Oct 13, 2008
October 2008 � atg Luther & Maelzer GmbH, in cooperation with the Capital Equipment Group (CEG) of Everett Charles Technologies introduces a test protocol called ''4-wire (Kelvin)''. The 4-wire-test has long been a selectable option in the newest flying probe testers from atg-LM, A6 and A5 models.
Small embedded resistors often have a trace resistor change in the milliohm level, which calls for a much more precise test technique to diagnose. The A6 and A5 Kelvin test places two probes on each pad. These probes are shielded from one another, assigning a separate current and voltage source.
Both tester types, A6 and A5, are the fastest flying probers in their class because of the 8 and 16 head design. In addition to manual load operation, the A6 and A5 also can be ordered with full PCB automation. A standard four head prober system can achieve a maximum (4-Wire) test speed of 22 test points/second (TP/s). On the other hand, an atg multi rail (8 or 16 test heads) system can reach (4-wire) test speeds in excess of 35-40 TP/s. atg-LM nearly doubles the 4-Wire test speed of its nearest competitor.
The universal interface on each probe head allows the user to adapt a wide range of test pin types. In addition to standard and soft touch needle, the 4-wire option offers two types of needles:
- Standard Kelvin needle
- Blade type Kelvin needle
The applicable 4-wire (Kelvin) needle can be mounted to suit the application and product surface material. The universal interface provides the flexibility to convert a standard PCB flying probe tester into a high resistance 4-wire measurement tool.
4-wire measurement achieves a minimal threshold value down to 0.1 mOhm. 4-wire (Kelvin) needles can meet the specification value down to 75 �m pad and 150 �m for pitch. The 4-Wire test gives the user high accuracy trace measurement and ultimate process control.
atg Luther & Maelzer GmbH, headquartered at Wertheim and Wunstorf, is the undisputed market leader worldwide for the electrical test of bare printed circuit boards with an annual turnover of 45 million EUR and approximately 1,680 active test systems installed worldwide.
