This part is a kind of semiconductor called TPA.

Function of this product has TRISIL for telecom equipment protection.

Trisil is a trade name for a thyristor surge protection device, an electronic component designed to protect electronic circuits against overvoltage.

Manufacturers : STMicroelectronics

Image and pinout :

Some of the text within the PDF file :

SMP50 / SMTPA / TPA Trisil™ for telecom equipment protection Features ■ Bidirectional crowbar protection ■ Voltage range from 62 V to 320 V ■ Low capacitance from 12 pF to 20 pF @ 50 V ■ Low leakage current : IR = 2 µA max ■ Holding current: IH = 150 mA min ■ Repetitive peak pulse current : IPP = 50 A (10/1000 µs) Main applications Telecommunication equipment such as: ■ Analog and digital line cards (xDSL, T1/E1, ISDN, ...) ■ Terminals (phone, fax, modem, ...) and central office equipment Description These Trisil series have been designed to protect telecommunication equipment against lightning and transient induced by AC power lines. They are available in SMA, SMB and DO-15 packages. Benefits Trisils are not subject to ageing and provide a fail safe mode in short circ [ ... ]

TPA PDF Datasheet Download