MAX1873REEE+T

The MAX1873REEE+T from Analog Devices (formerly Maxim Integrated) is a cost-effective switch-mode controller for charging lithium-ion battery packs. It supports 2-, 3-, or 4-series Li+ cells and can deliver charging currents of 4A or more. The device features a regulated charging current and voltage with high accuracy, achieving less than ±0.75% total voltage error at the battery terminals.

Designed for simplicity and efficiency, the MAX1873REEE+T utilizes an external P-channel MOSFET in a step-down DC-DC configuration. It incorporates control loops for smooth transitions between voltage and current regulation, along with an additional loop to limit input current, minimizing AC adapter size and cost. An analog output proportional to the charging current is provided for monitoring purposes.

This controller can also be used for charging NiCd or NiMH batteries in multi-chemistry charger designs. The MAX1873REEE+T is available in a space-saving 16-QSOP package, suitable for surface mounting. Its operating temperature range is -40°C to +85°C.

Key electrical specifications include an input voltage range up to 28V, a dropout voltage of 200mV enabling 100% duty cycle operation, and an adjustable charging current. A 300kHz PWM oscillator helps reduce noise in the system. The device also features a low shutdown battery current of 5µA.