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I am trying to identify a SMD diode that is used in a PFC circuit on a SMPS power supply board from a Hisense 50" smart TV with MTK5655EPDJ chassis. The diode is connected to a IDP2301 (multi-mode PFC and LLC controller) IC. There are 3 diodes with the same markings, each connected to one of the gate driver outputs of the IC.

The markings on the diode are:
A1 (horizontal)
W6n (vertical)

I think "A1" is a "type" marking, but I am not sure which diode "A1" refers to.

The closest code I found was "A2", which relates to a 1N4148 diode (data from Vishay website and datasheets).

The length of the diode body is 2.2mm. The closest match is SOD-123.

SMD diode - A1 marking code

SMD diode in circuit

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  • \$\begingroup\$ If you need to replace it, just go with a 400V SOD-123 type. Should be good enough for a PFC circuit. \$\endgroup\$
    – ElectronicsStudent
    Commented May 18, 2023 at 18:31

2 Answers 2

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Possibly a 1N4001 type of diode (similar to M1 etc.).

I suggest you look up the datasheet for the chip and look at the typical schematic.

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    \$\begingroup\$ Interestingly, nearly identical datasheets, or figures, are used by Jingdao Microelectronics (linked), Dongguan You Feng Wei Electronics, Master Instrument Corporation, Guangdong Shikewei Industrial, Samyang Electronics, and probably more. \$\endgroup\$
    – Tim Williams
    Commented Sep 2 at 15:30
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    \$\begingroup\$ @TimWilliams It's been a while since I've been in a diode factory, but my impression from Taiwan is that they generally don't make their own dies, so they might as well copy the figures from each other. \$\endgroup\$
    – Spehro 'speff' Pefhany
    Commented Sep 2 at 15:33
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    \$\begingroup\$ Indeed. I've gathered that impression from a number of products; there are many with common circuits, or chassis, buttons, etc., only differing by the label. Alphabet-soup branded budget soldering stations come to mind. Who knows what one (or perhaps several) factory(ies) are actually producing them. \$\endgroup\$
    – Tim Williams
    Commented Sep 2 at 15:35
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    \$\begingroup\$ @TimWilliams In mainland China there appear to be standard designs for things like relays that are produced in many factories using completely different tooling. You can tell from witness marks that different designs of tooling is used. From a distance it appears they could come out of the same factory, but in fact there might be scores of factories. For fun I managed to track down one such document for a vacuum gauge, but didn't make the small payment for the standard. Saving my WeChat balance. \$\endgroup\$
    – Spehro 'speff' Pefhany
    Commented Sep 2 at 16:11
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    \$\begingroup\$ At some trade shows they would have displays from individual provinces (eg. Jiangsu) and the parts would be compatible with those from Hebei but made in different factories. Not all of them would have sprung for the cost of overseas approvals, the domestic market is pretty vast. \$\endgroup\$
    – Spehro 'speff' Pefhany
    Commented Sep 2 at 16:14
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On May 19, 2023 at 14:04, David Fear contributed the following edit to their question:

I found this service manual:
https://pdfcoffee.com/hisense-noblex-ea32x5000-chasis-mtk5655epdj-pdf-free.html

The service manual has a schematic with a IDP2301 IC on it. The diodes on the gate drivers (HSGD, LGD AND PFCGD) are all: 1N4148W.

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