I have designed a wearable device and added a MAX30102 to it (MAX30102 home page, datasheet). The datasheet says the maximum current drawn by the IC (excluding the LEDs) should be 1200uA or 1.2mA.
The switching regulator can provide up to 200mA of 1.8V, and I have tested that. But as soon as I solder the MAX30102 back on it, the 1.8V drops to 0.8V and current increases from 5mA (of the whole PCB) to 95mA. So that's a 90mA increase caused by the MAX30102. The only thing using 1.8V rail is this IC.
I have attached the schematic of my PCB, as well as the typical application circuit in the ICs datasheet. and I cannot figure out why this is happening.
Best Answer
The 1.8 Vdd input on the chip only powers the ADC's and some digital logic. Unless there is internal damage, the pin should not draw anything like 95 mA.
Possibility #1: in this land grid package with 0.8 mm pitch between pads, the 1.8 Vdd pin (11) and the GND pin (12) are adjacent. Are you sure you don't have a solder bridge between those pins under the IC?
Possibility #2: could you have the IC flipped 180 degrees? That would feed the 1.8 Vdd into the LED driver ground pin.
Possibility #3: the chip is damaged. Bummer, but double check all your connections before you put in a new one. Good luck!