Title :
Leaky insulating paint for preventing discharge anomalies on circuit boards
Author :
Frederickson, A.R. ; Nanevicz, J.E. ; Thayer, J.S. ; Enloe, C. Lon ; Mullen, E.G. ; Parkinson, D.B.
Author_Institution :
US Air Force Geophys. Lab., Hanscom AFB, MA, USA
fDate :
12/1/1989 12:00:00 AM
Abstract :
A semi-insulting paint has been formulated and tested for preventing pulse discharges from causing damage to circuits on heavily irradiated circuit boards. The paint is tin-oxide-filled phenoxy resin with a bulk resistivity of 108 ohm-cm. A typical coating is then 1010 ohms per square. It is applied over the finished, conformally coated circuit board and connected to ground where possible on the board. It works by minimizing the stored electric field energy prior to the discharge. With such high resistivity it cannot load down most circuits. Tests were performed on circuit boards with and without the paint using energetic electron beams to simulate very high space exposure levels. Many potential damaging pulses were seen without the paint; application of the paint removed all large pulses, and only a few small pulses were seen
Keywords :
aerospace instrumentation; electron beam effects; filled polymers; polymer films; printed circuits; protective coatings; radiation hardening (electronics); semiconductors; PCBs; bulk resistivity; energetic electron beams; filled phenoxy resin; heavily irradiated circuit boards; high space exposure levels simulation; leaky insulating paint; preventing discharge anomalies on circuit boards; preventing pulse discharges; semi-insulting paint; semiinsulating paint; sheet resistivity; Circuit testing; Coatings; Conductivity; Electron beams; Insulation; Paints; Performance evaluation; Printed circuits; Pulse circuits; Resins;
Journal_Title :
Nuclear Science, IEEE Transactions on