The MAX1802 provides a complete power-supply solution for digital still cameras and video cameras by integrating two high-efficiency step-down DC-DC converters and three auxiliary step-up controllers. This complete solution is targeted for applications that use either three to four alkaline cells or two lithium-ion (Li+) cells.
The main step-down DC-DC controller accepts inputs from 2.5V to 11V and regulates a resistor-adjustable output from 2.7V to 5.5V. It uses a synchronous rectifier to regulate the output with up to 94% efficiency. An adjustable operating frequency (up to 1MHz) facilitates designs for optimum size, cost, and efficiency.
The core step-down DC-DC converter accepts inputs from 2.7V to 5.5V and regulates a resistor-adjustable output from 1.25V to 5.5V. It delivers 500mA with up to 94% efficiency.
The three auxiliary step-up controllers can be used to power the digital camera's CCD, LCD, and backlight. The MAX1802 also features expandability by supplying power, an oscillator signal, and a reference to the MAX1801, a low-cost slave DC-DC controller that supports step-up, single-ended primary inductance converter (SEPIC), and fly-back configurations.
The MAX1802 is available in a space-saving 32-pin TQFP package (5mm x 5mm body), and the MAX1801 is available in an 8-pin SOT-23 package. An evaluation kit (MAX1802EVKIT) featuring both devices is available to expedite designs.
关键特性
应用/使用
2.5V to 11V Input Voltage Range
Main DC-DC Controller
94% Efficiency
+2.7V to +5.5V Adjustable Output Voltage
Up to 100% Duty Cycle
Independent Shutdown
Core DC-DC Converter
94% Efficiency
Up to 500mA Load Efficiency
Output Voltage Adjustable Down to 1.25V
Independent Shutdown
Three Auxiliary DC-DC Controllers
Adjustable Maximum Duty Cycle
Independent Shutdown
Power, Oscillator, and Reference Outputs to Drive External Slave Controllers (MAX1801)
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