Complete Ride-Through DC/DC IC Provides 1A of Uninterrupted Output Current from Main Input or Single Supercapacitor Backup Supply

News Release 
Complete Ride-Through DC/DC IC Provides 1A of Uninterrupted Output
Current from Main Input or Single Supercapacitor Backup Supply
MILPITAS, CA – March 10, 2014 – Linear Technology Corporation introduces the LTC3355, a
complete ride-through DC/DC system IC. The LTC3355 features a main buck regulator with a
built-in boost converter for temporary backup, or ride-through, of VOUT during a sudden loss of
VIN power from a single supercapacitor energy source. The device includes all functions
necessary to provide seamless charging of a supercapacitor (or other storage element), including
the monitoring of VIN, VOUT and VCAP and automatic switchover to backup power. The
LTC3355’s nonsynchronous constant frequency current mode monolithic 1A buck switching
regulator provides a 2.7V to 5V regulated output voltage from an input supply up to 20V. The
device is ideal for ride-through, “dying gasp” or data backup supplies commonly used in power
meters, industrial alarms and solid state drives.
The LTC3355 uses a 1A programmable constant-current/constant-voltage (CC/CV) linear
charger powered from VOUT to charge a single supercapacitor, electrolytic capacitor or NiMH
battery. A thermal regulation loop maximizes charge current while limiting the die temperature to
110°C. When the VIN supply drops below the programmable power-fail comparator input (PFI)
threshold, the device’s constant frequency nonsynchronous current mode 5A boost switching
regulator delivers power from the supercapacitor to VOUT. Backup power can be delivered to VOUT
with capacitor voltages as low as 0.5V. The device has programmable boost, charger and VIN
current limits. Other features include a VIN power fail indicator, VCAP power good indicator, and
VOUT power-on reset (POR) output.
The LTC3355 is available in a thermally enhanced 20-lead, low-profile (0.75mm)
4mm x 4mm QFN package. The device operates over a -40°C to 125°C junction temperature
range and is available from stock. Pricing starts at $3.25 each for the E grade in 1,000-piece
quantities. For more information, visit
Complete Ride-Through DC/DC IC Provides 1A of Uninterrupted Output
Current from Main Input or Single Supercapacitor Backup Supply
page 2
Photo Caption: Complete Ride-Through DC/DC System IC
Summary of Features: LTC3355
VIN Voltage Range: 3V to 20V
VOUT Voltage Range: 2.7V to 5V
1A Current-Mode Buck Main Regulator
5A Boost Backup Regulator Powered from Single Supercapacitor
Boost Regulator Operates Down to 0.5V for Maximum Utilization
of Supercapacitor Energy
Programmable Supercapacitor Charge Current to 1A with Overvoltage Protection
Charger Supports Single Cell CC/CV Battery Charging
Programmable VIN Current Limit
Programmable Boost Current Limit
VIN Power Fail Indicator
VCAP Power Good Indicator
VOUT Power On Reset Output
Compact 20-Lead 4mm × 4mm x 0.75mm QFN Package
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
, LT, LTC, LTM, Linear Technology, the Linear logo 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