Other Parts Discussed in Thread: TPS63001, BQ24072,
Good day,
I'm working on a PCB design for a wearable sensor recording device.
The device will run from a 500mAh lithium battery (USB-C charging), the logic is 3.3V and around 200mAh at peak, 50mAh average, and sub-mAh on standby (RTC current draw).
We've selected the TPS63802 for the Precise Threshold Enable – the IC will be disabled when the input voltage drops below some threshold, which allows us to keep the RTC running directly on the remaining mAhs left in the battery. (Previously, we were using the TPS63001 with the TP4056, but are now changing to the TPS63802 with the BQ24072).
I've been following the TPS63802 Layout from the datasheet, but have some confusion around connecting the control and power grounds under the IC:
Our schematic:
Note: VIN to the TPS63802 comes from VOUT of the BQ24072.
Proposed PCB Layout of TPS63802:
4 Layer PCB, Top (Signal), Inner 1 (GND), Inner 2 (3V3), Bottom (Signal)
Top:
Inner 1 (GND):
Inner 2 (3V3):
Please let me know if the above design looks OK, specifically:
- If our GND connections on the Top layer look ok (AGND from C2 on 3V3 to GND from C1 which is Power VIN from BQ24072 named VOUT).
- If the VIA connections to the GND plane under the IC are OK
- If the VIA connections to the GND plane under C1 and C2 could cause a problem (not under/far from IC)
- Any other design suggestions?
Any help/feedback is greatly appreciated.
