DS18B20 and Arduino - Internall Pull-Up

Question

Can this DS18B20 sensor be used with Arduino internal pull-up or it require exactly 4.7k pull-up resistor?

score 1 · Accepted Answer · answered Feb 04 '17 at 02:43

The Arduino internal pull-up is something like 50k. That is a lot different from 4.7k. You would probably find that the pull-up is not strong enough to get clean pulses from the device. Also if you are using it in one-wire (parasitic) mode notice this from the datasheet:

To assure that the DS18B20 has sufficient supply current, it is necessary to provide a strong pullup on the 1-Wire bus whenever temperature conversions are taking place or data is being copied from the scratchpad to EEPROM.

Notice the words 'strong pullup'. The internal pullup is not strong.

score 0 · Answer 2 · answered Feb 03 '17 at 18:55

0

If the datasheet specifies a 4.7kΩ resistor then a 4.7kΩ resistor is what you need.

answered Feb 03 '17 at 18:55

Majenko

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DS18B20 and Arduino - Internall Pull-Up

2 Answers2