A low-power wideband Power-on-Reset (PoR) and supply brown out detection circuit is proposed, wherein a technique for accurately controlling the PoR trip points and hysteresis voltage is presented. The PoR circuit includes a CMOS circuit with asymmetric rise and fall delays for monitoring wideband supply voltage transients including supply brown out. Being a non-bandgap and non-comparator based circuit, it consumes a very small power and Si area.