cc2541 gpio output voltage when Vdd is 2.1 V

Arne Laugstol

Other Parts Discussed in Thread: CC2541, TPS62730

Hi
I am using cc2541 together with tps62730 for minimum power consumption. I would also like to use a gpio pin (configured as output) as power supply to my other sensors (consuming approximately 0.5 ma). What I am wondering about is what the voltage of an output pin in high state will be when Vdd is 2.1V.
In the cc2541 data-sheet in the DC CHARACTERISTICS section it is stated that Logic-1 output voltage on 4-mA pins will be minimum 2.4V when Vdd is 3.0 volt. What will be the output voltage be when Vdd is 2.1 V (output from tps62730).
Regards Arne

over 11 years ago

0 YiKai Chen over 11 years ago

Guru 735685 points

From HW perspective, I suggest you not using GPO as power source of other sensor.

0 Arne Laugstol over 11 years ago in reply to YiKai Chen

Prodigy 190 points

Why?

0 Greenja over 11 years ago in reply to Arne Laugstol

Guru 22270 points

Hello Arne,

There does not seem to be any data or charts that show a VDD to Port Pin Logic High ratio. The best case scenario would be to make an algebraic calculation of VDD at 3.0V with 4-mA @ 2.4V equal to VDD at 2.1V with 1.5V (-0.6V diode drop?) @ xmA.

You can drive the sensor with the output pin. There is an example in the SensorTag schematic swrr109b where the Gyroscope is powered by P1.1. http://www.ti.com/lit/zip/swrr109

There is also a current restriction on the Port itself. Although each Port Pin may be able to supply 4mA, they all cannot be at 4mA at the same time.

Thanks,

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cc2541 gpio output voltage when Vdd is 2.1 V