25. TVS Diode for 12V Automotive Supply Line Protection

John is designing an automotive electronic control module powered from the 12V vehicle battery. 

The automotive supply line is exposed to harsh transients including load dump (up to 40V), alternator spikes, inductive switching, and reverse battery conditions. 

To protect the module from these high-energy transients, he needs to place a unidirectional TVS diode across the 12V input. 

Key requirements: 

• Normal battery voltage range is 9V to 16V (including cranking and charging up to ~14.8V) 

• TVS standoff voltage: 18V to 22V (above max normal voltage with safe margin) 

• Clamping voltage: ≤38V (to protect downstream automotive-grade components) 

• Peak pulse power: ≥600W for load dump transients 

• Must be AEC-Q101 qualified for automotive reliability

• SMD package: SMB 

The company's approved vendor list (AVL) specifies Littelfuse for circuit protection components, so the part must be selected from Littelfuse on DigiKey. 

Help him select a suitable unidirectional, automotive-grade TVS diode from Littelfuse on DigiKey.