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AD630 - Building up supply voltage

Question asked by XantaMarius on Jun 24, 2015
Latest reply on Jun 25, 2015 by jstaley

Hello there,

 

in my application I use the AD630 as a synchronous demodulator (Lock-In Amplifier) for absorption measurement. I will measure a low level Signal so the power supply of the AD630 is curial. This application is planed as a low power design so I just have a battery to supply the IC.

My idea is to use a DC DC Converter to cache the specifications about the supply voltage of the AD630. After this converter follows a LDO (Low Dropout Voltage Regulator) to filter out the ripple of the device. Because the LDO has a frequency depends of PSRR (Power Supply Rejection Ratio) a pi-Filter follows the LDO to suppress high frequencies.

I ask myself if this really a good idea to use an LDO since the AD630 has an PSRR of 110 dB already (Unfortunately there is no Diagram about the PSRR in the data sheet so that the bandwith of that 110 dB is shown.). The LDO would contribute it's own noise to the power supply, which I would avoid if it's not necessary.

Does anybody have experience with the supply voltage of the AD630?

 

Best regards

Chris

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