Hello -
I have few questions regarding TRF3720 baseband input level. Q1. Interpretation of VinBB
The data sheet shows: I cannot find a good interpretation of "VinBB = 300 mVrms single-ended sine wave ..". I guess, it is based on Evaluation Board setup (but, I'm not sure). Then, among the cases below, which case does this test condition correspond to?
Q2. Recommended BB input level I cannot find the following information for the BB input. - recommended max Vrms - recommended max Vp-p (peak-to-peak)
Can I get some help to determine these values?
Thanks!
A1. Interpretation of VinBB
VinBB is measured using a high impedance, single-ended scope probe between one leg of the baseband input and ground. The measurement setup is illustrated below.
The EVM differential resistor, Z, can be 100ohms or open. It will change the level of voltage presented to the device, but the device gain is unaffected and output level will change accordingly.
A2: Recommended BB input level
Instead of specifying maximum input level, the datasheet specifies P1dB on the output. Gain through the device varies as noted in the datasheet plot. Because customers use the modulator in different electrical and environmental operating regimes, input levels may vary.
100mVrms is a reasonable target.