Frequency Response vs Capacitive Load (Figure 5-8). However, if there is a resistive load in parallel with the capacitive load, R_S creates a voltage divider. This voltage division introduces a DC error at the output and slightly reduces output swing. This error may be insignificant. For instance, with R_L = 10kΩ and R_S = 20Ω, there is an error of approximately 0.2% at the output.

Figure 6-6 Series Resistor in Unity-Gain Configuration Improves Capacitive Load Drive