This part is a kind of semiconductor called UDZ12B.

Function of this product has SURFACE MOUNT PRECISION ZENER DIODE.

Manufacturers : Diodes

Image and pinout :

Some of the text within the PDF file :

NEW PRODUCT UDZ2V0B-UDZ56B SURFACE MOUNT PRECISION ZENER DIODE Features UNDER DEVELOPMENT · Ultra-Small Surface Mount Package · Ideally suited for Automated Assembly Processes · Very Sharp Breakdown Characteristics · Very Tight Tolerance on Zener Breakdown Voltage Mechanical Data H · Case: SOD-323, Plastic · Case Material - UL Flammability Rating Classification 94V-0 · Moisture sensitivity: Level 1 per J-STD-020A · Terminals: Solderable per MIL-STD-202, Method 208 · Polarity: Cathode Band · Marking: Marking Code (See Table on Page 2) · Weight: 0.004 grams (approx.) · Ordering Information, See Below C Maximum Ratings @ TA = 25°C unless otherwise specified D G A B E SOD-323 Dim Min Max A 2.30 2.70 J B 1.60 1.80 C 1.20 1.40 D 1.05 Typical E 0.25 0.35 G 0.20 0.40 H 0.10 [ ... ]

UDZ12B PDF Datasheet Download