THREE AMPERE POSITIVE FIXED VOLTAGE REGULATORS

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1 Order this document by MC78T/D This family of fixed voltage regulators are monolithic integrated circuits capable of driving loads in excess of 3. A. These threeterminal regulators employ internal current limiting, thermal shutdown, and safearea compensation. Devices are available with improved specifications, including a % output voltage tolerance, on ACsuffix, 1 and V device types. Although designed primarily as a fixed voltage regulator, these devices can be used with external components to obtain adjustable voltages and currents. This series of devices can be used with a seriespass transistor to supply up to A at the nominal output voltage. Output Current in Excess of 3. A Power Dissipation: 5 W No External Components Required Output Voltage Offered in % and 4% Tolerance* Thermal Regulation is Specified Internal Thermal Overload Protection Internal Short Circuit Current Limiting Output Transistor SafeArea Compensation MAXIMUM RATINGS (TA = +5 C, unless otherwise noted.) Rating Symbol Value Unit Input Voltage ( V 1 V) Input Voltage ( V) Power Dissipation and Thermal Characteristics Plastic Package (Note 1) TA = +5 C Thermal Resistance, JunctiontoAir TC = +5 C Thermal Resistance, JunctiontoCase VI 35 4 PD RθJA PD RθJC Internally Limited 65 Internally Limited.5 Vdc C/W C/W THREEAMPERE POSITIVE FIXED VOLTAGE REGULATORS T SUFFIX PLASTIC PACKAGE CASE 1A Pin SEMICONDUCTOR TECHNICAL DATA 1. Input. Ground 3. Output 1 3 Heatsink surface is connected to Pin. Storage Junction Temperature Tstg + C Operating Junction Temperature Range (MC78TC, AC) TJ to +15 C NOTES: 1. Although power dissipation is internally limited, specifications apply only for P O P max, P max = 5 W. DEVICE TYPE/NOMINAL OUTPUT VOLTAGE MC78T5 MC78T8 V 8. V MC78T1 MC78T 1 V V ORDERING INFORMATION Input Cin*.33µF Simplified Application MC78TXX MOTOROLA ANALOG IC DEVICE DATA Output CO** A common ground is required between the input and the output voltages. The input voltage must remain typically. V above the output voltage even during the low point on the input ripple voltage. XX these two digits of the type number indicate voltage. ** Cin is required if regulator is located an appreciable distance from power supply filter. ** (See Applications Information for details.) ** CO is not needed for stability; however, it does improve transient response. Device MC78TXXCT MC78TXXACT VO Tol. 4% %* Operating Temperature Range TJ = to +15 C Package Plastic Power MC78TXXBT# 4% TJ = 4 to Plastic MC78TXXABT# %* +15 C Power XX Indicates nominal voltage. * % regulators available in 5, 1 and V devices. # Automotive temperature range selections are available with special test conditions and additional tests. Contact your local Motorola sales office for information. Motorola, Inc Rev 1 1

2 ELECTRICAL CHARACTERISTICS (Vin = 1 V, IO = 3. A, C TJ 15 C, PO Pmax [Note 1], unless otherwise noted.) MC78T5AC MC78T5C Characteristics Symbol Min Typ Max Min Typ Max Unit Output Voltage ( ma IO 3. A; ma IO. A, 7.3 Vdc Vin Vdc) Line Regulation (Note ) (7. Vdc Vin 35 Vdc, IO = ma, TJ = +5 C; 7. Vdc Vin 35 Vdc, IO = 1. A, TJ = +5 C; 8. Vdc Vin 1 Vdc, IO = 3. A, TJ = +5 C; 7.5 Vdc Vin Vdc, IO = 1. A) Load Regulation (Note ) ( ma IO 3. A) Thermal Regulation (Pulse = 1 ms, P = W, TA = +5 C) Quiescent Current ( ma IO 3. A) Quiescent Current Change (7. Vdc Vin 35 Vdc, IO = ma, TJ = +5 C; ma IO 3. A, TJ = +5 C; 7.5 Vdc Vin Vdc, IO = 1. A) Ripple Rejection (8. Vdc Vin 18 Vdc, f = 1 Hz, IO =. A, ) VO Regline mv Regload Regtherm %VO/W IB IB ma RR db Dropout Voltage (IO = 3. A, TJ = +5 C) VinVO Vdc Output Noise Voltage (1 Hz f 1 khz, TJ = +5 C) Vdc Vn 1 1 µv/vo Output Resistance (f = 1. khz) RO. mω mv ma Short Circuit Current Limit (Vin = 35 Vdc, TJ = +5 C) ISC A Peak Output Current (TJ = +5 C) Imax A Average Temperature Coefficient of Output Voltage (IO = ma) TCVO.. mv/ C NOTES: 1. Although power dissipation is internally limited, specifications apply only for P O P max, P max = 5 W.. Line and load regulation are specified at constant junction temperature. Changes in V O due to heating effects must be taken into account separately. Pulse testing with low duty cycle is used. MOTOROLA ANALOG IC DEVICE DATA

