MAX6948B

The MAX6948B general-purpose input/output (GPIO) peripheral drives a series string of white LEDs (WLEDs),and contains up to five general-purpose input/output (GPIO) ports to drive additional LEDs.The integrated 2MHz boost converter minimizes the size and cost of external components and supplies 30mA of load current at up to 28V. The converter is stable under all load conditions from 5V up to 28V and includes open-circuit detection to prevent damage to the IC. An I2C-programmable 10-bit pulse-width modulation (PWM) signal enables 1024 levels of WLED intensity.

Features of the MAX6948B are:(1)28V step-up DC-DC converter with integrated nMOS power switch; (2)built-in 10-bit PWM control for improved efficiency; (3)no discharge path during PWM off period for increased battery life; (4)fixed 2MHz switching for smaller components drives up to 6 series WLEDs; (5)five open-drain GPIOs Capable of Constant-Current LED drive with individual 8-bit PWM intensity control; (6)2.7V to 5V power-supply operation.The five GPIO ports function as logic inputs, opendrain logic outputs, or constant-current sinks in any combination. Ports withstand 5.5V independent of the MAX6948B's supply voltage. Two of the ports drive additional LEDs up to 30mA/port, while the other three ports drive LEDs at up to 10mA/port.

The absolute maximum ratings of the MAX6948B can be summarized as:(1)V+ to GND:-0.3V to +6V;(2)storage temperature range:-65 to +150;(3)operating temperature range:-40 to +105;(4)junction temperature:+150;(5)PGND to GND:-0.3V to +0.3V;(6)total GND current:150mA.Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; functional operation of the device at these or any other conditions above those indicated in the operational section of this specification is not implied.Exposure to absolute maximum rating conditions for extended periods may affect device reliability.The MAX6948B general-purpose input/output (GPIO) peripheral with integrated boost converter provides a boost converter capable of driving 6 WLEDs and five I/O ports capable of driving LEDs powered from an alternate power supply such as the Li+ battery. The integrated 2MHz boost converter minimizes the size and cost of external components and supplies 30mA of load current at up to 28V. The feedback input to the error amplifier has a typical set point of 0.1V to minimize power dissipation.