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, 2023 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, 2023 at 21:58
  • 1
    \$\begingroup\$ Hey thanks for sharing! \$\endgroup\$
    – floppydisk
    May 21, 2023 at 22:41
  • 1
    \$\begingroup\$ I found the same chip on the pcb of my vape disassembly project. Also a single use. What caught my attention was how thin the wires to the heating element are. Especially now that I read here that the wire needs to transport 5A of current. The heating element looks just as thin as the wires. Thoughts? Simple power calculation would be P=R*I^2 => 20 Watts = 0.8 Ohm * 5 A * 5 A. On the battery there are scorch marks... not a good sign I think. Thoughts? \$\endgroup\$
    – twildeman
    May 14 at 11:16
  • \$\begingroup\$ I've found quite a few different vapes in the past year. I use a battery tester to measure capacity. Most batteries were still usable, even if squashed by a car. Some I found at zero or low voltage. These often had less or no capacity and high internal resistance. Some had punctures and released lithium when charged. I guess that's not healthy. I charge tested cells an inspect them at later time. Some I found were puffed or lost their charge. Scorch marks may be result of a temporary short in the wires. I would check for holes, of okay test it and reuse if capacity is okay. \$\endgroup\$
    – Maxint
    May 15 at 19:41

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