An integrated time reference
R.A. Blauschild · 2002
The simplest and most common integrated time constant is the product of resistance and capacitance. Unfortunately, the R-C product can vary with both process and temperature by as much as 30-50%, so precision applications require trimming or external components. Many applications require an order of magnitude decrease in timing variation, and would benefit from the elimination of external components and their associated pins. The reference reported here uses mobility as a time standard to develop a resistance that is temperature stable and inversely proportional to oxide capacitance, yielding a precise RC product.>