SFFS376 May 2022 BQ25170
This document gives a Failure Mode Analysis (FMA) for the pins of the BQ25170 device. This IC targeted at space-limited applications supports 1-cell Li-Ion, Li-Polymer, and LiFePO4 batteries. The various failure conditions outlined in this document are circuit board level issues that impact the BQ25170 device pins.
There are several circuit board level problems that can impact the device pins. Board manufacturing defects can leave a device pin open circuited when it fails to solder to its board pad. A pin can also be open circuited if the circuit board is stressed to the point where the device pin breaks off its board pad. Manufacturing defects can short-circuit adjacent pins on a device when solder reflows between the pins. Both pin open circuit and adjacent pin short-circuit conditions are analyzed in this document.
Foreign objects on circuit boards can cause short-circuit problems when they short board traces. If any of these traces connect to the device, it will cause a short-circuit event on the corresponding device pin. An analysis of board level shorts impacting the BQ25170 is circuit board dependent. However, it is useful to analyze device pin shorts to the ground rail and to the highest magnitude positive and negative device power rails. First, these rails are usually the largest traces on a circuit board and therefore more prone to short-circuit events. Second, these rails represent the voltage and current-carrying extremes on the circuit board and are more liable to cause device issues when shorted to a device pin. Pin shorts to ground and pin shorts to the highest positive rail voltage are analyzed in the document. The BQ25170 does not have a negative rail voltage to analyze.
In summary, the BQ25170 pin affecting failure scenarios analyzed in this document are:
This document also details how these pin conditions affect the device: