THS4521: THS4521 driving capacitive loads.

Jun Huang1

Part Number: THS4521

On the THS4521 datasheet, section 8.3.10, It suggests to use small resistor in the series with the output to avoid phase shift. The topology of anti-aliasing filter used in Fig 79 looks like it's doing the opposite. Is it a mistake?

Can someone explain that? thanks.

over 4 years ago

0 Hasan Babiker31 over 4 years ago

TI__Genius 15555 points

Hello Jun,

In short, the 40.2-ohm resistors are acting like that isolation resistance in higher frequencies (when capacitor is shorted) and will help with the phase margin of the circuit. The difference between section 8.3.1.0 and figure 79 is that two different methods of compensation are being used in each circuit. I would recommend watching the following videos for greater detail:

https://training.ti.com/ti-precision-labs-op-amps-stability-5?context=1139747-1139745-14685-1138805-13952

https://training.ti.com/ti-precision-labs-op-amps-stability-6?context=1139747-1139745-14685-1138805-13953

Here are the youtube links to the same videos if any issues occur:

https://www.youtube.com/watch?v=ER2x0djZ7oU

https://www.youtube.com/watch?v=L6ecVTDJ2-4

Please let me know if you have any questions.

Best,

Hasan Babiker

Amplifiers

Amplifiers forum

THS4521: THS4521 driving capacitive loads.