©Vektrex 2014; 1 Introducing n+1 Load Board Topology February, 2014

What Makes A Load Board Successful Properties: Flexible to support testing of multiple sizes and types of devices Efficient, reliable electrical connections Support for series drive to reduce wiring and drivers needed Individual device selection for measurements Simple to design and manufacture Low thermal resistance to provide for small temperature rises and good temperature uniformity Standardized across all company departments Easy to work with – load, secure, maneuver and handle…etc. ©Vektrex 2014; 2

The Load Board Circuit Topology Influences Reliability System In Many Ways Topology – the way LEDs are connected and powered Circuit board routing on load board printed circuit boards System wiring from drivers to load boards Connectors in reliability chambers Switching systems used for measurements ©Vektrex 2014; 3

Circuit Topologies 2n provides 2 connections for each LED 4n adds 2 more to support 4 wire (kelvin) voltage measurements ©Vektrex 2014; 4

2n and 4n Topologies Increase System Cost Individual circuits for each LED increase wire count Copper wire costs can exceed 10-15% for reliability systems designed with 2n and 4n topologies Many connections on load boards = large expensive connectors 2n and 4n circuits complicate PCB layout, usually multiple layers are required Switching systems are more complex with 2n and 4n topologies ©Vektrex 2014; 5

n+1 Simplifies Circuit, Reducing Costs 2n provides 2 connections for each LED 4n adds 2 more to support 4 wire (kelvin) voltage measurements n+1 places LEDs in series circuit to minimize connections ©Vektrex 2014; 6

Topology Comparison ©Vektrex 2014; 7 4n2nn+1 Load Board PCB LayoutMultilayerUsually Multilayer Single Layer Connector Pin Count40 for 10 LEDs 20 for 10 LEDs 11 for 10 LEDs Connector TypeMultiple Double Sided Double Sided Small Single Sided Series DriveRequires External Connections Built Into Topology Drive Cable Wires40 for 10 LEDs 20 for 10 LEDs 2 for 10 LEDs

To Support Large Scale Testing 8 Groups Of 10 LEDs Are Placed On A Single Load Board ©Vektrex 2014;

The LED Groups Can Be Powered With Just A Few Wires ©Vektrex 2014; Two Drive Wires Used Per Connector For Reliability / Stress Operation

Dual Connectors Allow A 1-Layer PCB Design Dual symmetrical connectors allow 1 layer PCB design ©Vektrex 2014;

Example Design - Surface Mount Devices ©Vektrex 2014;

Example Design - COB (Chip on Board) with screw down ©Vektrex 2014;

A Single LED Can Be Isolated For Measurements 4 Wire Connection Maintained To Edge Of Load Board ©Vektrex 2014;

n+1 Topology Forms The Foundation For The Highest Performance Load Boards Simple circuit Low pin count Reduced cable wire count Flexible, supports many different kinds of LEDs N+1 is standard in Vektrex reliability systems ©Vektrex 2014; 14