Cymbet Corp. uses a similar LiPON solid electrolyte, but in an even smaller form factor, for a battery-in-a-chip package that aims to make local energy storage just another electronic component on the board or in the SiP. The chip-scale batteries are finding traction for embedded backup power to replace coin cells or supercapacitors in backing up memory, microcontrollers, and real time clocks in electronic systems.
These chip-like rechargeable lithium-based batteries, with nominal capacity of 50µAh in an 8x8 mm package, are made on silicon wafers with conventional deposition and etch tools, though unconventional materials. The chips withstand up to 260°C, so they can be reflow soldered in normal board assembly. They are sold as a bare die, or packaged with a power management ASIC in a SiP. Cymbet's power management IC converts and regulates input ranging from 2.5V to 5.5V and a steady 3.3V output.