3 ELECTRICAL CHARACTERISTICS (Vin = 13 V, IO = 3. A, C TJ 15 C, PO Pmax [Note 1], unless otherwise noted.) Output Voltage ( ma IO 3. A; ma IO. A, 1.4 Vdc Vin 3 Vdc) Line Regulation (Note ) (1.3 Vdc Vin 35 Vdc, IO = ma, TJ = +5 C 1.3 Vdc Vin 35 Vdc, IO = 1. A, TJ = +5 C 11 Vdc Vin 17 Vdc, IO = 3. A, TJ = +5 C 1.7 Vdc Vin 3 Vdc, IO = 1. A) Load Regulation (Note ) ( ma IO 3. A) Thermal Regulation (Pulse = 1 ms, P = W, TA = +5 C) MC78T8C Characteristics Symbol Min Typ Max Unit VO Vdc Regline 35 mv Regload mv Regtherm..3 %VO/W Quiescent Current ( ma IO 3. A) Quiescent Current Change (1.3 Vdc Vin 35 Vdc, IO = ma, TJ = +5 C; ma IO 3. A, TJ = +5 C; 1.7 Vdc Vin 3 Vdc, IO = 1. A) Ripple Rejection (11 Vdc Vin 1 Vdc, f = 1 Hz, IO =. A, ) IB 6. ma IB.3 1. ma RR 6 71 db Dropout Voltage (IO = 3. A, TJ = +5 C) VinVO..5 Vdc Output Noise Voltage (1 Hz f 1 khz, TJ = +5 C) Vn 1 µv/vo Output Resistance (f = 1. khz) RO. mω Short Circuit Current Limit (Vin = 35 Vdc, TJ = +5 C) ISC 1.5 A Peak Output Current (TJ = +5 C) Imax A Average Temperature Coefficient of Output Voltage (IO = ma) TCVO.3 mv/ C NOTES: 1. Although power dissipation is internally limited, specifications apply only for P O P max, P max = 5 W.. Line and load regulation are specified at constant junction temperature. Changes in V O due to heating effects must be taken into account separately. Pulse testing with low duty cycle is used. MOTOROLA ANALOG IC DEVICE DATA 3

4 ELECTRICAL CHARACTERISTICS (Vin = 17 V, IO = 3. A, C TJ 15 C, PO Pmax [Note 1], unless otherwise noted.) MC78T1AC MC78T1C Characteristics Symbol Min Typ Max Min Typ Max Unit Output Voltage ( ma IO 3. A, ma IO. A, 14.5 Vdc Vin 7 Vdc) Line Regulation (Note ) (14.5 Vdc Vin 35 Vdc, IO = ma, TJ = +5 C; 14.5 Vdc Vin 35 Vdc, IO = 1. A, TJ = +5 C; 16 Vdc Vin Vdc, IO = 3. A, TJ = +5 C; 14.9 Vdc Vin 7 Vdc, IO = 1. A) Load Regulation (Note ) ( ma IO 3. A) Thermal Regulation (Pulse = 1 ms, P = W, TA = +5 C) Quiescent Current ( ma IO 3. A) Quiescent Current Change (14.5 Vdc Vin 35 Vdc, IO = ma, TJ = +5 C; ma IO 3. A, TJ = +5 C; 14.9 Vdc Vin 7 Vdc, IO = 1. A) Ripple Rejection ( Vdc Vin 5 Vdc, f = 1 Hz, IO =. A, ) VO Regline mv Regload Regtherm %VO/W IB IB ma RR db Dropout Voltage (IO = 3. A, TJ = +5 C) Vin VO Vdc Output Noise Voltage (1 Hz f 1 khz, TJ = +5 C) Vdc Vn 1 1 µv/vo Output Resistance (f = 1. khz) RO. mω mv ma Short Circuit Current Limit (Vin = 35 Vdc, TJ = +5 C) ISC A Peak Output Current (TJ = +5 C) Imax A Average Temperature Coefficient of Output Voltage (IO = ma) TCVO.5.5 mv/ C NOTES: 1. Although power dissipation is internally limited, specifications apply only for P O P max, P max = 5 W.. Line and load regulation are specified at constant junction temperature. Changes in V O due to heating effects must be taken into account separately. Pulse testing with low duty cycle is used. 4 MOTOROLA ANALOG IC DEVICE DATA

