We are using a 1.8V regulator to drive the VDDLDOA and VDDLDOD pins. On our most recent custom design, we are driving the regulator’s EN line with a host microcontroller instead of by the EXTON pin. This was due to a misunderstanding of the DW1000 device, and will be corrected in the future. But it means that the DW1000 IC had power applied to all power connections except the VDDLDOx pins.
Once I cut traces and jumpered the regulator’s EN line to Vcc, the power-up sequence is as it should be. However, the DW1000 still isn’t responsive. The oscillator doesn’t start. In fact, there is a constant DC bias on both XTAL1 and XTAL2 pins. The nRST pin stays low.
Can the DW1000 become damaged if 3.3V is applied to all other power inputs while there is no power applied to VDDLDOx? If not, I’ll keep digging into this board…