Differential Input Load

Question

Hi, 
 
 I am trying to design a baseband network operating at 10MHz. My system is using the AD8376 differential VGA to drive a AD9259 ADC. 
 
 I am trying to design the output network for the AD8376 (selecting the correct bias resistors) but I can't seem to find the differential input load of the AD9259 on the datasheet. I can see that the input capacitance of the inputs is 7pf (screenshot attached), but there is no mention of the input impedance. Do I assume it is high impedance? Or if I'm driving 100Ohm differential lines, will RL = 100? 
 
 For reference I am looking at the AD8376 datasheet and trying to perform the following:

Thanks, 
 Louis

ADIApproved · Accepted Answer

The device has an impedance of 100 ohms differentially. 
 The data sheet has one examples how drive it, please take a look on page 20 AD9259 (Rev. F) (analog.com) , also I will put the link to our eval board design. 
 sch\9228CE01B (analog.com) 
 
 I hope this helps on your design. 
 
 Let us know if you have any another questions. 
 
 Sergio)

Partner Forums

Partner Libraries

Products Mentioned

Differential Input Load

Thread Notes