MAX1535D

The MAX1535B/MAX1535C/MAX1535D are highly integrated, multichemistry battery chargers that simplify construction of advanced smart chargers with a minimum number of external components. They use Intel's system management bus (SMBus™) to control the charge voltage, charge current, and the maximum current drawn from the AC adapter. High efficiency is achieved through use of a constant off-time step-down topology with synchronous rectification.

In addition to support of the Smart-Battery-Charger Specifications Rev 1.1, they include additional features. The maximum current drawn from the AC adapter is programmable to avoid overloads when supplying the load and the battery charger simultaneously. This enables the user to reduce the cost of the AC adapter. The MAX1535B/MAX1535C/ MAX1535D provide a digital output that indicates the presence of an AC adapter. Based on the presence or absence of the AC adapter, the MAX1535B/MAX1535C/MAX1535D automatically select the appropriate source for supplying power to the system by controlling two external p-channel MOSFETs. Under system control, they allow the battery to undergo a relearning or conditioning cycle in which the battery is completely discharged through the system load and then recharged.

The MAX1535B/MAX1535C/MAX1535D are capable of charging 2, 3, or 4 lithium-ion (Li+) cells in series, providing charge currents as high as 8A. The DC-DC converter in the MAX1535B/MAX1535C/MAX1535D uses a highside p-channel switch with an n-channel synchronous rectifier. The charge current and input current-limit sense amplifiers have low input-offset errors and can use smallvalue sense resistors (0.01Ω, typ).

The MAX1535B/MAX1535C/MAX1535D are available in a 5mm x 5mm, 32-pin, thin QFN package and operate over the extended -40°C to +85°C temperature range.An evaluation kit is available to reduce design time.