LM79MXX Series 3-Terminal Negative Regulators General Description The LM79MXX series of 3-terminal regulators is available with fixed output voltages of b5V, b12V, and b15V. These devices need only one external componentÐa compensation capacitor at the output. The LM79MXX series is packaged in the TO-220 power package, and is capable of supplying 0.5A of output current. These regulators employ internal current limiting, safe area protection, and thermal shotdown for protection against virtually all overload conditions. Low ground pin current of the LM79MXX series allows output voltage to be easily boosted above the preset value with a resistor divider. The low quiescent current of these devices with a specified maximum change with line and load ensures good regulation in the voltage boosted mode. For output voltage other than b5V, b12V, and b15V the LM137 series provides an output voltage range from b1.2V to b57V. Features Y Y Y Y Thermal, short circuit and safe area protection High ripple rejection 0.5A output current 4% tolerance on preset output voltage Connection Diagram TO-220 Plastic Package (T) TL/H/10483 – 7 Front View Order Number LM79M05CT, LM79M12CT or LM79M15CT See NS Package Number T03B C1995 National Semiconductor Corporation TL/H/10483 RRD-B30M115/Printed in U. S. A. LM79MXX Series 3-Terminal Negative Regulators December 1994 Absolute Maximum Ratings (Note 1) Power Dissipation (Note 2) If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/Distributors for availability and specifications. Input Voltage VO e b5V VO e b12V, b15V Input/Output Differential VO e b5V VO e b12V, b15V Internally Limited Operating Junction Temperature Range Storage Temperature Range Lead Temperature (Soldering, 10 sec.) ESD Susceptability b 25V b 35V 0§ C to a 125§ C b 65§ C to a 150§ C 230§ C TBD 25V 30V Electrical Characteristics LM79M05C Conditions unless otherwise noted: IOUT e 350 mA, CIN e 2.2 mF, COUT e 1 mF, 0§ C s TJ s a 125§ C Part Number LM79M05C Output Voltage b 5V Input Voltage (Unless Otherwise Specified) Symbol VO Parameter Output Voltage Units b 10V Conditions TJ e 25§ C 5 mA s IOUT s 350 mA Min Typ Max b 4.8 b 5.0 b 5.2 V b 5.25 V 50 mV 30 mV 100 mV b 4.75 ( b 25 s VIN s b 7) DVO Line Regulation TJ e 25§ C (Note 3) 8 (b 25 s VIN s b 7) 2 ( b 18 s VIN s b 8) DVO Load Regulation TJ e 25§ C, (Note 3) 5 mA s IOUT s 0.5A 30 IQ Quiescent Current TJ e 25§ C 1 DIQ Quiescent Current Change With Input Voltage IOMAX mA mA 0.4 mA (b 25 s VIN s b 8) With Load, 5 mA s IOUT s 350 mA Vn 2 0.4 Output Noise Voltage TA e 25§ C, 10 Hz s f s 100 Hz Ripple Rejection f e 120 Hz Dropout Voltage 150 mV 66 (b 18 s VIN s b 8) dB TJ e 25§ C, IOUT e 0.5A 1.1 V Peak Output Current TJ e 25§ C 800 mA Average Temperature Coefficient of Output Voltage IOUT e 5 mA, 0§ C s TJ s 100§ C b 0.4 mV/§ C 54 2 Electrical Characteristics LM79M12C, LM79M15C Conditions unless otherwise noted: IOUT e 350 mA, CIN e 2.2 mF, COUT e 1 mF, 0§ C s TJ s a 125§ C Part Number LM79M12C LM79M15C Output Voltage b 12V b 15V Input Voltage (Unless Otherwise Specified) b 19V b 23V Symbol VO DVO Parameter Output Voltage Line Regulation Conditions Units Min Typ Max Min Typ Max TJ e 25§ C b 11.5 b 12.0 b 12.5 b 14.4 b 15.0 b 15.6 V 5 mA s IOUT s 350 mA b 11.4 b 12.6 b 14.25 b 15.75 V TJ e 25§ C (Note 3) ( b 27 s VIN s b 14.5) ( b 30 s VIN s b 10.5) 5 80 ( b 30 s VIN s b 14.5) 3 50 ( b 25 s VIN s b 15) 5 80 (b 30 s VIN s b 17.5) 3 50 ( b 28 s VIN s b 18) mV mV DVO Load Regulation TJ e 25§ C, (Note 3) 5 mA s IOUT s 0.5A 30 240 30 240 mV IQ Quiescent Current TJ e 25§ C 1.5 3 1.5 3 mA DIQ Quiescent Current Change With Input Voltage 0.4 ( b 30 s VIN s b 14.5) 0.4 ( b 30 s VIN s b 27) mA 0.4 0.4 mA With Load, 5 mA s IOUT s 350 mA Vn IOMAX Output Noise Voltage TA e 25§ C, 10 Hz s f s 100 Hz Ripple Rejection f e 120 Hz Dropout Voltage TJ e 25§ C, IOUT e 0.5A 1.1 1.1 V Peak Output Current TJ e 25§ C 800 800 mA Average Temperature Coefficient of Output Voltage IOUT e 5 mA, 0§ C s TJ s 100§ C b 0.8 b 1.0 mV/§ C 400 54 70 ( b 25 s VIN s b 15) 400 54 70 ( b 30 s VIN s b 17.5) mV dB 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: Refer to Typical Performance Characteristics and Design Considerations for details. Note 3: Regulation is measued at a constant junction temperature by pulse testing with a low duty cycle. Changes in output voltage due to heating effects must be taken into account. 