Electrical Design Standard
Official Guidebolt Electrical-Design Standard
Required: all elements, RoHS-compliant (preferably RoHS3).
Preferred: all elements, REACH-compliant.
Preferred: all elements, halogen-free.
Preferred: all elements, flame-resistance UL94-V0.
Note that "X-Free" generally allows trace amounts below a standard threshold. For example, "halogen-free" and "zero halogen" are typically used interchangeably under the max 1500ppm of total halogens (IEC 61249-2-21).
Preferred: measurement standard, metric
Required: PCB build, fabrication-class IPC-2 (or better)
Preferred: all parts, automotive-grade (qualified to AEC-Q).
Required: all parts, temperature-range for operation and storage. See list below.
- -40C to 85C (minimum)
- -40C to 105C (acceptable)
- -40C to 125C (good)
- -55C to 150C (excellent)
Preferred: All power-connectors are glow-wire-capable.
Required: all PCBs, rounded corners.
Preferred: PCB rounded-corners, minimum radius 5mm.
Required: All PCBs have ENIG surface finish (or better).
Required: All parts are placed with at least 1mm spacing between parts.
Preferred: Fill to pad clearance, minimum 0.5mm
Preferred: PCB soldermask color, green.
Preferred: All signal PCBs are built with impedance control.
Required: All PCBs expected to endure high-moisture must have conformal-coating or encapsulation.
Required: Every PCB has the following silkscreen text (minimum). Refer to list below.
- company name
- part-number (with revision number)
- batch number
- part perimeter-outline (one per part)
- part reference-designator (one per part)
- functional-label (one per external-pin)
Preferred: All power PCBs have thermal conductivity of 0.7 W/mK (or better).
Required: All THT holes have a minimum-diameter equal to maximum-lead-diameter + 0.25mm (IPC-2222 Level A).
Required: All THT annular-rings have a minimum-diameter equal to minimum-hole-dia + 0.7mm (IPC-2221 Level A).
Preferred: standard sizes (hole-dia, annular-ring-dia).
- 0.4mm, 0.8mm (small)
- 0.5mm, 1mm (normal-compact)
- 0.5mm, 1.2mm (normal)
Preferred: full-depth vias (normal plated-thru-hole, no blind or buried)
Preferred: no vias in pad
Preferred: via-hole-edge to pad-edge spacing, minimum 0.2mm
Preferred: via-hole-edge to via-hole-edge spacing, minimum 0.5mm
Required: all pads, rounded corners
Required: pad rounded-corners, minimum radius 0.25mm
Required: all PCB-mounting-holes support metric screws
Preferred: All PCBs have at least 4 mounting holes.
Preferred: All PCB mounting holes are patterned as a simple shape (ex. square, rectangle).
PCB Board Edge Clearance
Required: board-edge to external-layer-conductor, minimum 0.25mm
Required: board-edge to internal-layer-conductor, minimum 0.5mm
Preferred: board-edge to any-layer-conductor, minimum 1mm
Required: board-edge to hole-edge, minimum 1mm
Required: board-edge to part-perimeter, minimum 1mm
Preferred: board-edge to SMT-part-perimeter, minimum 3mm
Required: All external pins have transient voltage protection.
Required: All electronics have at least 50K hours MTBF.
Preferred: All electronics have at least 150K hours MTBF.
Preferred: All MLCC capacitors have soft-terminated ends (bend-crack resistance).
Required: All high-value capacitors are aluminum-polymer type.