designing the filter

Mon, Apr 11, 2011

Current project status:

Using the FREQ slider on the JUNO106 results in a exponential filter control current from 32nA to 705µA. So, when feeding 32nA into the filter, its cutoff frequency should be 5Hz. Feeding the filter 705µA results in a 50kHz cutoff frequency. My LM13700 lowpass filterdesign is based on the lectures by Aaron Lanterman. This is a typical design:

resulting in the following plot (Iabc = 1mA)

cutoff frequency in this example is:

using this calculation I will determine the required resistor values for the exponential converter range (32nA – 705µA).