LT1521/LT1521-3 LT1521-3.3/LT1521-5 300mA Low Dropout Regulators with Micropower Quiescent Current and Shutdown DESCRIPTIO FEATURES 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: 12m A and shutdown. These devices are capable of supplying n No Protection Diodes Needed 300mA of output current with a dropout voltage of 0.5V. n Adjustable Output from 3.8V to 20V Designed for use in battery-powered systems, the low n Fixed Output Voltages: 3V, 3.3V, 5V quiescent current, 12m A operating and 6m A in n Controlled Quiescent Current in Dropout shutdown, makes them an ideal choice. The quiescent n Shutdown I = 6m A 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 U output capacitors. They are stable with only 1.5m F on the APPLICATIO S output while most older devices require between 10m F and 100m F for stability. Small ceramic capacitors can be used, n Low Current Regulator enhancing manufacturability. Also, the input may be con- n Regulator for Battery-Powered Systems nected to voltages lower than the output voltage, including n Post Regulator for Switching Supplies negative voltages, without reverse current flow from out- put 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 5m A will flow from the output pin to ground. , LTC and LT are registered trademarks of Linear Technology Corporation. TYPICAL APPLICATIO 5V Battery-Powered Supply with Shutdown Dropout Voltage 0.6 5V 8 1 IN OUT 300mA + 0.5 6V 1F LT1521-5 1.5F 0.4 5 2 SHDN SENSE GND 0.3 3 0.2 V (PIN 5) OUTPUT SHDN <0.25 OFF 0.1 >2.80 ON LT1521 TA01 NC ON 0 0 100 150 200 250 300 50 OUTPUT CURRENT (mA) LT1521 TA02 1521335fb 1 DROPOUT VOLTAGE (V) U ULT1521/LT1521-3 LT1521-3.3/LT1521-5 ABSOLUTE MAXIMUM RATINGS (Note 1) Input Voltage ...................................................... 20V* Storage Temperature Range ................. 65 C to 150 C Output Pin Reverse Current .................................. 10mA Operating Junction Temperature Range (Note 2) Adjust Pin Current ................................................ 10mA Commercial ........................................... 0 C to 125 C Shutdown Pin Input Voltage (Note 1) ..........6.5V, 0.6V Industrial ......................................... 40 C to 125 C Shutdown Pin Input Current (Note 1) ..................... 5mA Lead Temperature (Soldering, 10 sec).................. 300 C Output Short-Circuit Duration .......................... Indefinite *For applications requiring input voltage ratings greater than 20V, contact the factory. PACKAGE/ORDER INFORMATION TOP VIEW FRONT VIEW TOP VIEW OUT 1 8 IN 3 OUT OUT 1 8 IN SENSE/ADJ* 2 7 GND SENSE/ADJ* 2 7 NC TAB IS NC 3 6 NC 2 GND GND 3 6 GND GND GND 4 5 SHDN NC SHDN 4 5 MS8 PACKAGE 1 IN 8-LEAD PLASTIC MSOP S8 PACKAGE ST PACKAGE 8-LEAD PLASTIC SO *PIN 2 = SENSE FOR LT1521-3/ 3-LEAD PLASTIC SOT-223 LT1521-3.3/LT1521-5 *PIN 2 = SENSE FOR LT1521-3/LT1521-3.3/LT1521-5 PIN 2 = ADJ FOR LT1521 = ADJ FOR LT1521 T = 125 C, q = 70 C/ W T = 125 C, q = 50 C/ W JMAX JA JMAX JA T = 125 C, q = 125 C/ W JMAX JA SEE THE APPLICATIONS INFORMATION SECTION SEE THE APPLICATIONS INFORMATION SECTION ORDER PART NUMBER ORDER PART NUMBER ORDER PART NUMBER LT1521CS8 LT1521CST-3 LT1521CMS8 LT1521CS8-3 LT1521CST-3.3 LT1521CMS8-3 LT1521CS8-3.3 LT1521CST-5 LT1521CMS8-3.3 LT1521CS8-5 LT1521IST-3 LT1521CMS8-5 LT1521IS8 LT1521IST-3.3 LT1521IS8-3 LT1521IST-5 LT1521IS8-3.3 LT1521IS8-5 MS8 PART MARKING S8 PART MARKING ST PART MARKING LTEZ 1521 1521I 15213 1521I3 LTFB 15213 1521I3 152133 1521I33 LTDU 152133 1521I33 15215 1521I5 LTFA 15215 1521I5 Consult LTC Marketing for parts specified with wider operating temperature ranges. 1521335fb 2 U W U W U WW