California Micro announces low noise charge pump LED driver

Nov. 16, 2005
Date Announced: 16 Nov 2005 CM4072 PhotonIC(TM) LED Driver for Cost Sensitive Wireless Handset ApplicationsMILPITAS, Calif. -- California Micro Devices (Nasdaq: CAMD - News) today announced the CM4072, a single-chip low noise charge pump/linear regulator LED (light emitting diode) driver designed to power white LEDs to backlight TFT LCD displays in wireless handsets, PDAs and LCD modules. The CM4072 is the latest addition to the PhotonIC(TM) portfolio, a product family of highly integrated, efficient, compact and cost optimized LED drivers. The CM4072 is housed in a low profile, very small form factor 3mm x 3mm 10-lead TDFN package which makes it optimal for mobile electronics where space is critical. The CM4072 is an ideal solution for cost sensitive wireless handset platforms where superior performance is required in a tiny footprint while meeting strict cost targets.High Performance in Compact FootprintBy integrating the charge pump and linear regulator into one chip, the CM4072 is able to boost the input voltage via the charge pump circuitry and then feed it to the linear regulator to provide a constant 5V output and a continuous output current of 200mA. To control the brightness of the white LEDs, a PWM (pulse width modulation) signal is sent from the baseband processor to the enable pin of the CM4072. The charge pump operates at 250kHz which is well below the clock, cellular and PCS frequencies in wireless handsets.The CM4072 features are the following: -- Stable, low noise 5V output -- Wide input voltage range: 3V to 5V -- Up to 200mA of continuous output current -- Up to 83% efficiency -- 42dB PSRR over 100Hz to 30kHz frequency range -- Low operating current (180uA) for power saving -- Low shutdown modes to extend battery life -- Dual enable pins allow separate control of charge pump and LDO regulators for faster startup from sleep modes -- Overcurrent and over-temperature protection -- Stable with low ESR ceramic or tantalum capacitors -- requires 2 external capacitors -- Very small 3mm x 3mm 10-lead TDFN package for portable applicationsApplicationsThe CM4072 with an output voltage of 5V is able to support LEDs with forward voltages ranging from 2.2V to 4.0V. Typical wireless handsets use about 3 to 4 white LEDs to backlight the main TFT LCD displays where each LED has a maximum of 25mA applied to it. Since the CM4072 can deliver up to 200mA of current, it can easily support 5 WLEDs at 25mA each to backlight higher resolution, larger size QVGA TFT LCD displays. It can also be used in camera phones where a high brightness camera flash LED is used. The CM4072 can either drive three white LEDs with a maximum current of 65mA each or a single high brightness camera flash LED at 200mA. With the popularity of camera phones, two CM4072 LED drivers can be used in designs where one is in or near the LCD module and the other is placed near the camera module.Pricing and AvailabilityThe CM4072 is available for sampling and are priced at $0.69 each in 1,000 units. Volume production is scheduled for December 2005.

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