LM2678T-ADJ National Semiconductor, LM2678T-ADJ Datasheet
LM2678T-ADJ
Specifications of LM2678T-ADJ
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LM2678T-ADJ Summary of contents
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... The output voltage is guaranteed to a ance. The clock frequency is controlled to within a tolerance. Typical Application SIMPLE SWITCHER ® registered trademark of National Semiconductor Corporation. © 2005 National Semiconductor Corporation High Efficiency 5A Step-Down ® Features n Efficiency up to 92% n Simple and easy to design with (using off-the-shelf external components) n 120 mΩ ...
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... LM2678SD-5.0 5.0 LM2678SDX-5.0 ADJ LM2678SD-ADJ ADJ LM2678SDX-ADJ www.national.com 10088601 LM2678T-3.3, LM2678T-5.0, LM2678T-12 or LM2678T-ADJ See NSC Package Number TA07B Top View 10088641 LLP-14 See NS package Number SRC14A Package Marking S0003BB 250 Units on Tape and Reel S0003BB 2500 Units on Tape and Reel ...
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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 Boost Pin Voltage Feedback Pin Voltage Power Dissipation ESD (Note 2) Electrical Characteristics range of operation, − ...
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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. Specifica- tions appearing in normal type apply for T versions and V =24V for the 12V ...
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All Output Voltage Versions Electrical Characteristics Note 4: All limits are guaranteed at room temperature (standard type face) and at temperature extremes (bold type face). All room temperature limits are 100% tested during production with 25˚C. ...
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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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Typical Performance Characteristics Standby Quiescent Current ON/OFF Pin Current (Sourcing) Feedback Pin Bias Current (Continued) ON/OFF Threshold Voltage 10088640 10088614 10088616 7 10088613 Switching Frequency 10088615 www.national.com ...
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Typical Performance Characteristics 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 ...
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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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Application Hints The LM2678 provides all of the active functions required for a step-down (buck) switching regulator. The internal power switch is a DMOS power MOSFET to provide power supply designs with high current capability 5A, and highly ...
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Application Hints (Continued) 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 ...
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Application Hints (Continued) frequency. With the fixed 260KHz switching frequency of the LM2678, the output capacitor is selected to provide a unity gain bandwidth of 40KHz maximum. Each recommended capacitor value has been chosen to achieve this result. In some ...
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... The maximum load current is 4A. Through-hole components are preferred. Step 1: Operating conditions are: Vout = 3.3V Vin max = 16V Iload max = 4A Step 2: Select an LM2678T-3.3. The output voltage will have a tolerance of ± ± room temperature and 3% over the full operating temperature range ...
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Application Hints (Continued) The switching frequency of 260KHz is the nominal value to use to estimate the ON time of the switch during which energy is stored in the inductor. For this example E • found to be: ...
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Application Hints (Continued) Step 5: An input capacitor for this example will require at least a 35V WV rating with an rms current rating of 1.75A (1/2 Iout max). From Table 2 it can be seen that C12, a 33µF/35V ...
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Inductor Selection Guides FIGURE 3. LM2678-3.3 FIGURE 5. LM2678-12 www.national.com For Continuous Mode Operation 10088621 10088623 16 10088622 FIGURE 4. LM2678-5.0 10088624 FIGURE 6. LM2678-ADJ ...
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Inductor Selection Guides TABLE 1. Inductor Manufacturer Part Numbers Inductor Inductance Current Reference (µH) (A) 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 ...
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Capacitor Selection Guides Capacitor AVX TPS Series Reference Code C (µF) WV (V) C1 330 C2 100 C3 220 100 C10 22 C11 C12 C13 www.national.com TABLE 2. Input ...
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Capacitor Selection Guides Input and Output Capacitor Codes (continued) Capacitor Sanyo OS-CON SA Series Reference Irms Code C (µF) WV (V) ( 6.3 C2 150 6.3 1.95 C3 330 6.3 2.45 C4 100 10 1.87 C5 220 10 ...
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Capacitor Selection Guides TABLE 3. Output Capacitors for Fixed Output Voltage Application Output Inductance Voltage (V) (µ 3 100 Output Inductance Sanyo OS-CON ...
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Capacitor Selection Guides 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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Capacitor Selection Guides Reverse Voltage (V) 20V 30V 40V 50V or More International Rectifier Motorola General Semiconductor Diodes, Inc. www.national.com (Continued) TABLE 5. Schottky Diode Selection Table Surface Mount Through Hole More 3A SK32 1N5820 SR302 SK33 ...
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Capacitor Selection Guides TABLE 6. Output Capacitors for Adjustable Output Voltage Applications Output Voltage Inductance (V) (µ 1. 2 ...
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Capacitor Selection Guides Output Capacitors for Adjustable Output Voltage Applications (continued) Output Voltage Inductance Sanyo OS-CON SA (V) (µ 1. 2 ...
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Physical Dimensions 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 25 www.national.com ...
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... Physical Dimensions www.national.com inches (millimeters) unless otherwise noted (Continued) 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 26 ...
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