Low Voltage very high speed peak detector

I need a circuit that detects a peak and holds the peak for 15us to be sampled by a "slow" ADC. The output should be a stable, low noise signal that does not decay within 15us, only if reset by pin. If possible, the Peak-Detector should rise as fast as possible with the signal, no long delay between Vpeak and VoutPeak.

The pulses are very sharp rising ones with a short peak and then exponentially decay. Here are the smallest and largest pulses:

Smallest pulse:
Peak Value: 45mV
Signal rise: ~30ns
Signal fall: ~ 2 us

Largest pulse:
Peak Value:  800mV
Signal rise: ~50us
Signal fall:  ~11us

The following restrictions are given:

The circuit should be possible to be powered by single supply 3.3V.
The ADC reference is 2.5V Full scale, so the maximum possible gain on the largest possible pulse (1V) is 2.5
If possible, negative supplies should be avoided

Is there any reference design for this or part recommendation?