We present a capacitor-free, scalable CMOS neuron circuit that offers significant benefits, including a compact circuit area, low power consumption, adjustable firing threshold, and scalability. This circuit generates output pulses with widths that increase in proportion to the input current magnitude. It also features an adjustable firing threshold (1-6 nA), indicating the minimum input current required to trigger an output pulse. Fabricated using standard 180 nm CMOS technology, the circuit occupies an area of $200~{\mu }$ m2 and consumes 1.4 pJ of energy per output pulse.