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Details, datasheet, quote on part number:RM2991JXQMLV
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Datasheet text preview:
LM2991 Negative Low Dropout Adjustable Regulator
September 2000
LM2991 Negative Low Dropout Adjustable Regulator
General Description
The LM2991 is a low dropout adjustable negative regulator with a output voltage range between -3V to -24V. The LM2991 provides up to 1A of load current and features a On /Off pin for remote shutdown capability. The LM2991 uses new circuit design techniques to provide a low dropout voltage, low quiescent current and low temperature coefficient precision reference. The dropout voltage at 1A load current is typically 0.6V and a guaranteed worst-case maximum of 1V over the entire operating temperature range. The quiescent current is typically 1 mA with a 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). The LM2991 is short-circuit proof, and thermal shutdown includes hysteresis to enhance the reliability of the device when inadvertently overloaded for extended periods. The LM2991 is available in 5-lead TO-220 and TO-263 packages and is rated for operation over the automotive temperature range of -40°C to +125°C. Mil-Aero versions are also available.
Features
n Output voltage adjustable from -3V to -24V, typically -2V to -25V n Output current in excess of 1A n Dropout voltage typically 0.6V at 1A load n Low quiescent current n Internal short circuit current limit n Internal thermal shutdown with hysteresis n TTL, CMOS compatible ON/OFF switch n Functional complement to the LM2941 series
Applications
n Post switcher regulator n Local, on-card, regulation n Battery operated equipment
Typical Application
DS011260-1
VOUT = VREF (1 + R2/R1) *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 10 over the same operating temperature range as the regulator.
© 2000 National Semiconductor Corporation
DS011260
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LM2991
Connection Diagrams and Ordering Information
5-Lead TO-220 Straight Leads 5-Lead TO-220 Bent, Staggered Leads
DS011260-9
Front View Order Number LM2991T See NS Package Number T05A
DS011260-2
Front View Order Number LM2991T Flow LB03 See NS Package Number T05D TO263 5-Lead Surface-Mount Package
DS011260-11
Top View
DS011260-12
Side View Order Number LM2991S See NS Package Number TS5B 16-Lead Ceramic Dual-in-Line Package
16-Lead Ceramic Surface-Mount Package
DS011260-29 DS011260-30
Top View Order Number LM2991J-QMLV 5962-9650501VEA Order Number LM2991J-QML 5962-9650501QEA See NS Package Number J16A
Top View Order Number LM2991WG-QML 5962-9650501QXA See NS Package Number WG16A
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LM2991
Absolute Maximum Ratings (Note 1)
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 125°C
Storage Temperature Range Lead Temperature (Soldering, 10 sec.)
-65°C to +150°C 230°C
Operating Ratings (Note 1)
Junction Temperature Range (TJ) Maximum Input Voltage (Operational) -40°C to +125°C -26V
Electrical Characteristics
VIN = -10V, VO = -3V, IO = 1A, CO = 47 µF, R1 = 2.7k, TJ = 25°C, unless otherwise specified. Boldface limits apply over the entire operating junction temperature range. Parameter Reference Voltage Conditions 5 mA IO 1A 5 mA IO 1A, VO - 1V VIN -26V Output Voltage Range Line Regulation Load Regulation Dropout Voltage VIN = -26V IO = 5 mA, VO - 1V VIN -26V 50 mA IO 1A IO = 0.1A, VO 100 mV IO = 1A, VO 100 mV Quiescent Current Dropout Quiescent Current Ripple Rejection Output Noise ON /OFF Input Voltage ON /OFF Input Current Output Leakage Current Current Limit Vripple = 1 Vrms, f IO = 5 mA 10 Hz - 100 kHz, IO = 5 mA (VOUT: ON) (VOUT: OFF) VON/OFF = 0.8V (VOUT: ON) VON/OFF = 2.4V (VOUT: OFF) VIN = -26V, VON/OFF = 2.4V VOUT = 0V VOUT = 0V 2 1.5 A 200 1.2 1.3 0.1 40 60 2.4 10 100 250 µA µA 450 0.8 µV V
ripple
Typical (Note 4) -1.210
Min -1.234 -1.27
Max -1.186 -1.15 -3
Units V V V V %/V % V V mA mA dB
-2 -25 0.004 0.04 0.1 0.6 0.7 16 = 1 kHz, 60 50 -24
0.04 0.4 0.2 0.3 0.8 1 5 50
IO 1A VIN = VO, IO 1A
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the deivce 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 125°C and the LM2991 will go into thermal shutdown. For the LM2991, the junction-to-ambient thermal resistance is 53°C/W for the TO-220, 73°C/W for the TO-263, and junction-to-case thermal resistance is 3°C. If the TO-263 package is used, the thermal resistance can be reduced by increasing the PC board copper area thermally connected to the package. Using 0.5 square inches of copper area, JA is 50°C/W; with 1 square inch of copper area, JA is 37°C/W; and with 1.6 or more square inches of copper area, JA is 32°C/W. Note 4: Typicals are at TJ = 25°C and represent the most likely parametric norm.
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