LP2980IM5-ADJEP

LP2980-ADJEP Micropower SOT, 50 mA Ultra Low-Dropout Adjustable Voltage Regulator December 2006 LP2980-ADJEP Micropower SOT, 50 mA Ultra Low-Dropout Adjustable Voltage Regulator General Description The LP2980-ADJEP is a 50 mA adjustable voltage regulator designed to provide ultra low dropout in battery powered applications. Using an optimized VIP® (vertically Integrated PNP) process, the LP2980-ADJEP delivers unequalled performance in all specifications critical to battery-powered designs: Adjustable Output: output voltage can be set from 1.23V to 15V. Precision Reference: 0.75% tolerance. Dropout Voltage: typically 120 mV @ 50 mA load, and 7 mV @ 1 mA load. Ground Pin Current: typically 320 µA @ 50 mA load, and 80 µA @ 1 mA load. Sleep Mode: less than 1 μA quiescent current when on/off pin is pulled low. Smallest Possible Size: SOT-23 package uses minimum board space. ENHANCED PLASTIC • Extended Temperature Performance of -40°C to +125°C • Baseline Control - Single Fab & Assembly Site • Process Change Notification (PCN) • Qualification & Reliability Data • Solder (PbSn) Lead Finish is standard • Enhanced Diminishing Manufacturing Sources (DMS) Support Features ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ Ultra low dropout voltage Output adjusts from 1.23V to 15V Guaranteed 50 mA output current Uses tiny SOT-23 package Requires few external components 10Ω, and this usually causes oscillation problems. One caution about Tantalums if they are used on the input: the ESR of a Tantalum is low enough that it can be destroyed by surge current if powered up from a low impedance source 2.2 μF ESR Curves 20207022 7 www.national.com LP2980-ADJEP (like a battery) that has no limit on inrush current. In these cases, use a ceramic input capacitor which does not have this problem. CERAMIC: Ceramics are generally larger and more costly than Tantalums for a given amount of capacitance. Also, they have a very low ESR which is quite stable with temperature. Be warned that the ESR of a ceramic capacitor is typically low enough to make an LDO oscillate: a 2.2 μF ceramic demonstrated an ESR of about 15 mΩ when tested. If used as an output capacitor, this will cause instability (see ESR Curves). If a ceramic is used on the output of an LDO, a small resistance (about 1Ω) should be placed in series with the capacitor. If it is used as an input capacitor, no resistor is needed as there is no requirement for ESR on capacitors used on the input. EXTERNAL RESISTORS The output voltage is set using two external resistors (see Basic Application Circuit). It is recommended that the resistor from the ADJ pin to ground be 51.1k. The other resistor (RADJ) which connects between VOUT and the ADJ pin is selected to set VOUT as given by the formula: VOUT = 1.23 + 1.23 (RADJ/51.1k) REVERSE CURRENT PATH The power transistor used in the LP2980-ADJEP has an inherent diode connected between the input and output pin (see below). output pin and out the input pin. This current must be limited to < 100 mA to prevent damage to the part. The internal diode can also be turned on if the input voltage is abruptly stepped down to a voltage which is a VBE below the output voltage. To prevent mis-operation, an external Schottky diode (see below) must be used in applications where the internal diode may be turned on. Since the external Schottky diode turns on at a lower voltage than the internal diode, the Schottky conducts all of the current and prevents the internal diode from becoming forward biased. 