1500 W Zener TVS for telecom board protection
The Littelfuse 1.5SMB43A is a single-channel unidirectional Zener TVS diode in the 1.5SMB series, designed to clamp transients on telecom line cards, base stations, and networking power rails. The reverse standoff voltage is 36.8 V, meaning the diode stays off below that level and does not load the signal line during normal operation. Breakdown starts at 40.9 V minimum, and the clamping voltage is held to 76.6 V at the rated peak current — tight enough to protect a 48 V rail downstream of a hot-swap controller or a PoE PSE.
Package, temperature, and mounting
Housed in the DO-214AA (SMB) package, surface-mount, the 1.5SMB43A sits on a standard footprint shared across the 1.5SMB family. The operating junction temperature range spans -65°C to +150°C, covering outdoor telecom cabinets and uncontrolled indoor environments without derating concerns. The tape-and-reel and cut-tape packaging options suit both prototype assembly and production reflow.