The miSLIC™ Line Circuits together with a VoIP processor or SoC, provides an economical turn-key solution for derived voice applications. The versatile Le9653 miSLIC can be controlled via a PCM/SPI or ZSI interface. The Le9653 miSLIC 1 FXS tracking device in a 4x6 mm QFN package is a reduced footprint and space optimized version of the Le9651. The pin order from the Le9651 has been preserved with the Le9653 allowing easy PCB update for the Le9653. The Le9653 uses energy efficient power supply topologies for reduced BOM cost. The Le9653 can be configured to operate a buck-boost fixed tracking supply or an inverting boost tracking supply. Ringing and system power management are supported to limit the peak power requirements of the telephone line FXS port. The Le9653 features wideband clarity and complete BORSCHT functionality. Manufacturing test and subscriber line testing are standard features. All AC, DC, and power parameters are programmable making the miSLIC device suitable for any application requiring SLIC functionality.