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I have a led matrix PCB without a driver and I'm trying to figure out how to control it. I'm having trouble identifying one of the components on the PCB.

Here is a scheme of a part of the PCB: PCB part

These 6-pin parts have WDFN-6 package or similar. They have labels AP1 (I also met APN for the same parts). Here are the pictures: pic1 pic2

I thought it might be a Dual LDO Regulator or something similar, but it doesn't match the actual scheme.

Please provide any thoughts on what it might be.

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  • \$\begingroup\$ Are you sure pins 3 and 4 are not connected on all those chips? How many layers on the board? \$\endgroup\$
    – HandyHowie
    Apr 30 at 12:12
  • \$\begingroup\$ They are connected the same way as the first (left) one, I just skip this to not overcomplicate the scheme. Each unknown SMD component has a PUMH1 connected (double resistor-equipped transistor). I don't know how many layers the bord has, at least 2. Also, note that the last (right) SMD is rotated 180 deg. @HandyHowie \$\endgroup\$ Apr 30 at 12:38
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Possibly dual PNP transistors part number NSS60100DMT.

They are symmetrical so a 180° rotation does not matter.

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  • \$\begingroup\$ Thanks for your answer! I tried to replace my "unknown" chips on the scheme with the dual pnp transistors you shared. I know that this circuit should allow enabling a single random led. I cannot figure out if there is a way to achieve this using dual transistors. Do you think it is possible at all? \$\endgroup\$ Apr 30 at 14:19
  • \$\begingroup\$ I didn't really try to guess your circuit. If you probe (unpowered, of course) with a diode test setting it might allow you to rule out or suggest other options. \$\endgroup\$ Apr 30 at 14:20

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