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ADPD105 TIA ADC mode ,ADC output code rang is small

Question asked by cortex1188 on May 10, 2018
Latest reply on May 16, 2018 by Buckley

I have an EVAL-ADPD105Z-GEN kit with me.

I would like to use the TIA ADC MODE of the ADPD105 with the input to the trans-impedance amplifier as a sine wave.

 

The connections that I made are:

--> Function generator positive to PD2 pin with a 51 kilo ohm resistor in series to prevent the TIA from saturating

--> Function generator negative to GND

--> I am giving a 1.8V peak-to-peak sine wave as the function generator output.

--> To bypass the band-pass filter, I am using the ADPD OpenMarket Wavetool to write the values 0xAE65 to the register 0x43 and 0x45 (register values have been taken according to the datasheet's specifications).

--> I am also writing 0x1CB6 to the registers 0x42 and 0x44 in order to configure the integrator as an inverting buffer TIA      I would using the 0.9V   VBIAS setting (0x42[5:4] = 0x44[5:4] = 0x2)

 

ADC output  is  8100-8300 codes,why 1.8V peak-to-peak sine wave input, but output is small rang,can i config the TIA to get 0-16384 codes?

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