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reference input level over various input impedance and waveform at ADF4153

Question asked by daejung.kim on Apr 25, 2012
Latest reply on Apr 30, 2012 by JLKeip

Hi all,

 

our customers has been asking about min. reference input level over various input type at ADF4153.

 

so recently, this problem is definded two case as below.

 

also, we got a conversion equation when Vpp is converted by dBm at sinewave .

 

To conclude, minimum ref input range of square wave is decreased than sine wave as below.

 

1) where) 51ohm shunt resistor must use at reference input.

1)     Sine wave(need input level over -4dBm)

10log(0.4)^2/(0.008*50) = -3.98dBm

 

2)     Square wave(need input level over -1dBm)

10log(0.4)^2/(0.004*50) = -0.97dBm

2) when the CLK is high impedance and waveform is TTL, CMOS or sinewave form. the below spec will be used.

 

I want to discuss upper condition is right or not? could you please tell me if you  have another idea?

 

I wish to help when you design PLLIC.

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