lm5015mhx National Semiconductor Corporation, lm5015mhx Datasheet
lm5015mhx
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lm5015mhx Summary of contents
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... The de- vice is available in the TSSOP-14EP package featuring an exposed die attach pad to enhance thermal dissipation. Typical Application Schematic © 2009 National Semiconductor Corporation Features ■ Dual Integrated 75V N-Channel MOSFETs ■ ...
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... Connection Diagram Ordering Information Order Number LM5015MH LM5015MHE LM5015MHX www.national.com Top View TSSOP-14 EP Package Package Type NSC Package Drawing TSSOP-14 EP MXA14A 2 30034602 Supplied As 94 Units per Antistatic Tube 250 Units on Tape and Reel 2500 Units on Tape and Reel ...
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Pin Descriptions Pin Name Description 1 AGND Analog ground 2 RT Oscillator frequency programming and optional synchronization input 3 FB Feedback input of the internal error amplifier, for non-isolated applications 4 COMP Control input for the PWM comparator 5 CFB ...
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Absolute Maximum Ratings If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications AGND IN BST to AGND PVIN to HO, LO, PGND HO to PGND (Steady State ...
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Symbol Parameters PWM COMPARATOR Maximum Duty Cycle Min On-time Min On-time V COMP to PWM Comparator Offset COMP-OS ERROR AMPLIFIER V Feedback Reference Voltage FB-REF FB Bias Current DC Gain COMP Sink Current COMP Short Circuit Current COMP Open Circuit ...
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Typical Performance Characteristics Demo-board Efficiency (non-switching) vs VIN RDS(ON) vs VCC vs Temperature www.national.com and V OUT IN 30034603 30034605 30034607 6 VFB vs Temperature 30034604 VCC vs VIN 30034606 IEN vs VIN vs Temperature 30034608 ...
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ILIM vs VCC 30034609 Fsw 30034611 Fsw vs VCC 30034613 7 ILIM vs VCC vs Temperature 30034610 Fsw vs Temperature 30034612 Error Amplifier Gain/Phase 30034614 www.national.com ...
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FIGURE 1. Block Diagram 8 30034615 ...
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Functional Description The LM5015 high voltage switching regulator features all the functions necessary to implement an efficient power convert- er using a Two-Switch Forward or Two-Switch Flyback topol- ogy. The voltage across the MOSFETs employed in the two- switch topology ...
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The PVIN and PGND pins are internally connected to the high and low side power MOSFETs, respectively. When designing the PC board, the input filter capacitor should connect directly to these pins with short connection traces. The VIN operating range ...
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When isolation between primary and secondary circuits is re- quired, the Error Amplifier is usually disabled by connecting the FB pin to AGND. This allows the COMP pin to be driven directly by the collector of an opto-coupler. In isolated ...
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Application Information The following information is intended to provide guidelines for the power supply designer using the LM5015. TWO-SWITCH FORWARD TOPOLOGY Two-Switch Forward converter, like the conventional Single- Switch Forward converter, is derived from the Buck converter topology. The main ...
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Figure 5 shows the two operating modes of the Two-Switch Forward converter. During operation, the two MOSFETS are turned ON and OFF simultaneously. The output voltage is regulated by modulating the duty cycle of the MOSFETs. The relationship between the ...
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Note that the power transformer primary receives the voltage of the nearly equal magnitude but opposite polarities during the ON and OFF period of the power MOSFETs. In order to guarantee the volt-second balance between the magnetizing and demagnetizing intervals, ...
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EN / UVLO VOLTAGE DIVIDER SELECTION Two dedicated comparators connected to the EN pin are used to implement input under-voltage lockout and a shutdown condition. When the EN pin voltage is below 0.45V, the con- troller low ...
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SOFT-START Soft-start is implemented with an external capacitor C nected to the SS pin as shown in Figure 8. The SS discharge MOSFET conducts during Shutdown and Standby modes. When the SS pin is low, the COMP voltage is held ...
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CONVENTIONAL ISOLATED OUTPUT FEEDBACK DESIGNS When isolation between the primary and secondary circuits is required, the internal error amplifier is usually disabled by connecting the FB pin to AGND, and an external error ampli- fier is employed on the secondary ...
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FIGURE 10. High bandwidth Isolated Feedback Using CFB Pin The two external pull-up and pull-down resistors are effec- tively connected in parallel for ac signal, yielding a collector resistance on the opto-coupler of 0.5 kΩ. This resistance is 10 times ...
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IC. Judicious positioning of the PC board within the end prod- uct, along with use of any available air flow will help reduce the junction temperature. If using forced air cooling, avoid placing the LM5015 in the airflow shadow of ...
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ISOLATED TWO-SWITCH FORWARD The Isolated Two-Switch Forward converter shown in Figure 13 utilizes a 1.24V voltage reference (LMV431A) located on the isolated secondary side for the regulation set-point. The LM5015 internal error amplifier is disabled by grounding the FB ...
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DC-DC TRANSFORMER The DC-DC transformer shown in Figure 15 provides a 1:1 input voltage to output voltage conversion with ground isola- tion. The circuit operates in open loop manner operating at the maximum duty cycle limit of the LM5015. The ...
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Physical Dimensions www.national.com inches (millimeters) unless otherwise noted 14-Lead Exposed Pad Package NS Package Number MXA14A 22 ...
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Notes 23 www.national.com ...
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