65V, 3.5A/5A Peak (IOUT), Synchronous Step-Down Silent Switcher Delivers 94% Efficiency at 2MHz & Ultralow EMI Emissions

News Release  www.linear.com
65V, 3.5A/5A Peak (IOUT), Synchronous Step-Down Silent Switcher Delivers
94% Efficiency at 2MHz & Ultralow EMI Emissions
MILPITAS, CA – February 25, 2016 – Linear Technology Corporation announces the LT8641, a
3.5A, 65V input capable synchronous step-down switching regulator. A unique Silent Switcher®
architecture, combined with spread spectrum frequency modulation, reduces EMI/EMC
emissions by more than 25dB even with switching frequencies in excess of 2MHz, enabling it to
easily pass the automotive CISPR25 class 5 peak and average limits. Synchronous rectification
delivers efficiency as high as 94% with a switching frequency of 2MHz. Its 3V to 65V input
voltage range makes it ideal for single or dual cell automotive/transportation and industrial
The LT8641's internal high efficiency switches deliver up to 3.5A of continuous output
current and peak loads of 5A to voltages as low as 0.81V. The device's Burst Mode® operation
keeps quiescent current under 2.5µA in no load standby conditions, making it well suited for
applications such as automotive "always-on" systems, which need to extend operating battery
life. The LT8641's unique design maintains a minimum dropout voltage of only 130mV at 1A
under all conditions, enabling it to excel in scenarios such as automotive cold crank.
Furthermore, a fast minimum on-time of only 35ns enables 2MHz constant frequency switching
from a 24V input to a 3.3V output, equipping designers to optimize efficiency while avoiding
critical noise sensitive frequency bands. The LT8641's 18-lead 3mm x 4mm QFN package and
high switching frequency keep external inductors and capacitors small, providing a compact,
thermally efficient footprint.
The LT8641 utilizes internal top and bottom high efficiency power switches 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 10mVP-P. Special design techniques and a new high speed process enable high
efficiency over a wide input voltage range, and the LT8641’s current mode topology enables fast
65V, 3.5A/5A Peak (IOUT), Synchronous Step-Down Silent Switcher Delivers
94% Efficiency at 2MHz & Ultralow EMI Emissions
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transient response and excellent loop stability. Other features include internal compensation, a
power good flag, output soft-start/tracking and thermal shutdown.
The LT8641EUDC is packaged in a 3mm x 4mm QFN package. An industrial
temperature version, the LT8641IUDC, is tested and guaranteed to operate from a –40°C to
125°C operating junction temperature. Pricing starts $4.35 each in 1,000-piece quantities and
both versions are available from stock. For more information, visit
Photo Caption: 65V, 3.5A(IOUT), 2.2MHz Synchronous Step-Down Reduces EMI/EMC
Emissions by Over 25dB
Summary of Features: LT8641
Silent Switcher® Architecture
o Ultralow EMI/EMC Emissions
o Spread Spectrum Frequency Modulation
High Efficiency at High Frequency
o Up to 95% Efficiency at 1MHz
o Up to 94% Efficiency at 2MHz
Wide Input Voltage Range: 3V to 65V
Ultralow Quiescent Current Burst Mode® Operation
2.5µA IQ Regulating 12VIN to 3.3VOUT, Output Ripple < 10mVP-P
Fast Minimum Switch-On Time: 35ns
Low Dropout Under All Conditions: 130mV at 1A
Safely Tolerates Inductor Saturation in Overload
Adjustable & Synchronizable: 200kHz to 3MHz
Peak Current Mode Operation
Internal Compensation
Output Soft-Start & Tracking
Small 18-Lead 3mm × 4mm QFN
Pricing shown is for budgetary use only and may differ due to local duties, taxes, fees and
exchange rates.
65V, 3.5A/5A Peak (IOUT), Synchronous Step-Down Silent Switcher Delivers
94% Efficiency at 2MHz & Ultralow EMI Emissions
page 3
About Linear Technology Linear Technology Corporation, a member of the S&P 500, has been designing, manufacturing and marketing a broad line of high performance analog integrated circuits for major companies worldwide for over three decades. The Company’s products provide an essential bridge between our analog world and the digital electronics in communications, networking, industrial, automotive, computer, medical, instrumentation, consumer, and military and aerospace systems. Linear Technology produces power management, data conversion, signal conditioning, RF and interface ICs, µModule® subsystems, and wireless sensor network products. For more information, visit www.linear.com
, LT, LTC, LTM, Linear Technology, the Linear logo, Burst Mode, Silent Switcher and µModule are registered
trademarks of Linear Technology Corp. All other trademarks are the property of their respective owners.
Press Contacts:
North America / Worldwide
UK & Nordic
John Hamburger, Director Marketing
[email protected]
Tel: 408-432-1900 ext 2419
Alan Timmins
[email protected]
Tel: +44-1-252-629937
Doug Dickinson, Media Relations Manager
[email protected]
Tel: 408-432-1900 ext 2233