If you mean by 'delay' the down-going exponential slope, this looks like a capacitor discharging. Have you tried hooking up a 4k7 resistor to the DAC output and repeating the experiment?
If you mean by 'delay' the down-going exponential slope, this looks like a capacitor discharging. Have you tried hooking up a 4k7 resistor to the DAC output and repeating the experiment?