This part is a kind of semiconductor called S1M.

Function of this product has SMA controlled avalanche rectifiers.

Manufacturers : NXP

Image and pinout :

Some of the text within the PDF file :

DISCRETE SEMICONDUCTORS DATA SHEET book, halfpage M3D168 S1 series SMA controlled avalanche rectifiers Product specification 2000 Feb 14 Philips Semiconductors Product specification SMA controlled avalanche rectifiers FEATURES • Glass passivated • High maximum operating temperature • Ideal for surface mount automotive applications • Low leakage current • Excellent stability • Guaranteed avalanche energy absorption capability • UL 94V-O classified plastic package • Shipped in 12 mm embossed tape • Marking: cathode, date code, type code • Easy pick and place. Top view olumns S1 series DESCRIPTION DO-214AC surface mountable package with glass passivated chip. The well-defined void-free case is of a transfer-moulded thermo-setting plastic. The small rectangular pa [ ... ]

S1M PDF Datasheet Download