[GSoC Daily Log]: Weird voltages!

Friday, 30th May 2014:

  • Testing PCB for life signs
  • Setting up I2C test setup. I2C scan doesn’t show up AD9984A, whereas shows 2 other PCF8574A test devices on same bus. Something’s wrong.
  • On Powering up the PCB with 5V VCC. Power Supply Problem noticed.
    • OVDD: 3.35, Fine
    • PD: Expected voltage: 1.8V. Actual measured: 0.55-0.58 V, Critically Low
    • VD: Expected voltage: 1.8V. Actual measured:0.39V, Critically Low
  • May be due to OVDD having ADP3303-3V3 whereas PD and VD have ADP3334
  • Assuming problem with 1.8V LDO, Ordered samples for fixed voltage (1.8V) LDOs from TI and Analog Devices (SOIC and SOT23). Lets see if they get approved for samples!  

Found the reason for the weird voltages! 
Seems there was a slight mistake in feeback circuit designing which led to this major problem! Will post details in the weekly log! Trying to fix it in meantime for making the PCB usable.

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