ncp3127 ON Semiconductor, ncp3127 Datasheet
ncp3127
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ncp3127 Summary of contents
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... A Synchronous PWM Switching Converter The NCP3127 is a flexible synchronous PWM Switching Buck Regulator. The NCP3127 is capable of producing output voltages as low as 0.8 V. The NCP3127 also incorporates voltage mode control. Switching frequency is internally set. The NCP3127 is currently available in an SOIC−8 package. Features • ...
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... CIRCUIT DESCRIPTION UVLO POR + SCP Fault Latch − + Fault PWM R Comp PWM − Q OUT S Counter DtoA Count + Latch & − Logic VREG 0 − Fault Figure 3. NCP3127 Block Diagram Description http://onsemi.com 2 BST VIN + − VOCTH − − VCC 2 V ISET PGND VSW ...
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Table 2. MAXIMUM RATINGS Rating Main Supply Voltage Input Bootstrap Supply Voltage vs GND Bootstrap Supply Voltage vs Ground (spikes ≤ 50 ns) Bootstrap Pin Voltage High Side Switch Max DC Current V Pin Voltage SW Switch ...
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Table 3. ELECTRICAL CHARACTERISTICS min/max values unless otherwise noted.) Characteristic Input Voltage Range Boost Voltage Range SUPPLY CURRENT Quiescent Supply Current Shutdown Supply Current Boost Quiescent Current UNDER VOLTAGE LOCKOUT V UVLO Threshold IN V UVLO Hysteresis IN SWITCHING REGULATOR ...
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3.5 3 2.5 2.0 −60 −40 − JUNCTION TEMPERATURE (°C) J Figure 4. I vs. Temperature ...
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Figure 10. Duty Cycle Maximum vs. Temperature 100 5.0 V Output 1 0.8 V ...
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... General The NCP3127 is a PWM synchronous buck regulator intended to supply load for DC−DC conversion from 5 V and 12 V buses. The NCP3127 is a regulator that has integrated high−side and low−side NMOSFETs switches. The output voltage of the converter can be precisely regulated down to 800 mV $1 ...
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... Trip Set COMP Delay Figure 18. Soft−Start Sequence Overcurrent Threshold Setting NCP3127 overcurrent threshold can be set from 550 mV, by adding a resistor (R SET GND. During a short period of time following V over UVLO threshold, an internal 10 mA current (I sourced from the ISET pin, creating a voltage drop across R ...
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... ON Semiconductor has a Microsoft Excel® based design tool available online under the design tools section of the NCP3127 product page. The tool allows you to capture your design point and optimize the performance of your regulator based on your design criteria. Table 4. DESIGN PARAMETERS ...
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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 NCP3127 is given by the following equation ...
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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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In a typical converter design, the ESR of the output capacitor bank dominates the transient response. Please note that DV and DV are out of phase with each OUT−DIS OUT−ESR other, and the larger of these two voltages will determine ...
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When calculating the rise time and fall time of the high side MOSFET it is important to know the charge characteristic shown in Figure 22. Vth Figure 22. MOSFET Switching Characteristics RISE I ...
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... To start the design, a resistor value should be chosen for R components can be chosen. A good starting value is 10 kW. The NCP3127 allows the output of the DC−DC regulator to be adjusted down to 0.8 V via an external resistor divider ³ network. The regulator will maintain 0 the feedback (eq ...
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... The values can be adjusted in real time using the compensation tool comp calc, available for download at ON Semiconductor’s website. The value of the feed through resistor should always be at least 2X the value of R noise. Using the 2X assumption, R ...
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239 31 Feed through capacitor ...
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cross 2.119 kHz 57 Compensation capacitance Output capacitor ESR ESR C = Output capacitance OUT f = ...
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Assuming an output capacitance of 470 mF in parallel with 22 mF with a crossover frequency of 35 kHz, the compensation values for common output voltages can be calculated as shown in Table 6: Table 6. COMPENSATION VALUES V V ...
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... Equation 50. I _RMS + CLR 191 OUT V OUT I CLR_RMS V D OUT CR_PK CL 3 (eq. 49) http://onsemi.com 19 Load NCP3127 OUT OUT I + CR_PK OUT OUT (eq. 50) 3 330 Output resistance = Output voltage ...
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... For optimal performance, the NCP3127 should have a layout similar to the one shown in Figure 30. An important note is that the input voltage to the NCP3127 should have local decoupling to PGND. The recommended decoupling for input voltage general purpose ceramic capacitor and a 0 ...
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... COMP PGND Vin RC 2.94k GND_IN COMP CP CC 820pF 68n 50V 50V Figure 31. Standard Application 2 VIN C1 10uF C2 NCP3127 10uF 4 AGND 16V 16V 3 COMP PGND Vin RC 392 GND_IN COMP 330n 50V 50V Figure 32. Ceramic Capacitor Application 1 ...
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Figure 33. Application Bottom Layout (TOP) Figure 34. Application Top Layout (TOP) http://onsemi.com 22 ...
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... Table 7. NCP3127 APPLICATION BILL OF MATERIALS Item Reference Qty Description 1 C11 1 SMT Ceramic Capacitor SMT Ceramic Capacitor 3 C10 1 SMT Ceramic Capacitor SMT Ceramic Capacitor 5 CHF CP 2 SMT Ceramic Capacitor SMT Ceramic Capacitor 7 CBST 1 SMT Ceramic Capacitor SMT Ceramic ...
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... C 1.35 1.75 0.053 0.069 D 0.33 0.51 0.013 0.020 G 1.27 BSC 0.050 BSC H 0.10 0.25 0.004 0.010 J 0.19 0.25 0.007 0.010 J K 0.40 1.27 0.016 0.050 0.25 0.50 0.010 0.020 S 5.80 6.20 0.228 0.244 mm inches ON Semiconductor Website: www.onsemi.com Order Literature: http://www.onsemi.com/orderlit For additional information, please contact your local Sales Representative NCP3127/D _ ...