aryajur
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Below are attached 2 graphs showing the distribution of Vbe of a PNP BJT and Threshold Voltage of a PMOS transistor for a large number of wafer samples. The For the PMOS Threshold Voltage:
Average = 0.648 V
Standard Deviation = 0.0273V
For the Vbe of the PNP BJT:
Average = 689.83mV
Standard Deviation = 1.8384mV
So now the question is, are the PNP transistors better matched or the PMOS transistors better matched? Another way to put it will be, would it be better to make Current mirrors using these PNP transistors or these PMOS transistors?
Although the SD of Vthp is 27mV the current is a square function while the current is a exponential function, so that makes it harder to compare.....
Average = 0.648 V
Standard Deviation = 0.0273V
For the Vbe of the PNP BJT:
Average = 689.83mV
Standard Deviation = 1.8384mV
So now the question is, are the PNP transistors better matched or the PMOS transistors better matched? Another way to put it will be, would it be better to make Current mirrors using these PNP transistors or these PMOS transistors?
Although the SD of Vthp is 27mV the current is a square function while the current is a exponential function, so that makes it harder to compare.....