We want to understand any surprises with using nPM1100 on existing or future products.
I just bought two nPM1100-EK units and finished the first round of my evaluation.
Here is a summary of my findings and questions:
1. Pressing the SHPACT button with VBUS present: Section 3.5 of the nPM1100 datasheet "Using Ship mode" leaves the impression that ship mode won't be activated unless VBUS is discharged below VBUSmin. Based on testing, it looks to me like pressing the SHPACT button enters ship mode regardless of the voltage on VBUS. It's just that you will immediately exit shipmode when VBUS is high (that's one of the two ways to exit shipmode). Activating shipmode while VBUS is high will effectively powercycle whatever VOUT is connected to. The datasheet should be more clear.
2. Battery charge threshold 2.1V: If the battery voltage is < 2.1V when VBUS goes high, the nPM1100 will not start charging and signals a FAULT. Our battery pack currently as a protection chip built into it that will disconnect the external load from the cell if the cell voltage drops below 2.8V, so the external voltage seen by the nPM1100 becomes 0V. Is it correct that if our battery gets into this state, the nPM1100 will never charge it? This is important because our device isn't meant to be opened, so if the battery over-discharge circuit kicks in, this feature will "brick" our device.
3. Static inputs (VTERMSET, ICHG, VOUTBSETx): In the nPM1100 datasheet, section "3.1.1 In circuit configurations" states "Static input pins must be configured before power-on reset." I thought this meant that if you changed the polarities of these pins after reset, it would have no effect, but I found in testing that when I changed these after reset they still took effect (VTERM, ICHG and VOUT would all change at the moment I changed the switch positions on the nPM1100-EK board). Is there some reason these pins should not be changed dynamically? The datasheet should be clear about what should not be done vs what will have no effect.
4. POR: Datasheet section "3.3 Power-on reset (POR) and brownout reset (BOR)" states "VBATPOR has a minimum and maximum range. To ensure the device exits reset, the voltage should be above the maximum of the parameter." but Table 15 only gives a typical value of VBATpor, not max/min values.
