Would you please send me the BOM of EVAL-HMC703LP4E board. I need the part reference of 50 MHz TCXO used on this board.
I have attached the BOM for the HMC703 eval board and 50MHz VCXO datasheet.
I have moved your question to the RF and Microwave community.
Thanks for your reply.
CVHD-950 is a VCXO (voltage controlled) and not TCXO (temperature compensated). In addition, it has an output current capability of 24 mA max. In HMC703 eval board, it is loaded with a 51 ohm resistor (R57) in parallel with 100 ohm (R25) and HMC703 100 ohm internal resistor. The equivalent resistor is 25 ohm, which is a very heavy load for CVHD-950 (Load_max = 3.3V / 24mA = 137.5 ohm). Any way, all crystal oscillators are CMOS or clipped sine wave and are not supposed to drive 25 or 50 ohm loads. Do I miss some point?
How can I use a TCXO like Connor Winfield TB series with LVCMOS output (datasheet attached) as reference frequency for HMC703?
I used to use ADF4350 or equivalent AD synthesizers. They had high impedance reference inputs and were easily interfaced to standard TCXO's.
Another point: the BOM you have sent does not match to HMC703 eval board. It contains a prescalar HMC492LP3 which is very interesting for me. Would you please send me the schematics corresponding to this BOM?
I've attached the schematics. This design allows evaluation of VCOs with >8G output frequency but is not the board we include with the HMC703 evaluation kit. I have also attached the correct BOM for the HMC703 evaluation board. This design includes the 50MHz TCXO from Suntsu p/n SRSB348-50.000MHz.
Would you send me the datasheet of SRSB348-50.000MHz? I don't find it on the net!
I've attached the datasheet.
Thanks for the datasheet.
This is a regular crystal oscillator with CMOS output. In HMC703 eval board, it is loaded with 25 ohm (50 || 100 || 100). How do you explain this circuit?
Since the oscillator has a 3.3V CMOS output we added R57 (50 ohm) to reduce the output signal level to meet the maximum 2.5Vpp as specified in table 7.
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