Datasheet LT1121, LT1121-3.3, LT1121-5 (Analog Devices)

LT1121/LT1121-3.3/LT1121-5 Micropower Low Dropout Regulators with Shutdown
FEATURES DESCRIPTION
n 0.4V Dropout Voltage The LT®1121/LT1121-3.3/LT1121-5 are micropower low n 150mA Output Current dropout regulators with shutdown. These devices are ca- n 30µA Quiescent Current pable of supplying 150mA of output current with a dropout n No Protection Diodes Needed voltage of 0.4V. Designed for use in battery-powered sys- n Adjustable Output from 3.75V to 30V tems, the low quiescent current, 30µA operating and 16µA n 3.3V and 5V Fixed Output Voltages in shutdown, makes them an ideal choice. The quiescent n Controlled Quiescent Current in Dropout current is well-controlled; it does not rise in dropout as it n Shutdown does with many other low dropout PNP regulators. n 16µA Quiescent Current in Shutdown Other features of the LT1121/LT1121-3.3/LT1121-5 include n Stable with 0.33µF Output Capacitor the ability to operate with very small output capacitors. n Reverse Battery Protection They are stable with only 0.33µF on the output while most n No Reverse Current with Input Low older devices require between 1µF and 100µF for stability. n Thermal Limiting Small ceramic capacitors can be used, enhancing manu- n Available in the 8-Lead SO, 8-Lead PDIP, 3-Lead facturability. Also the input may be connected to ground SOT-23 and 3-Lead TO-92 Packages or a reverse voltage without reverse current flow from output to input. This makes the LT1121 series ideal for
APPLICATIONS
backup power situations where the output is held high and the input is at ground or reversed. Under these conditions n Low Current Regulator only 16µA will flow from the output pin to ground. n Regulator for Battery-Powered Systems L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear n Post Regulator for Switching Supplies Technology Corporation. All other trademarks are the property of their respective owners.
TYPICAL APPLICATION 5V Battery-Powered Supply with Shutdown Dropout Voltage
0.5 8 1 IN OUT 3.3VOUT 150mA + 0.4 5V LT1121-3.3 1μF SOLID TANTALUM 5 0.3 SHDN GND 3 0.2 DROPOUT VOLTAGE (V)
V
0.1
SHDN (PIN 5) OUTPUT
<0.25 OFF >2.8 ON NC ON 0 LT1121 • TA01 0 20 40 60 80 100 120 140 160 OUTPUT CURRENT (mA) LT1121 • TA02 1121fg 1 Document Outline Features Description Applications Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Applications Information Package Description Revision History Related Parts