Low-Profile Inductorless Charge-Pump IC Suits Cell Phones

Aug. 7, 2000

The CMOS SP6680 inductorless dc-dc charge-pump IC provides buck/boost performance with up to 96% efficiency. Ceramic capacitors replace large, bulky coils and expensive tantalum capacitors. The IC also boasts a switched multicapacitor topology. Thanks to these components, the SP6680 is packaged in a 10-pin plastic MSOP that measures just 0.118 by 0.116 by 0.040 in.

Designed by Sipex Corp. for appliances with limited space requirements, the SP6680 suits next-generation cellular phones, PDAs, MP3 players, and digital cameras. It's ideal for converting a 3.6-V Li-ion battery input to a 5.0-V regulated output. It can accept an input voltage ranging from 2.7 to 6.5 V and convert it to a pre-regulated output of 5.4 to 6.0 V. Its maximum power dissipation is 720 mW, derated at 8.84 mW/°C above a temperature of 70°C.

"The SP6680 can provide the same efficiency as coil-based circuits, but in less space and at a reduced cost," claims Tim Goodrow, Sipex's director of marketing for power management products. It supplies a regulated 5-V output at 60 mA. Rated for a quiescent current of 100 µA, it consumes only 4 µA in the shutdown mode.

This IC consists of seven major functional circuits: a voltage reference, a clock manager, a pump-switch configuration-control circuit, clock-phase control circuitry, output-voltage control, clock-phase drivers, and charge-pump switches. It operates at three different switching frequencies corresponding to three different output resistances and load-current ranges.

An external 32.768-kHz nominal clock signal is necessary to drive this device. The SP6680 also requires only two external capacitors. Typical applications use 3.3-µF capacitors. Its operating temperature ranges from −40°C to 85°C. Two control inputs can adjust the internal pump frequency on-the-fly. This can be set to the nominal frequency, or to one quarter or eight times the nominal frequency.

The SP6680 is available from stock. It starts at $1.07 each in 10,000-piece quantities. Samples also are available.

Sipex Corp., 22 Linnell Circle, Billerica, MA 01821; (978) 671-1907; fax (978) 670-9001; www.sipex.com.

About the Author

Roger Allan

Roger Allan is an electronics journalism veteran, and served as Electronic Design's Executive Editor for 15 of those years. He has covered just about every technology beat from semiconductors, components, packaging and power devices, to communications, test and measurement, automotive electronics, robotics, medical electronics, military electronics, robotics, and industrial electronics. His specialties include MEMS and nanoelectronics technologies. He is a contributor to the McGraw Hill Annual Encyclopedia of Science and Technology. He is also a Life Senior Member of the IEEE and holds a BSEE from New York University's School of Engineering and Science. Roger has worked for major electronics magazines besides Electronic Design, including the IEEE Spectrum, Electronics, EDN, Electronic Products, and the British New Scientist. He also has working experience in the electronics industry as a design engineer in filters, power supplies and control systems.

After his retirement from Electronic Design Magazine, He has been extensively contributing articles for Penton’s Electronic Design, Power Electronics Technology, Energy Efficiency and Technology (EE&T) and Microwaves RF Magazine, covering all of the aforementioned electronics segments as well as energy efficiency, harvesting and related technologies. He has also contributed articles to other electronics technology magazines worldwide.

He is a “jack of all trades and a master in leading-edge technologies” like MEMS, nanolectronics, autonomous vehicles, artificial intelligence, military electronics, biometrics, implantable medical devices, and energy harvesting and related technologies.