LP2975IMMX-3.3 National Semiconductor, LP2975IMMX-3.3 Datasheet

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... Block Diagram *R values are: 208k for 12V part, 72.8k for 5V part, and 39.9k for 3.3V SET part. © 2005 National Semiconductor Corporation Features n Simple to use, few external components n Ultra-small mini SO-8 package n 1.5% (A grade) precision output voltage n Low-power shutdown input < ...

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... L46A LP2975AIMM-5.0 L46A LP2975IMMX-5.0 L46B LP2975IMM-5.0 L46B LP2975AIMMX-3.3 L45A LP2975AIMM-3.3 L45A LP2975IMMX-3.3 L45B LP2975IMM-3.3 L45B 2 Supplied As: 3500 Units on Tape and Reel 1000 Units on Tape and Reel 3500 Units on Tape and Reel 1000 Units on Tape and Reel 3500 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. Storage Temperature Range Operating Junction Temperature Range Lead Temp. (Soldering, 5 seconds) ESD Rating Power Dissipation (Note 2) Electrical Characteristics Limits in standard typeface are for T J less otherwise specified ...

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Electrical Characteristics Note 2: The LP2975 has internal thermal shutdown which activates at a die temperature of about 150˚C. It should be noted that the power dissipated within the LP2975 is low enough that this protection circuit should never activate ...

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Typical Application Circuits *See Application Hints. ***If current limiting is not required, short out this resistor. (Continued) Adjustable Voltage 5A LDO Regulator 5 10003404 www.national.com ...

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Typical Performance Characteristics Unless otherwise specified 25˚ OFF pin is tied to 1.5V. Minimum Operating Voltage ON/OFF Threshold www.national.com = 1 µF, ON 10003405 Current Limit Sense Voltage 10003407 6 Referred Gate Clamp ...

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Typical Performance Characteristics is tied to 1.5V. (Continued) ON/OFF Pin Current ON/OFF Input Resistance Gate-Ground Saturation Unless otherwise specified: T Supply Current 10003409 10003411 Line Regulation 10003413 7 = 25˚ µF, ON/OFF pin A IN 10003410 Gate ...

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Typical Performance Characteristics is tied to 1.5V. (Continued) Load Regulation Controller Gain and Phase Response Reference Designs The LP2975 controller can be used with virtually any P-channel MOSFET to build a wide variety of linear voltage regulators. Since it would ...

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Reference Designs (Continued) Load Regulation Load regulation is defined as the maximum change in output voltage as the load current is varied measured by changing the load resistance and recording the minimum/ maximum output voltage. The measured change ...

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Reference Designs (Continued) The load resistor is connected to the regulator output using a switch so that the load current increases from 0 to 0.5A abruptly. The change in output voltage is shown in the scope photo (the vertical scale ...

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Reference Designs (Continued) DESIGN # 1.5V @ 6A. (Refer to Typical OUT Application Circuits, Adjustable Voltage Regulator) Components C = 1000 µF Aluminum Electrolytic 330 µF OSCON Aluminum Electrolytic OUT C = NOT ...

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Application Hints (Continued) 1) The Gate pin of the LP2975 (which drives the Gate of the FET) has a limited amount of current to source or sink. This means faster changes in Gate voltage (which corresponds to faster transient response) ...

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Application Hints (Continued) of 0.3–0.5˚C/W. The best source of information for this is heatsink catalogs (Wakefield, AAVID, Thermalloy) since they also sell mounting hardware. θ is the heatsink-to-ambient thermal resistance, which S-A defines how well a heatsink transfers heat into ...

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Application Hints (Continued) The ESR of the output capacitor is very important for stabil- ity creates a zero (f ) which cancels much of the phase z shift resulting from one of the poles present in the loop. ...

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Application Hints (Continued − ISS RSS G is the Gate-to-Drain capacitance, which is equal to RSS G is the transconductance of the FET. The FET data m sheet specifies forward ...

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Application Hints (Continued) Phase Shift Due to f Because of this, there is no exact number for f be given as a fixed limit for stable operation. However general guideline recommended that f If this is ...

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Application Hints (Continued) tributions of phase lag and lead from each one. As shown in the graphs, most of the phase lag (or lead) contributed by a pole (or zero) occurs within one decade of the frequency of the pole ...

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Application Hints (Continued) High ESR Unstable without Feed-Forward As shown, moving the location of f extends the bandwidth, pushing the crossover frequency f out to about 200 kHz. In viewing the plot, it can be seen that f and f ...

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Application Hints (Continued) LOW OUTPUT VOLTAGE AND C F The feed-forward capacitor C will provide a positive phase F shift (lead) which can be used to cancel some of the excess phase lag from any of the various poles present ...

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