NCP1546 ONSEMI | Alldatasheet
Document overview
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Technical content
Features
- V2 Architecture Provides Ultra−Fast Transient Response, Improved Regulation and Simplified Design
- 2.0% Error Amp Reference V oltage Tolerance
- Switch Frequency Decrease of 4:1 in Short Circuit Conditions Reduces Short Circuit Power Dissipation
- BOOST Lead Allows “Bootstrapped” Operation to Maximize Efficiency
- Sync Function for Parallel Supply Operation or Noise Minimization
- Shutdown Lead Provides Power−Down Option
- 1.0 /C0109A Quiescent Current During Power−Down
- Thermal Shutdown
- Soft−Start
- Pb−Free Packages are Available MARKING DIAGRAM http://onsemi.com 18−LEAD DFN MN SUFFIX CASE 505 NCP1546 AWLYYWW /C0071 /C0071 11 8 A = Assembly Location WL = Wafer Lot YY = Year WW = Work Week E = Automotive Grade /C0071= Pb−Free Package (Note: Microdot may be in either location) See detailed ordering and shipping information in the package dimensions section on page 12 of this data sheet.
ORDERING INFORMATION
Figure 1. Application Diagram, 4.5 V − 16 V to 3.3 V @ 1.0 A Converter *The maximum package power dissipation must be observed.
- 60 second maximum above 183 °C.
- −5 °C/0°C allowable conditions.
*See table above for load dump.
http://onsemi.com PACKAGE PIN DESCRIPTION PIN NO. PIN SYMBOL FUNCTION 1 BOOST The BOOST pin provides additional drive voltage to the on−chip NPN power transistor. The resulting decrease in switch on voltage increases efficiency. 2 VIN This pin is the main power input to the IC.
3 VSW This is the connection to the emitter of the on−chip NPN power transistor and serves as the
switch output to the inductor. This pin may be subjected to negative voltages during switch off− time. A catch diode is required to clamp the pin voltage in normal operation. This node can stand −1.0 V for less than 50 ns during switch node flyback. 4 SHDNB The shutdown pin is active low and TTL compatible. The IC goes into sleep mode, drawing less than 1.0 /C0109A when the pin voltage is pulled below 1.0 V. This pin should be left floating in normal position. 5 SYNC This pin provides the synchronization input. 6 GND Power return connection for the IC. 7 VFB The FB pin provides input to the inverting input of the error amplifier. If V FB is lower than 0.29 V, the oscillator frequency is divided by four, and current limit folds back to about 1 ampere. These features protect the IC under severe overcurrent or short circuit conditions.
8 VC The VC pin provides a connection point to the output of the error amplifier and input to the PWM
comparator. Driving of this pin should be avoided because on−chip test circuitry becomes active whenever current exceeding 0.5 mA is forced into the IC. 9, 11, 12, 14, 15, 18 NC No Connection PIN CONNECTIONS BOOST V IN VIN VIN Vsw VSW VSW SHDNB NC NC VC VFB NC NC GND NC NC SYNC 18−Lead DFN
http://onsemi.com ELECTRICAL CHARACTERISTICS (0°C < TJ < 70°C, 4.5 V< VIN < 40 V; unless otherwise specified.) Characteristic Test Conditions Min Typ Max Unit Oscillator Operating Frequency − 153 170 187 kHz Frequency Line Regulation − − 0.05 0.15 %/V Maximum Duty Cycle − 85 90 95 % VFB Frequency Foldback Threshold − 0.29 0.32 0.36 V PWM Comparator Slope Compensation Voltage Fix VFB, /C0068VC//C0068TON 5.0 9.0 17 mV//C0109s Minimum Output Pulse Width VFB to VSW − 100 200 ns Power Switch Current Limit VFB > 0.36 V 1.6 2.3 3.0 A Foldback Current VFB < 0.29 V 0.9 1.5 2.1 A Current Limit Delay Note 3 − 120 160 ns Error Amplifier Internal Reference Voltage − 1.244 1.270 1.296 V Reference PSRR Note 3 − 40 − dB FB Input Bias Current − − 0.02 0.1 /C0109A Output Source Current VC = 1.270 V, VFB = 1.0 V 15 25 35 /C0109A Output Sink Current VC = 1.270 V, VFB = 2.0 V 15 25 35 /C0109A Output High Voltage VFB = 1.0 V 1.39 1.46 1.53 V Output Low Voltage VFB = 2.0 V 5.0 20 60 mV Unity Gain Bandwidth Note 3 − 500 − kHz Open Loop Amplifier Gain Note 3 − 70 − dB Amplifier Transconductance Note 3 − 6.4 − mA/V Sync Sync Frequency Range − 190 − 355 kHz Sync Pin Bias Current VSYNC = 5.0 V − 360 485 /C0109A Sync Threshold Voltage − 0.9 1.5 1.9 V Shutdown Shutdown Threshold Voltage − 1.0 1.3 1.6 V Shutdown Pin Bias Current VSHDNB = 0 V 0.14 5.00 35 /C0109A Thermal Shutdown Overtemperature Trip Point Note 3 175 185 195 °C Thermal Shutdown Hysteresis Note 3 − 42 − °C 3. Guaranteed by design, not 100% tested in production.
- Guaranteed by design, not 100% tested in production.
