Step-Down Switching Regulator consumes as little as 2.8 µA.November 27, 2009 -
Supplied in 10-lead, 3 x 3 mm DFN or thermally enhanced MSOP packages, LT3991 offers 4.3-55 V input range, integrated boost diode, and Burst Mode® operation that keeps quiescent current under 2.8 µA in no-load standby conditions. Internal 1.7 A, 440 mOhm switch delivers up to 1.2 A continuous output current to voltages as low as 1.19 V, and switching frequency is user-programmable from 200 kHz to 2 MHz. Features include ripple below 15 mVpk-pk, current mode topology, and soft-start.
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Original Press release
Linear Technology Corp.
1630 McCarthy Blvd.
Milpitas, CA, 95035
USA
55V, 1.2A (IOUT) Step-Down DC/DC Converter with Only 2.8µA Quiescent Current
MILPITAS, CA - November 24, 2009 - Linear Technology Corporation announces the LT3991, a 1.2A, 55V step-down switching regulator with an integrated boost diode. Its Burst Mode® operation keeps quiescent current under 2.8µA in no load standby conditions. The LT3991's 4.3V to 55V input voltage range makes it ideal for automotive and industrial applications. Its internal 1.7A switch can deliver up to 1.2A of continuous output current to voltages as low as 1.19V. The LT3991's Burst Mode operation offers ultralow quiescent current, making it well suited for applications such as automotive or industrial systems that demand always-on operation and optimum battery life. Switching frequency is user programmable from 200kHz to 2MHz, enabling the designer to optimize efficiency while avoiding critical noise-sensitive frequency bands. The combination of its 10-lead 3mm x 3mm DFN or thermally enhanced MSOP packages and high switching frequency keep external inductors and capacitors small, providing a compact, thermally efficient footprint.
The LT3991 utilizes a high efficiency 1.7A, 440mOhm switch, with the necessary boost diode, oscillator, control and logic circuitry integrated into a single die. Low ripple Burst Mode operation maintains high efficiency at low output currents while keeping output ripple below 15mVPK-PK. Special design techniques and a new high voltage process enable high efficiency over a wide input voltage range, and the LT3991's current mode topology enables fast transient response and excellent loop stability. Other features include a power good flag, soft-start capability, external clock synchronization and internal compensation.
The LT3991EDD is packaged in a 3mm x 3mm DFN-10, and the LT3991EMSE is packaged in a thermally enhanced MSOP-10, priced starting at $2.95 each for 1,000 piece quantities. The LT3991IDD and LT3991IMSE are tested and guaranteed to operate from a -40ºC to 125ºC operating junction temperature and are priced at $3.28 each in 1,000 piece quantities. All versions are available from stock. For more information, visit www.linear.com.
Summary of Features: LT3991
Ultralow Quiescent Current:
2.8µA IQ Regulating 12VIN to 3.3VOUT
Low Ripple Burst Mode® Operation:
Output Ripple < 15mVP-P
Wide Input Voltage Range: 4.3V to 55V
1.2A Maximum Output Current
Adjustable Switching Frequency: 200kHz to 2MHz
Synchronizable Between 250kHz to 2MHz
Fast Transient Response
Accurate 1V Enable Pin Threshold
Low Shutdown Current: IQ = 700nA
Power Good Flag
Soft-Start Capability
Internal Compensation
Saturating Switch Design: 0.44Ohm On-Resistance
Output Voltage: 1.19V to 30V
Small Thermally Enhanced 10-Pin MSOP Package & (3mm x 3mm) DFN Packages
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, µModule® products, 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.
LT, LTC, LTM, µModule, Burst Mode and are registered trademarks of Linear Technology Corp. All other trademarks are the property of their respective owners.
Contacts
North America and General Information
John Hamburger
Tel: (408) 432-1900 ext. 2419
jhamburger@linear.com
Doug Dickinson
Tel: (408) 432 1900 ext. 2233
ddickinson@linear.com
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