3 Typical Performance Characteristics Output Voltage vs Temperature Ripple Rejection Output Impedance Minimum Input-Output Differential Quiescent Current vs Input Voltage Quiescent Current vs Load Current Maximum Average Power Dissipation (TO-220) Short-Circuit Current TL/H/10483 – 10 4 Schematic Diagrams b 5V TL/H/10483 – 8 b 12V and b 15V TL/H/10483 – 9 5 Design Considerations Typical Applications The LM79MXX fixed voltage regulator series have thermaloverload protection from excessive power, internal short-circuit protection which limits the circuit’s maximum current, and output transistor safe-area compensation for reducing the output current as the voltage across the pass transistor is increased. Although the internal power dissipation is limited, the junction temperature must be kept below the maximum specified temperature in order to meet data sheet specifications. To calculate the maximum junction temperature or heat sink required, the following thermal resistance values should be used: Bypass capacitors are necessary for stable operation of the LM79MXX series of regulators over the input voltage and output current ranges. Output bypass capacitors will improve the transient response of the regulator. The bypass capacitors (2.2 mF on the input, 1.0 mF on the output), should be ceramic or solid tantalum which have good high frequency characteristics. If aluminum electrolytics are used, their values should be 10 mF or larger. The bypass capacitors should be mounted with the shortest leads, and if possible, directly across the regulator terminals. Fixed Regulator Package TO-220 PDMAX e TJMax b TA iJC a iCA iJC (§ C/W) iJA (§ C/W) 3 40 or (1) TL/H/10483 – 2 *Required if regulator is separated from filter capacitor by more than 3× . For value given, capacitor must be solid tantalum. 25 mF aluminum electrolytic may be substituted. b TA T e JMax (Without a Heat Sink) iJA ² Required for stability. For value given, capacitor must be solid tantalum. iCA e iCS a iSA Solving for TJ: TJ e TA a PD (iJC a iCA) or e TA e a PDiJA (Without a Heat Sink) Where e Junction Temperature TJ TA e Ambient Temperature PD e Power Dissipation iJC e Junction-to-Case Thermal Resistance iCA e Case-to-Ambient Thermal Resistance iCS e Case-to-Heat Sink Thermal Resistance iSA e Heat Sink-to-Ambient Thermal Resistance iJA e Junction-to-Ambient Thermal Resistance 25 mF aluminum electrolytic may be substituted. Values given may be increased without limit. For output capacitance in excess of 100 mF, a high current diode from input to output (1N4001, etc.) will protect the regulator from momentary input shorts. Variable Output TL/H/10483 – 3 *Improves transient response and ripple rejection. Do not increase beyond 50 mF. VOUT e VSET # R1 a R2 R2 Select R2 as follows: LM79M05C 300X LM79M12C 750X LM79M15C 1k 6 J Typical Applications (Continued) g 15V, 1 Amp Tracking Regulators TL/H/10483 – 1 Load Regulation at 0.5A Output Ripple, CIN e 3000 mF, IL e 0.5A Temperature Stability Output Noise 10 Hz s f s 10 kHz Performance (Typical) (b15) ( a 15) 40 mV 2 mV 100 mVrms 100 mVrms 50 mV 50 mV 150 mVrms 150 mVrms *Resistor tolerance of R4 and R5 determine matching of ( a ) and ( b ) outputs. **Necessary only if raw supply filter capacitors are more than 3× from regulators. Dual Trimmed Supply TL/H/10483 – 4 7 LM79MXX Series 3-Terminal Negative Regulators Physical Dimensions inches (millimeters) TO-220 Plastic Package (T) Order Number LM79M05CT, LM79M12CT or LM79M15CT NS Package Number T03B LIFE SUPPORT POLICY NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF NATIONAL SEMICONDUCTOR CORPORATION. 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