Thermal Cycling Qualification For Boards A board in service sees the temperature change every time the equipment is switched on and every time the load changes. Each change makes the materials expand by different amounts, and the difference is carried by the joints, the vias and the interfaces between the…

Test Fixture Maintenance and Probe Replacement A test fixture is a precision assembly that is used until it fails, and its failure looks like a product failure. A probe that has worn, a fixture that has been dropped or a spring that has lost its force produces readings that send…

High Precision PCB Batch Prototyping and Stackup Control A high precision pcb run is decided long before the first panel enters the line. Batch prototyping means several panels are produced from one set of data, so any weakness in the preparation is repeated across the whole lot instead of appearing…

ARM Industrial Control Board Design for Fanless Systems An industrial controller that runs for years inside a cabinet has different priorities from a desktop computer. An arm industrial control board is built around those priorities: modest power, no moving parts and interfaces that survive being wired to a machine. What…

The Role of the PCB in the Electronics Production Process A consumer electronic product is usually judged by its case, but the schedule is normally set by the board inside it. In the electronics production process the printed circuit board is the item that connects the industrial design, the firmware…

Four Layer PCB Design Process From Schematic to Gerber A four layer board is the first stackup that gives a designer dedicated power and ground planes, and that changes the way the job is planned. The four layer pcb design process is not a longer version of a two layer…

ESD Control for SMT Lines and Component Handling Practice A discharge you cannot feel can destroy a component you cannot see damaged. Static voltages of a few hundred volts are imperceptible to a person and entirely capable of punching through the thin gate oxide of a modern device. Because the…

Solder Mask Adhesion and Copper Surface Preparation Solder mask adhesion is decided long before the mask is applied. The copper surface that the mask has to grip is produced by the etching process, modified by the surface treatment, and then exposed to storage and handling before the mask ever reaches…

Ultrasonic Transducer: Design Rules and Process Limits An ultrasonic transducer converts an electrical burst into pressure waves and converts the returning echo back into a voltage. The same ceramic element does both jobs on a simple ranging sensor, and the circuit has to drive it hard for a few cycles…

Time Domain Reflectometry For Impedance Measurement A controlled impedance requirement is a promise that the board will present a defined impedance to a signal, and the only way to keep that promise is to measure it. The measurement is made on a test coupon, which is a structure built into…