LTC3025-1/LTC3025-2/
LTC3025-3/LTC3025-4
500mA Micropower
VLDO Linear Regulators
FeaTures
DescripTion
The LTC®3025-X is a micropower, VLDO™ (very low drop-
out)linearregulatorwhichoperatesfrominputvoltagesas
low as 0.9V. The device is capable of supplying 500mA of
outputcurrentwithatypicaldropoutvoltageofonly85mV.
A BIAS supply is required to run the internal reference and
LDOcircuitrywhileoutputcurrentcomesdirectlyfromthe
IN supply for high efficiency regulation. The LTC3025-1
features an adjustable output with a low 0.4V reference
while the LTC3025-2, LTC3025-3, and LTC3025-4 have
fixed 1.2V, 1.5V and 1.8V output voltages respectively.
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Wide Input Voltage Range: 0.9V to 5.5V
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Stable with Ceramic Capacitors
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Very Low Dropout: 85mV at 500mA
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Adjustable Output Range: 0.4V to 3.6V (LTC3025-1)
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Fixed Output: 1.2V (LTC3025-2), 1.5V (LTC3025-3),
1.8V (LTC3025-4)
2ꢀ Voltage Accuracy over Temperature,
Supply and Load
Low Noise: 80µV
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(10Hz to 100kHz)
RMS
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BIAS Voltage Range: 2.5V to 5.5V
Fast Transient Recovery
The LTC3025-X’s low quiescent current makes it an ideal
choiceforuseinbattery-poweredsystems.For3-cellNiMH
and single cell Li-Ion applications, the BIAS voltage can
be supplied directly from the battery while the input can
come from a high efficiency buck regulator, providing a
high efficiency, low noise output.
Shutdown Disconnects Load from V and V
IN
BIAS
= 50µA Typ
= 0.01µA Typ
Low Operating Current: I = 4µA, I
Low Shutdown Current: I = 1µA, I
Output Current Limit
Thermal Overload Protection
Available in 6-Lead (2mm × 2mm) DFN Package
IN
BIAS
IN
BIAS
Other features include high output voltage accuracy,
excellent transient response, stability with ultralow ESR
ceramic capacitors as small as 1µF, short-circuit and
thermal overload protection and output current limiting.
The LTC3025-X is available in a tiny, low profile (0.75mm)
6-lead DFN (2mm × 2mm) package.
applicaTions
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Low Power Handheld Devices
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Low Voltage Logic Supplies
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DSP Power Supplies
Cellular Phones
Portable Electronic Equipment
Handheld Medical Instruments
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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. Protected by U.S. Patents including 7224204, 7218082.
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Post Regulator for Switching Supply Noise Rejection
Typical applicaTion
1MHz VIN Supply Rejection
1.2V Output Voltage from 1.5V Input Supply
50
45
40
35
30
25
20
15
10
5
C
= 10µF
OUT
V
= 1.2V
≤ 500mA
OUT
OUT
BIAS
OUT
SENSE
GND
I
0.1µF
1µF
Li-Ion
OR
1.5V HIGH
EFFICIENCY
DC/DC
LTC3025-2
C
= 1µF
OUT
1.5V
3-CELL
NiMH
IN
BUCK
0.1µF
OFF ON
SHDN
30251234 TA01
BIAS = 3.6V
OUT
I
I
= 100mA
= 300mA
OUT
OUT
V
= 1.2V
0
1.2
1.6 1.8 2.0
(V)
2.2 2.4 2.6
1.4
V
IN
30251234 TA01b
30251234ff
1