I'm trying to match the output impedance of the LTC6957-3 to a 50 Ohm transmission line. In the datasheet of the LTC6957 I didn't found any information regarding the output impedance of the -3/4 variant of the chip. In the datasheet of the evaluation board for the LTC6957-3 I found the following statement:
"NOTE: The CMOS outputs of the DC1766A are AC coupled and attenuated through two 100Ω resistors as shown in the DC1766A schematic diagram to present a 50Ω source impedance appropriate to connect to a 50Ω input impedance instrument." Source: https://www.analog.com/media/en/technical-documentation/user-guides/dc1766af.pdf (Page 2)
Through this impedance matching the output voltage level gets halved, which results in a Vp-p of approximately 1.65 V. This output swing is to small for the following circuit on my PCB. Therefore I'm looking for an alternative impedance matching. Do you have any suggestions?
I have seen other CMOS output drivers which have a output impedance of approx. 7 Ohms. In that case a 43 Ohm series resistor would be enough to match the output impedance to the transmission line and the output voltage swing would stay at 3.3 Vp-p. Is this approach suitable in the case of the LTC6957-3?
Thank you in advance.