Controller starts without external regulation

Edited by the Electronicstalk editorial team May 20, 2005

The LT3800 is a current mode, high voltage step-down controller with excellent line and load regulation, along with fast transient response that operates without an auxiliary regulator for startup.

Linear Technology has introduced the LT3800, a current mode, high voltage step-down controller with excellent line and load regulation, along with fast transient response that operates without requiring an auxiliary DC/DC regulator for startup.

An integrated regulator provides IC power directly from input supply.

The LT3800 operates from 4 to 60V supplies and regulates output voltages ranging from 1.23V to 36V at load currents up to 10A.

By driving N-channel MOSFETs synchronously with maximum gate-source on voltage, this controller operates at 94% efficiency while converting 60V input to 12V at 36W output.

Moreover, the LT3800 incorporates burst mode operation, which reduces no load quiescent current to less than 100uA, a feature required in automotive maintenance power supplies.

The LT3800 has applications in 12 and 42V automotive, 48V telecomms supplies, avionics and industrial control systems.

The LT3800 operates at a 200kHz fixed frequency.

The device employs a reverse-current inhibit feature to increase efficiency during light loads.

This feature disables the synchronous switch if inductor current approaches zero.

Another feature of the LT3800 is its adaptive nonoverlap control.

Nonoverlap control maintains a constant dead time, preventing shoot-through switch currents, independent of the type, size or operating conditions of the external MOSFET switches.

The LT3800 is offered in a 16-pin thermally enhanced TSSOP and is rated for operation from -40 to +125C.

1000-piece pricing starts at $3.10.