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.
The five GPIO ports function as logic inputs, open-drain 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 MAX6948B features shutdown and standby modes for low-power dissipation. The constant-current drivers contain programmable PWM outputs and allow staggering to reduce the input peak-current requirements. The I/O ports also feature ramp-up and ramp-down controls.
The MAX6948B features a single input to select from four I²C slave addresses. Programming and functionality for the five GPIO ports is identical to the MAX6946/MAX6947 I/O expanders.
The MAX6948B is available in a 25-bump (2.31mm x 2.31mm) WLP package for cell phones, PDAs, and other portable consumer electronic applications. The MAX6948B operates over the -40°C to +105°C temperature range.
关键特性
应用/使用
28V Step-Up DC-DC Converter with Integrated nMOS Power Switch
Built-In 10-Bit PWM Control for Improved Efficiency
No Discharge Path During PWM Off Period for Increased Battery Life
Fixed 2MHz Switching for Smaller Components
Drives up to 6 Series WLEDs
±8kV Human Body Model (HBM) ESD Protection for GPIOs and Boost-Converter Output
Five Open-Drain GPIOs Capable of Constant-Current LED Drive with Individual 8-Bit PWM Intensity Control
2.7V to 5V Power-Supply Operation
Register Compatible with MAX6946/MAX6947 GPIO Port Expanders
400kbps, 5.5V Tolerant I²C Interface
Four I²C Slave Address Choices
Active-Low RST Input Clears Serial Interface and Exits Shutdown (Reset-Run Option)
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