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Overview
California Micro Devices introduces the
new CM4072, a single-chip LED driver designed to power white LEDs
to backlight TFT LCD display in wireless handsets, PDAs and LCD modules.
The CM4072, part of CMD's PhotonIC™ family, comprises
a low noise charge pump and linear regulator housed in a compact 3mm
x 3mm 10-lead TDFN package. The CM4072's very small package size make
it optimal for mobile applications where space is critical. The CM4072
satisfies the need for superior performance, a compact footprint and
a pricepoint demanded by the cost-driven wireless device marketplace.
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Features
The CM4072 integrates a charge pump and
linear regulator into one package. The charge pump boosts the input
voltage which is then fed to the linear regulator to produce 5V
with an output current of 200mA. The ENABLE input can be used to
control the LED brightness by modulating it with a PWM (pulse width
modulated) signal from the baseband processor. The charge pump operating
frequency of 250kHz is well below the clock, cellular and PCS frequencies
in wireless handsets minimizing the chance for any interference
from the CM4072.
CM4072 Typical Application
The CM4072's features include:
- Stable and 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 (180µA)
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
- Over-current and over-temperature
protection
- Stable with low ESR ceramic
or tantalum capacitors – requires 2 external capacitors
to power CM4072
- Very small 3mm x 3mm 10-lead
TDFN package for portable applications
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Product
Applications
LCD Backlight
Applications
The CM4072 is ideal for LED driver applications. These include:
- White backlight LEDs for main display in
wireless handsets and LCD modules,
- Power flash LEDs for camera phones.
The CM4072 with an output voltage of
5V is able to support LEDs that have forward voltages that range
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 and 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 these designs where one is
in or near the LCD module while the other is placed near the camera
module.
Suitable For
Other Applications
The CM4072 is ideal for
other applications requiring stable, low noise regulated voltage
conversion, such as:
- 3.3V to 5V conversion in PCMCIA cards,
PCI Express Cards, other applications needing 5V,
- 5V analog supply for audio CODEC in notebook
computers, PDAs, MP3 players, etc.
Sampling,
Pricing and Availability
The 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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