I want to use a transformer on the output of a DAC on a AD9834 DDS IC. Heres is a picture of using a transformer on the output of one of Analog devices DDS IC's.
If I want to transform from 200ohms (which is what the DAC needs to stay in compliance) to 50 ohms output Z. Is this correct;
Turns ratio for transforming 200 -> 50
Square root of 200/50 = 2
Primary inductance for 3db at 10kHz is 159uH. I calculated this based on examples from application notes coil craft and here.
I'm after as low a frequency I can get to at least 10 Mhz using the same toroid as this guy. (35T0501-10H)
10 KHz to 85 MHz. A SIMPLE BROADBAND TRANSFORMER.Now my question about the center tap primary. My calculated primary inductance is 159uH as already mentioned for correct transformation do I put two 159uH windings on the primary or just one 159uH winding on the primary and tap it at the mid point 79.5 uH?