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Capacitance of Input Stage of ADRF6510 for bandwidth estimation?

Question asked by Wavefunction on Aug 15, 2012
Latest reply on Aug 16, 2012 by Wavefunction

Hello,

 

I'm using the ADRF6510 as a VGA after the 12-bit DAC of AD9963 in our transmit link. In order to set the common mode voltages at DAC o/p and at the VGA i/p, a level shifter interface similar to the one in the attached figure has been used. (Although, the component values I'm using are different from the ones in the figure.)

 

Since the maximum baseband signal bandwidth in our system can be 10 MHz, I would like to perform a sanity check - if the resistor dividers of the level shifter network are reducing the bandwidth by forming a pole with the input capacitance of the ADRF6510?  Is it possible to get a rough estimate of this input capacitance (to ground)?

 

As an added info, the effective resistance (from level shifter) at a single node of ADRF6510 is now 1.217 Kohm. So, any input capacitance greater than 10 pF might get us into trouble..

 

Thanks in advance!

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