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• IC1 (TPS5430DDA): This is a step-down switching regulator capable of providing a 5V output from a 12V input. It features low power consumption, high efficiency, and robust protection features. The pin configuration includes bootstrapping, voltage sensing, enable, ground, input, and phase pins.
• U1 (S-LMBR340FT1G): A Schottky Barrier Rectifier, which offers fast switching and low forward voltage drop, used to improve the overall efficiency of the converter.
• Inductor L1: 10 µH inductor for energy storage and smooth current transitions during the switching process.
• Capacitors:

  • C1: 100µF output capacitor for filtering voltage ripples.
  • C2: 47µF input capacitor to stabilize input voltage and minimize ripple.
  • C3: 100nF capacitor for bootstrapping purposes.

• Resistors:

  • R1: 33kΩ resistor for feedback network.
  • R2: 10kΩ resistor for feedback network.

• D1: TVS Diode for protection against voltage spikes and transients to ensure circuit reliability.

• 12V Input: The power is supplied through the 12V net and connected to various components to maintain a stable operation.
• 5V Output: Delivers regulated 5V power from the output.

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1. Inductor (L1) Selection:

   • Value: Typically around 10-22 µH for a buck converter with this specification. The exact value can be chosen based on ripple current and efficiency needs.
   • Connect IC1:PH to one terminal of L1.
   • Connect the other terminal of L1 to the output node.

2. Output Capacitor (Cout) Selection:

   • Value: Typically, starting at around 100-470 µF with a voltage rating above 5V plus additional headroom.
   • Connect L1's output side to one terminal of Cout.
   • Connect the other terminal of Cout to IC1:GND.

3. Input Capacitor (Cin) Selection:

   • Value: Usually in the range of 10-47 µF with a voltage rating above the maximum input voltage (24V in your case).
   • Connect IC1:VIN to one terminal of Cin.
   • Connect the other terminal of Cin to IC1:GND.

4. Feedback Resistor Network (R1, R2):

   • Values for R1 and R2: Use the formula $ V_{\text{OUT}} = V_{\text{REF}} \times (1 + \frac{R1}{R2}) $ where $ V_{\text{REF}} $ is typically 1.221V for TPS5430DDA.
   • Calculate R1 and R2 for a 5V output. You might use standard values like R1 = 33kΩ and R2 = 10kΩ.
   • Connect R1 between IC1:VSENSE and the output node.
   • Connect R2 between IC1:VSENSE and IC1:GND.

5. Bootstrapping Capacitor (Cboot):

   • Value: Typically 0.01 µF.
   • Connect IC1:BOOT to IC1:PH.

6. Enable Pin (EN) Control:

   • If you want to have controller enable/disable functionality driven by an external circuit or microcontroller, connect IC1:EN accordingly. If always on, connect it to IC1:VIN or leave it open, depending on your specific startup sequencing requirements.

• Inductor Selection: Choose an inductor with a current rating above 3A with low DC resistance to minimize losses. It should handle the peak current without saturation.
• Capacitor Requirements: Use low-ESR capacitors to minimize output voltage ripple and improve efficiency.
• Heat Dissipation: Use adequate copper area on the PCB and thermal vias under the IC to dissipate heat. The TPS5430DDA features an exposed thermal pad for this purpose.
• Protection and Stability: Consider adding input and output capacitors, Snubber circuits on the switch node to dampen voltage spikes, and diode clamping for additional protection.

• Input Fuse: To protect against overcurrent conditions.
• TVS Diode: For input transient voltage suppression.
• Overcurrent Protection: Can be integrated into the design or calculated based on the chosen components’ ratings.

• Connect IC1:VIN to Vin.
• Connect IC1:GND to Ground.
• Connect IC1:PH to L1 and Cboot.
• Connect IC1:VSENSE to feedback network resistors R1 and R2.
• Connect IC1:BOOT to the other side of Cboot.

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1. Stand-off Voltage (V_WM):

   • Choose a diode with a stand-off voltage slightly above your maximum input voltage to prevent unnecessary clamping during normal operation.
   • Since your input is 5.5-24V, a TVS with a stand-off voltage around 26-30V could be suitable.

2. Clamping Voltage (V_C):

   • This is the voltage the TVS diode will clamp during a transient. It should be low enough to protect your circuit but above the normal operating voltage.

3. Peak Pulse Current (I_PP):

   • Ensure the TVS diode can handle the expected peak pulse current of your application, which depends on the anticipated level of transients.

4. Power Dissipation:

   • Look for a TVS diode with adequate power dissipation capability to handle the energy of the surge.

5. Package Type:

   • Choose a package type that matches your PCB layout and space constraints.

• Placement:

  • Place the TVS diode as close to the power input connector as possible. This minimizes the loop area to reduce the inductance and improve the response time to transients.

• Connection:

  • Connect the cathode of the TVS diode to the positive input line (Vin).
  • Connect the anode to ground.

1. SMBJ24A:

   • Stand-off Voltage: 24V
   • Clamping Voltage: Around 38.9V at 1A
   • Peak Pulse Current: 6.7A
   • Package: DO-214AA (SMB)

2. SMAJ26A:

   • Stand-off Voltage: 26V
   • Clamping Voltage: Around 42.1V at 1A
   • Peak Pulse Current: 5.8A
   • Package: DO-214AC (SMA)

3. P6KE24A:

   • Stand-off Voltage: 24V
   • Clamping Voltage: 33.2V
   • Peak Pulse Current: 22A
   • Package: DO-15

• Reverse Standoff Voltage should exceed the working DC voltage.
• Ensure the clamping voltage is below the maximum voltage rating of components in your circuit to safely absorb transients.
• Use TVS diodes with low leakage current to minimize their effect in normal operations.

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1. Inductor (L1):

   • Ensure that the inductor is connected between IC1:PH and the output node.
   • Make sure the inductor can handle at least 3A with some margin to prevent saturation and reduce losses (~10-22µH).

2. Output Capacitor (C1):

   • Connected between the output and IC1:GND.
   • Use a low-ESR capacitor (100-470µF, voltage rating >5V with headroom).

3. Input Capacitor (C2):

   • Connected between IC1:VIN and IC1:GND.
   • Select value between 10-47µF, >24V rating.

4. Feedback Resistor Network (R1, R2):

   • IC1:VSENSE should connect to the junction of the resistor divider R1 & R2.
   • R1 and R2 are selected to set V_OUT using the formula $ V_{\text{OUT}} = V_{\text{REF}} \times \left(1 + \frac{R1}{R2}\right) $, where $ V_{\text{REF}} = 1.221 , \text{V} $ for this IC.
   • With R1 = 33kΩ and R2 = 10kΩ: $V_{\text{OUT}} = 1.221 \times \left(1 + \frac{33k}{10k}\right) \approx 5.007 \, \text{V}$ (close to the desired 5V).

5. Bootstrapping Capacitor (C3):

   • Connect IC1:BOOT to IC1:PH with a 0.01 µF capacitor.

6. Enable Pin (EN):

   • Connect IC1:EN appropriately based on the intended power-on sequence.

• Check Inductor and Capacitor Ratings: Ensure they are rated for the necessary current and voltage.
• Thermal Management: Adequately size the PCB copper areas for thermal dissipation; consider thermal vias under the IC.
• Noise Considerations: Keep high-frequency switching paths short and wide to minimize electromagnetic interference (EMI).

• The calculated V_OUT is approximately 5.007V based on the chosen resistor values (R1 = 33kΩ and R2 = 10kΩ).