5 ELECTRICAL CHARACTERISTICS (Vin = V, IO = 3. A, C TJ 15 C, PO Pmax [Note 1], unless otherwise noted.) MC78TAC MC78TC Characteristics Symbol Min Typ Max Min Typ Max Unit Output Voltage ( ma IO 3. A; ma IO. A, 17.5 Vdc Vin 3 Vdc) Line Regulation (Note ) (17.6 Vdc Vin 4 Vdc, IO = ma, TJ = +5 C; 17.6 Vdc Vin 4 Vdc, IO = 1. A, TJ = +5 C; Vdc Vin 6 Vdc, IO = 3. A, TJ = +5 C; 18 Vdc Vin 3 Vdc, IO = 1. A) Load Regulation (Note ) ( ma IO 3. A) Thermal Regulation (Pulse = 1 ms, P = W, TA = +5 C) Quiescent Current ( ma IO 3. A) Quiescent Current Change (17.6 Vdc Vin 4 Vdc, IO = ma, TJ = +5 C; ma IO 3. A, TJ = +5 C; 18 Vdc Vin 3 Vdc, IO = 1. A) Ripple Rejection (18.5 Vdc Vin 8.5 Vdc, f = 1 Hz, IO =. A, ) VO Regline mv Regload Regtherm %VO/W IB IB ma RR db Dropout Voltage (IO = 3. A, TJ = +5 C) VinVO Vdc Output Noise Voltage (1 Hz f 1 khz, TJ = +5 C) Vdc Vn 1 1 µv/vo Output Resistance (f = 1. khz) RO. mω mv ma Short Circuit Current Limit (Vin = 4 Vdc, TJ = +5 C) ISC A Peak Output Current (TJ = +5 C) Imax A Average Temperature Coefficient of Output Voltage (IO = ma) TCVO.6.6 mv/ C NOTES: 1. Although power dissipation is internally limited, specifications apply only for P O P max, P max = 5 W.. Line and load regulation are specified at constant junction temperature. Changes in V O due to heating effects must be taken into account separately. Pulse testing with low duty cycle is used. MOTOROLA ANALOG IC DEVICE DATA 5

6 VOLTAGE REGULATOR PERFORMANCE The performance of a voltage regulator is specified by its immunity to changes in load, input voltage, power dissipation, and temperature. Line and load regulation are tested with a pulse of short duration (< 1µs) and are strictly a function of electrical gain. However, pulse widths of longer duration (> 1. ms) are sufficient to affect temperature gradients across the die. These temperature gradients can cause a change in the output voltage, in addition to changes caused by line and load regulation. Longer pulse widths and thermal gradients make it desirable to specify thermal regulation. Thermal regulation is defined as the change in output voltage caused by a change in dissipated power for a specified time, and is expressed as a percentage output voltage change per watt. The change in dissipated power can be caused by a change in either the input voltage or the load current. Thermal regulation is a function of IC layout and die attach techniques, and usually occurs within 1 ms of a change in power dissipation. After 1 ms, additional changes in the output voltage are due to the temperature coefficient of the device. Figure 1 shows the line and thermal regulation response of a typical MC78T5AC to a W input pulse. The variation of the output voltage due to line regulation is labeled ➀ and the thermal regulation component is labeled ➁. Figure shows the load and thermal regulation response of a typical MC78T5AC to a W load pulse. The output voltage variation due to load regulation is labeled ➀ and the thermal regulation component is labeled ➁. Figure 1. MC78T5AC Line and Thermal Regulation Figure. MC78T5AC Load and Thermal Regulation V O, OUTPUT VOLTAGE DEVIATION (V) V in, INPUT VOLTAGE (V) (. mv/div) I O, OUTPUT V O, OUTPUT CURRENT (A) VOLTAGE DEVIATION (V). 1 (. mv/div) Vout = V Vin = 8. V 18 V 8. V Iout =. A t, TIME (. ms/div) 1 = Regline =.4 mv = Regtherm =.%VO/W Vout = V Vin = Iout = A. A A t, TIME (. ms/div) 1 = Regline = 4.4 mv = Regtherm =.%VO/W Representative Schematic Diagram Q1 1.k 1.k Q Q Q 6.7V 1 Q1 Input 16k Q4 Q5 3 Q3 3.6k 6.4k Q8 Q1 Q9 5.6k 1.k 3.k Q19 Q16 1pF Q3 3 Q4 1 Q5 Q6 Q Output Q6 Q7 Q1.6k 8. V O V.k O 3.9k Q11 Q13 6.k Q17 Q Q18 4 pf 6.k Q14.8k Gnd 6 MOTOROLA ANALOG IC DEVICE DATA

