FD3603英文规格书.pdf

FD3603 PWM Control 3A Step-Down Converter 深圳市宝安区新安街道办新安 43 区广深路 251 号华江达大厦 606 室 TEL:0755-27894616 Fax:0755-27894606 1/7 GENERAL DESCRIPTION FD3603 consists of step-down switching regulator with PWM control.These devise include a reference voltage source,oscillation circuit,error amplifier,internal PMOS and etc.FD3603 provides low-ripple power,high efficiency,and excellent transient characteristics.The PWM control circuit is able to the duty ratio linearly form 0 up to 100%.This converter is build out soft start function that prevents overshoot and inrush current at startup.An over current protect function and short circuit protect function are built inside,and when OCP or SCP happens,the operation frequency will be reduced.The operating frequency is decided by outside resistance.An external compensation is easily to system stable.With the addition of an internal P-channel Power MOS,a coil,capacitors,and a diode connected externally,these ICs can function as step-down switching regulators.They serve as ideal power supply units for portable devices when coupled with the SOP8-EP with exposed pad package,providing such outstanding features as low current consumption.Since this converter can accommodate an input voltage up to 30V,it is also suitable for the operation via an AC adapter.FEATURES-Input voltage：4.2V to 30V-Output voltage：0.8V to 28V-Duty ratio：0%to 100%PWM control-Oscillation frequency range is 50K 500KHz by outside resistance setting-Current Limit,Short Circuit Protect(SCP)and Thermal Shutdown protection-Built-in internal SW P-channel MOS.-SOP8-EP Pb-Free package.Block Diagram FD3603 PWM Control 3A Step-Down Converter 深圳市宝安区新安街道办新安 43 区广深路 251 号华江达大厦 606 室 TEL:0755-27894616 Fax:0755-27894606 2/7 PIN ASSIGNMENT The package of FD3603 is SOP8-EP;the pin assignment is given by:NameDescription 1SW Switch pin.Connect external inductor&diode here.2FB Feedback pin 3COMPCompensation pin 4OSC Frequency Set Pin.The pin connect a resistance to GND.5EN ON/OFF Shutdown OPEN ON/L OFF 6GND GND pin 7OC Add an external resistor to set max output current.8VCC IC power supply pin ORDER/MARKING INFORMATION Order Information Top Marking Absolute Maximum Ratings(at Ta=25)Characteristics SymbolRating Unit VCC Pin Voltage VCC VSS-0.3 to VSS+32 V Feedback Pin Voltage VFB VSS-0.3 to 6 V EN Pin Voltage VEN/SS VSS-0.3 to 6 V OSC Pin Voltage VOSC VSS-0.3 to 3 V COMP Pin Voltage VCOMP VSS-0.3 to 6 V OC Pin Voltage VOCSET VSS-0.3 to VCC V Switch Pin Voltage VSW VSS-0.3 to VCC+0.3 V FD3603 PWM Control 3A Step-Down Converter 深圳市宝安区新安街道办新安 43 区广深路 251 号华江达大厦 606 室 TEL:0755-27894616 Fax:0755-27894606 3/7 Power Dissipation PD Internally limited mW Storage Temperature Range TST-65 to+150 Operating Junction Temperature Range TOJP-40 to+125 Operating Supply Voltage VOP 4.2 to 30 V Thermal Resistance from Junction to case JC 15/W Thermal Resistance from Junction to ambient JA 40/W Note:JA is measured with the PCB copper area(need connect to Exposed Pad)of approximately 1.5 in2(Multi-layer).Electrical Characteristics(VCC=12V,Ta=25,unless otherwise specified)Characteristics Symbol Conditions Min Typ Max UnitsFeedback Voltage VFB VCC=10V30V IOUT=0 to 2A Tj=-20125 0.784 0.800 0.816V Quiescent Current ICCQ VFB=1.2V force driver off-3 6 mA Feedback Bias Curren IFB IOUT=0.1A-0.1 0.5 uA Shutdown Supply Current ISD VEN/SS=0V-150 300 uA Switch Current ISW 3.5-A Adjustable frequency range FOSC 50-500 KHzShort frequency FOSC/FOSCS VCC=10V30V 6 EN Pin Shutdown Logic input threshold voltage VENL -0.8 V Internal MOSFET RDSON RDSON VCC=12V,VFB=0V-30 m Efficiency EFFI VCC=12V,VOUT=5V,IOUT=2A-91 -%VCC=30V,VOUT=5V,IOUT=2A 86 Application Circuit 1 FD3603 PWM Control 3A Step-Down Converter 深圳市宝安区新安街道办新安 43 区广深路 251 号华江达大厦 606 室 TEL:0755-27894616 Fax:0755-27894606 4/7 Compensation Table Frequency L1 R1 C2 C1 50K120K 68-160uH 330 8.2n 6.8n 120K180K 