ARCHIVE 2009 - BiTS Workshop

2009Session 3Adventures in Test & Burn-in OperationsBurn-in DataAverage 38% of power saved by reverse substrate bias> Unit-to-unit savings range is 23% - 58%Vnw = Vdd + 0.5VVsb = - 0.5VEffect of Vnw and Vsb bias on core IddCore Idd% powersaved100.080.060.040.020.0units0.03/2009 Substrate Bias: Application in Final Test and Burn-in of High-Power CPU’s 7• Vnw is positiveOven Complications> But occupies oven power supplies that could otherwisebe used for core Vdd• Vsb is negative> Oven doesn’t have a negative power supply> A custom board-level circuit was added for +DC/-DCconversion• Adjust thermal control to avoid under-temps forlow-power samples> Tune oven heat/cool rate of response> Tune oven ambient temperature3/2009 Substrate Bias: Application in Final Test and Burn-in of High-Power CPU’s 8Paper #4March 8 - 11, 20094