I've been trying to reverse-engineer this circuit but I'm an ME, so my knowledge of electronics is limited to pretty much Arduinos.

I have a simple circuit and I'm trying to identify one of the components.

The component is a small IC, DFN-6 (3x3) package size, and is wired as shown in the drawn schematic. The part number that I can make out I think is 26T6 TIW 957M.

The circuit is on a lithium BMS board and is used for the initial handshake when connecting a tool to the battery.

The circuit is separate from the rest of the BMS as I've isolated the components.

With the circuit isolated, applying a 1 kHz positive square wave produces the signal shown in the below oscilloscope screen capture.

What I've concluded is that it's some sort of fixed/pre-programmed oscillator, but the input is the same as the output...?

(Click on an image for a larger version)

Traced schematic

Figure 1: Traced schematic

Oscilloscope capture

Figure 2: Oscilloscope capture

Top marking on unknown device

Figure 3: Top marking on unknown device

PCB showing unknown device

Figure 4: PCB showing unknown device


1 Answer 1


It is probably a 1-wire temperature sensor and unique ID something like this although the package is different:

1-Wire® Temperature Sensor:

Battery charging is critically dependent on measuring the battery temperature enter image description here

  • \$\begingroup\$ There's a separate circuit and pin for an NTC thermistor that's embedded directly against the lithium cells. This chip is placed far any current path or other components that I think would need temp monitoring. \$\endgroup\$ Commented Mar 14, 2021 at 21:05
  • \$\begingroup\$ @ericthepoolboy It's definitely a 1-wire something. Maybe some kind of ID chip, to say that it's a genuine battery pack for whatever tool it's used with--unfortunately a fairly common practice. \$\endgroup\$
    – Hearth
    Commented Mar 14, 2021 at 22:21

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.