Other Parts Discussed in Thread: ISO7220M,
Please review attached, two BQ76PL536As are stacked up for 8-cell Li-ion battery. Sleep mode is not working as specified. When sleep mode is set, the leakage current is near 4mA which is higher than 20uA per datasheet. Both REG50 pins are slowly decade to 0V when we used multi-meter to measure them. All 5.1V zener MSZ5231BT1G have 3.5V across them.
All 8 interfaced pins (FAULT_H to CS_H) are tied to Digital Isolators (TI's ISO7220M) which are not powered after commanding Sleep Mode. Would abnormal leakage current go to zener diodes or un-powered Digital Isolators?
By comparing attached schematics with Figure 4 and Figure 17 of BQ76PL536A datasheet, the differences are
1. VC6 and VC5 are not individually tied to VC8 through 1K resistor. VC6 VC5, VC4 are tied together then tied to VC8 through 1K resistor..
2 No series resistors between interfaced pins (CONV_N... vs CONV_S...) of two BQ76PL536As
Are these differences OK?