LM25005_06 NSC [National Semiconductor], LM25005_06 Datasheet
LM25005_06
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LM25005_06 Summary of contents
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LM25005 42V, 2.5A Step-Down Switching Regulator General Description The LM25005 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 includes a ...
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Connection Diagram Ordering Information Order Number Package Type LM25005MH Exposed Pad TSSOP-20 LM25005MHX Exposed Pad TSSOP-20 www.national.com 20170002 Top View 20-Lead TSSOP NSC Package Drawing MXA20A MXA20A 2 Supplied As 73 Units in Rail 2500 Units on Tape and Reel ...
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Pin Descriptions Pin(S) Name 1 VCC Output of the bias regulator 2 SD Shutdown or UVLO input 3, 4 Vin Input supply voltage 5 SYNC Oscillator synchronization input or output The internal oscillator can be synchronized to an external 6 ...
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Pin(S) Name 20 BST Boost input for bootstrap capacitor NA EP Exposed Pad www.national.com Description An external capacitor is required between the BST and the SW pins. A 0.022µF ceramic capacitor is recommended. The capacitor is charged from Vcc via ...
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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 ...
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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 THERMAL SHUTDOWN ...
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Soft Start Current vs Temperature 20170022 7kΩ L 20170024 Demoboard Efficiency vs I and V OUT IN 20170026 12V IN Error Amplifier Gain/Phase A = 101 ...
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Typical Application Circuit and Block Diagram www.national.com 8 ...
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Detailed Operating Description The LM25005 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 LM25005 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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The Sample and Hold DC level illustrated in Figure 6. is de- rived from a measurement of the re-circulating Schottky diode anode current. The re-circulating diode anode should be con- nected to the IS pin. The diode current flows through ...
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Current Limit The LM25005 contains a unique current monitoring scheme for control and over-current protection. When set correctly, the emulated current sense signal provides a signal which is proportional to the buck switch current with a scale factor of 0.5 ...
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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 Table1. The circuit shown in Figure 1 is configured for ...
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RMS current rating and minimum ripple voltage. 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 ...
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Components R4 and C5 configure the error amplifier as a type II configuration which has a pole at DC and a zero at f (2πR4C5). The error amplifier zero cancels the modulator pole leaving a single pole response at the ...
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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 17 20170018 20170019 www.national.com ...
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PCB LAYOUT AND THERMAL CONSIDERATIONS The circuit in Figure 1 serves as both a block diagram of the LM25005 and a typical application board schematic for the LM25005 buck regulator there are two loops where cur- rents are ...
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PCB Layout Component Side Solder Side Silkscreen 19 20170029 20170030 20170031 www.national.com ...
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Physical Dimensions www.national.com inches (millimeters) unless otherwise noted 20-Lead TSSOP Package NS Package Number MXA20A 20 ...
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Notes 21 www.national.com ...
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THE CONTENTS OF THIS DOCUMENT ARE PROVIDED IN CONNECTION WITH NATIONAL SEMICONDUCTOR CORPORATION (“NATIONAL”) PRODUCTS. NATIONAL MAKES NO REPRESENTATIONS OR WARRANTIES WITH RESPECT TO THE ACCURACY OR COMPLETENESS OF THE CONTENTS OF THIS PUBLICATION AND RESERVES THE RIGHT TO MAKE ...