I am using a CD4009UB for a switching application that is sensitive to mV errors on a microsecond timescale. I have hardwired it "deadbug" style on a copper ground plane. All power is supplied by high-quality HP DC supplies.
- VDD = 12V
- VCC = 10V
- VSS = 0V
- All unused inputs are tied to VDD.
- Input pulse is a positive, 8V pulse at 100 Hz, 1% duty cycle.
My requirements are:
- switches from 10V to 0V.
- transition time less than 80 ns.
- settles to error band of 5 mV in 200 ns.
Here is what I measure (Tek P6139A passive 500MHz 8pF probe into a Tek TDS3012 100MHz scope):
I need to eliminate that 20 mV hump that occurs after the initial ringing. Can anyone suggest how I could do that? (Note: I have verified that the "hump" is NOT found in the trigger pulse, which is provided by an Agilent 33250A arbitrary waveform generator.)
