Harrisburg, PA- Design engineers are being driven to cut PCB size in efforts to reduce the overall product sizes," says Phoenix Contact Product Manager Greg Jerrehian. Other pressures are cutting component cost and assembly time.
He notes that as circuitry gets smaller voltage clearance between components is important, but connection pin spacings have also been coming down: from "the classic pin spacing of 5.0 mm in the early 80s, to the MINI-COMBICON line (3.5 mm) at the end of the decade, to 2.5 mm in the last two years with the MICRO-COMBICON products." But lower voltage applications have allowed spacing reductions and users are designing systems to match specific uses at lower voltages rather than generic higher voltages where voltage clearance could pose a problem.
Jerrehian adds that as contact spacing is reduced, options for attaching wires have increased. Screws used with larger pin spacings are not as practical due to the difficulty of accessing screwheads. Other mating options include spring cage, IDC (insulation-displacement connectors), and crimping. He notes an additional benefit of these methods is that they can be up to 60% faster to install, cutting assembly cost.
Design tips. He offers a couple of hints in specifying connectors:
- Reduce cost by surface-mount compatibility, even for through-hole connectors. This way they can survive high-temperature processing used for surface-mount components and won't dictate any additional processing.
- Try to specify production standard pin spacing to insure availability.
He adds, miniaturization is economically beneficial in many areas. "The cost of real estate is high, be it on the circuit board or factory floor."
When considering terminal blocks and connectors in miniaturized, or any, design, Jerrehian concludes, "A designer should take advantage of vendor expertise. Work with your vendor to expand your options, particularly in insuring open designs for future plugs and headers. And don't accept any reduction in excellence regarding materials, assembly, and quality checks."