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Original question:

MSP430FR6989: Calibration process

MSP430FR5989: ESI: supply issue

Samuel Pérez
Prodigy 205 points
Part Number: MSP430FR5989


Dear TI team,

I'm working on a design with MSP430FR5989 for water mettering with ESI. I'm primary lithium battery.

We tried to use the device with a power supply at different voltages: 3.6, 3.3, 3, 2.5, 2 and 1.8 in order to test what could happen with battery degradation.

1. The device does not work properly with the 2 and 1.8 V supply and the datasheet says operation range goes from 1.8- 3.6V.

2. Moreover, we're debugging it with an UART, and we noticed that if we supply the device proverly (3.3 V for example) and to a HW reset, the device does not work properly, we need to disconnect all the cables and the supply, and then connect it again

Can I have help with this?

Best regards

Samuel

  • +1
    TI__Guru 71216 points

    Hi Samuel,

    The datasheet for this device does indicate that the device will operate from 3.6v 'down to' 1.8v.  There is a note in the datasheet referencing a table with details that help clarify this.  I will paste here for convenience.

    Basically what the SVS power up level is saying is, when power is applied, VCC needs to be at least 2v in order for the SVS (supply side voltage supervisor) to release the device from reset.  This is max, so some devices may come out of reset at 1.88v (typ) or as low as 1.77v (min).  But this will vary from device to device, lot to lot and across temperature.  But, if the device VCC starts above 2v, it is design to run down to SYS power down level, which can be as soon as 1.85v (max), 1.80v (typ), or as low as 1.75 (min).

    So how are you performing your tests?  Are you starting at 1.8v? Or do you start above 2v and bring the voltage down, much like would happen in the field operating on battery?

  • 0 in reply to Dennis Lehman
    Prodigy 205 points

    Hi Dennis,

    Thank you very much, I've read about SVS in one part of the DS the 1.8V needed, didn't see it could go until 2V.

    Best regards

    Samuel

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