Hi!
The company I work for have a product that uses the LDLN025 LDO regulator.
The LDO drives an SIGFOX module, a couple of pullup resistors that goes to a always-powered uC and to a ST25DV64K IC.
All of them has 100nF decoupling capacitors + a 22uF of buck capacitor in the SIGFOX module.
The regulator has an input/output capacitors of 1uF GFRM155R7j105
During the lab test, the regulator worked well but for production units, the company has a custoimer that has no issues and another that has several problems in the field.
The main diferences are:
- ambient temperature
- relative humidity
- diffetent imput power supply
We've seen that the capacitors used have a defating in terms of DC voltage, that makes the regulator enter into the unstable (or untested zone). However we've never seen an oscillation in the output voltage (maybe ceause the input capacitor of the module of 22uF)
When enabled, we measure a inrush current of about 0,5A for a VERY short time, and the the load current do not pass 200mA during operation.
The problem is that eventually, the LDOS get fried. Some how we do not find.
Does anyone has any suggestions in order to find the actual problem?
Thanks in advance.
