lm20145mhx National Semiconductor Corporation, lm20145mhx Datasheet
lm20145mhx
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lm20145mhx Summary of contents
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... The LM20145 is offered in a 16-pin eTSSOP package with an exposed pad that can be soldered to the PCB, eliminating the need for bulky heatsinks. Typical Application Circuit ® PowerWise is a registered trademark of National Semiconductor Corporation. © 2007 National Semiconductor Corporation Adjustable Frequency Synchronous Buck Features ■ Input voltage range 2.95V to 5.5V ■ ...
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... Connection Diagram Ordering Information Order Number Package Type LM20145MH eTSSOP-16 LM20145MHE LM20145MHX Pin Descriptions Pin # Name 1 SS/TRK Soft-Start or Tracking control input. An internal 5 µA current source charges an external capacitor to set the Soft-Start ramp rate. If driven by a external source less than 800 mV, this pin overrides the internal reference that sets the output voltage ...
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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. Voltages from the indicated pins to GND AVIN, PVIN, EN, PGOOD, SS/TRK, COMP, FB, RT Storage Temperature Junction Temperature ...
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Symbol Parameter Enable V EN Pin turn-on Threshold IH_EN V EN Pin Hysteresis EN_HYS Thermal Shutdown T Thermal Shutdown SD T Thermal Shutdown Hysteresis SD_HYS Thermal Resistance θ Junction to Ambient JA Note 1: Absolute Maximum Ratings indicate limits beyond ...
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Error Amplifier Gain vs. Frequency 30030736 Load Regulation 30030738 Switching Frequency vs. Temperature 30030739 Line Regulation Feedback Pin Voltage vs. Temperature Switching Frequency vs 30030737 30030751 T 30030750 www.national.com ...
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Quiescent Current vs. V Enable Threshold vs. Temperature Peak Current Limit vs. Temperature www.national.com (Not Switching) IN 30030740 30030728 30030742 6 Shutdown Current vs. Temperature 30030741 UVLO Threshold vs. Temperature 30030745 Peak Current Limit vs. V OUT 30030754 ...
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Peak Current Limit vs 30030755 Line Transient Response 30030743 Start-Up (Tracking) 30030733 Load Transient Response Start-Up (Soft-Start) Power Down 7 30030734 30030744 30030732 www.national.com ...
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Short Circuit Input Current vs. V www.national.com P IN 30030756 8 vs. I GOOD PGOOD 30030727 ...
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Block Diagram 9 30030703 www.national.com ...
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Operation Description GENERAL The LM20145 switching regulator features all of the functions necessary to implement an efficient low voltage buck regula- tor using a minimum number of external components. This easy to use regulator features two integrated switches and is ...
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When activated, typically at 160°C, the LM20145 tri-states the power FETs and resets soft start. After the junction cools to approximately 150°C, the part starts up using the normal start up routine. This feature is provided to ...
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Design Guide This section walks the designer through the steps necessary to select the external components to build a fully functional power supply. As with any DC-DC converter numerous trade- offs are possible to optimize the design for efficiency, size, ...
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Where, C (F) is the minimum required output capacitance, OUT L (H) is the value of the inductor, V DROOP voltage drop ignoring loop bandwidth considerations, ΔI (A) is the load step change, R STEP ESR capacitor ESR, V (V) ...
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FIGURE 4. LM20145 Loop Compensation The power stage transfer function is dictated by the modula- tor, output LC filter, and load; while the feedback transfer function is set by the feedback resistor ratio, error amp gain, and external compensation network. ...
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If different start up times are needed the equation shown be- low can be used to calculate the start up time. As shown above, the start up time is influenced by the value of the Soft-Start capacitor C (F) and ...
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The second most common power on behavior is known as a ratiometric start up. This start up is preferred in applications where both supplies need the final value at the same time. Similar to the Soft-Start function, ...
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FIGURE 10. Schematic of LM20145 Highlighting Layout Sensitive Nodes 17 30030722 www.national.com ...
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Typical Application Circuits This section provides several application solutions with a bill of materials. All bill of materials reference the below figure. Bill of Materials ( Designator Description U1 Synchronous Buck Regulator C 100 µF, 1210, ...
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Designator Description 4.99 kΩ, 0603 R FB1 10 kΩ, 0603 R FB2 Part Number Manufacturer CRCW06034991F-e3 Vishay-Dale CRCW06031002F-e3 Vishay-Dale 19 Qty 1 1 www.national.com ...
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Physical Dimensions www.national.com inches (millimeters) unless otherwise noted 16-Lead eTSSOP Package NS Package Number MXA16A 20 ...
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Notes 21 www.national.com ...
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... National Semiconductor and the National Semiconductor logo are registered trademarks of National Semiconductor Corporation. All other brand or product names may be trademarks or registered trademarks of their respective holders. ...