Keysight B1505A Configuration and Connection Guide 5-53Connection Guide for Wafer Prober and Your Own Test FixtureAbout Cable Connections• For the non-Kelvin connection, the voltmeter measures the voltage drop of resistancesrF1 , RDUT , and rF2 .• For the Kelvin connection, the voltmeter measures the voltage drop of resistance RDUTonly. The impedance of the voltmeter is very high, so the voltage drop of resistancesrS1 and rS2 can be ignored.The Kelvin connection is effective even when forcing voltage. The voltage drop due to theresidual resistance of the Force line wiring is fed back to the voltage source via acomparator in the Sense line. The input impedance of comparator is high, and current flowinto the Sense line is very low. So output error is not significant if the Sense line wiring hasa residual resistance of 10 or less. Therefore, the specified voltage appears at the sensepoint (point where Sense line contacts Force line)NOTE Kelvin connection and non-Kelvin connectionTo make the Kelvin connection, use both Force and Sense terminals. Connecting the Forceand Sense lines together at the terminal of the DUT (device under test) minimizes themeasurement error caused by the residual resistance of the connection cables. The Kelvinconnection is effective for the low resistance measurement and the high currentmeasurement.If you want to simplify the cable connections, open the Sense terminals and use the Forceterminals only. This is the non-Kelvin connection. The Force terminals can be used to forceand measure dc voltage or current.To Connect UHVU/HVSMU/HVMCU OutputTo prevent discharge and any accident, make enough space between the cable ends, alsobetween the high side cable end and the shield or chassis. For example, make space ofabout 32 mm from the high side cable end for maximum 10 kV output. Also the creepagedistance must be more than 100 mm for 10 kV.Figure 5-28 Space around Cable EndTo UHVU High To UHVU LowDUTShieldSignal lineInsulator SHV CableUHV CableInsulator¡32 mm for 10 kV¡100 mm for 10 kV
