2021.8.27

Features

• Battery clip for CR1025 3V coin cell battery on the back of the board for EXT_BAT
• Regulator for EXT_BAT -> 1.1V VDDD
• Regulator for EXT_BAT -> 1.8V VBAT and IMU_VDDD
• EXT_BAT range from 2.2V to 5V
• Voltage divider from NRF_VDDD to VDDD
• 1.64" x 1.42"

Voltage conversion

One of the versions has DC-DC regulators. The other version has LDOs.

Regulators

• Ablic S-85S1AB11-I6T1U
• Ablic S-85S1AB18-I6T1U

LDOs

• TLV70311DBVR
• LP5907MFX-1-8-NOPB

Feedback 2021.09.01

• Independentize the power input for LDO/regulator 1.1V. Put a jumper between 1.1V input and BAT_EXT
• Replace little battery with big battery if possible: https://www.digikey.com/en/products/detail/adam-tech/BH-32C-1/13537762
• Send this out ASAP
• Rename to Sulu

Feedback 2021.09.02

• Make more space for the big battery 2477
• Components for 10 boards
• update BOM

SMA

Need to keep trace less than 12.5 cm / 10 long. Don't worry about impedance. Surround with GND on all possible sides. Copy old design.