LM25085MM/NOPB National Semiconductor, LM25085MM/NOPB Datasheet
LM25085MM/NOPB
Specifications of LM25085MM/NOPB
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LM25085MM/NOPB Summary of contents
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... R of the PFET or an external sense resistor can be DS(ON) used to sense current for over-current detection. Typical Application, Basic Step Down Controller © 2009 National Semiconductor Corporation LM25085 Features ■ LM25085Q is an Automotive Grade product that is AEC- Q100 grade 1 qualified (-40°C to 125°C operating junction temperature) ■ ...
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Connection Diagrams Top View 8-Lead MSOP-EP Top View 8-Lead MSOP Ordering Information Package NSC Package Order Number Type LM25085QMYE MSOP-8EP LM25085QMY MSOP-8EP LM25085QMYX MSOP-8EP LM25085MYE MSOP-8EP LM25085MY MSOP-8EP LM25085MYX MSOP-8EP LM25085MME MSOP-8 LM25085MM MSOP-8 LM25085MMX MSOP-8 LM25085SDE LLP-8 LM25085SD LLP-8 ...
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Pin Descriptions Pin Name Description No. 1 ADJ Current Limit Adjust 2 RT On-time control and shutdown 3 FB Voltage Feedback from the regulated output 4 GND Circuit Ground 5 ISEN Current sense input for current limit detection. 6 PGATE ...
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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. VIN to GND ISEN to GND ADJ to GND RT GND Electrical Characteristics junction temperature (T ) range of -40°C to +125°C. Minimum and Maximum limits are guaranteed through test, design, or statistical J correlation ...
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... CC Note 4: For detailed information on soldering plastic MSOP and LLP packages refer to the Packaging Data Book available from National Semiconductor Corporation. Note 5: Tested layer JEDEC board. Four vias provided under the exposed pad. See JEDEC standards JESD51-5 and JESD51-7. ...
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Typical Performance Characteristics Unless otherwise specified the following conditions apply: T Efficiency (Circuit of Figure 4) Shutdown Current vs vs www.national.com = 25° 24V 30079305 IN 30079307 CC 30079309 6 Input Operating ...
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Off-Time vs. V and 30079312 ADJ Pin Current vs 30079317 Shutdown Current vs. Temperature 30079352 Voltage at the RT Pin Input Operating Current vs. Temperature VCC vs. Temperature 7 30079313 30079318 30079353 www.national.com ...
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On-Time vs. Temperature Off-Time vs. Temperature ADJ Pin Current vs. Temperature www.national.com Minimum On-Time vs. Temperature 30079354 Current Limit Comparator Offset vs. Temperature 30079356 PGATE Driver Output Resistance vs. Temperature 30079314 8 30079355 30079357 30079310 ...
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Feedback Reference Voltage vs. Temperature RT Pin Shutdown Threshold vs. Temperature Soft-Start Time vs. Temperature 30079315 30079358 9 30079316 www.national.com ...
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Block Diagram Sense resistor method shown for current limit detection. Minimum output ripple configuration shown. www.national.com 10 30079319 ...
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Functional Description OVERVIEW The LM25085 is a PFET buck (step-down) DC-DC controller using the constant on-time (COT) control principle. The input operating voltage range of the LM25085 is 4.5V to 42V. The use of a PFET in a buck regulator ...
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For V = 42V and t = 100 ns, the simplified equation is SHUTDOWN The LM25085 can be shutdown by grounding the RT pin (see Figure 1). In this mode the PFET is held off, and the VCC ...
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For t in Equation 11 use the minimum on-time at the SW ON node. To determine this time period add the “Minimum on- time in current limit” specified in the Electrical Characteristics (t -4) to the difference of the turn-off ...
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SOFT-START The internal soft-start feature of the LM25085 allows the reg- ulator to gradually reach a steady state operating point at power up, thereby reducing startup stresses and current surges. Upon turn-on, when Vcc reaches its under-voltage lockout threshold, the ...
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Using equation 7 with the minimum value for the ADJ pin current (32 µA), the required R resistor calculates to: ADJ A standard value 2.1 kΩ resistor is selected. The nominal current ...
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C : The capacitor at the VCC pin (from VIN to VCC) pro- VCC vides not only noise filtering and stability for the VCC regula- tor, but also provides the surge current for the PFET gate drive. The typical recommended ...
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FIGURE 5. Efficiency vs. Load Current and V FIGURE 6. Frequency vs 30079305 (Circuit of Figure 4) IN 30079344 (Circuit of Figure 4) www.national.com ...
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FIGURE 8. LM25085 Power Dissipation (Circuit of Figure 4) www.national.com FIGURE 7. Current Limit vs. V (Circuit of Figure 30079345 30079346 ...
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Alternate Output Ripple Configurations The minimum ripple configuration, using C1, C2 and R3, used in the example circuit figure 4, results in a low ripple amplitude at V determined mainly by the characteristics of the output OUT capacitor and the ...
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FIGURE 10. Lowest Cost Ripple Generating Configuration PC Board Layout In most applications, the heat sink pad or tab con- nected to the switch node, i.e. the junction of Q1, L1 and D1. While it is common ...
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Physical Dimensions inches (millimeters) unless otherwise noted 8-Lead MSOP-EP Package NS Package Number MUY08A 8-Lead MSOP Package NS Package Number MUA08A 21 www.national.com ...
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LLP Package NS Package Number SDA08A 22 ...
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Notes 23 www.national.com ...
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