75V Boost DC/DC Converter with Fixed Voltage Drop APD Current Monitor

News Release ⎜ www.linear.com
75V Boost DC/DC Converter with
Fixed Voltage Drop APD Current Monitor
MILPITAS, CA – February 18, 2009 – Linear Technology announces the LT3571, a fixed
frequency, current mode step-up DC/DC converter with an integrated high-side avalanche
photodiode (APD) current monitor. The device can deliver output voltages up to 75V from
inputs ranging from 2.7V to 20V, making it ideal for a wide array of fiber optic applications. The
LT3571 features a high-side fixed voltage drop APD current monitor, providing better than 10%
relative accuracy over the -40◦C to 125◦C temperature range. The fixed 5V (+ 5%) drop across
the current monitor is unique to the LT3571 and enables higher data bandwidths in many fiber
optic applications. The power switch, Schottky diode and APD current monitor are integrated
into a single IC that is packaged in a 3mm x 3mm QFN, providing a tiny solution footprint.
The LT3571’s internal 75V, 350mA switch offers output voltages as high as 75V. Its
switching frequency can be programmed between 250kHz and 2MHz, enabling the designer to
optimize efficiency while minimizing the size of the external components. Constant frequency
architecture is used to keep output ripple below 500uVPK-PK, which is critical in most APD
applications. To further reduce noise concerns, the LT3571 is externally synchronizable. The
LT3571 combines a traditional voltage loop and a unique current loop design to operate as a
constant current source or constant voltage source, providing both excellent transient response as
well as APD protection. It is equipped with both a 1.222V internal reference and an auxiliary
reference input (via the CNTRL pin), enabling the output voltage to be adjusted while the chip is
operating without any polarity inversion. Other features include soft-start, internal compensation
and thermal shutdown.
The LT3571EUD is available in a 3mm x 3mm QFN-16 and is priced at $2.45 each in
1,000-piece quantities. An industrial grade version, the LT3571IUD, is tested and guaranteed to
operate from a -40°C to 125°C operating junction temperature and is priced at $2.72 each in
1,000-piece quantities. Both versions are available from stock. For more information, visit
75V Boost DC/DC Converter with
Fixed Voltage Drop APD Current Monitor
page 2
Photo Caption: 75V Boost Converter with APD Current Monitor
Summary of Features: LT3571
High Output Voltage: Up to 75V
Integrated Schottky Diode
75V, 350mA Internal Switch
High Side Fixed Voltage Drop APD Current Monitor
Adjustable Frequency: 250kHz to 2MHz
Frequency Synchronization
Wide VIN Range: 2.7V to 20V
Constant-Voltage and Constant-Current Regulation
Programmable Current Limit Protection
Surface Mount Components
Low Shutdown Current <1uA
Internal Soft-Start
Internal Compensation
CTRL Pin Allows Output Adjustment with No Polarity Inversion
3mm × 3mm 16-Lead QFN 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,
uModule™ 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 and
are registered trademarks and uModule is a trademark of Linear Technology Corp. All other
trademarks are the property of their respective owners.
Press Contacts:
John Hamburger, Director Marketing Communications
[email protected]
Tel: 408-432-1900 ext 2419
Doug Dickinson, Media Relations Manager
[email protected]
Tel: 408-432-1900 ext 2233