The MAX8713 multichemistry battery charger simplifies construction of smart chargers with a minimum number of external components. It uses the Intel System Management Bus (SMBusTM) to control the charge voltage and charge current. High efficiency is achieved through the use of a constant off-time step-down topology with synchronous rectification. The MAX8713 charges one to four lithium-ion (Li+) cells in series and delivers over 2A charge current--scalable with the sense resistor. The MAX8713 drives n-channel MOSFETs for improved efficiency and reduced cost. A low-offset charge-current-sense amplifier provides highaccuracy charge current with small sense resistors. The MAX8713 is available in a space-saving 24-pin 4mm x 4mm thin QFN package and operates over the extended (-40C to +85C) temperature range. An evaluation kit is available to reduce design time.