LM2747MTC/NOPB National Semiconductor, LM2747MTC/NOPB Datasheet
LM2747MTC/NOPB
Specifications of LM2747MTC/NOPB
*LM2747MTC/NOPB
LM2747MTC
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LM2747MTC/NOPB Summary of contents
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... In addition, the shutdown pin of the IC can be used for providing startup delay, and the soft-start pin can be used for implementing precise tracking, for the purpose of sequencing with respect to an external rail. Typical Application © 2006 National Semiconductor Corporation Features ± 1% feedback voltage accuracy over temperature n ± ...
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Connection Diagram Ordering Information Order Number Package Type LM2747MTC TSSOP-14 LM2747MTCX Pin Description 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 ...
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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 I SEN FREQ/SYNC Voltage All other pins Junction Temperature Storage Temperature Electrical Characteristics V = 3.3V unless otherwise indicated. Typicals and limits appearing in plain type apply for T CC boldface type apply over full Operating Temperature Range ...
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Electrical Characteristics V = 3.3V unless otherwise indicated. Typicals and limits appearing in plain type apply for T CC boldface type apply over full Operating Temperature Range. Datasheet min/max specification limits are guaranteed by design, test, or statistical analysis. Symbol ...
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Typical Performance Characteristics Efficiency (V = 1.2V) OUT V = 3.3V MHz CC SW Frequency vs Temperature Switch Waveforms V = 3.3V 5V OUT nF, f ...
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Typical Performance Characteristics Start-Up (No-Load 3. MHz SS SW Load Transient Response V = 3.3V 14V MHz ...
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Typical Performance Characteristics Maximum Duty Cycle 600 kHz SW (Continued) Maximum Duty Cycle 20150993 MHz SW 20150994 www.national.com ...
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Block Diagram Application Information The LM2747 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 buck convert- ers. ...
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Application Information is approximated by the curve FREQUENCY vs. FRE- QUENCY ADJUST RESISTOR in the Typical Performance Characteristics section. When it is desired to synchronize the switching frequency with an external clock source, the LM2747 has the unique ability to ...
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Application Information target values at the same time. For this case, the equation governing the values of the tracking divider resistors R R is: T2 The current through R should be about 4 mA for precise T1 tracking. The final ...
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Application Information For example, if the master supply output voltage slew rate was 1V/ms and the desired delay time between the startup of the master supply and LM2747 output voltage was 5 ms, then the desired SD pin slew rate ...
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Application Information the Miller plateau level. This may therefore affect the choice of the threshold voltage of the external MOSFETs, and that in turn may depend on the chosen V So far, in the discussion above, the forward drop across ...
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Application Information POWER GOOD SIGNAL The open drain output on the Power Good pin needs a pull-up resistor to a low voltage source. The pull-up resistor should be chosen so that the current going into the Power Good pin is ...
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Application Information will be reduced in turn to a flat level equal to the current limit threshold. The third benefit of the soft-start capacitor dis- charge is a smooth, controlled ramp of output voltage when the current limit condition is ...
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Application Information In this example, in order to maintain a 2% peak-to-peak output voltage ripple and a 40% peak-to-peak inductor cur- rent ripple, the required maximum ESR is 20 mΩ. The Sanyo 4SP560M electrolytic capacitor will give an equivalent ESR ...
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Application Information FIGURE 13. Power Stage and Error Amp One popular method for selecting the compensation compo- nents is to create Bode plots of gain and phase for the power stage and error amplifier. Combined, they make the overall bandwidth ...
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Application Information as high as possible. Two zeroes f and f Z1 double pole frequency to cancel the double pole phase lag. Then, a pole placed at the frequency of the ESR zero final pole f ...
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Application Information In practice, a good trade off between phase margin and bandwidth can be obtained by selecting the closest capacitor values above what are suggested for C ± the closest 10% capacitor value below the suggestion for ± C ...
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Application Information P = 0 300 kHz 61. The FDS6898A has a typical turn-on rise time t fall time and 16 ns, respectively. ...
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Example Circuits PART PART NUMBER U1 LM2747 Q1 FDS6898A D1 MBR0520LTI L1 DO3316P-472 C 1 16SP100M 6SP220M VJ1206Y104KXXA CC BOOT VJ0805Y332KXXA C3 C VJ0805A123KXAA SS C ...
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Example Circuits (Continued) PART PART NUMBER U1 LM2747 Q1 FDS6898A D1 MBR0520LTI L1 DO3316P-682 C 1 16SP100M 10SP56M VJ1206Y104KXXA CC BOOT VJ0805Y182KXXA C3 C VJ0805A123KXAA SS ...
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Example Circuits (Continued) PART PART NUMBER U1 LM2747 Q1 FDS6898A D1 MBR0520LTI L1 DO3316P-332 C 1 16SP100M 6SP220M VJ1206Y104KXXA CC BOOT VJ0805Y222KXXA C3 C VJ0805A123KXAA SS ...
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