LM25574MTX/NOPB National Semiconductor, LM25574MTX/NOPB Datasheet
LM25574MTX/NOPB
Specifications of LM25574MTX/NOPB
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LM25574MTX/NOPB Summary of contents
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... TSSOP-16 package. The LM25574 is supported by the full suite of WEBENCH On-Line design tools. ® Simplified Application Schematic WEBENCH ® registered trademark of National Semiconductor Corporation. © 2009 National Semiconductor Corporation LM25574/LM25574Q Features ■ LM25574Q is an Automotive Grade product that is AEC- Q100 grade 1 qualified (−40° 125°C operating junction temperature) ■ ...
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Connection Diagram Ordering Information Order Number Package Type LM25574MT TSSOP-16 LM25574MTX TSSOP-16 LM25574QMT TSSOP-16 LM25574QMTX TSSOP-16 * Automotive Grade (Q) product incorporates enhanced manufacturing and support processes for the automotive market, including defect detection methodologies. Reliability qualification is compliant with ...
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Pin Descriptions Pin(s) Name 1 VCC Output of the bias regulator 2 SD Shutdown or UVLO input 3 Vin Input supply voltage 4 SYNC Oscillator synchronization input or output The internal oscillator can be synchronized to an external 5 COMP ...
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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 GND IN BST to GND PRE to GND SW to GND (Steady State) BST SD GND CC Electrical Characteristics apply over full Operating Junction Temperature range. V Symbol ...
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Symbol Parameter RAMP GENERATOR Ramp Current 1 Ramp Current 2 PWM COMPARATOR Forced Off-time Min On-time COMP to PWM Comparator Offset ERROR AMPLIFIER Feedback Voltage FB Bias Current DC Gain COMP Sink / Source Current Unity Gain Bandwidth DIODE SENSE ...
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Soft Start Current vs Temperature 7kΩ L Demoboard Efficiency vs I www.national.com 20214122 IN 20214124 and V OUT IN 20214126 12V IN 20214123 Error Amplifier Gain/Phase ...
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Typical Application Circuit and Block Diagram 7 www.national.com ...
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Detailed Operating Description The LM25574 switching regulator features all of the functions necessary to implement an efficient high voltage buck regu- lator using a minimum of external components. This easy to use regulator integrates a 42V N-Channel buck switch with ...
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Shutdown / Standby The LM25574 contains a dual level Shutdown (SD) circuit. When the SD pin voltage is below 0.7V, the regulator low current shutdown mode. When the SD pin voltage is greater than 0.7V but less ...
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FIGURE 5. Simplified Oscillator Block Diagram and SYNC I/O Circuit Error Amplifier and PWM Comparator The internal high gain error amplifier generates an error signal proportional to the difference between the regulated output voltage and an internal precision reference (1.225V). ...
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FIGURE 6. Composition of Current Sense Signal The sample & hold DC level illustrated in Figure 6 is derived from a measurement of the re-circulating Schottky diode an- ode current. The re-circulating diode anode should be con- nected to the ...
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Maximum Duty Cycle / Input Drop- out Voltage There is a forced off-time of 500ns implemented each cycle to guarantee sufficient time for the diode current to be sam- pled. This forced off-time limits the maximum duty cycle of the ...
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Application Information EXTERNAL COMPONENTS The procedure for calculating the external components is il- lustrated with the following design example. The Bill of Mate- rials for this design is listed in Table 1. The circuit shown in Figure 1 is configured ...
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A good approximation for the re- quired ripple current rating necessary is I Quality ceramic capacitors with a low ESR should be selected for the input filter. To allow for capacitor tolerances and volt- age effects, one ...
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The error amp gain at frequencies greater than f is R5, which is approximately 5 (14dB). Z FIGURE 10. Error Amplifier Gain and Phase The overall loop can be predicted as the sum (in dB) ...
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FIGURE 12. VCC Bias from VOUT for 8V < VOUT < 14V FIGURE 13. VCC Bias with Additional Winding on the Output Inductor www.national.com 20214118 20214119 16 ...
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PCB LAYOUT AND THERMAL CONSIDERATIONS The circuit in Figure 1 serves as both a block diagram of the LM25574 and a typical application board schematic for the LM25574 buck regulator there are two loops where cur- rents are ...
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... CAPACITOR, CER, TDK CAPACITOR, CER, TDK DIODE, 60V, CENTRAL INDUCTOR, COOPER NOT USED NOT USED RESISTOR RESISTOR RESISTOR RESISTOR REGULATOR, NATIONAL SEMICONDUCTOR 18 VALUE 1µ, 100V 470p, 100V 0.01µ, 100V 0.022µ, 100V 0.022µ, 100V 0.47µ, 16V 22µ, 16V 100µ ...
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PCB Layout Component Side Solder Side Silkscreen 19 20214129 20214130 20214131 www.national.com ...
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Typical Schematic for High Frequency (1MHz) Application www.national.com 20 20214140 ...
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Physical Dimensions inches (millimeters) unless otherwise noted 16-Lead TSSOP Package NS Package Number MTC16 21 www.national.com ...
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