22. TVS Diode for 24VDC Industrial Input Protection

Susan is designing an industrial sensor board powered from a 24VDC supply bus. 

The bus runs through a factory floor with long cables near motors, solenoids, and switching equipment, causing voltage transients and surges on the supply line. 

To protect the board's input from fast transient spikes, she needs to place a unidirectional TVS diode across the 24V power input. 

Key requirements: 

• Supply is 24VDC nominal (can be up to 26.4V with ±10% tolerance) 

• TVS standoff voltage: 27V to 30V (above max normal bus voltage, but not too high) 

• Clamping voltage: ≤50V (to protect downstream components rated for max 50V) 

• Peak pulse power: ≥400W for industrial surge levels 

• SMD package: SMA 

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

Help her select a suitable unidirectional TVS diode from Littelfuse on DigiKey.