LM2990QML LM2990QML Negative Low Dropout Regulator Literature Number: SNVS391 LM2990QML Negative Low Dropout Regulator General Description Features The LM2990 is a three-terminal, low dropout, 1 ampere negative voltage regulator available with a fixed output voltage of −5V. The LM2990 uses new circuit design techniques to provide low dropout and low quiescent current. The dropout voltage at 1A load current is typically 0.6V and a guaranteed worstcase maximum of 1V over the entire operating temperature range. The quiescent current is typically 1 mA with 1A load current and an input-output voltage differential greater than 3V. A unique circuit design of the internal bias supply limits the quiescent current to only 9 mA (typical) when the regulator is in the dropout mode (VOUT − VIN ≤ 3V). Output voltage accuracy is guaranteed to ±5% over load, and temperature extremes. The LM2990 is short-circuit proof, and thermal shutdown includes hysteresis to enhance the reliability of the device when overloaded for an extended period of time. ■ ■ ■ ■ ■ ■ ■ 5% output accuracy over entire operating range Output current in excess of 1A Dropout voltage typically 0.6V at 1A load Low quiescent current Internal short circuit current limit Internal thermal shutdown with hysteresis Functional complement to the LM2940 series Applications ■ Post switcher regulator ■ Local, on-card, regulation ■ Battery operated equipment Ordering Information NS Package Number Package Description LM2990-5.0 MD8 NS Part Number SMD Part Number (Note 1) Bare Die LM2990-5.0 MW8 (Note 1) Bare Die Note 1: FOR ADDITIONAL DIE INFORMATION, PLEASE VISIT THE HI REL WEB SITE AT: www.national.com/analog/space/level_die 16-Lead Ceramic Dual-in-Line Package 20158633 Top View See NS Package Number J16A © 2010 National Semiconductor Corporation 201586 www.national.com LM2990QML Negative Low Dropout Regulator December 8, 2010 20158608 LM2990QML Equivalent Schematic www.national.com 2 LM2990QML Absolute Maximum Ratings (Note 2) Input Voltage Power Dissipation (Note 3) Junction Temperature (TJmax) Storage Temperature −26V to +0.3V Internally Limited 150°C −65°C ≤ TA ≤ +150°C Thermal Resistance θJA Ceramic Dip (Still Air @ 0.5°C/W) Ceramic Dip (500LF/Min Air flow @ 0.5°C/W) 75°C/W 35°C/W θJC Ceramic Dip (Note 4) Package Weight Ceramic Dip Lead Temperature (Soldering, 10 sec.) ESD Susceptibility (Note 5) 5°C/W TBD 260°C 2KV Recommended Operating Conditions (Note 2) −55°C ≤ TJ ≤ +125°C −26V Temperature Range (TJ) Maximum Input Voltage (Operational) Quality Conformance Inspection Mil-Std-883, Method 5005 - Group A Subgroup Description Temp (°C) 1 Static tests at +25 2 Static tests at +125 3 Static tests at -55 4 Dynamic tests at +25 5 Dynamic tests at +125 6 Dynamic tests at -55 7 Functional tests at +25 8A Functional tests at +125 8B Functional tests at -55 9 Switching tests at +25 10 Switching tests at +125 11 Switching tests at -55 12 Settling time at +25 13 Settling time at +125 14 Settling time at -55 3 www.national.com LM2990QML LM2990-5.0 Electrical Characteristics DC Parameters The following conditions apply, unless otherwise specified. Symbol Parameter VIN = −5V + VO Nom, IO = 1A, CO = 47µF (Note 6) Conditions Notes Min Max Unit Subgroups -5.10 -4.90 V 1 -5.25 -4.75 V 2, 3 40 mV 1, 2, 3 70 mV 1 100 mV 2, 3 0.3 V 1, 2, 3 IO = 1A, ΔVO ≤ 100mV 1.0 V 1, 2, 3 IO ≤ 1A 5.0 mA 1 10 mA 2, 3 IO = 1A, VIN = VO Nom 50 mA 1, 2, 3 VO Output Voltage 5mA ≤ IO ≤ 1A VRLine Line Regulation IO = 5mA, VO Nom -1V > VIN > -26V VRLoad Load Regulation 50mA ≤ IO ≤ 1A VDO Dropout Voltage IO = 0.1A, ΔVO ≤ 100mV IQ Quiescent Current RL = 1Ω IOS Short Circuit Current IMax Maximum Output Current RR Ripple Rejection VRipple = 1VRMS, FRipple = 1KHz, IO = 5mA VOn Output Noise Voltage 10Hz-100Khz, IO = 5mA 1.5 A 1 (Note 7) 1.3 A 2, 3 (Note 7) 1.5 A 1 50 dB 1 µV 1, 2, 3 750 Note 2: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics. The guaranteed specifications apply only for the test conditions listed. Some performance characteristics may degrade when the device is not