LM2990 LM2990 Negative Low Dropout Regulator Literature Number: SNVS093C LM2990 Negative Low Dropout Regulator tion over the automotive temperature range of -40C to +125 C. General Description The LM2990 is a three-terminal, low dropout, 1 ampere negative voltage regulator available with fixed output voltages of -5, -5.2, -12, and -15V. 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. The LM2990 is available in a 3-lead TO-220 package and is rated for opera- Features 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 Typical Application 1080101 *Required if the regulator is located further than 6 inches from the power supply filter capacitors. A 1 F solid tantalum or a 10 F aluminum electrolytic capacitor is recommended. **Required for stability. Must be at least a 10 F aluminum electrolytic or a 1 F 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 10 over the same operating temperature range as the regulator. Ordering Information and Connection Diagrams Temperature Range Output Voltage Package -5.0 -5.2 -12 -15 LM2990T-5.0 LM2990T-5.2 LM2990T-12 LM2990T-15 TO-220 -40C to +125C LM2990S-5.0 LM2990S-12 LM2990S-15 TO-263 -55C to +125C LM2990J-5.0-QML 5962-9571101QEA LM2990J-12-QML 5962-9571001QEA LM2990J-15-QML 5962-9570901QEA J16A LM2990WG5.0-QML 5962-9571101QXA (c) 2010 National Semiconductor Corporation WG16A 10801 www.national.com LM2990 Negative Low Dropout Regulator August 31, 2010 LM2990 16-Lead Ceramic Surface Mount Package 3-Lead TO-220 1080102 Front View Order Number LM2990T-5.0, LM2990T-5.2, LM2990T-12 or LM2990T-15 See NS Package Number T03B TO-263 Surface-Mount Package 1080134 Top View Order Number LM2990WG5.0-QML (5962-9571101QXEA) See NS Package Number WG16A 1080111 Top View 1080112 Side View Order Number LM2990S-5.0, LM2990S-12 or LM2990S-15 See NS Package Number TS3B 16-Lead Ceramic Dual-in-Line Package 1080133 Top View Order Number LM2990J-5.0-QML (5962-9571101QEA), LM2990J-12-QML (5962-9571001QEA), or LM2990J-15-QML (5962-9570901QEA), See NS Package Number J16A www.national.com 2 If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Input Voltage ESD Susceptibility (Note 2) Power Dissipation (Note 3) Junction Temperature (TJmax) -26V to +0.3V 2 kV Internally Limited 125C -65C to +150C 260C, 10 sec 235C, 30 sec Operating Ratings (Note 1) Junction Temperature Range (TJ) Maximum Input Voltage (Operational) -40C to +125C -26V Electrical Characteristics VIN = -5V + VO(NOM) (Note 6) , IO = 1A, CO = 47 F, unless otherwise specified. Boldface limits apply over the entire operating temperature range, -40C TJ 125C, all other limits apply for TJ = 25C. LM2990-5.0 Parameter Output Voltage (VO) Conditions Typ (Note 4) 5 mA IO 1A LM2990-5.2 Limit (Note 5) Typ (Note 4) -4.90 -5.10 -5 5 mA IO 1A Line Regulation IO = 5 mA, Limit (Note 5) Units (Limit) -5.10 V (max) -5.30 mV (min) -5.2 V -4.75 -4.94 -5.25 -5.46 V (min) V (max) 4 40 4 40 mV (max) 1 40 1 40 mV (max) VO(NOM) -1V > VIN > -26V Load Regulation 50 mA IO 1A Dropout Voltage IO = 0.1A, VO 100 mV 0.1 0.3 0.1 0.3 V (max) IO = 1A, VO 100 mV 0.6 1 0.6 1 V (max) 1 5 1 5 mA (max) Quiescent Current (Iq) IO 1A 9 50 9 50 mA (max) Short Circuit Current IO = 1A, VIN = VO(NOM) RL = 1 (Note 7) 1.8 1.5 1.8 1.5 A (min) Maximum Output Current (Note 7) 1.8 1.5 1.8 1.5 A (min) Ripple Rejection Vripple = 1 Vrms, 58 50 58 50 dB (min) 750 250 750 V (max) ripple = 1 kHz, IO = 5 mA Output Noise Voltage 10 Hz-100 kHz, IO = 5 mA 250 Long Term Stability 1000 Hours 2000 2000 ppm Electrical Characteristics VIN = -5V + VO(NOM) (Note 6) , IO = 1A, CO = 47 F, unless otherwise specified. Boldface limits apply over the entire operating temperature range, -40C TJ 125C, all other limits apply for TJ = 25C. LM2990-12 Parameter Output Voltage (VO) Conditions Typ (Note 4) 5 mA IO 1A LM2990-15 Limit (Note 5) Typ (Note 4) -11.76 -12.24 -12 5 mA IO 1A -11.40 IO = 5 mA, -14.70 V (max) -15.30 V (min) -14.25 V (max) -15 V -15.75 V (min) 6 60 6 60 mV (max) 3 50 3 50 mV (max) -12.60 Line Regulation Limit (Note 5) Units (Limit) VO(NOM) -1V > VIN > -26V Load Regulation 50 mA IO 1A Dropout Voltage IO = 0.1A, VO 100 mV 0.1 0.3 0.1 0.3 V (max) IO = 1A, VO 100 mV 0.6 1 0.6 1 V (max) 3 www.national.com LM2990 Storage Temperature Soldering Temperature TO-220 (T), Wave TO-263 (S) Absolute Maximum Ratings (Note 1) LM2990 LM2990-12 Parameter Quiescent Current (Iq) Conditions IO 1A IO = 1A, VIN = VO(NOM) LM2990-15 Units (Limit) Typ (Note 4) Limit (Note 5) Typ (Note 4) Limit (Note 5) 1 5 1 5 mA (max) 9 50 9 50 mA (max) RL = 1 (Note 7) 1.2 0.9 1.0 0.75 A (min) Maximum Output Current (Note 7) 1.8 1.4 1.8 1.4 A (min) Ripple Rejection Vripple = 1 Vrms, 52 42 52 42 dB (min) 1500 600 1800 V (max) Short Circuit Current ripple = 1 kHz, IO = 5 mA Output Noise Voltage 10 Hz-100 kHz, IO = 5 mA 500 Long Term Stability 1000 Hours 2000 