THS4631

CF3

−V(Bias)

Note: A capacitive T-network enables fine control of the effective feedback capacitance using relatively large capacitor values.

Figure 8-11. Alternative Transimpedance Configuration 3

8.3 Power Supply Recommendations

8.3.1 Slew-Rate Performance With Varying Input-Step Amplitude and Rise-and-Fall Time

Some FET input amplifiers exhibit the peculiar behavior of having a larger slew rate when presented with smaller input voltage steps and slower edge rates due to a change in bias conditions in the input stage of the amplifier under these circumstances. This phenomena is most commonly seen when FET input amplifiers are used as voltage followers. This behavior is typically undesirable, and the THS4631 has been designed to avoid these issues. Larger amplitudes lead to higher slew rates, as anticipated, and fast edges do not degrade the slew rate of the device. The high slew rate of the THS4631 allows for improved SFDR and THD performance, especially noticeable at frequencies greater than 5MHz.

Product Folder Links: THS4631