operated under the listed test conditions. Note 3: The maximum power dissipation must be derated at elevated temperatures and is dictated by TJmax (maximum junction temperature), θJA (package junction to ambient thermal resistance), and TA (ambient temperature). The maximum allowable power dissipation at any temperature is PDmax = (TJmax - TA)/ θJA or the number given in the Absolute Maximum Ratings, whichever is lower. Note 4: The package material for these devices allows much improved heat transfer over our standard ceramic packages. In order to take full advantage of this improved heat transfer, heat sinking must be provided between the package base (directly beneath the die), and either metal traces on, or thermal vias through, the printed circuit board. Without this additional heat sinking, device power dissipation must be calculated using θJA, rather than θJC, thermal resistance. It must not be assumed that the device leads will provide substantial heat transfer out of the package, since the thermal resistance of the leadframe material is very poor, relative to the material of the package base. The stated θJC thermal resistance is for the package material only, and does not account for the additional thermal resistance between the package base and the printed circuit board. The user must determine the value of the additional thermal resistance and must combine this with the stated value for the package, to calculate the total allowed power dissipation for the device. Note 5: Human body model, 1.5 kΩ in series with 100 pF. Note 6: VO Nom is the nominal (typical) regulator output voltage, −5V. Note 7: The −5V version, tested with a lower input voltage, does not reach the foldback current limit and therefore conducts a higher short circuit current level. If the LM2990 output is pulled above ground, the maximum allowed current sunk back into the LM2990 is 1.5A. www.national.com 4 Dropout Voltage: The input-output voltage differential at which the circuit ceases to regulate against further reduction in input voltage. Measured when the output voltage has dropped 100 mV from the nominal value obtained at (VO + 5V) input, dropout voltage is dependent upon load current and junction temperature. Input Voltage: The DC voltage applied to the input terminals with respect to ground. Input-Output Differential: The voltage difference between the unregulated input voltage and the regulated output voltage for which the regulator will operate. Line Regulation: The change in output voltage for a change in the input voltage. The measurement is made under conditions of low dissipation or by using pulse techniques such that the average chip temperature is not significantly affected. Typical Performance Characteristics Dropout Voltage Normalized Output Voltage 20158614 20158615 LM2990-5.0 Quiescent Current LM2990-5.0 Low Voltage Behavior 20158619 20158616 5 www.national.com LM2990QML Load Regulation: The change in output voltage for a change in load current at constant chip temperature. Long Term Stability: Output voltage stability under accellerated life-test conditions after 1000 hours with maximum rated voltage and junction temperature. Output Noise Voltage: The RMS AC voltage at the output, with constant load and no input ripple, measured over a specified frequency range. Quiescent Current: That part of the positive input current that does not contribute to the positive load current. The regulator ground lead current. Ripple Rejection: The ratio of the peak-to-peak input ripple voltage to the peak-to-peak output ripple voltage. Temperature Stability of VO: The percentage change in output voltage for a thermal variation from room temperature to either temperature extreme. Definition of Terms LM2990QML LM2990-5.0 Line Transient Response LM2990-5.0 Load Transient Response 20158620 20158621 LM2990-5.0 Ripple Rejection LM2990-5.0 Output Impedance 20158626 20158625 Maximum Output Current Maximum Output Current 20158627 www.national.com 20158630 6 LM2990QML Typical Applications 20158601 *Required if the