NCV8851B ON Semiconductor, NCV8851B Datasheet
NCV8851B
Related parts for NCV8851B
NCV8851B Summary of contents
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... NCV8851B Automotive Grade Synchronous Buck Controller The NCV8851B is an adjustable output, synchronous buck controller, which drives dual N−channel MOSFETs, ideal for high power applications. Average current mode control is employed for very fast transient response and tight regulation over wide input voltage and output load ranges. The IC incorporates an internal fixed 6.0 V low− ...
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... NCV8851B Enable TSD Fault EN 11 Logic LDO UVLO Enable V 3 IN_IC Fault Soft Start Fixed−Frequency 1 SYNC Oscillator V SS Ramp Clock 20 R OSC Max Duty Q S Min On Time R Q Reset Dominant PWM Fault C 15 COMP OCP V OCP CEA + ...
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... Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect device reliability. NCV8851B Function , to V forms a boost circuit. ...
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... OSCILLATOR Switching Frequency Ramp Voltage Amplitude VOLTAGE ERROR AMPLIFIER DC Gain Gain−Bandwidth Product Charge Currents FB Bias Current CURRENT SENSE AMPLIFIER Common−Mode Range Amplifier Gain NCV8851B = 51.1 kW, unless otherwise specified) OSC Conditions Sleep Mode IN −40°C < T < 125° 13 ...
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... Source Current GH GL Sink Current GL Source Current Delay Delay SOFT START Time ENABLE (EN) Input Threshold Input Current NCV8851B = 51.1 kW, unless otherwise specified) OSC Conditions Guaranteed by Design Guaranteed by Design Source 1.75 V COMP Sink 1.75 V COMP Guaranteed by Design 1.2 V ≤ CSN ≤ 10.0 V ...
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... Load Capacitance (nF) Figure 6. Driver Rise Time vs. Load Capacitance 101% 100% 99% 98% − 100 150 Ambient Temperature (°C) Figure 9. Average Current−Limit Threshold vs. Temperature NCV8851B TYPICAL CHARACTERISTICS = 13 51.1 kW, unless otherwise noted) IN OSC 4.0 3.5 3.0 2.5 2.0 1.5 1.0 170 220 270 320 370 420 470 Switching Frequency (kHz) Figure 4 ...
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... Ambient Temperature (°C) Figure 12. Oscillator Frequency vs. Temperature 100.50% 100.25% 100.00% 99.75% 99.50% 0.00 5.00 10.00 15.00 20.00 LDO Load Current (mA) Figure 15. LDO Load Regulation NCV8851B TYPICAL CHARACTERISTICS = 13 51.1 kW, unless otherwise noted) IN OSC − 100 150 Ambient Temperature (° ...
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... This frequency is conveniently set with an external resistor to ground. An external clock signal can also be used to synchronize the NCV8851B to a higher operating frequency during operation. To protect against possible damage of external power−stage components, excessive inrush of current during start− ...
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... There is a built in minimum off−time which ensures that the bootstrap supply is charged every cycle, determining the maximum duty cycle at a given frequency. is conducting, ZEN2 The NCV8851B can achieve at least a 95% duty cycle Z while operating at frequencies up to 200 kHz (89 have ZEN2 500 kHz) ...
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... Fault Figure 23. Gate Driver Block Diagram Since the BST capacitor only recharges when the low−side MOSFET is on, pulling V NCV8851B has a minimum off−time. This also means that higher than the BST capacitor cannot be arbitrarily large, since 6V OUT needs to be able to charge it up during this minimum off− ...
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... SYNC Feature An external clock signal can synchronize the NCV8851B to a higher frequency. The rising edge of the SYNC pulse turns on the power switch to start a new switching cycle, as shown in Figure 24. There is a 0.5 ms delay between the rising edge of the SYNC pulse and rising edge of the V pin voltage ...
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... Design Methodology Choosing external components for the NCV8851B encompasses the following design process: 1. Define operational parameters 2. Select switching frequency 3. Select current sensor 4. Select output inductor 5. Select output capacitors 6. Select input capacitors 7. Select compensator components (1) Operational Parameter Definition Before proceeding with the rest of the design, certain operational parameters must be defined. These are application− ...
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... Both mechanical and electrical considerations influence the selection of an output inductor. From a mechanical perspective, smaller inductor values generally correspond to NCV8851B smaller physical size. Since the inductor is often one of the largest components in the power supply, a minimum inductor value is particularly important in space− ...
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... As can be seen from the above equation, to minimize inductor losses, an inductor with very low DCR should be chosen. NCV8851B (5) Output Capacitor Selection The output capacitor is a basic component for the fast response of the power supply. During a load step, for the first ) few microseconds, it supplies the current to the load ...
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... The large majority of the ripple spectrum will be at the switching frequency. The above equation reaches its maximum value with IN(RMS) NCV8851B capacitors must be rated to handle a ripple current of one−half the maximum output current at the switching frequency. ESR is the majority cause of losses in the input capacitors. ...
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... Thermal Considerations The power dissipation of the NCV8851B varies with the MOSFETs used, V and the boost voltage (V IN average MOSFET gate current typically dominates the control IC power dissipation. The IC power dissipation can be estimated as follows ...
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... 0.100 (0.004) −T− SEATING PLANE 16X 0.36 *For additional information on our Pb−Free strategy and soldering details, please download the ON Semiconductor Soldering and Mounting Techniques Reference Manual, SOLDERRM/D. NCV8851B PACKAGE DIMENSIONS TSSOP−20 CASE 948E−02 ISSUE Í ...
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... Europe, Middle East and Africa Technical Support: Phone: 421 33 790 2910 Japan Customer Focus Center Phone: 81−3−5773−3850 http://onsemi.com 18 ON Semiconductor Website: www.onsemi.com Order Literature: http://www.onsemi.com/orderlit For additional information, please contact your local Sales Representative NCV8851B/D Datasheet pdf - http://www.DataSheet4U.net/ ...