ADS131M08: The source-termination resistor placed at the clock buffer

Hi Ivy,

The source-termination technique shown in the following figure is commonly used to absorb the reflections, limit slew rate and prevent ringing with an impedance equal to the impedance of transmission line which usually is 50Ω (Zo). The following example shows a 39Ω output impedance of the source driver, so an approximate 10Ω resistor (Rt) is required in series with the output impedance of the driver. You may have to check the output impedance of the oscillator you are planning to use first, then select a proper value of termination resistor. The ADS131M08 EVM can be a good reference, you can check the schematic in the ADS131M08EVM user guide here.

Best regards,

Dale