The MAX8822 drives up to four white light-emitting diodes (LEDs) with regulated constant current for display backlighting in cell phones, digital cameras, PDAs, and other handheld devices. By utilizing a proprietary negative 0.5x inverting charge pump and innovative independent low-dropout (LDO) adaptive current regulators, very high efficiency is achieved over the full 1-cell Li+ battery voltage range, even with large LED VF mismatch. The 1MHz fixed-frequency switching allows for tiny external components. The regulation scheme is optimized to ensure low EMI and low input ripple. Two 200mA, low-noise, high power-supply-rejection-ratio (PSRR) LDOs with programmable output voltages are included on-chip to provide power to camera modules or other devices.
The MAX8822 features a single-wire, serial-pulse control-logic interface that programs LED current and the output voltages of the LDOs. The LED dimming range is pseudo-logarithmic from 24mA to 0.1mA in 31 steps. LDO output voltages are programmable in 16 different combinations to meet various camera module requirements.
The MAX8822 includes soft-start, thermal shutdown, open- and short-circuit protection.
Key Features
Applications/Uses
High-Efficiency Charge Pump for Up to Four White LEDs
Independent Adaptive Voltage Supply for Each LED
24mA to 0.1mA Dimming Range
1% (typ) Current Accuracy and 0.3% Current Matching
Low 65µA (typ) Quiescent Current
Dual 200mA Low-Noise, High PSRR LDOs
16 Different Output Voltage Combinations Up to 3.3V
High 60dB PSRR at 10kHz
Flexible Single-Wire Control for Dimming and LDO Output Voltage
Low 0.5µA (typ) Shutdown Mode
Soft-Start Limits Inrush Current
Thermal Shutdown and Open- and Short-Circuit Protection
Tiny 16-Pin, 3mm x 3mm Thin QFN Package (0.8mm max Height) with Exposed Paddle
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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