LTC3114 devices failing in application taken from datasheet
Customer Kuhnt has an issue with LTC3114EFE.
About 30 devices of 40 in total were damaged.
They use an application like the lead acid battery charger on page 29 of the data
sheet, with the optional diode.
The deviations from the datasheet schematics is
- they have a 24V battery instead of 12V
- hence the output voltage is set to 27,5V
- with a prog-resistor of 100k they set a current limit of 250mA,
- they have a regulated input voltage of 24V
- they use a 10uH inductor (Bourns SRR0745A-100M).
The layout of the four layer PCB is based on the recommendation on page
18 of the data sheet. There is a shottky diode between the regulator
output and the battery to prevent reverse current.
-> Damaged parts have a shortcut either from SW1 to ground or from SW2 to ground.
The application has also been simulated with LTspice and did not show any fault.