LT3028 Datasheet, PDF (1/16 Pages) Linear Technology – Dual 100mA/500mA Low Dropout, Low Noise,Micropower Regulators with Independent Inputs

FEATURES
■ _{Low Noise: 20µVRMS (10Hz to 100kHz)}
■ _{Low Quiescent Current: 30µA/Output}
■ _{Independent Inputs}
■ _{Wide Input Voltage Range: 1.8V to 20V}
■ _{Output Current: 100mA/500mA}
■ _{Very Low Shutdown Current: <0.1µA}
■ _{Low Dropout Voltage: 300mV/320mV at}
100mA/500mA
■ _{Adjustable Outputs from 1.22V to 20V}
■ _{Stable with as Low as 1µF/3.3µF Output Capacitor}
■ _{Stable with Aluminum, Tantalum or}
Ceramic Capacitors
■ _{Reverse-Battery Protected}
■ _{No Protection Diodes Needed}
■ _{Overcurrent and Overtemperature Protected}
■ _{Tracking/Sequencing Capability}
■ _{Thermally Enhanced 16-Lead TSSOP and 16-Lead}
(5mm × 3mm) DFN Packages
U
APPLICATIO S
■ _{Cellular Phones}
■ _Pagers
■ _{Battery-Powered Systems}
■ _{Frequency Synthesizers}
■ _{Wireless Modems}
■ _{Tracking/Sequencing Power Supplies}
LT3028
Dual 100mA/500mA
Low Dropout, Low Noise,
Micropower Regulators with
Independent Inputs
DESCRIPTIO
The LT^®3028 is a dual, micropower, low noise, low drop-
out regulator with independent inputs. With an external
0.01µF bypass capacitor, output noise is a low 20µV_RMS
over a 10Hz to 100kHz bandwidth. Designed for use in
battery-powered systems, the low 30µA quiescent current
per output makes it an ideal choice. In shutdown, quies-
cent current drops to less than 0.1µA. Shutdown control
is independent for each output, allowing for flexibility in
power management. The device is capable of operating
over an input voltage range of 1.8V to 20V. Output 1 can
supply 500mA of output current with a dropout voltage of
320mV. The device can supply 100mA of output current
from Output 2 with a dropout voltage of 300mV. Quiescent
current is well controlled in dropout.
The LT3028 regulator is stable with output capacitors as
low as 1µF for the 100mA output and 3.3µF for the 500mA
output. Small ceramic capacitors can be used without the
series resistance required by other regulators.
Internal protection circuitry includes reverse-battery pro-
tection, current limiting and thermal limiting protection.
The device is available as an adjustable device with a 1.22V
reference voltage. The LT3028 regulator is available in the
thermally enhanced 16-lead TSSOP and 16-lead, low
profile (5mm × 3mm × 0.75mm) DFN packages.
, LTC and LT are registered trademarks of Linear Technology Corporation.
Protected by U.S. Patents including 6118263, 6144250.
TYPICAL APPLICATIO
V_IN1
3.7V TO
20V
V_IN2
2.9V TO
20V
3.3V/2.5V Low Noise Regulators
IN1
OUT1
1µF
SHDN1
BYP1
ADJ1
LT3028
OUT2
IN2
1µF
SHDN2 _BYP2
ADJ2
GND
0.01µF _422k
3.3V AT 500mA
10µF ^{20µVRMS NOISE}
249k
0.01µF _261k
2.5V AT 100mA
20µV_RMS NOISE
10µF
249k
3028 TA01a
10Hz to 100kHz Output Noise
V_OUT
100µV/DIV
20µV_RMS
3028 TA01b
3028f
1