Press Release

Contact Doug Dickinson

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

Mar 10 2014 - MILPITAS, CA
  • 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.

    Complete Ride-Through DC/DC System IC

    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 × 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

    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 × 0.75mm QFN Package


    Download PDF version

  • About Analog Devices
  • Innovation, performance, and excellence are the cultural pillars on which Analog Devices has built one of the longest standing, highest growth companies within the technology sector. Acknowledged industry-wide as the world leader in data conversion and signal conditioning technology, Analog Devices serves over 60,000 customers, representing virtually all types of electronic equipment. Analog Devices is headquartered in Norwood, Massachusetts, with design and manufacturing facilities throughout the world. Analog Devices is included in the S&P 500 Index.
  • Editor's Contact Information
Stay Informed