lm2744mtcx National Semiconductor Corporation, lm2744mtcx Datasheet
lm2744mtcx
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lm2744mtcx Summary of contents
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... Typical Application © 2007 National Semiconductor Corporation Features ■ Power stage input voltage from 1V to 16V ■ ...
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... Connection Diagram Ordering Information Order Number LM2744MTC LM2744MTCX Pin Descriptions BOOT (Pin 1) - Bootstrap pin. This is the supply rail for the high-side gate driver. When the high-side MOSFET turns on, the voltage on this pin should be at least one gate threshold above the regulator input voltage V MOSFET ...
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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 BOOT Voltage All other pins Junction Temperature Storage Temperature Soldering Information Lead Temperature (soldering, 10sec) Electrical Characteristics ...
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Symbol Parameter GATE DRIVE I BOOT Pin Quiescent Current Q-BOOT R High-Side MOSFET Driver Pull- HG_UP Up ON resistance R High-Side MOSFET Driver Pull- HG_DN Down ON resistance R Low-Side MOSFET Driver Pull- LG_UP Up ON resistance R Low-Side MOSFET ...
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Typical Performance Characteristics Efficiency (V = 1.2V, V OUT V = 3.3V 300kHz CC SW Efficiency (V = 3.3V, V OUT 300kHz Operating Current plus BOOT Current vs Frequency CC ...
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BOOT Pin Current vs Temperature for BOOT Voltage = 300kHz, FDS6898A FET, No-Load SW Frequency vs Temperature (F set to 600kHz nominal) SW Switch Waveforms (HG Rising 3.3V 5V REF ...
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Start-Up (No-Load 3.3V 5V 0.6V REF OUT C = 12nF 300kHz SS SW Shutdown (Full-Load 3.3V 5V 0.6V REF OUT ...
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Line Transient Response ( 3.3V 0.6V REF 300kHz OUT SW www.national.com = 3V to 7V) Line Transient Response ( 1.2V V OUT CC 20106054 ...
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Block Diagram Application Information THEORY OF OPERATION The LM2744 is a voltage-mode, high-speed synchronous buck regulator with a PWM control scheme designed for use in set-top boxes, thin clients, DSL/Cable modems, and other applications that require high efficiency ...
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Where and kΩ. SW FADJ TRACKING A VOLTAGE LEVEL The LM2744 can track the output of a master power supply during soft-start by connecting a resistor divider to the SS/ TRACK pin. In ...
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FIGURE 4. Sequencing Circuit A desired delay time t between the startup of the master DELAY supply output voltage and the LM2744 output voltage can be set based on the SD pin low-to-high threshold V slew rate of the voltage ...
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This bootstrap voltage is usually supplied from a local charge pump structure. But looking at the Typical Appli- cation schematic, this also means that the difference voltage which is the voltage the bootstrap capacitor ...
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LM2744 continues regardless of the state of the Power Good signal. The Power Good flag will return to logic high whenever the feedback pin voltage ...
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another voltage between 1. (see the Electrical Characteristics table). CC DESIGN CONSIDERATIONS The following is a design procedure for all the components needed to create the Typical Application Circuit shown on ...
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... Alternatively, the DSON 1.3 can be ignored and the R of the MOSFET estimated DSON using the R Vs. Temperature curves in the MOSFET DSON datasheets. Gate charging loss results from the current driving the gate capacitance of the power MOSFETs, and is approximated as ...
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In the equation for f , the variable R DP sistance, and represents the inductor DCR plus the on resis- tance of the high-side MOSFET. R divided by output current. The power stage transfer function G is given by the ...
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One method to select use an iterative pro- EA cess beginning with these worst-case conditions. 1. Increase Check overall bandwidth and phase margin 3. Change V to minimum and recheck overall bandwidth IN ...
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As with the generic equation, G EA-ACTUAL take into account the limited bandwidth of the error amplifier. The result is: The total control loop transfer function H is equal to the power stage transfer function multiplied by the error amplifier ...
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There are few additional losses that are taken into account: IC Operating Loss (P IC Q_VCC CC where I is the typical operating V Q-VCC 1.5mA *3.3V = 4.95mW IC ...
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Example Circuits FIGURE 15 3.3V @ 2A, V PART PART NUMBER U LM2744 1 Q FDS6898A 1 D MBR0520LTI 1 L DO3316P-472 16SP100M 6SP220M VJ0805Y104KXXA BOOT ...
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FIGURE 16. 3.3V to 2.5V @ 2A, V PART PART NUMBER U LM2744 1 Q FDS6898A 1 D MBR0520LTI 1 L DO3316P-332 16SP100M 6SP220M VJ0805Y104KXXA BOOT ...
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Physical Dimensions www.national.com inches (millimeters) unless otherwise noted TSSOP-14 Pin Package NS Package Number MTC14 22 ...
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Notes 23 www.national.com ...
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