Linear regulator boasts extended safe operating area

Linear Technology Corporation recently debuted a rugged 1.5A wide input voltage range linear regulator with key usability, monitoring and protection features. The LT3081 boasts an extended safe operating area (SOA) compared to existing regulators, making it ideal for high input-to-output voltage and high output current applications where older regulators limit the output.

The LT3081 uses a current source reference for single resistor output voltage settings and output adjustability down to "0." Output current limit can be set externally with a single resistor. Combined with a low millivolt regulation, this regulator architecture enables multiple ICs to be paralleled easily for heat spreading and higher output current. The current from the device's current monitor can be summed with the set current for line-drop compensation, where the output of the LT3081 increases with current to compensate for line drops.

The device achieves line and load regulation of under 2mV independent of output voltage and features an input voltage range from 1.2V to 40V. The device fits well in applications requiring multiple rails. Output voltage is programmable with a single resistor from 0V to 38.5V with a 1.2V dropout. The on-chip trimmed 50?A current reference is ±1 per cent accurate. The regulation, transient response and output noise (30?Vrms) are independent of output voltage due to the device's voltage follower architecture. The LT3081 is configurable as a 2-terminal current source with just two resistors. Input or output capacitors for stability are optional in either linear regulator or current-source mode of operation.

Linear's latest regulator provides several monitoring and protection functions. Current limit, accurate to ±10 per cent, can be programmed with a single resistor. Monitor outputs provide a current output proportional to temperature (1?A/°C) and output current (200?A/A), allowing easy ground-based measurement. The current monitor can be used to compensate for cable drops. Its internal protection circuitry includes reverse input protection, reverse-current protection, internal current limiting and thermal shutdown.

The LT3081 is offered in a variety of thermally enhanced surface-mount compatible packages, including a low profile (0.75mm) 12-lead 4x4mm DFN, a 16-lead thermally enhanced TSSOP and a 7-lead DD-Pak; all dissipate 2W in surface mount applications with no heat sink.