2000 ppm Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is intended to be functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics. Note 2: Human body model, 100 pF discharged through a 1.5 k resistor. Note 3: The maximum power dissipation is a function of TJmax, JA, and TA. The maximum allowable power dissipation at any ambient temperature is PD = (TJmax - TA)/JA. If this dissipation is exceeded, the die temperature will rise above 125C, and the LM2990 will eventually go into thermal shutdown at a TJ of approximately 160C. For the LM2990, the junction-to-ambient thermal resistance, is 53C/W, 73C/W for the TO-263, and the junction-to-case thermal resistance is 3C. If the TO-263 package is used, the thermal resistance can be reduced by increasing the P.C. board copper area thermally connected to the package. Using 0.5 square inches of copper area, JA is 50C/W; with 1 square inch of copper area, JA is 37C/W; and with 1.6 or more square inches of copper area, JA is 32C/W. Note 4: Typicals are at TJ = 25C and represent the most likely parametric norm. Note 5: Limits are guaranteed and 100% production tested. Note 6: VO(NOM) is the nominal (typical) regulator output voltage, -5V, -5.2V, -12V or -15V. Note 7: The short circuit current is less than the maximum output current with the -12V and -15V versions due to internal foldback current limiting. The -5V and -5.2V versions, 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. 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 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. www.national.com 4 LM2990 Typical Performance Characteristics Dropout Voltage Normalized Output Voltage 1080114 1080115 LM2990-5.0 and LM2990-5.2 Quiescent Current LM2990-12 Quiescent Current 1080116 1080117 LM2990-15 Quiescent Current LM2990-5 and LM2990-5.2 Low Voltage Behavior 1080119 1080118 5 www.national.com LM2990 LM2990-5 and LM2990-5.2 Line Transient Response LM2990-5 and LM2990-5.2 Load Transient Response 1080120 1080121 LM2990-12 and LM2990-15 Low Voltage Behavior LM2990-12 and LM2990-15 Line Transient Response 1080123 1080122 LM2990-12 and LM2990-15 Load Transient Response LM2990-5 and LM2990-5.2 Ripple Rejection 1080124 1080125 www.national.com 6 LM2990 LM2990-5 and LM2990-5.2 Output Impedance Maximum Output Current 1080127 1080126 LM2990-12 and LM2990-15 Ripple Rejection LM2990-12 and LM2990-15 Output Impedance 1080129 1080128 Maximum Output Current Maximum Power Dissipation (TO-220) 1080130 1080131 7 www.national.com LM2990 Maximum Power Dissipation (TO-263) (See (Note 3)) 1080132 Typical Applications Post Regulator for an Isolated Switching Power Supply 1080105 Adjustable Current Sink The LM2940 is a positive 1A low dropout regulator; refer to its datasheet for further information. Fixed Current Sink 1080110 1080107 www.national.com 8 EXTERNAL CAPACITORS The LM2990 regulator requires an output capacitor to maintain stability. The capacitor must be at least 10 F aluminum electrolytic or 1 F solid tantalum. The output capacitor's ESR must be less than 10, or the zero added to the regulator frequency response by the ESR could reduce the phase margin, creating oscillations (refer to the graph on the right). An input capacitor, of at least 1 F solid tantalum or 10 F aluminum electrolytic, is also needed if the regulator is situated more than 6 from the input power supply filter. Output Capacitor ESR 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 1080109 9 www.national.com LM2990 over 1 ms, the output should be clamped with a Schottky diode to ground. Application Hints 1080108 LM2990 Equivalent Schematic www.national.com 10 LM2990 Physical Dimensions inches (millimeters) unless otherwise noted TO-220 3-Lead Molded Package Order Number LM2990T-5.0, LM2990T-5.2, LM2990T-12 or LM2990T-15 NS Package Number T03B 11 www.national.com LM2990 TO-263 3-Lead Plastic Surface Mount Package Order Number LM2990S-5.0, LM2990S-12 or LM2990S-15 NS Package Number TS3B 16-Lead Ceramic Dual-in-Line Package LM2990J-5.0-QML (5962-9571101QEA), LM2990J-12-QML (5962-9571001QEA), or LM2990J-15-QML (5962-9570901QEA), NS Package Number J16A www.national.com 12 LM2990 16-Lead Ceramic Surface-Mount Package LM2990WG5.0-QML (5962-9571101QXA) NS Package Number WG16A 13 www.national.com LM2990 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(R) 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(R) Solutions Serial Digital Interface (SDI) www.national.com/sdi Temperature Sensors www.national.com/tempsensors SolarMagicTM www.national.com/solarmagic PLL/VCO www.national.com/wireless www.national.com/training PowerWise(R) Design University THE CONTENTS OF THIS DOCUMENT ARE PROVIDED IN CONNECTION WITH NATIONAL SEMICONDUCTOR CORPORATION ("NATIONAL") PRODUCTS. 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