USB-Compatible Linear Battery Charger MAX8895

MAX8895_ is a USB-compatible linear battery charger that can be powered by a USB port or a dedicated charger and can automatically detect the adapter type and USB enumeration. MAX8895X/MAX8895Y integrates a battery disconnect switch, current sensing circuit, MOSFET pass tube components, and thermal management circuitry to build the simplest and smallest stand-alone charging solution without an external reverse protection Schottky diode.

The MAX8895_ includes automatic detection of the charging adapter type, which can distinguish between USB 2.0 devices, USB chargers, and proprietary chargers. In addition, the MAX8895X/MAX8895Y include a USB enumeration feature that automatically negotiates with the USB host to obtain the maximum current from a USB 2.0 device or USB charger without processor intervention. Adapter type detection complies with the USB 2.0 specification as well as the USB Charging Specification Revision 1.1.

The MAX8895_ controls the charging sequence of a single-cell Li+ battery, starting from the initial power-good indication, through precharge, fast charge, top-off charge, and finally charge termination. Charging is controlled using a constant-current, constant-voltage, and constant-die-temperature (CCCVCTj) regulation scheme to ensure safe operation under all conditions. Maximum charge current is adaptively controlled using the input current limit minus the system current to ensure maximum charge current under any given condition.

The MAX8895_'s optimized intelligent power control makes reasonable use of limited USB or adapter power. The battery charging current is independent of the SYS_ input current limit, and the battery is charged under the premise of ensuring system power supply. The automatic input selection switch controls the connection between the system, battery, and external power supply. This allows the system to work normally without battery power or when the battery is completely discharged or discarded.

Other features include undervoltage lockout (UVLO), overvoltage protection (OVP), charge status indication, charge fault indication, power-good monitoring, battery temperature monitoring, charge timer and 3.3V output.

The MAX8895_ operates from a +4.0V to +6.6V supply with overvoltage protection up to +16V. The MAX8895_ operates over the extended temperature range (-40°C to +85°C) and is available in a compact 2.36mm x 2.36mm, 25-bump WLP package (0.4mm bump pitch).

Key Features

● Automatically detect adapter type

● Enumeration function does not require processor intervention

● USB low-speed operation without external crystal (MAX8895W/MAX8895X)

● USB full speed operation, using external crystal oscillator (MAX8895Y)

● Comply with USB 2.0 specification

● Comply with USB charging specification (version 1.1)

● Adaptive input current limit adjustment for dedicated chargers

● Up to 16V input overvoltage protection

● Automatically distributes current between battery charging and system power supply

Smart Power Selector™ allows operation even when the battery is fully discharged or no battery is inserted

● NTC monitors battery temperature

● No external MOSFET required

Thermal management to prevent overheating

● 2µA shutdown current

● Tiny 2.36mm x 2.36mm, 25-bump, 0.4mm pitch WLP package

application

● Bluetooth® headset

Charging stand

Portable devices