I’m powering my BC127 from a Torex XC6210 LDO. This works fine 99% of the time, but sometimes the BC127 doesn’t power up because of the voltage drop at startup. The datasheet describes a fast transient filter, but none of the designs I’ve found online implement it. I’m using a fixed 3.3V power supply configuration.
My questions are:
- Is that a 2ohm or 2k ohm resistor specified?
- How should the filter be laid out?
A) Should VCHG be connected between the 2R and the 4.7uF capacitor or should all pins be powered downstream of the filter?
- Is there anything else I can do to make sure the module powers at boot? My current board revision has a 4.7uF cap downstream of VCHG only, and I’m considering placing it downstream of all 3.3v pins.
Here’s the filter in the datasheet:
This is the circuit I’m considering, along with a 2ohm resistor (not pictured):