SNOSDG3 December 2024 LM74681
PRODUCTION DATA
The TVS at input or output is not required for the LM74681 to operate, but it may be required to clamp the voltage transients caused by lightning, switching surges, or power disturbances that can exceed the voltage ratings of MOSFETs and the controller possibly causing damage. A TVS diode protects against such events by clamping the transient voltages to safe levels. For 48V PoE PD application, a unidirectional TVS like SMAJ58A with a standoff voltage above the maximum input DC voltage and a clamping voltage below the MOSFET's maximum rating is recommended. This TVS is recommended to be placed as close to the LM74681 as possible. In well-regulated applications with minimal transient risks, a TVS diode may not be necessary.