SLUSF18A October 2023 – December 2023 BQ25638
PRODUCTION DATA
Refer to the PDF data sheet for device specific package drawings
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.