AD9144 output circuit configuration

Question

Hello, 
 we are going to use your AD9144 in a new board and we need to better understand what is the right configuration for the output circuitry. 
 In your EVB ( EVAL-AD9144) there are a couple of transformers for each output channel. 
 What is the meaning of each transformer ? 
 What is the expected output power with the hardware configuration present on the EVB ? 
 Thanks for the support. 
 Edoardo Vitali.

JMMina · Accepted Answer

Hi EVI , 
 RF Transformers such as T12 and T13 (ADT2-1T-1P+) in the AD9144 Evaluation Board (AD9144-FMC-EBZ) convert the differential current output of each AD9144 DAC to a single ended signal driving a 50 ohm cable or load. The transformer serves to convert differential to single ended and isolates the DAC output from reactive loads presented by transmission lines. This improves overall distortion performance. One RF transformer for each DAC should be all you need. The RF transformer is a band pass device. The ADT2-1T-1P+ has a 3dB bandwidth of 8MHz-600MHz. 
 On the other hand, T4 and T6 (ADTL1-12) are transmission line transformers. They provide isolation between the output impedance of each DAC and the impedance of a cable. They are more useful when driving a long transmission line or passive filter. A choking reactance isolates the input from the output. 
 Best regards, Marco)

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AD9144 output circuit configuration