identify surface mount component: SOT223 marked IY20903 newline 112115

Question

This component is likely some sort of power transistor, but the markings a very small and hard to read because of the reflection from the conformal coating.

package: SOT223 (black 3-pin SMT package with cooling flange)
markings: IY20903 (very uncertain about this, very hard to read) newline 112115
pcb-id: LIC110 (visible in photo below pin1 of component)

Please have a look and see if you can identify it. I had no luck with many online searches. Thanks.

Answer 1

I think it's a Analog Devices LT1121IST-5 LDO and the actual marking is

LT209e3
1121I5

(the 'e3' is not always rotated like in the image, see for example LT1117IST)

(Source: alibaba.com)

Here is my reasoning:

• The pinout is reasonable
• The designator LICxxx makes more sense for a LDO regulator than a transistor
• The Linear Technology 'LT' logo could be interpreted as 'IY' under conformal coating (especially with the old marking style, see last picture)
• If 'e3' is not roated, the top line would read LT + 5 characters like described
• The bottom line '1121I5' is very close to what is described
• The last '1' in your picture looks more like an 'I' to me

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A picture of the LT1117IST as reference, I think your part uses this older marking style:

(Source: lcsc.com)