My customer want to design various Up/Down converter block using BiCMOS Mixers(ex.HMC686, HMC687.....).
According to the application circuit of these mixers, balun is recommended for single-ended type in IF stage as below.
But, the customer want to use single-ended without balun in IF stage.
Is it possible to use only positive line in IF stage without balun?
Could you please provide an application note for the solution that do not use balun ?
The IFP and IFN pins are differential. In theory you could use either of the pins to get single ended performance and terminate the other port. The conversion gain will now be ~3dB lower.
In practice there is going to be some phase deviation and amplitude imbalance between IFP and IFN and you would measure the conversion gain for each port and choose the port with best conversion gain.
Hope this helps,