LT3085_15 Datasheet, PDF (1/28 Pages) Linear Technology – Adjustable 500mA Single Resistor Low Dropout Regulator

FEATURES
n _{Outputs May be Paralleled for Higher Current and}
Heat Spreading
n _{Output Current: 500mA}
n _{Single Resistor Programs Output Voltage}
n _{1% Initial Accuracy of SET Pin Current}
n _{Output Adjustable to 0V}
n _{Current Limit Constant with Temperature}
n _{Low Output Noise: 40μVRMS (10Hz to 100kHz)}
n _{Wide Input Voltage Range: 1.2V to 36V}
n _{Low Dropout Voltage: 275mV}
n _{< 1mV Load Regulation}
n _{< 0.001%/ V Line Regulation}
n _{Minimum Load Current: 0.5mA}
n _{Stable with Minimum 2.2μF Ceramic Capacitor}
n _{Current Limit with Foldback and Overtemperature}
Protected
n _{8-Lead MSOP, and 6-Lead 2mm × 3mm DFN Packages}
APPLICATIONS
n _{High Current All Surface Mount Supply}
n _{High Efficiency Linear Regulator}
n _{Post Regulator for Switching Supplies}
n _{Low Parts Count Variable Voltage Supply}
n _{Low Output Voltage Power Supplies}
LT3085
Adjustable 500mA Single
Resistor Low Dropout
Regulator
DESCRIPTION
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.
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).
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
V_IN
1.2V TO 36V
IN
V_CONTROL
1μF
LT3085
+
–
OUT
SET
R_SET
V_OUT = R_SET • 10μA
3085 TA01a
V_OUT
2.2μF
N = 1676
9.80
9.90
10.00
10.10 10.20
SET PIN CURRENT DISTRIBUTION (μA)
3085 TA01b
3085fb
1