Tool/software:
Dear Expert
The datasheet indicates that: "The 5V-tolerant open drain IO type does not have the output-high PMOS, pullup resistor, or clamping diode."
Except for the 5V port, all other pins have clamp diodes, which means that SDIO (standard drive), SDIO (standard drive) with wake and HDIO (High drive) have clamp diodes，right？
Hello Janz
I have an application that connects to battery voltage through a switch, and the MCU samples through a resistor divider ADC.
The normal operating voltage of the battery is 9-18V, and the maximum operating voltage is 26V,
Like this
There is no problem during normal operation, and the AD sampling voltage is less than 3V; When the voltage is greater than 19V, the voltage sampled by AD will be higher than 3.3V. Is this design feasible? Can I use clamp diodes for protection?
Or do I need to lower the voltage sampled by AD to below 3.3V?
Best Regards,
Haibo
Hello Haibo,
Yes, you 'd better to lower the voltage sampled by AD. I recommend the input on GPIO need lower than 3.3 V better. No matter what method you use, please lower the input voltage to below 3.3V. Such as adjusting the resistance of the voltage divider resistor
In our datasheet, you can find this.
Best Regards,
Janz Bai
As a practical matter, you seem to be limiting the current enough that there should not be a problem. But note that if you are turning off the MCU when the battery voltage is present, you could get enough current to turn on the MCU at a low voltage condition which can put it in a weird state.
For the MSPM0L1306 - which is the closest data sheet I have handy, the Absolute Maximum diode current is 2 mA, and you should be well below that.
