SM72485X/NOPB National Semiconductor, SM72485X/NOPB Datasheet
SM72485X/NOPB
Specifications of SM72485X/NOPB
Related parts for SM72485X/NOPB
SM72485X/NOPB Summary of contents
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... Internal start-up regulator ■ No loop compensation required ■ Ultra-Fast transient response Typical Application, Basic Step-Down Regulator © 2011 National Semiconductor Corporation SM72485 ■ On time varies inversely with input voltage ■ Operating frequency remains constant with varying line voltage and load current ■ ...
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Connection Diagram Ordering Information Order Number Package Type SM72485E SM72485 SM72485X Pin Descriptions Pin Name Description 1 SW Switching Node 2 BST Boost Pin (Boot–strap capacitor input) 3 RCL Current Limit OFF time set pin 4 RTN Ground pin 5 ...
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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 GND IN BST to GND SW to GND (Steady State) ESD Rating (Note 5) Human Body Model BST Electrical Characteristics apply over full Operating Junction Temperature range. V ...
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... For guaranteed specifications and test conditions, see the Electrical Characteristics. Note 2: For detailed information on soldering plastic LLP packages, refer to the Packaging Data Book available from National Semiconductor Corporation. Note 3: All limits are guaranteed. All electrical characteristics having room temperature limits are tested during production with T limits are guaranteed by correlating the electrical characteristics to process and temperature variations and applying statistical process control ...
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Typical Performance Characteristics Efficiency vs. Load Current and V (Circuit of Figure ON-Time vs Input Voltage and R Maximum Frequency vs 30142324 Current Limit Off-Time vs 30142325 and V I OUT IN CC 30142326 5 ...
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Block Diagram Functional Description The SM72485 Step Down Switching Regulator features all the functions needed to implement a low cost, efficient, Buck bias power converter. This high voltage regulator contains a 100 V N-Channel Buck Switch, is easy to implement ...
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The SM72485 regulates the output voltage based on ripple voltage at the feedback input, requiring a minimum amount of ESR for the output capacitor C2. A minimum of 25mV to 50mV of ripple voltage at the feedback pin (FB) is ...
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Regulation Comparator The feedback voltage compared to an internal 2.5V reference. In normal operation (the output voltage is regulat- ed), an on-time period is initiated when the voltage at FB falls below 2.5V. The buck switch will ...
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FIGURE 3. Shutdown Implementation Current Limit The SM72485 contains an intelligent current limit OFF timer. If the current in the Buck switch exceeds 0.3A the present cycle is immediately terminated, and a non-resetable OFF timer is initiated. The length of ...
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SM72485’s current limit threshold (360 mA) with- out saturating, since the current limit is reached during start- up. The ...
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... Kemet C1206C103K5RAC TDK C3216X7R2A104M Diodes Inc. DFLS1100 COILTRONICS DR125-221-R, or TDK SLF10145T-221MR65 Vishay CRCW12063011F Vishay CRCW12061001F Vishay CRCW12063R30F Vishay CRCW12063093F Vishay CRCW12063163F National Semiconductor SM72485 11 30142318 Value 1 µF, 100V 22 µF, 25V 0.47 µF, 50V 0.01 µF, 50V 0.1 µF, 100V 100V, 1A 220 µH 3.01 kΩ ...
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LOW OUTPUT RIPPLE CONFIGURATIONS For applications where low output ripple is required, the fol- lowing options can be used to reduce or nearly eliminate the ripple. a) Reduced ripple configuration: In across R to AC-couple the ripple at V FB2 ...
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Minimum ripple configuration: If the application requires a lower value of ripple (<10 mVp-p), the circuit of be used removed, and the resulting output ripple volt- age is determined by the inductor’s ripple current and C2’s characteristics. ...
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FIGURE 9. Alternate Minimum Output Ripple 14 30142323 ...
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Physical Dimensions inches (millimeters) unless otherwise noted 8-Lead LLP Package NS Package Number SDC08B 15 www.national.com ...
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