01RDS(on) or Qg for synchronous-rectifier MOSFETs?
Both. RDS(on) × I²rms dominates conduction loss, while Qg × VGS × fsw sets drive power and heating; then check Qrr and Coss. Frequency decides the trade-off — high frequency favors low Qg, low-frequency high-current favors low RDS(on) — and the SGT process lowers both together. Integrated-MOS rectifiers lock on-resistance and voltage rating to one part number; a discrete MOSFET is more flexible. The LV/MV MOSFET category lists Qg_Typ and Coss_Typ columns for comparison.
02What is the difference between a "protocol-only" and an "integrated" PD IC?
A protocol-only (PD Source) IC handles CC-line communication and power negotiation, leaving output regulation to an external DC-DC or flyback loop; it can be reused across power platforms, but the power stage must track protocol commands during power steps. An integrated IC combines protocol negotiation with part of the power control, shrinking BOM and footprint — suited to single-port, fixed-power designs, with the power range locked by the chip. Multi-port designs also need dynamic allocation and port priority. Filter the PD category by type and port.
03What does the "-12" suffix on a wafer part number mean, and what extra parameters does bare-die selection need?
"-12" marks a 12-inch wafer format; for most part numbers, the same name without it is the 8-inch version. The gross-die range in the guide is counted per 8" wafer, so confirm the wafer format first, then run cost from gross die. Bare-die selection also checks process and channel configuration, RDS(on) at your gate-drive VGS grade, die size, thickness grade and ESD integration — and never infers die RDS(on) from a packaged part, since package resistance is a real share.
04Why is RDS(on) specified at several VGS levels, and which one applies to low-voltage gate drive?
RDS(on) depends on gate-drive voltage, so datasheets grade it at VGS = 10V, 4.5V and 2.5V, and one device's figures can differ a lot between grades. Read the grade that matches your actual drive voltage; a gate driven directly at logic level should use the 2.5V column. Ordering on the lowest 10V figure leaves you with a much higher real resistance under low-voltage drive. Use the Max value, not Typ, for thermal budgeting. The LV/MV MOSFET and wafer categories on this site list Typ/Max at all three grades.
05Which voltage ranges do SGT and superjunction MOSFETs cover, and how do I pick the route?
SGT adds a shield electrode beside the trench gate to cut gate-drain capacitance and the Miller effect, giving low switching loss; it covers low-to-medium voltage (about 12V–230V in the catalog) for synchronous rectification, battery management, motor drive and load switches. Superjunction uses vertical charge balance to raise the rating while keeping on-resistance low, covering roughly 300V–800V for off-line supplies, adapters and industrial power. The routes complement rather than replace each other: low-voltage high-frequency designs weigh switching loss and drive matching; medium-to-high voltage designs weigh voltage margin and avalanche energy.
06Why do appliance inverters use IPMs rather than discrete IGBTs?
An IPM packs six IGBTs, freewheeling diodes, gate drive, under-voltage and over-current protection into one DIP module with isolation and creepage already engineered, removing driver design and layout debugging. Listed IGBT-based IPMs are 600V class, rated 6A~30A with 12A~60A peaks — the range of air-conditioner and washer inverter boards. The trade-off: drive timing and gate-resistor knobs are fixed and protection thresholds preset, so check the application level against actual conditions; only high-power or unusual topologies go back to discrete parts.
07RC-IGBT or IGBT + FRD inside an IPM — how to choose?
Check the current tier first: pick ICP (listed about 12A~60A) from motor start-up and stall peaks, not rated power alone. Then the structure: RC-IGBT is reverse-conducting with higher integration; IGBT&FRD uses a separate freewheeling diode whose recovery behavior can be chosen on its own. Freewheel-side VF of about 1.5V~2.35V and Trr of about 0.15~0.3μs set freewheeling loss and commutation EMI — weigh them by carrier frequency and EMI targets. The two are not drop-in equivalents; re-evaluate recovery behavior when swapping.