There is no direct competition for the LTC4123. At present, an integrated wireless Li-ion solution does not exist other than Linear’s own LTC4120, but that is meant for higher power applications as previously noted. The most likely competition would be a two-chip solution consisting of a linear Li-ion battery charger and a step-down switching regulator, such as a small 2mm x 3mm or smaller sized charger plus a small 300mA, 2mm x 2mm DFN-packaged buck regulator. While NiMH batteries may not provide as much run time as the same size Li-ion battery, the Li-ion solution requires an additional step-down voltage regulation stage, for example to power the hearing aid audio ASIC. This regulation stage increases the overall solution size and adds switching noise that must be managed. The primary advantage of the LTC4123 is that it provides a complete, drop-in single-chip wireless charging solution for today. Here is a summary of the other LTC4123 advantages: direct charge of NiMH cells - low voltage and temperature compensated charge voltage, wireless front end to handle rectification and power control, small overall solution footprint, and no EMI from a switching buck regulator.