The MAX1848 drives white LEDs with a constant current to provide backlight in cell phones, PDAs, and other hand-held devices. The step-up converter topology allows series connection of the white LEDs so that the LED currents are identical for uniform brightness. This configuration eliminates the need for ballast resistors and expensive factory calibration. Other benefits include greater simplicity, lower cost, higher efficiency, and greater reliability.
This step-up PWM converter includes an internal, high-voltage, low RDSON N-channel MOSFET switch for high efficiency and maximum battery life. A single analog voltage Dual Mode™ input provides a simple means of brightness adjustment and on/off control. Fast 1.2MHz current-mode PWM control allows for small input and output capacitors and a small inductor while minimizing ripple on the input supply/battery. Programmable soft-start eliminates inrush current during startup.
The MAX1848 is available in space-saving 8-pin thin QFN (3mm x 3mm) and 8-pin SOT23 packages.
Key Features
Applications/Uses
Constant Current Regulation for Uniform Illumination
High 87% Efficiency
Analog or Logic Control of LED Intensity
0.8W Output Power with Internal High-Voltage MOSFET Switch
Small, Low-Profile External Components
2.6V to 5.5V Input Range
13V Maximum Output with Overvoltage Protection
Optimized for Low Input Ripple
Programmable Soft-Start
0.3µA Shutdown Current
Small 8-pin Thin QFN (3mm x 3mm) and
8-Pin SOT23 Packages
Notes: **This pricing is BUDGETARY, for comparing similar parts. Prices are in
U.S. dollars and subject to change. Quantity pricing may vary
substantially and international prices may differ due to local
duties, taxes, fees, and exchange rates. For volume-specific prices
and delivery, please see the price and availability page
or contact an authorized distributor.
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