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PSoC™ 5, 3 & 1 Forum Discussions

Anonymous
Not applicable

I have a sensor with 5V supply and two digital pins, supposedly 5V levels, and a 4.7V analog output. 

   

My PSOC is tied to 3.3V supply by hardware. 

   

1) Is it safe to drive these two digital pins with 3.3V outputs from PSOC?

   

2) Is it ok to sample the 4.7V analog output with the ADC with 6X Vref, i.e. 6.1V? I read that the ADC can measurement up to 6 times of internal reference voltage. 

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odissey1
Level 9
Level 9
First comment on KBA 1000 replies posted 750 replies posted
        1. Depends whether the sensor's digital input are TTL or CMOS. 5V TTL will work. If 5V CMOS, minimum required voltage is 3.5V, which is more than 3.3V PSoC can provide. You can use external pull-up resistor to correct issue: https://www.allaboutcircuits.com/textbook/digital/chpt-3/logic-signal-voltage-levels/ 2. No, that won't work. Use resistor divider to bring sensor output voltage to <3.3V.   

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odissey1
Level 9
Level 9
First comment on KBA 1000 replies posted 750 replies posted
        1. Depends whether the sensor's digital input are TTL or CMOS. 5V TTL will work. If 5V CMOS, minimum required voltage is 3.5V, which is more than 3.3V PSoC can provide. You can use external pull-up resistor to correct issue: https://www.allaboutcircuits.com/textbook/digital/chpt-3/logic-signal-voltage-levels/ 2. No, that won't work. Use resistor divider to bring sensor output voltage to <3.3V.   
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