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!
UPDATE:
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.
