500mA Standalone Li-Ion Battery Charger plus Synchronous Buck Converter in 3mm x 3mm DFN

LTC News for Immediate Release
For more information, tel. 408-432-1900
Doug Dickinson, Media Relations Mgr., ext. 2233
John Hamburger, Dir., Mkting Comm., ext. 2419
500mA Standalone Li-Ion Battery Charger plus
Synchronous Buck Converter in 3mm x 3mm DFN
MILPITAS, CA – June 15, 2006 – Linear Technology Corporation introduces the
LTC4080, a multi-function IC featuring a standalone linear battery charger and a highly-efficient
synchronous buck converter. The USB-compatible battery charger can charge a single-cell
Li-Ion battery up to 500mA without overheating the device or surrounding components. The
300mA buck converter features selectable mode operation and synchronous rectification to
achieve efficiencies up to 96%. The device is designed to work with supplies up to 5.5V,
including those within USB specifications and from 5V wall adapters. Its 3mm x 3mm DFN
package ensures a tiny solution footprint for space-constrained, smaller battery capacity powered
handheld applications such as wireless headsets, Bluetooth devices, portable MP3 players, and
multi-function wristwatches.
The LTC4080’s battery charger requires no external MOSFET, sense resistor or blocking
diode. A patented thermal regulation scheme prevents the junction temperature of the IC from
exceeding 115°C by reducing charge current during high power or high ambient temperature
operation. This fully-featured charger offers timer termination, recharge, and C/10 detection.
Other features of the LTC4080 include a charge status indicator, a 4.2V 0.5% accurate float
voltage, 5% charge accuracy, and an open drain AC Present status pin to indicate the presence of
an input supply such as a wall adapter. Charge current is adjustable with a standard off-the-shelf
resistor. During shutdown, the supply current is only 5uA and battery drain current is less than
The highly-efficient synchronous step-down converter features a 2.7V to 5.5V input
operating voltage range (powered from the BAT pin) with corresponding output voltage range
from 0.8V to VBAT. Burst Mode® operation reduces supply current to only 23uA to maximize
light load efficiency, but can be disabled via an external pin in favor of fixed constant frequency
(2.25MHz) operation if very low switching noise is required.
500mA Standalone Li-Ion Battery Charger Plus
Synchronous Buck Converter in 3mm x 3mm DFN
Page 2
The LTC4080 is housed in a tiny 10-lead 3mm x 3mm DFN package and is rated for
operation from -40°C to 85°C. Pricing starts at $1.90 each in 1,000-piece quantities.
Photo Caption: Standalone Li-Ion Charger with Synchronous Buck Converter
Summary of Features: LTC4080
Standalone Linear Charger with Integrated Buck Converter in 3mm x 3mm DFN Package
Programmable Charge Current up to 500mA with ±5% Accuracy
Safety Timer Termination with C/10 Charge Current Detection Output
Thermal Regulation Maximizes Charge Rate without Risk of Overheating
Charge Status and AC Present Indicators
No External MOSFET, Sense Resistor or Blocking Diode Required
High Efficiency Synchronous Buck Converter: up to 96%
Buck Converter Output Current: 300mA
Buck Converter Input Voltage Range: 2.7V to 5.5V (powered from BAT pin)
Buck Converter Output Voltage Range: 0.8V to VBAT
Buck Mode Selection: Low Quiescent Current Burst Mode or Constant Frequency
Tiny Low-Profile (0.75mm) 10-Lead 3mm x 3mm DFN Package
About Linear Technology
Linear Technology Corporation, a manufacturer of high performance linear integrated circuits,
was founded in 1981, became a public company in 1986 and joined the S&P 500 index of major
public companies in 2000. Linear Technology products include high performance amplifiers,
comparators, voltage references, monolithic filters, linear regulators, DC-DC converters, battery
chargers, data converters, communications interface circuits, RF signal conditioning circuits, and
many other analog functions. Applications for Linear Technology’s high performance circuits
include telecommunications, cellular telephones, networking products such as optical switches,
notebook and desktop computers, computer peripherals, video/multimedia, industrial
instrumentation, security monitoring devices, high-end consumer products such as digital
cameras and MP3 players, complex medical devices, automotive electronics, factory automation,
process control, and military and space systems. For more information, visit www.linear.com
Doug Dickinson, Media Relations Manager
Linear Technology Corporation
1630 McCarthy Boulevard
Milpitas, CA 95035-7417
READER SERVICE: Call toll-free 1-800-4-LINEAR (for literature only), or go to the company’s web site:
Note: LT, LTC, LTM, Burst Mode and
are registered trademarks of Linear Technology Corp.