Why Are High Voltage PMOS and Low Current HV MOSFETs Hard to Find for 1500V Circuits?

High voltage PMOS transistors with ratings around 1500V are difficult to find compared to NMOS devices due to inherent physical and manufacturing limitations; NMOS devices benefit from electron majority carriers which enable higher voltage and speed performance. High voltage MOSFETs typically target high current applications, making low current, high voltage MOSFETs rare and often expensive with large package sizes due to heat dissipation and creepage requirements. Alternatives for low current high voltage switching include reed relays (e.g., from Pickering) which handle low currents without contact wear issues. Photomos relays are available up to about 1000V but not at 1500V, complicating low frequency, low current switching at these voltages. IGBTs with high voltage and current ratings exist and include complementary PNP devices, but may not suit low current applications. Optical isolation is recommended for safety and control at these voltages. The Panasonic AQV258H5 photomos relay supports up to 1500V and may be a viable option. High voltage supplies with very low current can be safe to handle, but currents above 20mA at high voltage are dangerous. Overall, device availability and design constraints limit options for low current, high voltage PMOS and MOSFET switches at 1500V, requiring consideration of alternative components and isolation methods.
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