Introduction: Choosing between 2KV and 15KV SMD high voltage diodes starts with worst-case reverse voltage, board space, and recovery behavior in the compact power stage.
A compact high voltage supply rarely gives you room to overbuild every part. You may have a tight keep-out on one side, a kilovolt-level recurring waveform on the other, and a thermal target that rules out a slow body diode before you open a supplier search. The practical job is to translate system withstand voltage, PCB area, and recovery needs into a short list of SMD voltage grades, then ask for the right PD5 Series data before you commit a footprint. The sequence that works in design reviews is voltage margin first, package fit second, and supplier data last.
Start with the voltage the diode actually sees, not the nominal output printed on the power supply label. A 2KV grade can be the right choice in a tightly clamped circuit, while a 15KV grade belongs in a design with a higher recurring reverse voltage or a larger isolation boundary. The comparison only becomes useful after you add startup overshoot, load-step ringing, and your own derating rule. That is why the first design review question is not “which voltage is available? ” but “what is the highest repeatable reverse voltage this SMD pad will survive? ”
Capture the diode reverse voltage at startup, at full load, at load release, and during switching transitions. Look for ringing that pushes the peak above the steady-state value, then use the recurring peak—not a single lab spike—as the base for derating. Include the isolation requirement of the surrounding circuit: a floating high-voltage rail can put more reverse stress on a small SMD part than the schematic first suggests. Once that number is clear, map it to the 2KV to 15KV range and leave the final grade decision open until the datasheet confirms the exact PD5A to PD5N mapping.
A SMD outline is only the starting point for board area. High voltage clearance and creepage can require a larger keep-out than the package body, and the solder joint, thermal pad, and reflow tolerance all need room around the part. If the layout is already dense, check whether the selected voltage grade forces a wider spacing rule or a different pad geometry before you freeze the footprint. TI’s high-voltage clearance and creepage guidance is a practical cross-check for this step, while your own board validation and applicable IEC requirements remain the final reference.
Fast recovery behavior matters most when the diode is asked to switch cleanly in a high-frequency or fast-edge power stage. Reverse recovery affects switching loss and conversion efficiency, so a fast recovery high voltage diode is often the better fit when the thermal budget is tight and the diode cannot be treated as an ideal switch. The tradeoff is that forward conduction, die area, and package thermal path still matter: a part that recovers quickly but runs hot at your forward current is not a compact solution. Review the PD5 Series Fast Recovery behavior together with your actual forward current waveform, ambient temperature, and switching frequency rather than treating the recovery label as a standalone score. The SMD package form should support the board you can actually build. A surface-mount high voltage diode saves lead-forming space and suits automated assembly, but the package still needs a solderable pad, a clean thermal path, and enough creepage to the next net. In a compact power stage, the best package is the one that lets you route the high-voltage net with controlled spacing, place the diode close to the switching loop, and keep the joint temperature within your design target. That is the point where fast recovery, forward conduction, and package fit meet: the part should reduce loss without creating a new hot spot or a layout compromise you cannot manufacture repeatably.
Once you know the recurring reverse voltage, the PCB keep-out, and the recovery target, turn those numbers into a precise PD5 Series request. Start with the voltage grade you need within the 2KV to 15KV range, then ask for the PD5A to PD5N suffix that matches it. Add the expected forward current waveform, switching frequency, ambient temperature, and the reverse voltage test condition you want to see. A high voltage diode manufacturer can answer faster when the request includes the actual circuit conditions instead of a generic “2KV to 15KV” phrase. Hvdiode’s PD5 Series is a surface-mount high voltage diode family with Fast Recovery behavior, covering 2KV to 15KV, and the series includes PD5A to PD5N model variants. A useful datasheet package should include the voltage grade, package drawing with pad geometry, test conditions for reverse voltage and recovery, and the sample plan for your board. Ask for the exact PD5A to PD5N voltage mapping, IF, Trr, VF, package dimensions, tape-and-reel quantity, MOQ, lead time, and pricing in the official datasheet or RFQ response. When you work with a high voltage diode supplier, also ask for the sample quantity you need for reflow and high-voltage screening, plus the packing format your assembly line can accept. That request gives the supplier a clear target and gives your team a traceable basis for the footprint, test plan, and first article review.
The selection becomes manageable when you stop comparing voltage labels in isolation. Set the recurring reverse voltage with startup, load change, and ringing included; reserve enough board area for creepage, solder joints, thermal spreading, and assembly tolerance; then match Fast Recovery behavior and SMD package form to the real power stage. With those three inputs ready, the PD5 Series conversation is specific: voltage grade, PD5A to PD5N suffix, package drawing, test conditions, and sample needs. Send the worst-case reverse voltage, PCB keep-out, recovery target, and required sample quantity to Hvdiode, and ask for the official datasheet and RFQ response before you lock the footprint.
A: Choose from the highest recurring reverse voltage at the diode, not from the nominal supply output. If the circuit clamps tightly and the recurring peak stays well below 2KV after derating, the 2KV end can fit; if the rail, isolation, or ringing pushes the recurring voltage higher, move up the range and reserve more creepage. Use the PD5 datasheet to confirm the exact PD5A to PD5N grade for your target voltage.
A: Ask for Trr at your actual forward current, di/dt, and temperature, plus the test circuit and waveform. Also request reverse recovery charge if available, VF at your operating current and temperature, and any junction capacitance data that affects the switching node. The PD5 Series carries Fast Recovery behavior; the exact Trr value and test conditions come from the official datasheet or RFQ response.
A: Yes. Hvdiode supports PD5 Series datasheet and sample requests for a specific voltage grade before a formal RFQ. Send the target PD5A to PD5N suffix or voltage range, the operating voltage and current waveform, PCB keep-out, test conditions, and sample quantity; the response can confirm sample availability, packing, MOQ, lead time, and pricing.
Texas Instruments: High-Voltage Clearance and Creepage Considerations
Texas Instruments: Understanding Diode Reverse Recovery in Power Conversion
