36V, 800mA linear regulator features an extended SOA

The LT3089 uses a current source reference for single resistor output voltage settings and output adjustability down to 0V. Output current limit can be set externally with a single resistor. This regulator architecture, combined with low millivolt line and load regulation, enables multiple ICs to be parallelled 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 LT3089 increases its current to compensate for line drops.

The LT3089 achieves unmatched line and load regulation of under 2mV, independent of output voltage and features an input voltage range from 1.2 to 36V. The device fits well in applications requiring multiple rails. Output voltage is programmable with a single resistor from 0 to 34.5V with a 1.2V dropout. The on-chip trimmed 50µA current reference is ±1% accurate. The regulation, transient response and output noise (27µV_RMS) are independent of output voltage due to the device’s voltage follower architecture. The LT3089 is configurable as a 2-terminal current source using only two resistors. Input or output capacitors for stability are optional in either linear regulator mode or current-source mode of operation.

The LT3089 provides several monitoring and protection functions. Current limit can be programmed with a single resistor. Monitor outputs provide a current output proportional to temperature (1µA/°C) and output current (200µA/A), allowing easy ground-based measurement. The current monitor can be used to compensate for cable drops. The LT3089’s internal protection circuitry includes reverse input protection, reverse-current protection, internal current limiting and thermal shutdown.

Robert Dobkin, CTO and Vice President, Engineering, Linear Technology, commented: “The LT3089 regulator’s robust architecture, protection and monitoring features provide designers with new tools for reliable designs. A DD-Pak package for high power dissipation and various surface mount packages for lower power applications are available. System power and temperature are easily checked for proper operation.”

The LT3089 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. A wide variety of grades/temperature ranges are offered including: E and I grades (-40 to +125°C), H grade (-40°C to +150°C) and the high reliability MP grade (-55°C to +150°C). Pricing starts at $2.13 each for the E grade in 1,000 unit quantities.