The output stage of the TLV232x is designed to sink and source relatively high amounts of current (see Section 5.10). If the output is subjected to a short-circuit condition, this high-current capability is able to cause device damage under certain conditions. Output current capability increases with supply voltage.

Although the TLV232x possess excellent high-level output voltage and current capability, methods are available to boost this capability, if needed. The simplest method uses a pullup resistor (R_P) connected from the output to the positive supply rail (see Figure 7-6). Using this circuit has two disadvantages. First, the NMOS pulldown transistor sinks a comparatively large amount of current. In this circuit, the pulldown transistor behaves like a linear resistor with an on-resistance between approximately 60Ω and 180Ω, depending on how hard the operational amplifier input is driven. With very low values of R_P, a voltage offset from 0V at the output occurs. Secondly, pullup resistor R_P acts as a drain load to the pulldown transistor. Thus, the gain of the op amp is reduced at output voltage levels where the corresponding pullup transistor is not supplying the output current.

Figure 7-6 Resistive Pullup to Increase v_OH

Figure 7-7 Test Circuit for Output Characteristics

All operating characteristics of the TLV232x are measured using a 20pF load. The device drives higher capacitive loads. However, as output load capacitance increases, the resulting response pole occurs at lower frequencies, thereby causing ringing, peaking, or even oscillation (see Figure 7-7 and Figure 7-8). In many cases, adding some compensation in the form of a series resistor in the feedback loop alleviates the problem.

Figure 7-8 Effect of Capacitive Loads