Hi,
我们想使用DA14581(进行了交流le UART) with an MCU with VDD of 1.8V. The MCU IO pin has abs max voltage of 2.1V. However, the VOH of DA14581 at VBAT=3V is equal or greater than 1.88V. Will there be an issue here? And do you have any suggestions for this application scenario? Thanks.
Device:
Hi enormous,
You will not have a problem if you are working in boost mode and you configure your pins in VBAT1 mode, if you do that you are limiting the voltage from 0.72 up to 1.8V. In buck mode since VBAT1 is constantly to ground you cant turn your pins to VBAT1 mode and the VOH will be equal or greater than the 1.88V meaning that it will reach up to 3.3V. If you dont have the option or you dont want to work in boost mode what you can do is to make your pins voltage tollerant up to 3.3V with a resistor in series (assuming that your MCU has protection diodes).
Thanks MT_dialog
Thanks for the detailed explanations. Is there any relationship between the VOH and the VBAT1/VBAT3, like VOH=0.8*VBAT? So if we apply 1.8V to VBAT1, the VOH won't be as low as 0.72, right?
Hi enormous,
There is no such a relation between the VOH and the VBAT1 and VBAT3. The VOH in the datasheet indicates that the minimum voltage you are going to get is 0.72V when the VBAT1 = 0.9V this is something that is guarranted by the 580 as the minimum value of the 580 when 0.9V are applied. If you apply 1.8V your VOH min should be around 1.6V and will decay as the voltage of your battery battery decreases. Also dont forget to configure your pins to VBAT1V mode since if you dont, you are going to output 3V.
Thanks MT_dialog