I have this chip that's part of an electronic cigar (or vape, whatever it's called.)

I would like to exploit this board as a charging circuit for another device.


I believe the chip does both charging the battery and switching on the heating element since there are no other ICs on the board. It has USB input, air flow sensor and the battery both connected directly to it.

The chip

It has 8 legs, the longer side is 3mm long (measured with calipers).

The top row I believe says CSC9090B and on the bottom row there is something like STO(BK) (the last two letters are not readable.) Google search on these combinations does not produce anything useful.

What's this type of package called?


2 Answers 2


The marking is CSC909DB: Available in Baidu store Seems to be a dedicated chip for the purpose, but it's difficult to tell from the sources available.


I have the same smelly PCB with the same chip. Searching for a datasheet, I first found this post, then I found this datasheet: http://www.cschip.com/upload/cn/propdf/CSC909X.pdf Seems like a factory making many more similar chips, specifically aimed at vaping products. See also the chips in this list: http://www.cschip.com/cn/pro/205.html##

Some details from the datasheet:

Overview and Features CSC909X is an electronic cigarette control circuit. Its main features are:

  • The working power supply voltage range is 3.0~4.2V, and the quiescent current is small (<5μA) in power-saving mode;
  • Optional 3.36/3.42/3.50/3.60/3.70V constant average voltage output;
  • Heating wire resistance as low as 0.8Ω;
  • Optional 10/5/7.5/12.5 seconds long-time smoking protection; undervoltage protection threshold 3.1V;
  • The charging input voltage range is 4.2~5.5V; the charging current at the power input terminal is 350/580/700mA
  • Optional; Smoking is allowed or not allowed when charging;
  • Monochrome LED display;
  • \$\begingroup\$ Why is it smelly? Do you mean small? \$\endgroup\$ May 21 at 21:54
  • 2
    \$\begingroup\$ Nah, next to small it is smelly because I obtained it from a discarded eVape sigarrette with black-berry cherry flavor. That flavor comes in the form of a sticky sirup that protrudes throughout the device. Even after cleaning with IPA, it still is smelly. The LiPo battery is still useful though and worth salvaging. This one has a charging port, making it even more interesting. \$\endgroup\$
    – Maxint
    May 21 at 21:58
  • 1
    \$\begingroup\$ Hey thanks for sharing! \$\endgroup\$
    – floppydisk
    May 21 at 22:41

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