THS4541: ths4541 - feedback resistor values

Hi Zeev,

We typically recommend customers stick to 402 ohm feedback resistors for this device as increasing Rf could lead to stability issues due to the speed of the device. Regarding feedback capacitor values, you could use them for this device but we recommend simulating the desired circuit to see its behavior. Considering you are using larger Rf resistors as well as feedback capacitors, I would recommend adding a capacitor directly across the inputs of the FDA stage. This is a technique used to tune and shape the noise gain of the circuit to ensure you remain in a stable configuration. I would look at section 9.2.1 Designing Attenuators in the datasheet. Although this is explaining an attenuator circuit the same idea applies if you are using larger resistors or if you are using capacitors in the feedback. The addition of the capacitor I am referring to can be seen in Figure 9-2 and it is capacitor C3. This is something we recommend to all customers as a placeholder incase it is needed to tune the circuit.

Best Regards,

Ignacio

Hi,

pls. review the design of the ths4541 which attach. (rf value, cf value, isolation resistor between the opamp's)

regards

zeev gerber

Part Number: THS4541

Hi,

pls. review the design of the ths4541 which attach. (rf value, cf value, isolation resistor between the opamp's)

regards

zeev gerber