Hello,
I am using TPS71918-28 to supply a cmos camera sensor with 1.8V digital power and 2.8V analog power. The issue is before I plug into the camera sensor, power supply is accuarte, after I plug into the camera sensor, the digital power drifts to 2.1V and analog power drifts to 3V. This power supply drifts influnence the function of camera sensor because its digital core voltage requirement is 1.8V+/-10%. The load current of camera is less than 50mA. Do you have any idea of this phenomenon?
By the way, I chose the DRV Package for TPS71918-28. I made a mistake in my layout that I didn't connect the thermal pad at the bottom of the chip to ground. This mistake may cause excessive power dissipation or inadequate heatsink. From the datasheet, I know when the junction temperature rises above 140 degree, it will trigger thermal protection circuit. But I check the "Output voltage vs Temperature" (Fig.6 in page 6 of the datasheet) that the output voltage drops with temperature rises.
So I am comfused what's wrong with my circuit and how can I solve this problem?
p.s. the power consumption of LDO is (Vin-Vout)*Iout, in my case Vin=3.3V, Vout1=1.8V, Vout2=2.8V, Iout<=50mA
Thanks!
Wei Wu
