I have a small SOT-26 (6 pins) device that is used in a MOSFET-based SMPS. It may be a PWM controller to switch the MOSFET. I need to identify it, but I can't find the component code anywhere at all. The code is 30653. Like in this image



1 Answer 1


It does look like a SiFirst SF1530. enter image description here


update, some similar parts from other manufacturers: On-bright ob2263, Winsemi WS2283, TI ucc28700-q1, MAxim MAX5021-MAX5022

  • \$\begingroup\$ we also want to know cross reference of SF1530 in Branded company like st,ti,ON semi,Fairchild etc. \$\endgroup\$ May 29, 2018 at 5:32
  • \$\begingroup\$ Sir can we replace OB2263 directly in SMPS board or some peripheral component is also required to change. \$\endgroup\$ May 30, 2018 at 7:43
  • \$\begingroup\$ @PradipBharambe, if you look at both IC's characteristics, you can see they are almost clones. Some differences, ex. 50ns on T_blanking, UVLO , but pin to pin compatible; I would install a OB2263 with same components, but do check if anything is damaged before \$\endgroup\$
    – johnger
    May 30, 2018 at 8:07
  • \$\begingroup\$ @PradipBharambe compare the datasheets : cnledw.com/inter/upload/2011082311525256277.pdf and file.yizimg.com/332467/2010080308450435.pdf \$\endgroup\$
    – johnger
    May 30, 2018 at 8:09
  • \$\begingroup\$ @PradipBharambe if older comps failed and destroyed the older ic, it will destroy the new, should check before. \$\endgroup\$
    – johnger
    May 30, 2018 at 8:17

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