ADP3050-EVAL

FEATURES Wide input voltage range: 3.6 V to 30 V Adjustable and fixed (3.3 V, 5 V) output options Integrated 1 A power switch Uses small surface-mount components Cycle-by-cycle current limiting Peak input voltage (100 ms): 60 V Configurable as a buck, buck-boost, and SEPIC regulator Available in 8-lead SOIC package Supported by ADIsimPower™ design tool FUNCTIONAL BLOCK DIAGRAM SD 6 GND 7 BIAS IN 3 8 FREQUENCY AND CURRENT LIMIT FOLDBACK Industrial power systems PC peripheral power systems Preregulator for linear regulators Distributed power systems Automotive systems Battery chargers FB CURRENT LIMIT 200kHz OSCILLATOR + APPLICATIONS CURRENT SENSE AMPLIFIER 2.50V REGULATOR 4 2 BOOST 1 SWITCH CMP S Q DRIVER R 1.2V gm ADP3050 00125-001 Data Sheet 200 kHz, 1 A High Voltage Step-Down Switching Regulator ADP3050 5 COMP Figure 1. GENERAL DESCRIPTION The ADP3050 is a current mode monolithic buck (step down) PWM switching regulator that contains a high current 1 A power switch and all control, logic, and protection functions. It uses a unique compensation scheme allowing the use of any type of output capacitor (tantalum, ceramic, electrolytic, OS-CON). Unlike some buck regulators, the design is not restricted to using a specific type of output capacitor or ESR value. A special boosted drive stage is used to saturate the NPN power switch, providing a system efficiency higher than conventional bipolar buck switchers. Further efficiency improvements are obtained by using the low voltage regulated output to provide the internal operating current of the device. A high switching frequency allows the use of small external surface-mount components. A wide variety of standard off-the-shelf devices can be used, providing a great deal of design flexibility. A complete regulator design requires only a few external components. The ADP3050 includes a shutdown input that places the device in a low power mode, reducing the total supply current to under 20 µA. Internal protection features include thermal shutdown circuitry and a cycle-by-cycle current limit for the power switch to provide complete device protection under fault conditions. The ADP3050 provides excellent line and load regulation, maintaining typically less than ±3% output voltage accuracy over temperature and under all input voltage and output current conditions. The ADP3050 is specified over the industrial temperature range of −40°C to +85°C and is available in a thermally enhanced 8-lead (not Pb-free only) SOIC package and a standard 8-lead (Pb-free only) RoHS-compliant SOIC package. Rev. C Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781.329.4700 www.analog.com Fax: 781.461.3113 ©2008–2012 Analog Devices, Inc. All rights reserved. ADP3050 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Catch Diode Selection ............................................................... 13 Applications ....................................................................................... 1 Input Capacitor Selection .......................................................... 14 Functional Block Diagram .............................................................. 1 Discontinous Mode Ringing ..................................................... 14 General Description ......................................................................... 1 Setting the Output Voltage ........................................................ 14 Revision History ............................................................................... 2 Frequency Compensation ......................................................... 14 Specifications..................................................................................... 3 Current Limit/Frequency Foldback ......................................... 15 Absolute Maximum Ratings............................................................ 4 Bias Pin Connection .................................................................. 15 ESD Caution .................................................................................. 4 Boosted Drive Stage ................................................................... 15 Pin Configuration and Function Descriptions ............................. 5 Start-Up/Minimum Input Voltage ........................................... 15 Typical Performance Characteristics ............................................. 6 Thermal Considerations............................................................ 16 Theory of Operation ...................................................................... 10 Board Layout Guidelines ............................................................... 17 Setting the Output Voltage ........................................................ 