ADF4372 Reference Port REFP Input Impedance For Single-Ended Configuration

Question

Hello, 
 When driving the REFP port in single-ended configuration (Bit 6 in Address 0x22 set to 0), what is the input impedance of this port? Figure 29 in datasheet suggests it is 100ohms with external bypass cap to ground on REFN port. Is this true? Is the REFP port input impedance 100ohms?

kpeker · Accepted Answer

Hi, 
 Yes, in single-ended configuration input impedance is 100ohm with REFN is AC-coupled to GND. 
 An external 100ohm to GND can be used on REFP to have a 50ohm matching. Alternatively, REFN is left floating and external 50ohm is used on REFP. 
 
 Regards, Kazim

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ADF4372 Reference Port REFP Input Impedance For Single-Ended Configuration

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