MAX1811 USB powered Li+ charger
The MAX1811 is a single‑cell lithium‑ion battery charger that can be powered directly from a USB port or an external supply up to 6.5 V. It offers 0.5 % overall charging accuracy, internal FET current regulation up to 500 mA, and safety features such as pre‑conditioning, voltage and current monitoring, and thermal regulation.
The device is packaged in a thermally enhanced 8‑pin SO (1.4 W) and includes pins for battery regulation voltage selection (SELV), charge‑current selection (SELI), enable (EN), and an open‑drain charge‑status indicator (CHG). It is intended for use in PDAs, digital cameras, MP3 players, cell phones, and other portable electronics.
| Input Supply Voltage | 4.35 V to 6.50 V |
|---|---|
| Charging Current (SELI = GND) | 100 mA (typ) – 500 mA (max) |
| Battery Regulation Voltage (SELV = IN) | 4.20 V typical, 4.22 V max |
| Thermal Regulation Die Temperature Limit | +125 °C |
| Package | 8‑pin SO, 1.4 W thermally enhanced |
It operates from 4.35 V up to 6.5 V.
The charger can be set to either 100 mA or 500 mA using the SELI pin.
The SELV pin selects a 4.1 V or 4.2 V regulation set point; low (<0.8 V) selects 4.1 V, high (>2.0 V) selects 4.2 V.
When the die temperature exceeds +125 °C, the thermal loop reduces the charging current.