lm25576q0 National Semiconductor Corporation, lm25576q0 Datasheet
lm25576q0
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lm25576q0 Summary of contents
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... Simplified Application Schematic WEBENCH ® registered trademark of National Semiconductor Corporation. © 2008 National Semiconductor Corporation Features ■ LM25576Q0 is an Automotive Grade product that is AEC- Q100 grade 0 qualified ■ -40°C to 150°C operating junction temperature ■ Integrated 42V, 170mΩ N-channel MOSFET ■ ...
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... Package Type LM25576Q0MH Exposed Pad TSSOP-20 MXA20A LM25576Q0MHX Exposed Pad TSSOP-20 MXA20A * Automotive Grade (Q) product incorporates enhanced manufacturing and support processes for the automotive market, including defect detection methodologies. Reliability qualification is compliant with the requirements and temperature grades defined in the AECQ100 standard. Automotive Grade products are identified with letter Q ...
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... This open drain output can be connected to SW pin to aid charging the bootstrap capacitor during very light load conditions or in applications where the output may be pre- charged before the LM25576Q0 is enabled. An internal pre- charge MOSFET is turned on for 265ns each cycle just prior to the on-time interval of the buck switch. ...
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Pin(s) Name 20 BST Boost input for bootstrap capacitor NA EP Exposed Pad www.national.com Description An external capacitor is required between the BST and the SW pins. A 0.022µF ceramic capacitor is recommended. The capacitor is charged from Vcc via ...
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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 PRE to GND SW to GND (Steady State) BST ...
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Symbol Parameter RAMP GENERATOR Ramp Current 1 Ramp Current 2 PWM COMPARATOR Forced Off-time Min On-time COMP to PWM Comparator Offset ERROR AMPLIFIER Feedback Voltage FB Bias Current DC Gain COMP Sink / Source Current Unity Gain Bandwidth DIODE SENSE ...
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Soft Start Current vs Temperature 30071247 7kΩ L 30071224 Demoboard Efficiency vs I and V OUT IN 30071226 12V IN Error Amplifier Gain/Phase A = 101 ...
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Typical Application Circuit and Block Diagram www.national.com 8 ...
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... TSSOP-20 package featuring an exposed pad to aid thermal dissipation. The functional block diagram and typical application of the LM25576Q0 are shown in Figure 1. The LM25576Q0 can be applied in numerous applications to efficiently step-down a high, unregulated input voltage. The device is well suited for telecom, industrial and automotive power bus voltage ranges. ...
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... Thus, if the SYNC pins of several LM25576Q0 IC’s are connected together, the IC with the highest internal clock fre- quency will pull the connected SYNC pins low first and termi- nate the oscillator ramp cycles of the other IC’ ...
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... In applications where the input voltage may be relatively large in comparison to the output voltage, controlling small pulsewidths and duty cycles is necessary for regulation. The LM25576Q0 utilizes a unique ramp generator, which does not actually measure the buck switch current but rather recon- structs the signal. Reconstructing or emulating the inductor ...
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The sample & hold DC level illustrated in Figure 6 is derived from a measurement of the re-circulating Schottky diode an- ode current. The re-circulating diode anode should be con- nected to the IS pin. The diode current flows through ...
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... Boost Pin The LM25576Q0 integrates an N-Channel buck switch and associated floating high voltage level shift / gate driver. This gate driver circuit works in conjunction with an internal diode and an external bootstrap capacitor. A 0.022µF ceramic ca- pacitor, connected with short traces between the BST pin and SW pin, is recommended ...
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... The worst case is to assume a short circuit load condition. In this case the diode will carry the output cur- rent almost continuously. For the LM25576Q0 this current can be as high as 4.2A. Assuming a worst case 1V drop across the diode, the maximum diode power dissipation can be as high as 4 ...
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... R4 and C5. The overall loop gain is the product of the modulator gain and the error ampli- fier gain. The DC modulator gain of the LM25576Q0 is as follows: DC Gain The dominant low frequency pole of the modulator is deter- ...
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Components R4 and C5 configure the error amplifier as a type II configuration which has a pole at DC and a zero at f π (2 R4C5). The error amplifier zero cancels the modulator pole leaving a single pole response ...
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FIGURE 12. VCC Bias from VOUT for 8V < VOUT < 14V FIGURE 13. VCC Bias with Additional Winding on the Output Inductor 17 30071218 30071219 www.national.com ...
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... R x 1.1, and no airflow, the predicted junction temperature for the OUT LM25576Q0 will (45 x 1.9) = 110°C. If the evaluation board is operated at 3A output current and 42V input voltage for a prolonged period of time the thermal shutdown protec- tion within the IC may activate. The IC will turn off allowing the junction to cool, followed by restart with the soft-start capac- itor reset to zero ...
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Typical Schematic for High Frequency (1MHz) Application Typical Schematic for Buck/Boost (Inverting) Application Schematic 3.3V, 3A, 1MHz 19 30071240 30071242 www.national.com ...
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Physical Dimensions www.national.com inches (millimeters) unless otherwise noted 20-Lead TSSOP Package NS Package Number MXA20A 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. ...