LM2678SX-3.3/NOPB National Semiconductor, LM2678SX-3.3/NOPB Datasheet
LM2678SX-3.3/NOPB
Specifications of LM2678SX-3.3/NOPB
*LM2678SX-3.3/NOPB
LM2678SX-3.3
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LM2678SX-3.3/NOPB Summary of contents
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... The output voltage is guaranteed to a ±2% toler- ance. The clock frequency is controlled to within a ±11% tolerance. Typical Application SIMPLE SWITCHER ® registered trademark of National Semiconductor Corporation © 2008 National Semiconductor Corporation ® High Efficiency 5A Step-Down Features ■ Efficiency up to 92% ■ ...
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Connection Diagrams and Ordering Information TO-263 Package Top View Order Number LM2678S-3.3, LM2678S-5.0, LM2678S-12 or LM2678S-ADJ See NSC Package Number TS7B Ordering Information for LLP Package Output Voltage Order Information 12 LM2678SD-12 12 LM2678SDX-12 3.3 LM2678SD-3.3 3.3 LM2678SDX-3.3 5.0 LM2678SD-5.0 ...
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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. Input Supply Voltage ON/OFF Pin Voltage Switch Voltage to Ground (Note 12) Boost Pin Voltage Feedback Pin Voltage Power Dissipation Electrical Characteristics of operation, −40°C to 125°C. Specifications appearing in normal type apply for T LM2678-3 ...
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All Output Voltage Versions Electrical Characteristics Limits appearing in bold type face apply over the entire junction temperature range of operation, −40°C to 125°C. Specifications appearing in normal type apply for T justable versions and V =24V for the 12V ...
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Note 1: Absolute Maximum Ratings are limits beyond which damage to the device may occur. Operating Ratings indicate conditions under which of the device is guaranteed. Operating Ratings do not imply guaranteed performance limits. For guaranteed performance limits and associated ...
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Typical Performance Characteristics Normalized Output Voltage Efficiency vs Input Voltage Switch Current Limit www.national.com 10088609 10088611 Operating Quiescent Current 10088604 6 Line Regulation 10088610 Efficiency vs I LOAD 10088612 10088605 ...
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Standby Quiescent Current 10088640 ON/OFF Pin Current (Sourcing) 10088614 Feedback Pin Bias Current 10088616 ON/OFF Threshold Voltage Switching Frequency 7 10088613 10088615 www.national.com ...
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Continuous Mode Switching Waveforms V = 20V 5V OUT μ 400 μF, C OUT A: V Pin Voltage, 10 V/div Inductor Current, 2 A/div C: Output Ripple Voltage, 20 ...
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Block Diagram * Active Inductor Patent Number 5,514,947 † Active Capacitor Patent Number 5,382,918 9 10088606 www.national.com ...
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... LM267X Made Simple (version 2.0) a complete switching power supply can be de- signed quickly. The software is provided free of charge and can be downloaded from National Semiconductor's Internet site located at http://www.national.com. SWITCH OUTPUT This is the output of a power MOSFET switch connected di- rectly to the input voltage ...
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FIGURE 2. Basic circuit for adjustable output voltage applications Power supply design using the LM2678 is greatly simplified by using recommended external components. A wide range of inductors, capacitors and Schottky diodes from several manufacturers have been evaluated for use ...
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When parallel combinations of capacitors are re- quired it has been assumed that each capacitor is the exact same part type. The RMS current and working voltage (WV) ...
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SIMPLE DESIGN PROCEDURE Using the nomographs and tables in this data sheet (or use the available design software at http://www.national.com) a complete step-down regulator can be designed in a few sim- ple steps. Step 1: Define the power supply operating ...
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ON time of the switch during which energy is stored in the inductor. For this example E•T is found to be: Using Figure 6, the intersection of 27V•μS horizontally and the 3.5A vertical line (I max) ...
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Inductor Selection Guides For Continuous Mode Operation FIGURE 3. LM2678-3.3 FIGURE 4. LM2678-5.0 FIGURE 5. LM2678-12 10088621 10088622 10088623 15 10088624 FIGURE 6. LM2678-ADJ www.national.com ...
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Inductor Inductance Current Reference (µH) Number L23 33 1.35 L24 22 1.65 L25 15 2.00 L29 100 1.41 L30 68 1.71 L31 47 2.06 L32 33 2.46 L33 22 3.02 L34 3.65 15 L38 68 2.97 L39 47 3.57 L40 ...
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Capacitor Selection Guides Capacitor AVX TPS Series Reference C (µF) WV (V) Code C1 330 C2 100 C3 220 100 C10 22 C11 C12 C13 TABLE 2. Input and ...
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Capacitor Sanyo OS-CON SA Series Reference C (µF) WV (V) Code C1 47 6.3 C2 150 6.3 C3 330 6.3 C4 100 10 C5 220 100 16 C8 150 16 C9 100 20 C10 47 ...
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TABLE 3. Output Capacitors for Fixed Output Voltage Application Output Inductance Voltage (V) (µ 3 100 Output Inductance Sanyo OS-CON SA Voltage (V) ...
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TABLE 4. Input Capacitors for Fixed Output Voltage Application (Assumes worst case maximum input voltage and load current for a given inductance value) Output Inductance Voltage (V) (µ 3 ...
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TABLE 5. Schottky Diode Selection Table Reverse Surface Mount Voltage More (V) 20V SK32 30V SK33 MBRD835L 30WQ03F 40V SK34 MBRD1545CT 30BQ040 6TQ045S 30WQ04F MBRS340 MBRD340 SK35 50V or More 30WQ05F Diode Manufacturer Contact Numbers Phone International ...
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TABLE 6. Output Capacitors for Adjustable Output Voltage Applications Output Voltage Inductance (V) 1.21 to 2.50 2.5 to 3.75 3. 6.25 6.25 to 7.5 7 12.5 12 ...
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Output Capacitors for Adjustable Output Voltage Applications (continued) Output Voltage Inductance Sanyo OS-CON SA (V) (µH) No. 33* 2 1.21 to 2.50 47* 2 33* 1 2.5 to 3. ...
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Physical Dimensions www.national.com inches (millimeters) unless otherwise noted TO-263 Surface Mount Power Package Order Number LM2678S-3.3, LM2678S-5.0, LM2678S-12 or LM2678S-ADJ NS Package Number TS7B 24 ...
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TO-220 Power Package Order Number LM2678T-3.3, LM2678T-5.0, LM2678T-12 or LM2678T-ADJ NS Package Number TA07B 14-Lead LLP Package NS Package Number SRC14A 25 www.national.com ...
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