10 Typical Applications ................................................................... 17 Applications Information .............................................................. 11 Inverting (Buck Boost) Regulator ............................................ 18 ADIsimPower Design Tool ....................................................... 11 Outline Dimensions ....................................................................... 20 Inductor Selection ...................................................................... 11 Ordering Guide .......................................................................... 20 Output Capacitor Selection ....................................................... 12 REVISION HISTORY 6/12—Rev. B to Rev. C Change to Features Section ............................................................. 1 Added ADIsimPower Design Tool Section ................................. 11 Changes to Ordering Guide .......................................................... 20 3/08—Rev. A to Rev. B Updated Format .................................................................. Universal Changes to General Description Section ...................................... 1 Changes to Figure 3 and Figure 5 ................................................... 6 Changes to Table 2 ............................................................................ 4 Deleted Table 4 ................................................................................ 14 Changes to Table 5 .......................................................................... 15 Deleted Table 8 ................................................................................ 15 Deleted Table 7 ................................................................................ 16 Deleted Table 9 ................................................................................ 16 Changes to Boosted Drive Stage Section and Thermal Considerations Sections................................................................. 19 Changes to Figure 27 ...................................................................... 20 Changes to Ordering Guide .......................................................... 23 Rev. C | Page 2 of 20 Data Sheet ADP3050 SPECIFICATIONS VIN = 10 V, TA = −40°C to +85°C, unless otherwise noted. Table 1. Parameter 1 FEEDBACK Feedback Voltage ADP3050 ADP3050-3.3 ADP3050-5 Line Regulation Load Regulation Symbol Conditions VFB Over line and temperature Input Bias Current ERROR AMPLIFIER Transconductance 2 Voltage Gain2 Output Current ADP3050 ADP3050-3.3 ADP3050-5 OSCILLATOR Oscillator Frequency 3 Minimum Duty Cycle Maximum Duty Cycle SWITCH Average Output Current Limit 4 ADP3050 ADP3050-3.3 ADP3050-5 Peak Switch Current Limit 5 Saturation Voltage Leakage Current SHUTDOWN Input Voltage Low Input Voltage High SUPPLY Input Voltage Range 6 Minimum BIAS Voltage Minimum BOOST Voltage IN Supply Current Normal Mode Shutdown Mode BIAS Supply Current BOOST Supply Current IFB VIN = 10 V to 30 V, no load ILOAD = 100 mA to 1 A, ADP3050AR only ADP3050AR-3.3, ADP3050AR-5 ADP3050AR only Min Typ Max Unit 1.16 3.20 4.85 1.20 3.30 5.00 0.005 +0.1 +0.1 0.65 1.24 3.40 5.15 V V V %/V %/A %/A μA −1.0 −0.5 gm AVOL COMP = 1.0 V, FB = 1.1 V to 1.3 V COMP = 1.0 V, FB = 3.0 V to 3.6 V COMP = 1.0 V, FB = 4.5 V to 5.5 V fOSC DMIN DMAX +1.0 +0.5 2 1250 300 μMho V/V ±115 ±120 ±135 μA μA μA 170 200 10 90 240 kHz % % 1.0 1.0 1.0 1.5 1.25 1.25 1.25 1.7 0.65 50 1.5 1.5 1.5 2.1 0.95 A A A A V nA 0.4 V V 30 3.0 3.0 V V V 1.5 40 6.0 mA μA mA mA mA ICL(AVG) BOOST = 15 V, FB = 1.1 V BOOST = 15 V, FB = 3.0 V BOOST = 15 V, FB = 4.5 V ICL(PEAK) BOOST = 15 V, ILOAD = 1 A 2.0 VIN VBIAS VBOOST IQ IBIAS IBOOST 3.6 BIAS = 5.0 V SD = 0 V, VIN ≤ 30 V BIAS = 5.0 V BOOST = 15 V, ISW = 0.5 A BOOST = 15 V, ISW = 1.0 A 0.7 15 4.0 18 20 40 All limits at temperature extremes are guaranteed via correlation using standard statistical quality control (SQC). Transconductance and voltage gain measurements refer to the internal amplifier without the voltage divider. To calculate the transconductance and gain of the fixed voltage parts, divide the values shown by FB/1.20. 3 The switching frequency is reduced when the feedback pin is lower than 0.8 × FB. 4 See Figure 24 for typical application circuit. 5 Switch current limit is measured with no diode, no inductor, and no output capacitor. 6 Minimum input voltage is not measured directly, but is guaranteed by other tests. The actual minimum input voltage needed to keep the output in regulation depends on output voltage and load current. 1 2 Rev. C | Page 3 of 20 ADP3050 Data Sheet ABSOLUTE MAXIMUM RATINGS Table 2. Parameter IN Voltage Continuous Peak (