I am using a broadband 6-bit digital attenuator MMIC from www.astramtl.com
Its a very good chip, but sometimes, I get ripple in the attenuation states... particularly in last 15-20 states. And by the time all 6 bits are switched on, the ripple goes to almost 3 dB.
This chip has an on-chip TTL driver, so there is not much I can do about the control to different attenuation states.
Can someone help please.
Yes I have followed the exact assembly diagram. I am using 220Ohm resistors for control inputs and 100pF single layer capacitors for DC blocking... No DC blocks required at control inputs I feel...
Its seems that the RF output signal is below the mininmal value of detection at the test instrument (I think you might be using a Spectrum Analyzer ).
Try the following:
1. Increase the power of the RF Power input (not above 25dBm as said in the datasheet).
2. Lower the attenuation (digital) inside the S.A. (spectrum analyzer).