40-V, 1.5-A linear regulator offers current and temperature monitor outputs
The LT3081 has 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. This regulator architecture, combined with low millivolt regulation, 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 LT3081 achieves unmatched line and load regulation of under 2 mV independent of output voltage and features an input voltage range from 1.2 V to 40 V. The device fits well in applications requiring multiple rails. Output voltage is programmable with a single resistor from 0 V to 38.5 V with a 1.2 V dropout. The on-chip trimmed 50 µA current reference is ±1% accurate. The regulation, transient response and output noise (30 µVrms) 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.
The LT3081 provides several monitoring and protection functions. Current limit, accurate to ±10%, 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 LT3081’s 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 (0.75 mm) 12-lead 4 mm x 4 mm DFN, a 16-lead thermally enhanced TSSOP and a 7-lead DD-Pak; all dissipate 2 W in surface mount applications with no heat sink.
Availability and Pricing
The LT3081 is also available in a 7-lead TO-220 power package for vertical mounting to heat sinks for higher power dissipation capability. A wide variety of grades/temperature ranges are offered including: E & I grades -40°C to +125°C, H grade -40°C to +150°C and the high reliability MP grade -55°C to +150°C. 1,000-piece pricing starts at $2.60 each for the E grade.
More information about the LT3081 linear regulator at
www.linear.com/product/LT3081
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