Questions about the BQ27427 Fuel Gauge Schematic.

[Dicko]

Hello there,

I have been looking at the BQ27427 fuel gauge by Texas Instruments and I want to replicate the design and add a small adjustment. However, when copying the design in KiCad I noticed a few points that I didn't understand and wondered if anybody is able to help. I contacted TI but they replied that this is outwith their scope.

I've attached the datasheet, their schematic (from page 13/24) and my schematic with a small modification to the original.

My questions are:

1) On the J2 header, pin 2. What is expected to be connected here? Is this ground to pull-down R1? or something else.
2) On the J3 header, pin 2. What is expected to be connected here? Is this ground to pull-down the 10K resistor ?
3) Page 16 (section 9.2) of the datasheet says "If battery pack’s thermistor will not be connected to BIN pin, a 20 kohm
pull-down resister should be connected to the BIN pin." Is this instead of R2 (the 10 kohm resistor) ? Or does the 10k represent the thermistor?
4) On headers J8 and J9, pin 2. What do they connect to?
5) I would like the option to be able to choose between using a thermistor in the design, and not using one. In the schematic I have added in a 3-pin header so that I can jump between the default setting using the 10k resistor, or a 2-pin terminal block for a thermistor. Does this look ok?
6) Following on from 5) and related to question 2) these connect to J3, pin 2, but the schematic doesn't show what should be connected here, I'm assuming ground, is this correct? If it is, why wasn't it tied to ground on the PCB? Or was this in-case we connected to another device with a different ground?
7) J10, pin 4, is this is meant to be unconnected ? Just using the VSS, SCL and SDA.
As per the guidance in the datasheet, I have connected a 1.8M ohm resistor (R5) between BIN and VDD. Does this look ok?
9) Do you see any issues with my design that I would need to correct before getting the board manufactured?

Thank you very much.