7 1. Figure 3. Temperature Stability 1 Figure 4. Output Impedance NORMALIZED OUTPUT VOLTAGE 1. Vin Vout = 1 V Iout = 1 ma ro, OUTPUT IMPEDANCE ( Ω ) Vout = V Vin = 7.5 V Iout = 1. A CO = TJ, JUNCTION TEMPERATURE ( C) k 1 k 1 k 1. M 1 M 1 M f, FREQUENCY (Hz) 1 Figure 5. Ripple Rejection versus Frequency 1 Figure 6. Ripple Rejection versus Output Current RR, RIPPLE REJECTION (db) Iout = 1.5 A Iout = 5 ma Vout = V Vin = 1 V CO = RR, RIPPLE REJECTION (db) Vout = V Vin = 1 V CO = f = 1 Hz k 1 k 1 k 1. M 1 M 1 M f, FREQUENCY (Hz) Iout, OUTPUT CURRENT (A) IB, QUIESCENT CURRENT (ma) 3.. Figure 7. Quiescent Current versus Input Voltage TJ = C TJ = 15 C 1. TJ = C TJ = 15 C Vin, INPUT VOLTAGE (Vdc) IB, QUIESCENT CURRENT (ma) Figure 8. Quiescent Current versus Output Current TJ = 15 C Iout, OUTPUT CURRENT (A) TJ = C VinVout = V MOTOROLA ANALOG IC DEVICE DATA 7

8 I I MC78T Series Figure 9. Dropout Voltage Figure 1. Peak Output Current.5 8. V in V out, INPUT TO OUTPUT VOLTAGE DIFFERENTIAL (Vdc) VO = 5 mv Iout = 3. A Iout = 1. A Iout =.5 A TJ, JUNCTION TEMPERATURE ( C) max, PEAK OUTPUT CURRENT (A) 6.. TJ = C TJ = 15 C VinVO, INPUTOUTPUT VOLTAGE (Vdc) Figure 11. Line Transient Response Figure 1. Load Transient Response V in, INPUT VOLTAGE V out, OUTPUT VOLTAGE CHANGE (V) DEVIATION (V) Vout = V Iout = ma CO = t, TIME (µs) out, OUTPUT VOLTAGE DEVIATION (V) V out, OUTPUT CURRENT (A) Vin = 1 V CO = t, TIME (µs) PD(AV), MAXIMUM AVERAGE POWER DISSIPATION (W) C/W 6.3 C/W 1.5 C Figure 13. Maximum Average Power Dissipation for MC78TCT, ACT θsa of Heatsinks.4 C/W 1.3 C/W Maximum Ambient Temperature TA, AMBIENT TEMPERATURE ( C) Infinite Heatsink 8 MOTOROLA ANALOG IC DEVICE DATA

