L4974 STMicroelectronics, L4974 Datasheet
L4974
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L4974 Summary of contents
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... SWITCHING REGULATOR MULTIPOWER BCD TECHNOLOGY POWERDIP ( ORDERING NUMBER : L4974A the L4974A include reset and power fail for micro- processors, feed forward line regulation, soft start, limiting current and thermal protection. The device is mountedin a Powerdip16 + plastic package and requires few external components. Efficient ...
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... L4974A ABSOLUTE MAXIMUM RATINGS Symbo l V Input Voltage 11 V Input Operating Voltage 11 V Output DC Voltage 20 Output Peak Voltage 0 200khz I Maximum Output Current 20 V Boostrap Voltage I Boostrap Operating Voltage Input Voltage at Pins Reset Output Voltage 3 I Reset Output Sink Current ...
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... The Feedback Terminal of the Regulation Loop. The output is connected directly to this terminal for 5.1V operation connected via a divider for higher voltages. 10 SYNC INPUT Multiple L4974A’s are synchronized by connecting pin 10 inputs together or via an external syncr. pulse. 11 SUPPLY VOLTAGE Unregulated Input Voltage. ...
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... L4974A CIRCUIT OPERATION The L4974A is a 3.5A monolithic stepdown switch- ing regulatorworking in continuousmode realized in the new BCD Technology. This technology allows theintegrationofisolatedverticalDMOS powertran- sistors plus mixed CMOS/Bipolar transistors. The device can deliver3.5A at anoutputvoltagead- justable from 5.1V to 40V and contains diagnostic and control functions that make it particularly suit- able for microprocessor based systems ...
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... Figure 1 : Feedforward Waveform. Figure 2 : Soft Start Function. Figure 3 : Limiting Current Function. L4974A 5/22 ...
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... L4974A Figure 4 : Reset and Power Fail Functions 6/22 ...
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... Min. T yp 15V to 50V 1mA 125 C 0 est Cond ition Min. T yp. 11 50V 0 1mA L4974A = 30K , 4 Max. Unit Fig . 5 0.4 V 0.7 5 ...
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... L4974A ELECTRICAL CHARACTERISTICS (continued) DC CHARACTERISTICS Symbo l Parameter V Turn-on Threshold 11on V Turn-off Hysteresys 11 Hyst I Quiescent Current 11Q I Operating Supply Current 11OQ I Out Leak Current 20L SOFT START (pin 8) Symbo l Parameter I Soft Start Source Current 8 V Output Saturation Voltage 8 ERROR AMPLIFIER Symbo l Parameter ...
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... 50V 4. 5.3V 4.7V 15mA 4. 50V 4.955 13 0.4 = 100KHz) sw L4974A Max. Unit Fig . ref ref -100 -80 mV Vref ref -200 -160 mV 5.1 5. 1.1 1 ...
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... L4974A Figure 6a : Component Layout of fig scale). Evaluation Board Available PART LIST R = 30K 10K 15K 30K 4. see table OPTION 4. 1000 F 63V EYF (ROE 2,2 F 50V 390pF Film 22nF MKT 1837 (ERO) ...
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... Figure 6b: P.C. Board and Component Layout of the Circuit of Fig. 5. (1:1 scale) Figure Test Circuits. L4974A 11/22 ...
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... L4974A Figure 7A. Figure 7B. Figure 7C. 12/22 ...
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... Figure 7D. Figure 8 : Quiescent Drain Current vs. Supply Voltage (0% duty cycle - see fig. 7A). Figure 9 : QuiescentDrain Current vs. Junction Temperature (0% duty cycle). L4974A 13/22 ...
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... L4974A Figure 10 : Quiescent Drain Current vs. Duty Cy- cle. Figure 12 : Reference Voltage (pin 13) vs. Junc- tion Temperature (see fig. 7). Figure 14 : Reference Voltage (pin 14) vs. Junc- tion Temperature (see fig. 7). 14/22 Figure 11 : Reference Voltage (pin 13) vs. Vi (see fig. 7). Figure 13 : ReferenceVoltage (pin 14) vs. Vi (see fig. 7). ...
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... Figure 16 : Switching Frequency vs. Input Voltage (see fig. 5). Figure 18 : Switching Frequency vs. R4 (see fig.5). Figure 20 : Supply Voltage Ripple Rejection vs. Frequency (see fig. 5). Figure 17 : Switching Frequency vs. Junction Temperature (see fig. 5). Figure 19 : Maximum Duty Cycle vs. Frequency. Figure 21 : Efficiency vs. Output Voltage. L4974A 15/22 ...
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... L4974A Figure 22 : Line Transient Response (see fig. 5). Figure 24 : Dropout Voltage between Pin 11 and Pin 20 vs. Current at Pin 20. Figure 26 : Power Dissipation (device only) vs. Input Voltage. 16/22 Figure 23 : Load Transient Response (see fig. 5). Figure 25 : .Dropout Voltage between Pin 11 and Pin 20 vs. Junction Temperature. Figure 27 : Power Dissipation (device only) vs. ...
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... Figure 28 : Power Dissipation (device only) vs. Output Voltage. Figure 30 : Power Dissipation (device only) vs. Output Current. Figure 32 : Efficiency vs. Output Current. Figure 29 : Power Dissipation (device only) vs. OutputVoltage. Figure 31 : Power Dissipation (device only) vs. Output Current. Figure 33 : Test PCB Thermal Characteristic. L4974A 17/22 ...
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... L4974A Figure 34 : Junctionto AmbientThermal Resistance vs. Area onBoard Heatsink (DIP 16+2+2) Figure 36: Open Loop Frequency and Phase of Er- ror Amplifier (see fig. 7C). 18/22 Figure 35: Maximum Allowable Power Dissipa- tion vs. Ambient Temperature (Pow- erdip) ...
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... Figure 37 : 3.5A – 5.1V Low Cost Application Circuit. Figure 5.1V/12VMultiple Supply. Note the Synchronization between the L4974A and L4970A. L4974A 19/22 ...
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... L4974A Figure 39 : L4974A’s Sync. Example. Figure 40: 1A/24V Multiple Supply. Note the synchronization between the L4974A and L4962 20/22 ...
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... DIM. MIN. TYP. MAX. MIN. TYP. a1 0.51 0.020 B 0.85 1.40 0.033 b 0.50 0.020 b1 0.38 0.50 0.015 D 24.80 E 8.80 0.346 e 2.54 0.100 e3 22.86 0.900 F 7.10 I 5.10 L 3.30 0.130 Z 1.27 OUTLINE AND MECHANICAL DATA MAX. 0.055 0.020 0.976 0.280 0.201 Powerdip 20 0.050 L4974A 21/22 ...
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... L4974A Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the conse- quences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specification mentioned in this publication are subject to change without notice ...