LT1521/LT1521-3 LT1521-3.3/LT1521-5 300mA Low Dropout Regulators with Micropower Quiescent Current and Shutdown FEATURES DESCRIPTION n Dropout Voltage: 0.5V The LT 1521/LT1521-3/LT1521-3.3/LT1521-5 are low n Output Current: 300mA dropout regulators with micropower quiescent current n Quiescent Current: 12A and shutdown. These devices are capable of supply- n No Protection Diodes Needed ing 300mA of output current with a dropout voltage n Adjustable Output from 3.8V to 20V of 0.5V. Designed for use in battery-powered systems, n Fixed Output Voltages: 3V, 3.3V, 5V the low quiescent current, 12A operating and 6A in n Controlled Quiescent Current in Dropout shutdown, makes them an ideal choice. The quiescent n Shutdown I = 6A current is well controlled it does not rise in dropout as it Q n Reverse Battery Protection does with many other low dropout PNP regulators. n No Reverse Current Other features of the LT1521/LT1521-3/LT1521-3.3/ n Thermal Limiting LT1521-5 include the ability to operate with very small output capacitors. They are stable with only 1.5F on the APPLICATIONS output while most older devices require between 10F and 100F for stability. Small ceramic capacitors can be n Low Current Regulator used, enhancing manufacturability. Also, the input may n Regulator for Battery-Powered Systems be connected to voltages lower than the output voltage, n Post Regulator for Switching Supplies including negative voltages, without reverse current flow from output to input. This makes the LT1521 series ideal for backup power situations where the output is held high and the input is low or reversed. Under these conditions only 5A will flow from the output pin to ground. All registered trademarks and trademarks are the property of their respective owners. TYPICAL APPLICATION 5V Battery-Powered Supply with Shutdown Dropout Voltage 0.6 5V 8 1 IN OUT 300mA 0.5 + 6V 1F 1.5F LT1521-5 0.4 5 2 SHDN SENSE GND 0.3 3 0.2 V (PIN 5) OUTPUT SHDN 0.1 <0.25 OFF >2.80 ON LT1521 TA01 0 NC ON 0 50 100 150 200 250 300 OUTPUT CURRENT (mA) LT1521 TA02 Rev. C 1 Document Feedback For more information www.analog.com DROPOUT VOLTAGE (V)LT1521/LT1521-3 LT1521-3.3/LT1521-5 ABSOLUTE MAXIMUM RATINGS (Note 1) Input Voltage .........................................................20V* Storage Temperature Range ................... 65C to 150C Output Pin Reverse Current ...................................10mA Operating Junction Temperature Range (Note 2) Adjust Pin Current ..................................................10mA Commercial............................................ 0C to 125C Shutdown Pin Input Voltage (Note 1) ...........6.5V, 0.6V Industrial ......................................... 40C to 125C Shutdown Pin Input Current (Note 1) ......................5mA Lead Temperature (Soldering, 10 sec) .................. 300C *For applications requiring input voltage ratings greater than 20V, contact Output Short-Circuit Duration .......................... Indefinite the factory. PIN CONFIGURATION TOP VIEW FRONT VIEW TOP VIEW OUT 1 8 IN OUT 1 8 IN 3 OUT SENSE/ADJ* GND SENSE/ADJ* 2 7 NC 2 7 NC 3 6 NC TAB IS GND 3 6 GND 2 GND 5 SHDN GND 4 GND NC 4 5 SHDN MS8 PACKAGE 1 IN 8-LEAD PLASTIC MSOP S8 PACKAGE *PIN 2 = SENSE FOR LT1521-3/ 8-LEAD PLASTIC SO ST PACKAGE LT1521-3.3/LT1521-5 3-LEAD PLASTIC SOT-223 *PIN 2 = SENSE FOR LT1521-3/LT1521-3.3/LT1521-5 PIN 2 = ADJ FOR LT1521 = ADJ FOR LT1521 T = 125C, = 50C/W JMAX JA T = 125C, = 125C/W JMAX JA SEE THE APPLICATIONS INFORMATION SECTION T = 125C, = 70C/W JMAX JA SEE THE APPLICATIONS INFORMATION SECTION ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LT1521CMS8 PBF LT1521CMS8 TRPBF LTEZ 8-Lead Plastic MSOP 0C to 125C LT1521CMS8-3 PBF LT1521CMS8-3 TRPBF LTFB 8-Lead Plastic MSOP 0C to 125C LT1521CMS8-3.3 PBF LT1521CMS8-3.3 TRPBF LTDU 8-Lead Plastic MSOP 0C to 125C LT1521CMS8-5 PBF LT1521CMS8-5 TRPBF LTFA 8-Lead Plastic MSOP 0C to 125C LT1521CS8 PBF LT1521CS8 TRPBF 1521 8-Lead Plastic SOIC 0C to 125C LT1521CS8-3 PBF LT1521CS8-3 TRPBF 15213 8-Lead Plastic SOIC 0C to 125C LT1521CS8-3.3 PBF LT1521CS8-3.3 TRPBF 152133 8-Lead Plastic SOIC 0C to 125C LT1521CS8-5 PBF LT1521CS8-5 TRPBF 15215 8-Lead Plastic SOIC 0C to 125C LT1521IS8 PBF LT1521IS8 TRPBF 1521I 8-Lead Plastic SOIC 40C to 125C LT1521IS8-3 PBF LT1521IS8-3 TRPBF 1521I3 8-Lead Plastic SOIC 40C to 125C LT1521IS8-3.3 PBF LT1521IS8-3.3 TRPBF 1521I33 8-Lead Plastic SOIC 40C to 125C LT1521IS8-5 PBF LT1521IS8-5 TRPBF 1521I5 8-Lead Plastic SOIC 40C to 125C Rev. C 2 For more information www.analog.com