The MAX8822ETE+ 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 MAX8822ETE+ 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 MAX8822ETE+ includes soft-start, thermal shutdown, open- and short-circuit protection.
Feature
- 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
Applications
- Cell Phones and Smartphones
- White LED Backlighting