4768uH 330 4.7n 1.8n 180K250K 3347uH 330 1.8n 1n 250K330K 2233uH 330 1n 510p 330K410K 1522uH 100 510p 510p 410K500K 1015uH 100 330p 330p Function Descriptions EN This pin can be supplied shutdown function.It is inside pull high function.For normal application,the pin must be connected a capacitor to ground.Allow the switching regulator circuit to be shutdown pulling this pin below a 0.8V threshold voltage;the shutdown supply current is approximately 150uA.OSC External frequency set pin.The pin connects a resistance(R4)to reduce system frequency.This converters frequency can be set from 50K to 500KHz,Please refer the below table to set frequency.R4 510K 220K 91K 47K 27K 20K Frequenc 50KHz 100KHz 200KHz 300KHz400KHz500KHz COMP Compensation pin.For EL output capacitor application,the COMP pin connects R2 and C2 to ground for all condition;OC The current limit threshold is setting by the external resistor connecting from VCC supply to OC.The internal 60uA sink current crossing the resistor sets the voltage at pin of OC.When the Vs voltage is less than the voltage at OC an over-current condition is triggered.FD3603 PWM Control 3A Step-Down Converter 深圳市宝安区新安街道办新安 43 区广深路 251 号华江达大厦 606 室 TEL:0755-27894616 Fax:0755-27894606 5/7 Application Information Setting the Output Voltage Application circuit item shows the basic application circuit with adjustable output version.The external resistor sets the output voltage according to the following equation:Table 1 Resistor select for output voltage setting VOUT R5R35V 1.3K 6.8K 3.3V 1.5K 4.7K 2.5V 2.2K 4.7K 1.8V 2K 2.5K 1.5V 2.2K 2.0K 1.2V 2K 1K Inductor Selection For most designs,the different frequency can be reducing the inductor value;The FD3603 is suggested 15H to 160H for 50K to 500KHz frequencies.Please refer the below table to design.L1 recommend value(VIN=830V,VOUT=5V,IOUT=3A)Frequency(Hz)300KHz500KHz200K300KHz100K200K 50K100K L1 Value(uH)10uH 22uH 22uH 47uH33uH 68uH 68uH 160uH Where is inductor Ripple Current.Large value inductors lower ripple current and small value inductors result in high ripple currents.Choose inductor ripple current approximately 20%of the maximum load current 3A,IL=0.6A.The DC current rating of the inductor should be at least equal to the maximum load current plus half the ripple current to prevent core saturation(3A+0.3A).Input Capacitor Selection This capacitor should be located close to the IC using short leads and the voltage rating should be approximately 1.5 times the maximum input voltage.The RMS current rating requirement for the input capacitor of a buck regulator is approximately 12 the DC load current.A low ESR input capacitor sized for maximum RMS current must be used.A 470F low ESR capacitor for most applications is sufficient.FD3603 PWM Control 3A Step-Down Converter 深圳市宝安区新安街道办新安 43 区广深路 251 号华江达大厦 606 室 TEL:0755-27894616 Fax:0755-27894606 6/7 Output Capacitor Selection The output capacitor is required to filter the output and provide regulator loop stability.The important capacitor parameters are;the 100 KHz Equivalent Series Resistance(ESR),the RMS ripples current rating,voltage rating,and capacitance value.For the output capacitor,the ESR value is the most important parameter.The ESR can be calculated from the following formula.V RIPPLE=IL ESR=0.6A x 80m=48mV An aluminum electrolytic capacitors ESR value is related to the capacitance and its voltage rating.In most case,higher voltage electrolytic capacitors have lower ESR values.Most of the time,capacitors with much higher voltage ratings may be needed to provide the low ESR values required for low output ripple voltage.It is recommended to replace this low ESR capacitor by using a 470F low ESR values 80m.Demoboard PCB layout FD3603 PWM Control 3A Step-Down Converter 深圳市宝安区新安街道办新安 43 区广深路 251 号华江达大厦 606 室 TEL:0755-27894616 Fax:0755-27894606 7/7 Package Outlines SOP8-EP