SNAS739D June 2018 – May 2020 LMX2615-SP
PRODUCTION DATA.
One strategy for the choice of the pullup component is to a resistor (R). This is typically chosen to be 50-Ω and under the assumption that the part output impedance is high, then the output impedance will theoretically be 50 ohms, regardless of output frequency. As the output impedance of the device is not infinite, the output impedance when the pullup resistor is used will be less than 50 ohms, but reasonably close. There will be some drop across the resistor, but this does not seem to have a large impact on signal swing for a 50-Ω resistor provided that OUTx_PWR≤31.