LT3085
Adjustable 500mA Single
Resistor Low Dropout
Regulator
DESCRIPTION
FEATURES
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Outputs May be Paralleled for Higher Current and
Heat Spreading
Output Current: 500mA
Single Resistor Programs Output Voltage
1% Initial Accuracy of SET Pin Current
Output Adjustable to 0V
Current Limit Constant with Temperature
Low Output Noise: 40μVRMS (10Hz to 100kHz)
Wide Input Voltage Range: 1.2V to 36V
Low Dropout Voltage: 275mV
< 1mV Load Regulation
< 0.001%/ V Line Regulation
Minimum Load Current: 0.5mA
Stable with Minimum 2.2μF Ceramic Capacitor
Current Limit with Foldback and Overtemperature
Protected
8-Lead MSOP, and 6-Lead 2mm × 3mm DFN Packages
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A key feature of the LT3085 is the capability to supply a
wide output voltage range. By using a reference current
through a single resistor, the output voltage is programmed
to any level between zero and 36V. The LT3085 is stable
with 2.2μF of capacitance on the output, and the IC uses
small ceramic capacitors that do not require additional
ESR as is common with other regulators.
Internal protection circuitry includes current limiting
and thermal limiting. The LT3085 is offered in the 8-lead
MSOP and a low profile (0.75mm) 6-lead 2mm × 3mm
DFN package (both with an Exposed Pad for better thermal
characteristics).
APPLICATIONS
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The LT®3085 is a 500mA low dropout linear regulator that
can be paralleled to increase output current or spread
heat on surface mounted boards. Designed as a precision
current source and voltage follower, this new regulator
finds use in many applications requiring high current,
adjustability to zero, and no heat sink. The device also
brings out the collector of the pass transistor to allow
low dropout operation—down to 275mV—when used
with a second supply.
High Current All Surface Mount Supply
High Efficiency Linear Regulator
Post Regulator for Switching Supplies
Low Parts Count Variable Voltage Supply
Low Output Voltage Power Supplies
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and VLDO
and ThinSOT are trademarks of Linear Technology Corporation. All other trademarks are the
property of their respective owners.
TYPICAL APPLICATION
Variable Output Voltage 500mA Supply
LT3085
IN
VIN
1.2V TO 36V
N = 1676
VCONTROL
+
–
1μF
OUT
VOUT
SET
RSET
VOUT = RSET • 10μA
3085 TA01a
2.2μF
9.80
10.00
10.20
9.90
10.10
SET PIN CURRENT DISTRIBUTION (μA)
3085 TA01b
3085fb
1
