72V Fixed-Ratio DC/DC Controller Eliminates Power Inductor

The LTC7820 fixed ratio charge pump DC/DC controller eliminates the power inductor in a non-isolated intermediate bus converter, allowing up to a 50% reduction in circuit size and up to 4000W/in³ power density. The device drives external MOSFETs in voltage divider, doubler or inverter configurations with an efficiency of up to 99%. Its open loop fixed duty makes it desirable for non-isolated intermediate bus applications in power distribution, datacom, telecom, high-end computing and industrial systems. The LTC7820 operates over a 6V to 72V (80V abs max) input voltage range and can produce output currents in multiple tens of amps, depending on the topology and choice of external components. It can be configured for a 2:1 step-down ratio from an input voltage up to 72V. Two of the LTC7820 IC’s can be cascaded for a 4:1 step-down ratio. For even higher step-down ratios, such as a 6:1, the Dickson converter topology is recommended and is viable for 54V input to a 9V outputs, requiring only a single LTC7820. The controller can also be configured for a 1:2 step-up ratio or a 1:1 inverter ratio from an input voltage as high as 36V. External MOSFETs switch at a fixed frequency, programmable from 100kHz to 1MHz. The LTC7820’s powerful 1.1Ω N-channel MOSFET gate drivers maximize efficiency and can drive multiple MOSFETs in parallel for higher power applications. The LTC7820 is available in a 4 mm x 5 mm QFN-28 package. Extended and industrial temperature versions are available from –40°C to +125°C. Price starts at $4.70 each/1,000. For more information, visit http://www.linear.com/product/LTC7820.


Linear Technology Corp.

Milpitas, CA.




Analog Devices Inc.

Norwood, MA