ADF4252 has 2 independent PLL channels，IF channel and RF channel. If I use the RF channel only, do I still need to provide the power supply to IF channel or can I leave the power pins for IF channel float. Thanks!
To avoid internal protection diodes being turned on – it is better to supply power to the IF channel.
In this case just tie the IF power pins (Vdd2/Vp2) to the RF power pins.
When configuring the part the datasheet mentions (pasted below) you do not need to write to the IF registers. this will
ensure the IF channel stays in powerdown. you can leave the IF input pins IFINa/IFINb floating.
All GND pins should be common.
“It is necessary to write only to Registers R3, R2, R1, and R0 when powering up the RF synthesizer only. The IF side will
remain in power-down until Registers R6, R5, R4, and R3 are written to.”
From: Ning Jia firstname.lastname@example.org
Sent: 11 May 2010 10:43
To: Harney, Austin
Subject: ADI Internal: RF New message: "ADF4252s power supply"
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ADF4252‘s power supply
created by Ning Jia<http://ez.analog.com/people/NJia> in ADI Internal: RF - View the full discussion<http://ez.analog.com/message/9905#9905
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