Filing it down to R.I.P in 0.1mm increments

A project log for Trimming down Dallas™ DS18B20s

Need to fit that TO-92 case into a tight place? How much can be trimmed? Let's see..

JanJan 05/05/2018 at 19:080 Comments

The following pics show how much you can file off the case before the sensor starts malfunctioning.

Height before: 4.55mm. Height after: 4.15mm

Thickness before: 3.6mm. Thickness after: 2.4mm

I kept filing it down:

At 3.9mm height, copper starts to show. Still working!

3.8mm: the copper tab is around 3.4x0.5mm in size. Still working. In this state it reacts instantly to temperature changes! Still working.

Height: 3.3mm. We're getting close...

3.3mm height, 4.5mm width, 2.4mm thick. Still working!

That's it. Our beloved sensor is dead now. The two shiny spots you see is the part of the actual die. It is located in the back of the case (where the case is rounded).

Sensor reads a steady 24°C at this point. No change whatever you do.


You could file off another 0.2mm off front and back to get to a final thickness of around 2mm. Your final sized down sensor would have the following dimensions:

Height: 3.4mm (to be safe), thickness: 2mm, width: 4.6mm

Cheers, Jan