ncp3155a ON Semiconductor, ncp3155a Datasheet
ncp3155a
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ncp3155a Summary of contents
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... Features • Input Voltage Range from 4 • Adjustable Output Voltage • 1 MHz Operation (NCP3155A – 500 kHz) • Internally Programmed 1.2 ms Soft−Start (NCP3155A – 2.4 ms) • 0.8 ± 1.0% Reference Voltage • HS−FET and 18 mW LS−FET • Current Limit Protection • ...
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VIN OSCILLATOR COMP REF FB PIN FUNCTION DESCRIPTION Pin Pin Name 1 PGND The PGND pin is the high current ground pin for the lower MOSFET and drivers which should be soldered to a large copper area to reduce thermal ...
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ABSOLUTE MAXIMUM RATINGS (measured vs. GND pin 8, unless otherwise noted) Rating Main Supply Voltage Input Boost to V differential voltage SW High Side Drive Boost Pin Switch Voltage Node Transconductance Amplifier Output Feedback Current Limit Set Operating Junction Temperature ...
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... Oscillator Frequency NCP3155B T Ramp−Amplitude Voltage Ramp Valley Voltage PWM Minimum Duty Cycle Maximum Duty Cycle Soft Start Ramp Time NCP3155A NCP3155B ERROR AMPLIFIER (GM) Transconductance Open Loop dc Gain Output Source Current Output Sink Current FB Input Bias Current Feedback Voltage COMP High Voltage ...
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... Figure 45 4.9 0 0.4 2 2.5 3 Figure 6. Load Regulation vs Input Voltage Input = 18 V, Output = 5.0 V, Load = 2 A, CH3 (Purple CH3: 200 mVac/div; CH2: 50 mVac/div; CH1: 5.0 V/div Time Scale: 2.0 ms/div; Figure 45 Figure 8. Switching Waveforms (NCP3155A) http://onsemi.com 5 3.3 V 1.2 V 1.5 V NCP3155B Typical Application Circuit Figure ...
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... TEMPERATURE (°C) Figure 13. Transconductance vs Temperature 808 806 804 802 800 798 796 794 792 −40 −25 −10 Figure 10. Feedback Reference Voltage vs 1120 NCP3155A 1100 1080 1060 1040 1020 1000 980 960 940 920 900 880 860 110 125 − ...
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... Input = 12 V, Output = 1.8 V, Load = 2 A, CH3 (Purple CH3: 10 V/div; CH2: 2.0 V/div; CH1: 5.0 V/div Time Scale: 1.0 ms/div; Figure 45 Figure 18. Startup Waveforms (NCP3155A) Input = 12 V (CH2) Green = V CH2: 0.5 V/div; CH1: 5.0 V/div Time Scale: 2.0 ms/div; Figure 45 Figure 20. Current Limit Waveforms (NCP3155A) http://onsemi.com 110 125 TEMPERATURE (° ...
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... Figure 24. Derating Curve Input DS(on) 3.5 1 3.3 V 2.5 2 1.5 1 0.5 NCP3155A Figure 26. Derating Curve Input http://onsemi.com 5 − ...
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TYPICAL PERFORMANCE CHARACTERISTICS 3 5.0 V out 2.5 2 3.3 V 1.5 1 0.5 NCP3155B AMBIENT TEMPERATURE (°C) A Figure 27. ...
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... Some overshoot may be evident at the start of each step depending on the voltage loop phase margin and bandwidth. The total soft−start time is 2.4 ms for the NCP3155A and 1.2 ms for the NCP3155B Steps 32 Voltage Steps Figure 30. Soft−Start Details http://onsemi ...
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OOV and OUV The output voltage of the buck converter is monitored at the feedback pin of the output power stage. Two comparators are placed on the feedback node of the OTA to monitor the operating window of the feedback ...
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V (vref *125%) 0.8 V (vref *100%) 0.6 V (vref *75%) FB Voltage Latch off Reinitiate Softstart Softstart Complete Figure 33. Powerup Sequence and Overvoltage Latch 1.0 V (vref *125%) 0.8 V (vref *100%) 0.6 V (vref * 75%) ...
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CURRENT LIMIT AND CURRENT LIMIT SET Overview The NCP3155 uses the voltage drop across the High Side MOSFET during the on time to sense inductor current. The Ilim Out CONTROL 6 DAC / COUNTER Itrip Ref−63 Steps, 6.51 mV/step Current ...
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No Trip: Vsense < I Itrip Ref Vsense ¾ Ton−2 1/4 1/2 3/4 Ton−1 Each switching cycle’s Ton is counted time steps. The 3/4 sample time value is held and used for the following cycle’s limit sample ...
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Reduced sampling time occurs at high duty cycles where the low side MOSFET is off for the majority of the switching period. Reduced sampling time causes errors in the regulated voltage on the boost pin. High duty cycle / input ...
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VIN VBOOST Maximum Normal VIN VBOOST Maximum Normal VIN VBOOST Figure 39. Typical Waveforms for Region 1 (top), Region 2 (middle), and Region 3 (bottom) To illustrate, a 0.1 mF boost capacitor operating at > 80% duty cycle and > ...
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Voltage Ripple Maximum Allowable Voltage 16 Maximum Boost Voltage 4.5 Inductor Selection When selecting the inductor important to know the input and output requirements. Some example conditions are listed ...
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... In contrast, smaller values of inductance increase the regulator’s maximum achievable slew rate and decrease the necessary capacitance, at the expense of higher ripple current. The peak−to−peak ripple current for the NCP3155A is given by the following equation 3.3 V out Ipp is the peak to peak current of the inductor ...
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... The output capacitor must be rated to handle the ripple current at full load with proper derating. The RMS ratings given in datasheets are generally for lower switching frequency than used in switch mode power supplies but a multiplier is usually given for higher frequency operation. The RMS current for the output capacitor can be calculated ...
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Compensation Type II This compensation is suitable for electrolytic capacitors. Components of the Type II (Figure 42) network can be specified by the following equations: Figure 42. Type II Compensation ...
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Output Current Derating The NCP3155 has a wide input voltage and output voltage capability. It also operates in a variety of thermal environments. These thermal conditions limit the maximum output current for a given input and output voltage. Therefore, proper ...
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... V VIN 150m 22m 12n 220p 22.1k 4.7k 0.1m 8.2m BST VIN VSW 680p PGND NCP3155A 1.5 ISET FB1 COMP AGND Figure 45. Typical Application Circuit 0.1m 4.7m BST VIN VSW 680p PGND NCP3155B 1.5 ISET FB1 COMP AGND Figure 46. Typical Application Circuit http://onsemi.com ...
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V VIN 150m 22m 1.2n 10p 24k 27k 10 − VIN 150m 22m 8.2n 150p 22.1k 6.8k 0.1m 4.7m BST VIN VSW 680p PGND NCP3155B 1.5 ISET FB1 COMP AGND Figure 47. Typical Application Circuit ...
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... *For additional information on our Pb−Free strategy and soldering details, please download the ON Semiconductor Soldering and Mounting Techniques Reference Manual, SOLDERRM/D. ON Semiconductor and are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes without further notice to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does SCILLC assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages. “ ...