Controller cuts step-up designs down in size

Edited by the Electronicstalk editorial team Dec 25, 2007

The LTC3813 can regulate output voltages up to 100V and has powerful 1ohm onboard dual N-channel MOSFET gate drivers that are capable of supplying high currents.

New from Linear Technology, the LTC3813 is a synchronous no-sense-resistor step-up switching regulator controller that eliminates the boost diode and the heatsink normally required in medium to high power nonsynchronous boost convertors.

The LTC3813 can regulate output voltages up to 100V and has powerful 1ohm onboard dual N-channel MOSFET gate drivers that are capable of supplying high currents to slew large MOSFET gates quickly.

This minimises transition losses and allows paralleling of MOSFETs for higher current applications.

In addition, the LTC3813 can regulate a 50V at 4A output with up to 97% efficiency from a 10 to 40V input source.

Applications include automotive, avionics, telecomms, networking equipment, servers, industrial control systems and basestations where a step-up DC/DC convertor must deliver high power with low heat dissipation in a small solution sise.

The LTC3813 uses current mode control and maintains +/-0.875% reference voltage accuracy over an operating temperature range of -40 to +85C.

Furthermore, this part uses a constant off-time peak current control architecture and has a high bandwidth (25MHz) error amplifier that provides very fast line and load transient response.

The constant off-time current mode architecture provides accurate cycle-by-cycle current limit protection; a feature that is essential to protect high voltage outputs from over-current conditions.

The operating frequency is selected by an external resistor from 100kHz to 1MHz which is also compensated for input-voltage variations and can be synchronised to an external clock for noise sensitive applications.

Moreover, this part has a programmable soft-start, programmable undervoltage lockout and a power good signal that monitors the output voltage.

The LTC3813 is offered in the SSOP-28 package which provides three unconnected pins between adjacent high and low voltage pins for extra PC board trace clearance, compliant with circuit board design standard IPC-2221 regarding high voltage pin spacing.

Pricing for 1000-piece quantities begins at US $3.75 each.