LTC1844_15 Datasheet, PDF (1/12 Pages) Linear Technology – 150mA, Micropower, Low Noise, VLDO Linear Regulator

FEATURES
■ _{Very Low Dropout:}
90mV at 150mA
30mV at 50mA (LTC1844-3.3)
■ _{Wide Input Voltage Range: 1.6V to 6.5V}
■ _{Low 35µA Supply Current, Even in Dropout}
■ _{Low Noise: 60µVRMS (10Hz to 100kHz)}
■ _{±1.75% Voltage Accuracy Over Temperature,}
Voltage and Current Ranges
■ _{Fast Transient Response}
■ _{10nA Supply Current in Shutdown}
■ _{Fixed Output Voltages: 1.5V, 1.8V, 2.5V, 2.8V, 3.3V}
■ _{Adjustable Output Voltage: 1.25V to 6V}
■ _{Output Current Limit}
■ _{Reverse-Battery and Reverse-Current Protection}
■ _{No Protection Diodes Needed}
■ _{Stable with 1µF Output Capacitor}
■ _{Stable with Ceramic Capacitors}
■ _{Short-Circuit and Thermal Overload Protection}
■ _{Low Profile (1mm) SOT-23 Package}
U
APPLICATIO S
■ _{Portable Instruments and Battery-Powered Systems}
■ _{Bluetooth/802.11 Cards}
■ _{Cellular Phones}
■ _{PDAs and Notebook Computers}
LTC1844 Series
150mA, Micropower,
Low Noise, VLDO
Linear Regulator
DESCRIPTIO
The LTC^®1844 Series are low noise VLDO^TM (very low
dropout) linear regulators designed for low power/portable
applications. These regulators can operate from input
voltages as low as 1.6V. Typical output noise is only
30µV_RMS and typical dropout for the LTC1844-3.3 is just
90mV at the maximum load current of 150mA, reducing to
30mV at 50mA.
The internal P-channel MOSFET pass transistor requires
no base current, allowing the device to draw only 35µA
during normal operation, independent of the dropout
voltage and load current. The quiescent current falls to a
negligible 10nA during shutdown.
Other features include high output voltage accuracy,
excellent transient response, stability with ultralow ESR
ceramic capacitors as small as 1µF, reverse-battery and
reverse-current protection, short-circuit and thermal
overload protection and output current limiting.
The LTC1844 regulators are available in a low profile
(1mm) SOT-23 (ThinSOT^TM) package.
, LTC and LT are registered trademarks of Linear Technology Corporation.
VLDO and ThinSOT are trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
TYPICAL APPLICATIO
Fixed Voltage Low Noise, VLDO Linear Regulator
V_IN
3.3V TO 6.5V
OFF ON
IN
OUT
1µF
LTC1844-3.3
SHDN BYP
GND
V_OUT
3.3V
1µF
0.1µF
1844 TA01
LTC1844-3.3 Dropout Voltage vs Load Current
120
100
80
60
40
20
0
0 25 50 75 100 125 150
I_OUT (mA)
1844 TA02
1844fa
1