ZHCSU23A October 2023 – December 2023 BQ25638
PRODUCTION DATA
The typical TS resistor network is illustrated below.
The value of RT1 and RT2 are determined from the resistance of the recommended 103AT-2 thermistor at 0oC and 60 oC (RTH0oC= 27.28 kΩ and RTH60oC = 3.02 kΩ) and the corresponding voltage thresholds VTS_COLD and VTS_HOT (expressed as percentage of REGN with value between 0 and 1).


Assuming a 103AT-2 NTC thermistor on the battery pack, the RT1 and RT2 are calculated to be 5.24 kΩ and 30.31 kΩ respectively.
If the thermistor is biased from TS_BIAS, the maximum current should be checked against ITS_BIAS_FAULT. For the worst-case condition of thermistor at 0 Ω impedance (very hot), the bias current is:
For 5.30 kΩ RT1, this has a maximum IBIAS of 0.94 mA, which is well below the minimum ITS_BIAS_FAULT threshold. The 103AT-2 NTC thermistor is the recommended thermistor and has 10 kΩ nominal impedance. Using a lower impedance thermistor will change the value of R1 and may produce a bias current that exceeds the TS_BIAS pin fault threshold. TS_STAT[2:0] is set to 111.