Part Number: RF430FRL152H
Dear TI,
I have checked the datasheet for RF430FRL152H and found out about the Vddr. I would like to use Vddr without using Vddb. The reason is because when I try to measure biosignal, the supplied power from rf430 chip is fluctuating. I believed it would be better to use Vddr instaed of that I make my own rectifier and regulator. Could you recommend me the best way to provide a constance voltage from NFC to run the circuit and measure using the chip ADC? Also, is Vddr the same as GPIO voltage?
Second question is about making a large antenna using FEIG tuner and Reader. I was able to tune many different antennas using the tuner and reader. However, when I try to make a massive antenna, I encounter a difficulty on the tuning. Based on my undestanding, the total length of antenna (I am using a thick copper wire) has to be between 1/8 (2.765m) and 1/4 (5.53m) of the frequency wavelength. However, I wish I can make an antenna with the total length around 7.2m (1/2 of the wavelength =11.06m). In this case, the resistance of the antenna wire is too large and the frequency matching is not possible by only using capacitors. I am just asking this question in case you have any suggestion on this. For example, add certain components in pallel on the antenna wire and start tuning?
Thank you very much. Iam not an expert in this area but hope you understand what I am asking about.
Best,