regulator is located further than 6 inches from the power supply filter capacitors. A 1 μF solid tantalum or a 10 μF aluminum electrolytic capacitor is recommended. **Required for stability. Must be at least a 10 μF aluminum electrolytic or a 1 μF solid tantalum to maintain stability. May be increased without bound to maintain regulation during transients. Locate the capacitor as close as possible to the regulator. The equivalent series resistance (ESR) is critical, and should be less than 10Ω over the same operating temperature range as the regulator. Post Regulator for an Isolated Switching Power Supply 20158605 The LM2940 is a positive 1A low dropout regulator; refer to its datasheet for further information. gin, creating oscillations (refer to the graph on the right). An input capacitor, of at least 1 μF solid tantalum or 10 μF aluminum electrolytic, is also needed if the regulator is situated more than 6″ from the input power supply filter. Fixed Current Sink FORCING THE OUTPUT POSITIVE Due to an internal clamp circuit, the LM2990 can withstand positive voltages on its output. If the voltage source pulling the output positive is DC, the current must be limited to 1.5A. A current over 1.5A fed back into the LM2990 could damage the device. The LM2990 output can also withstand fast positive voltage transients up to 26V, without any current limiting of the source. However, if the transients have a duration of over 1 mS, the output should be clamped with a Schottky diode to ground. 20158607 Adjustable Current Sink Output Capacitor ESR 20158610 Application Hints EXTERNAL CAPACITORS The LM2990 regulator requires an output capacitor to maintain stability. The capacitor must be at least 10 μF aluminum electrolytic or 1 μF solid tantalum. The output capacitor's ESR must be less than 10Ω, or the zero added to the regulator frequency response by the ESR could reduce the phase mar- 20158609 7 www.national.com LM2990QML Revision History Released 12/08/2010 www.national.com Revision A Section Changes New Release, Corporate format 8 MDS data sheet converted into Corp. data sheet format. Data Sheet referencing Die NSID LM2990– 5.0 MD8 and MW8 only. Package products are Code K no longer available. Archive the 3 MDS data sheets MNLM2990-5.0-X Rev 0B1, MNLM2990-12-X Rev 0B0, and MNLM2990-15-X Rev 0B0. LM2990QML Physical Dimensions inches (millimeters) unless otherwise noted 16–Lead Ceramic Dual–in–Line Package NS Package Number J16A 9 www.national.com LM2990QML Negative Low Dropout Regulator Notes For more National Semiconductor product information and proven design tools, visit the following Web sites at: www.national.com Products Design Support Amplifiers www.national.com/amplifiers WEBENCH® Tools www.national.com/webench Audio www.national.com/audio App Notes www.national.com/appnotes Clock and Timing www.national.com/timing Reference Designs www.national.com/refdesigns Data Converters www.national.com/adc Samples www.national.com/samples Interface www.national.com/interface Eval Boards www.national.com/evalboards LVDS www.national.com/lvds Packaging www.national.com/packaging Power Management www.national.com/power Green Compliance www.national.com/quality/green Switching Regulators www.national.com/switchers Distributors www.national.com/contacts LDOs www.national.com/ldo Quality and Reliability www.national.com/quality LED Lighting www.national.com/led Feedback/Support www.national.com/feedback Voltage References www.national.com/vref Design Made Easy www.national.com/easy www.national.com/powerwise Applications & Markets www.national.com/solutions Mil/Aero www.national.com/milaero PowerWise® Solutions Serial Digital Interface (SDI) www.national.com/sdi Temperature Sensors www.national.com/tempsensors SolarMagic™ www.national.com/solarmagic PLL/VCO www.national.com/wireless www.national.com/training PowerWise® Design University THE CONTENTS OF THIS DOCUMENT ARE PROVIDED IN CONNECTION WITH NATIONAL SEMICONDUCTOR CORPORATION (“NATIONAL”) PRODUCTS. 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