[Mounting on ECU boards] Pinpointing Open Joints for Pads for BGAs and Connectors! Non-contact sensor technology VTEP

One of the common issues when mounting BGA (ball grid array) ICs on PCBs (printed circuit boards) is the open joints caused by the differences in linear expansion between the device and PCB. Test points are necessary to check such open joints because probing the balls is impossible. With the reduction of the number of test points, entire tests tend to be given up. What if you can observe almost all open joints except those for the balls for the supply voltage and ground? CET technology makes it possible by combining boundary scan technology with Keysight’s patented VTEP technology. 

Check what you cannot probe! 

A VTEP sensor is a high-sensitivity sensor plate based on Keysight’s patented technologies, and can detect extremely low capacitance. By applying an AC signal to the pins of ICs and connectors on which a VTEP sensor is mounted so as to determine the very low capacitance values between the sensor and pins or internal bonding wires in the ICs and connectors, assembly failure that is not accessible with a probing pin can be pinpointed. 

Use CET to pinpoint open failures for BGAs 

If a BGA IC capable of boundary scans is connected to connectors / analog ICs, mount a VTEP sensor onto such components. Then, use the BGA IC as a source for the boundary scan signal, and analyze the connections between the BGA IC and other components around. If a ball in a BGA IC has no contact with the solder pad, the circuit is open, and therefore capacitance is not detected. 

N1125A Boundary Scan Analyzer 

Tiny yet powerful box that realizes CET by working with VTEP. Also, good for embedding into function test systems. 

Technologies still continuing to evolve 

Keysight is the company that started non- contact tests with TestJet technology a long time ago. VTEP continues evolving, aiming for higher sensitivity and broader test coverage. 

Use ICTs (in-channel tests) if your chip doesn’t support boundary scans 

Just add test points on your PCB, and apply 

AC signals through them to detect opens with + a VTEP sensor placed directly on the BGA IC. Portable/benchtop ICTs are the perfect solution when checking only suspicious points. 

Worldwide support system 

Local support is essential for the N1125A, which
is actively used in manufacturing lines. Even if you share manufacturing technologies and standardize equipment across borders, Keysight will seamlessly support you everywhere from your manufacturing engineering bases to local factories.