LTC3025-3_15 Datasheet, PDF (1/14 Pages) Linear Technology – 500mA Micropower VLDO Linear Regulators

Features
n _{Wide Input Voltage Range: 0.9V to 5.5V}
n _{Stable with Ceramic Capacitors}
n _{Very Low Dropout: 85mV at 500mA}
n _{Adjustable Output Range: 0.4V to 3.6V (LTC3025-1)}
n _{Fixed Output: 1.2V (LTC3025-2), 1.5V (LTC3025-3),}
1.8V (LTC3025-4)
n _{±2% Voltage Accuracy over Temperature,}
Supply and Load
n _{Low Noise: 80µVRMS (10Hz to 100kHz)}
n _{BIAS Voltage Range: 2.5V to 5.5V}
n _{Fast Transient Recovery}
n _{Shutdown Disconnects Load from VIN and VBIAS}
n _{Low Operating Current: IIN = 4µA, IBIAS = 50µA Typ}
n _{Low Shutdown Current: IIN = 1µA, IBIAS = 0.01µA Typ}
n _{Output Current Limit}
n _{Thermal Overload Protection}
n _{Available in 6-Lead (2mm × 2mm) DFN Package}
Applications
n _{Low Power Handheld Devices}
n _{Low Voltage Logic Supplies}
n _{DSP Power Supplies}
n _{Cellular Phones}
n _{Portable Electronic Equipment}
n _{Handheld Medical Instruments}
n _{Post Regulator for Switching Supply Noise Rejection}
LTC3025-1/LTC3025-2/
LTC3025-3/LTC3025-4
500mA Micropower
VLDO Linear Regulators
Description
The LTC^®3025-X is a micropower, VLDO™ (very low drop-
out) linear regulator which operates from input voltages as
low as 0.9V. The device is capable of supplying 500mA of
output current with a typical dropout voltage of only 85mV.
A BIAS supply is required to run the internal reference and
LDO circuitry while output current comes directly from the
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.
The LTC3025-X’s low quiescent current makes it an ideal
choice for use in battery-powered systems. For 3-cell NiMH
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.
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.
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.
Typical Application
1.2V Output Voltage from 1.5V Input Supply
Li-Ion
OR
3-CELL
NiMH
1.5V HIGH
EFFICIENCY _1.5V
DC/DC
BUCK
0.1µF
0.1µF
OFF ON
BIAS
OUT
LTC3025-2
IN
SENSE
SHDN
GND
V_OUT = 1.2V
1µF ^{IOUT ≤ 500mA}
30251234 TA01
1MHz V_IN Supply Rejection
50
45
C_OUT = 10µF
40
35
C_OUT = 1µF
30
25
20
15
10
5 ^{BIAS = 3.6V}
V_OUT = 1.2V
0
1.2 1.4 1.6
1.8 2.0
V_IN (V)
I_OUT = 100mA
I_OUT = 300mA
2.2 2.4 2.6
30251234 TA01b
30251234ff
1