9 APPLICATIONS INFORMATION Design Considerations The MC78T Series of fixed voltage regulators are designed with Thermal Overload Protection that shuts down the circuit when subjected to an excessive power overload condition, Internal Short Circuit Protection that limits the maximum current the circuit will pass, and Output Transistor SafeArea Compensation that reduces the output short circuit current as the voltage across the pass transistor is increased. In many low current applications, compensation capacitors are not required. However, it is recommended that the regulator input be bypassed with a capacitor if the regulator is connected to the power supply filter with long wire lengths, or if the output load capacitance is large. An input bypass capacitor should be selected to provide good high frequency characteristics to insure stable operation under all load conditions. A.33 µf or larger tantalum, mylar, or other capacitor having low internal impedance at high frequencies should be chosen. The bypass capacitor should be mounted with the shortest possible leads directly across the regulator s input terminals. Normally good construction techniques should be used to minimize ground loops and lead resistance drops since the regulator has no external sense lead. Input.33µF Figure 14. Current Regulator MC78T5 IO The MC78T5 regulator can also be used as a current source when connected as above. In order to minimize dissipation the MC78T5 is chosen in this application. Resistor R determines the current as follows: IO = V R + IB IB.7 ma over line, load and Temperature changes IB ma For example, a. A current source would require R to be a.5 Ω, 1 W resistor and the output voltage compliance would be the input voltage less 7. V. R Constant Current to Grounded Load Input Figure. Adjustable Output Regulator.33µF MC78T5 1.k MC1741 1k Output VO, 8. V to V Vin VO.5 V The addition of an operational amplifier allows adjustment to higher or intermediate values while retaining regulation characteristics. The minimum voltage obtainable with this arrangement is 3. V greater than the regulator voltage..1µf Figure 16. Current Boost Regulator N4398 or Equiv Input Figure 17. Current Boost With Short Circuit Protection Rsc N4398 or Equiv. R 1.µF MC78TXX.1µF Output XX = digits of type number indicating voltage. The MC78T series can be current boosted with a PNP transistor. The N4398 provides current to A. Resistor R in conjuction with the VBE of the PNP determines when the pass transistor begins conducting; this circuit is not short circuit proof. Inputoutput differential voltage minimum is increased by the VBE of the pass transistor. R MJ955 or Equiv. 1.µF MC78TXX Output XX = digits of type number indicating voltage. The circuit of Figure 17 can be modified to provide supply protection against short circuits by adding a short circuit sense resistor, RSC, and an additional PNP transistor. The current sensing PNP must be able to handle the short circuit current of the threeterminal regulator. Therefore, an eightampere power transistor is specified. MOTOROLA ANALOG IC DEVICE DATA 9

10 OUTLINE DIMENSIONS H Q Z L V G B N D A K F T U S R J T SUFFIX PLASTIC PACKAGE CASE 1A6 ISSUE Y C T SEATING PLANE NOTES: 1. DIMENSIONING AND TOLERANCING PER ANSI Y14.5M, CONTROLLING DIMENSION: INCH. 3. DIMENSION Z DEFINES A ZONE WHERE ALL BODY AND LEAD IRREGULARITIES ARE ALLOWED. INCHES MILLIMETERS DIM MIN MAX MIN MAX A B C D F G H J K L N Q R S T U V Z MOTOROLA ANALOG IC DEVICE DATA

11 Motorola reserves the right to make changes without further notice to any products herein. Motorola makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does Motorola assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation consequential or incidental damages. Typical parameters which may be provided in Motorola data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including Typicals must be validated for each customer application by customer s technical experts. Motorola does not convey any license under its patent rights nor the rights of others. Motorola products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which the failure of the Motorola product could create a situation where personal injury or death may occur. Should Buyer purchase or use Motorola products for any such unintended or unauthorized application, Buyer shall indemnify and hold Motorola and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that Motorola was negligent regarding the design or manufacture of the part. Motorola and are registered trademarks of Motorola, Inc. Motorola, Inc. is an Equal Opportunity/Affirmative Action Employer. MOTOROLA ANALOG IC DEVICE DATA 11

12 How to reach us: USA / EUROPE / Locations Not Listed: Motorola Literature Distribution; JAPAN: Nippon Motorola Ltd.; TatsumiSPDJLDC, 6F SeibuButsuryuCenter, P.O. Box 91; Phoenix, Arizona or Tatsumi KotoKu, Tokyo 135, Japan MFAX: RMFAX@ .sps.mot.com TOUCHTONE ASIA/PACIFIC: Motorola Semiconductors H.K. Ltd.; 8B Tai Ping Industrial Park, INTERNET: 51 Ting Kok Road, Tai Po, N.T., Hong Kong MOTOROLA ANALOG IC DEVICE MC78T/D DATA

13 This datasheet has been download from: Datasheets for electronics components.