LT5538

Hello Rumeysa,

It seems likely that the s parameter file may not be accurate. The cause could be, for example, the reference plane for the s-parameter file of data may not be at the IN+ pin. 

For broadband matching of this device, we would definitely recommend the resistive matching like shown in datasheet Figure 6. For slightly higher sensitivity, R1 could be increased for example up to 75 or 82 Ohms, depending on the application and requirement. In Figure 6, we see L1 helping to tune out small amounts of input capacitance, then C8 helps extend matching bandwidth further. 

Hello Rumeysa,

It seems likely that the s parameter file may not be accurate. The cause could be, for example, the reference plane for the s-parameter file of data may not be at the IN+ pin. 

For broadband matching of this device, we would definitely recommend the resistive matching like shown in datasheet Figure 6. For slightly higher sensitivity, R1 could be increased for example up to 75 or 82 Ohms, depending on the application and requirement. In Figure 6, we see L1 helping to tune out small amounts of input capacitance, then C8 helps extend matching bandwidth further.