Problem & Context
The global semiconductor shortage of early 2020s created critical supply chain disruptions for legacy PCB designs. Key components – specifically high side switches and micro-controllers – became severely constrained, threatening production continuity. Additionally we lacked ownership of critical design files, as these had been outsourced years prior. While legacy project files existed, we did not have the software required to work on those files. The combination of component obsolescence and lack of design control necessitated a comprehensive board consolidation and redesign effort. The project had been on our radar as a cost saving effort for both mfr and assembly, but we weren't pressed to take it on.
Scope of Work
- Migrate legacy PCB designs from inaccessible software to EasyEDA, establishing full design ownership and version control.
- Consolidate two separate PCB assemblies into a unified board design, eliminating inter-board jumper wiring and reducing assembly complexity.
- Address electrical integration challenges including noise coupling, voltage regulation under combined loads, thermal management with increased component density, and potential crosstalk between previously isolated circuits.
- Redesign around alternative micro-controller package footprints to enable supply chain flexibility and protect against future component shortages.
- Source and validate replacement high-side switching components, as legacy parts reached EOL (end-of-life) with no pin compatible alternatives available.
- Develop and execute accelerated life testing protocols, cycling boards through complete functional sequencing thousands of times under temperature extremes representative of field deployment conditions.
Technical Approach
Converted legacy project files to EasyEDA through a multi-stage process involving manual construction of missing component footprints, schematic symbols, and design rules constraints. Also merged separate BOMs.
Consolidated power planes which required careful analysis of combined current draws, voltage drops, and ground plane partitioning.
Replaced rail-to-rail op-amps with standard op-amps after determining this was necessary due to a shared 3.3V power plane.
Implemented Zener diode clamp protection for stepper motor driver back-EMF suppression, protecting against inductive kickback that could damage the stepper driver.
Sourced alternative high-side switch ICs with comparable specs to those being EOL.
Upgraded the GPS power supply IC to a higher current capacity to accommodate module peak demands for latest and greatest GPS.
Accelerated life testing rig with multiple consolidated boards under thermal cycling and functional sequencing validation
Results
- Reduced per-unit manufacturing cost by consolidating two boards into one, eliminating assembly labor for inter-board wiring and reducing connector hardware requirements.
- Established full ownership of design files (schematics, BOMs, Gerbers, and assembly drawings) enabling rapid design iterations and eliminating dependency on external design resources.
- Improved supply chain resilience through micro-controller package diversification, allowing production to continue during component allocation constraints.
- Enhanced system reliability through comprehensive thermal and electrical testing, validating performance across operation temperature range with zero failures observed after extended cycle testing.
- Simplified assembly process and improved first-pass yield by replacing error-prone manual wire harness connections with integrated PCB traces.
(Models and drawings are omitted due to proprietary constraints)