DS18B20 alternatives: protocol and cable conditions come first
The DS18B20 is a 1-Wire digital temperature sensor, commonly supplied in TO-92. Matching three leads does not guarantee the register format, supply method or probe construction is the same.
Confirm the interface, not just the package
DS18B20, DS18S20 and MAX31820 are related Maxim devices, but their measurement formats, resolution and detailed behaviour differ. Firmware that parses raw registers can return the wrong temperature after a substitution.
NTCs, PT100 devices, LM75 and TMP102 also measure temperature, but they need an ADC, current source or I2C interface. They are not socket-level replacements.
Long cables expose bus problems
Many 1-Wire failures come from the bus, not the sensor: pull-up value, cable capacitance, stub length, strong pull-up and parasitic power all matter. On a long or multi-drop bus, changing supply mode can turn an occasional packet loss into a complete failure.
TO-92, SOP-8 and potted probe assemblies are different products. For a probe, confirm cable length, insulation, shield, connector, temperature range and sealing.
Validate the complete assembly
Test at room and temperature extremes, on the real cable length and node count. Read the full 64-bit ROM and verify CRC, then monitor packet loss and bus recovery. Inspect the probe construction if it will be exposed to moisture or vibration.
View the DS18B20 part page or send the probe and bus details for a sourcing check.
Common questions
The package and bus may be similar, but register format and default resolution differ. Firmware using raw register access must be checked.
A pull-up is commonly used, but the value depends on cable length, node count and controller. Follow the bus requirements.
No. Cable, length, potting material, temperature range and connector also define the assembly.
Related alternative guides
Send the BOM with quantities, gate-drive or bus conditions, and target lead time.