PRELIMINARY
CALIFORNIA MICRO DEVICES
CM3702
Micropower Low-Noise Charge-Pump and Linear Regulator
Features
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Low noise regulator with integrated charge
pump voltage-booster
5V output with input voltage as low as 2.8V
Charge pump can also power external LDO
Low noise in 20Hz to 20kHz audio band
Up to 200mA continuous output current
Low operating and shutdown currents
Stable with low-ESR ceramic or tantalum
capacitors
10-Lead MSOP and TDFN packages
Lead-free finishing
Block Diagram
Applications
5V analog supply for audio codec in notebook
computers, PDAs, MP3 players, etc.
3.3V to 5V conversion in PCMCIA cards, PCI
Express Cards, other applications needing 5V
Product Description
The CM3702 low-noise charge pump LDO regulator is designed to provide accurate and “clean” power to a
subsystem, e.g an audio codec, LED driver, or flash memory. The 5V output provides up to 100mA continuous
current for input voltages from 2.8V to 5.5V, and up to 200mA for a narrower range. This is accomplished with an
integrated charge pump that boosts the input voltage before feeding it to an internal LDO linear regulator. The
charge pump is designed to maintain a nominal 0.8V differential between the input and output of the LDO
regulator. This allows the LDO regulator to operate with good power supply ripple rejection across the audio band
while maintaining good power efficiency. The charge pump works with two external capacitors and operates at
250kHz, well outside the audible frequency band. In addition, separate analog and digital ground pins are
provided for the charge pump and the rest of the circuitry to eliminate ground noise feed-through from the charge
pump to the regulated output.
The CM3702 is fully protected, offering both overload current limiting and high temperature thermal shutdown.
Two enable inputs provide flexibility in powering down the device. For maximum power saving in shutdown, both
the charge pump and LDO regulator should be disabled. For applications that require the 5V output to be re-
established with minimum delay after shutdown, the charge pump can be left enabled while the regulator is
disabled. This avoids the delay that may otherwise be required for the charge pump to reach full operating
voltage after being disabled. The CMOS LDO regulator features low quiescent current even at full load, making it
very suitable for power sensitive applications.
A bandgap reference bypass pin is provided to further minimize noise by connecting an external capacitor
between this pin and ground. Another, external, regulator can be connected to the charge pump output pin Cs, if
required.
The CM3702 is available in 10-pin MSOP and TDFN packages, both with optional lead-free finishing, and are
ideal for space critical applications.
STANDARD PART ORDERING INFORMATION
Standard Finish
Pins
10
10
Package
MSOP-10
TDFN-10
Ordering Part
Number
CM3702-50MR
CM3702-50DF
Part Marking
3702 50S
CM370 250DF
Lead-free Finish
Ordering Part
Number
CM3702-50MS
CM3702-50DE
Part Marking
3702 50
CM370 250DE
© 2004 California Micro Devices Corp. All rights reserved.
9/22/04
430 N. McCarthy Blvd, #100, Milpitas , CA 95035
Tel: (408) 263-3214
Fax: (408) 263-7846
www.calmicro.com
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CALMIRCO [ CALIFORNIA MICRO DEVICES CORP ]