Figure 2. Block Diagram
2.9 V LDO
http://onsemi.com The worse case of the diode average current occurs during maximum load current and maximum input voltage. For the diode to survive the short circuit condition, the current rating of the diode should be equal to the Foldback Current Limit. See Table 1 for Schottky diodes from ON Semiconductor which are suggested for use with the NCP1546 regulator. Inductor Selection When choosing inductors, one might have to consider maximum load current, core and copper losses, component height, output ripple, EMI, saturation and cost. Lower inductor values are chosen to reduce the physical size of the inductor. Higher value cuts down the ripple current, core losses and allows more output current. For most applications, the inductor value falls in the range between 2.2 /C0109H and 22 /C0109H. The saturation current ratings of the inductor shall not exceed the I L(PK), calculated according to IL(PK) /C0043IO /C0041VO(VIN /C0042VO) 2(fS)(L)(VIN) The DC current through the inductor is equal to the load current. The worse case occurs during maximum load current. Check the vendor’s spec to adjust the inductor value under current loading. Inductors can lose over 50% of inductance when it nears saturation. The core materials have a significant effect on inductor performance. The ferrite core has benefits of small physical size, and very low power dissipation. But be careful not to operate these inductors too far beyond their maximum ratings for peak current, as this will saturate the core. Powered Iron cores are low cost and have a more gradual saturation curve. The cores with an open magnetic path, such as rod or barrel, tend to generate high magnetic field radiation. However, they are usually cheap and small. The cores providing a close magnetic loop, such as pot−core and toroid, generate low electro−magnetic interference (EMI). There are many magnetic component vendors providing standard product lines suitable for the NCP1546. Table 2 lists three vendors, their products and contact information. Table 1. Part Number VBREAKDOWN (V) IAVERAGE (A) V(F) (V) @ IAVERAGE Package 1N5817 20 1.0 0.45 Axial Lead 1N5818 30 1.0 0.55 Axial Lead 1N5819 40 1.0 0.6 Axial Lead MBR0520 20 0.5 0.385 SOD−123 MBR0530 30 0.5 0.43 SOD−123 MBR0540 40 0.5 0.53 SOD−123 MBRS120 20 1.0 0.55 SMB MBRS130 30 1.0 0.395 SMB MBRS140 40 1.0 0.6 SMB Table 2. Vendor Product Family Web Site Telephone Coiltronics UNI−Pac1/2: SMT, barrel THIN−PAC: SMT, toroid, low profile CTX: Leaded, toroid www.coiltronics.com (516) 241−7876 Coilcraft DO1608: SMT, barrel DS/DT 1608: SMT, barrel, magnetically shielded DO3316: SMT, barrel DS/DT 3316: SMT, barrel, magnetically shielded DO3308: SMT, barrel, low profile www.coilcraft.com (800) 322−2645 Pulse − www.pulseeng.com (619) 674−8100 Device Package Shipping† NCP1546MNR2G DFN18 (Pb−Free) 2500 Units / Tape & Reel †For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging Specifications Brochure, BRD8011/D.
http://onsemi.com PACKAGE DIMENSIONS DFN18 6x5, 0.5P CASE 505−01 ISSUE D C0.15 L b18X A D NOTES: 1. DIMENSIONS AND TOLERANCING PER ASME Y14.5M, 1994. 2. DIMENSIONS IN MILLIMETERS. 3. DIMENSION b APPLIES TO PLATED TERMINAL AND IS MEASURED BETWEEN 0.25 AND 0.30 MM FROM TERMINAL 4. COPLANARITY APPLIES TO THE EXPOSED PAD AS WELL AS THE TERMINALS. E C e A B DIM MIN MAX MILLIMETERS A 0.80 1.00 A1 0.00 0.05 A3 0.20 REF b 0.18 0.30 D 6.00 BSC D2 3.98 4.28 E 5.00 BSC E2 2.98 3.28 e 0.50 BSC K 0.20 −−− L 0.45 0.65 C0.15 PIN 1 LOCATION (A3) SEATING PLANE C0.08 C0.10 18X K18X A0.10 BC
0.05 C NOTE 3
5.30 18X 3.24 0.75 18X 0.30 4.19 PITCH DIMENSIONS: MILLIMETERS 0.50 SOLDERING FOOTPRINT* *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. “Typical” parameters which may be provided in SCILLC data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each customer application by customer’s technical experts. SCILLC does not convey any license under its patent rights nor the rights of others. SCILLC products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which the failure of the SCILLC product could create a situation where personal injury or death may occur. Should Buyer purchase or use SCILLC products for any such unintended or unauthorized application, Buyer shall indemnify and hold SCILLC and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, direct ly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that SCILLC was negligent regarding the design or manufacture of the part. SCILLC is an Equal Opportunity/Affirmative Action Employer. This literature is subject to all applicable copyright laws and is not for resale in a ny manner. NCP1546/D V2 is a trademark of Switch Power, Inc. PUBLICATION ORDERING INFORMATION N. American Technical Support: 800−282−9855 Toll Free USA/Canada Europe, Middle East and Africa Technical Support: Phone: 421 33 790 2910 Japan Customer Focus Center Phone: 81−3−5773−3850 LITERATURE FULFILLMENT: Literature Distribution Center for ON Semiconductor P.O. Box 5163, Denver, Colorado 80217 USA Phone: 303−675−2175 or 800−344−3860 Toll Free USA/Canada Fax: 303−675−2176 or 800−344−3867 Toll Free USA/Canada Email: orderlit@onsemi.com ON Semiconductor Website: www.onsemi.com Order Literature: http://www.onsemi.com/orderlit For additional information, please contact your local Sales Representative