You are posting in the analog circuit design section, impulse response is however a theoretical concept found in signal theory and digital signal processing. It hasn't much to do with real circuits which neither support infinite magnitude nor zero signal duration.
Rectangular waveforms do exist in real circuits but only with finite bandwidth. Active circuits involve non-linear signal limitations like maximum slew rate.
"Impulse signals" in analog circuit designs are either idealizations in small signal analysis or real pulses with well defined magnitude and rise time which can be applied in transient analysis.