This circuit somehow manages to function correctly. Meaning, it accepts input only for voltage level between 2V -3.6V, when higher voltage is applied, it closes the PMOS (M4 in CircuitLab and M1 in LtSpice).
But the problem is ripple and the spikes! I know spike is formed because M1 can not open fast enough to compansate fast rise of Vin to gate of M2. But I can't think anything for getting rid of ripples.
spike occurs at both circuitlab and ltSpice.
But in circuit lab, ripples not seen.
Thanks in advance.