20207025 20207024 ON/OFF INPUT OPERATION The LP2980-ADJEP is shut off by driving the ON/OFF input low, and turned on by pulling the ON/OFF input high. If this feature is not to be used, the ON/OFF input must be tied to VIN to keep the regulator output on at all times (the ON/OFF input must not be left floating). To ensure proper operation, the signal source used to drive the ON/OFF input must be able to swing above and below the specified turn-on/turn-off voltage thresholds which guarantee an ON or OFF state (see Electrical Characteristics). It is also important that the turn-on (and turn-off) voltage signals applied to the ON/OFF input have a slew rate which is greater than 40 mV/μs. IMPORTANT: The shutdown function will not operate correctly if a slow-moving signal is used to drive the S/D input. If the output is forced above the input by more than a VBE, this diode will become forward biased and current will flow into the www.national.com 8 LP2980-ADJEP Physical Dimensions inches (millimeters) unless otherwise noted 5-Lead Small Outline Package (M5) NS Package Number MF05A 9 www.national.com LP2980-ADJEP Micropower SOT, 50 mA Ultra Low-Dropout Adjustable Voltage Regulator Notes THE CONTENTS OF THIS DOCUMENT ARE PROVIDED IN CONNECTION WITH NATIONAL SEMICONDUCTOR CORPORATION (“NATIONAL”) PRODUCTS. NATIONAL MAKES NO REPRESENTATIONS OR WARRANTIES WITH RESPECT TO THE ACCURACY OR COMPLETENESS OF THE CONTENTS OF THIS PUBLICATION AND RESERVES THE RIGHT TO MAKE CHANGES TO SPECIFICATIONS AND PRODUCT DESCRIPTIONS AT ANY TIME WITHOUT NOTICE. NO LICENSE, WHETHER EXPRESS, IMPLIED, ARISING BY ESTOPPEL OR OTHERWISE, TO ANY INTELLECTUAL PROPERTY RIGHTS IS GRANTED BY THIS DOCUMENT. TESTING AND OTHER QUALITY CONTROLS ARE USED TO THE EXTENT NATIONAL DEEMS NECESSARY TO SUPPORT NATIONAL’S PRODUCT WARRANTY. EXCEPT WHERE MANDATED BY GOVERNMENT REQUIREMENTS, TESTING OF ALL PARAMETERS OF EACH PRODUCT IS NOT NECESSARILY PERFORMED. NATIONAL ASSUMES NO LIABILITY FOR APPLICATIONS ASSISTANCE OR BUYER PRODUCT DESIGN. BUYERS ARE RESPONSIBLE FOR THEIR PRODUCTS AND APPLICATIONS USING NATIONAL COMPONENTS. PRIOR TO USING OR DISTRIBUTING ANY PRODUCTS THAT INCLUDE NATIONAL COMPONENTS, BUYERS SHOULD PROVIDE ADEQUATE DESIGN, TESTING AND OPERATING SAFEGUARDS. EXCEPT AS PROVIDED IN NATIONAL’S TERMS AND CONDITIONS OF SALE FOR SUCH PRODUCTS, NATIONAL ASSUMES NO LIABILITY WHATSOEVER, AND NATIONAL DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY RELATING TO THE SALE AND/OR USE OF NATIONAL PRODUCTS INCLUDING LIABILITY OR WARRANTIES RELATING TO FITNESS FOR A PARTICULAR PURPOSE, MERCHANTABILITY, OR INFRINGEMENT OF ANY PATENT, COPYRIGHT OR OTHER INTELLECTUAL PROPERTY RIGHT. LIFE SUPPORT POLICY NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS PRIOR WRITTEN APPROVAL OF THE CHIEF EXECUTIVE OFFICER AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein: Life support devices or systems are devices which (a) are intended for surgical implant into the body, or (b) support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided in the labeling can be reasonably expected to result in a significant injury to the user. A critical component is any component in a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system or to affect its safety or effectiveness. National Semiconductor and the National Semiconductor logo are registered trademarks of National Semiconductor Corporation. All other brand or product names may be trademarks or registered trademarks of their respective holders. Copyright© 2007 National Semiconductor Corporation For the most current product information visit us at www.national.com National Semiconductor Americas Customer Support Center Email: new.feedback@nsc.com Tel: 1-800-272-9959 National Semiconductor Europe Customer Support Center Fax: +49 (0) 180-530-85-86 Email: europe.support@nsc.com Deutsch Tel: +49 (0) 69 9508 6208 English Tel: +49 (0) 870 24 0 2171 Français Tel: +33 (0) 1 41 91 8790 National Semiconductor Asia Pacific Customer Support Center Email: ap.support@nsc.com National Semiconductor Japan Customer Support Center Fax: 81-3-5639-7507 Email: jpn.feedback@nsc.com Tel: 81-3-5639-7560 www.national.com