4.5到24V输入，3.3V/1A输出，MP2359-MP2359_r1.21.pdf』5 MP23

文件名称: 4.5到24V输入，3.3V/1A输出，MP2359-MP2359_r1.21.pdf

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详细说明：4.5到24V输入，3.3V/1A输出，MP2359-MP2359_r1.21.pdf』5 MP2359-1.2A. 24V.1. 4MHz STEP-DOWN CONVERTER INA TSOT23-6 ELECTRICAL CHARACTERISTICS VIN= 12V, TA=+25C, unless otherwise noted. Parameters Symbol Condition MinTypMaxUnits Feedback Voltage 4.5V≤V小N≤24 0.7900.8100.830V Feedback Current VEB=0.8V 0.1 UA Switch-On Resistance R DS(ON) 0.35 Q Switch Leakage VEN =OV, VsW=OV 10 UA Current limit (5) A Oscillator Frequency fsw VFB=0.6V 1.2 1.4 1.7 MHZ Fold-back Frequency VEB=OV 460 KHZ Maximum Duty cycle VEB=0.6V 87 % Minimum on-Time t 100 ns Under Voltage Lockout Threshold Rising 2.5 3.1 Under Voltage Lockout Threshold Hysteresis 150 m EN Input Low Voltage 0.4 EN Input High voltage 1.2 EN Input Current VEN=2V 2.1 UA VEN = OV 0.1 Supply Current(Shutdown VEN =OV 0110A Supply Current(Quiescent) Q VEN=2V,VFB=1V 0.8 mA Thermal shutdown 150 C Note 5) Guaranteed by design PIN FUNCTIONS Pin# Name Description Bootstrap. A capacitor is connected between SW and BS pins to form a floating supply across bst the power switch driver. This capacitor is needed to drive the power switch's gate above the supply voltage 2G/0 Ground. This pin is the voltage reference for the regulated output voltage. For this reason care must be taken in its layout. This node should be placed outside of the D1 to C1 ground path to prevent switching current spikes from inducing voltage noise into the part Feedback. An external resistor divider from the output to GND, tapped to the FB pin sets the output voltage. To prevent current limit run away during a short circuit fault condition, the FB frequency foldback comparator lowers the oscillator frequency when the FB voltage is below 250mV EN On/Off Control Input. Pull EN above 1.2V to turn the device on For automatic enable, connect a 456 100kQ2 resistor between this pin and vin pin Supply Voltage. The MP2359 operates from a +4.5v to +24V unregulated input C1 is needed to prevent large voltage spikes from appearing at the input SWWitch Output P2359Rev.1.21 ww. MonolithicPower com 3 7/18/2011 MPS Proprietary Information Patent Protected. Unauthorized Photocopy and duplication Prohibited C 2011 MPS. All Rights Reserved 』5 MP2359-1.2A. 24V.1. 4MHz STEP-DOWN CONVERTER INA TSOT23-6 TYPICAL PERFORMANCE CHARACTERISTICS VIN= 12V, VOuT =3.3V,L=4.7uH, C1=10uF, C2=22uF, TA=+25C, unless otherwise noted Efficiency Vs Efficiency VS Load current Load current 100 100 /|N=18V 70 VIN= 24V VIN = 24V 50 40 LL 近30 30 20 10 OUT =2.5 10 VOUT= 5V 0 0.01 0.1 10 0.01 0.1 10 LOAD CURRENT(A LOAD CURRENT (A) Feedback Voltage vs Switching Frequency Vs Die Temperature Die Temperature 0.820 0.818 1.48 之0.816 N工E>OzuOu2LozOE 1.46 L 0.814 44 占0.812 0.810 1.40 0.808 L1.38 m0.806 36 0.80 1.34 0.802 1.32 0.800 1.30 50-250255075100125150 -50250255075100125150 DIE TEMPERATURE(OC) DIE TEMPERATURE(C) P2359Rev.1.21 ww. MonolithicPower com 4 7/18/2011 MPS Proprietary Information Patent Protected. Unauthorized Photocopy and duplication Prohibited C 2011 MPS. All Rights Reserved 』5 MP2359-1.2A. 24V.1. 4MHz STEP-DOWN CONVERTER INA TSOT23-6 TYPICAL PERFORMANCE CHARACTERISTICS (continued) VIN= 12V, VOuT =3.3V,L=4.7uH, C1=10uF, C2=22uF, TA=+25C, unless otherwise noted Current limit vs Load transient Test Steady state Test Duty Cycle lOUT=0. 2A to 0. BA step at O 8A/us OUT =0.5A 30 2.5 OUT 20mV/div -uY2 AC Couple 50mV/diy 1.5 1.0 1A/di 500mA/div 0.5 ILOAD 0 20406080100 100us/div 400ns/diy DUTY CYCLE(%) Short circuit en Short Circuit Recovery Start-up through Enable No load VOUT 1V/diy 1V/div SW/ 10V/div 1A/div 500mA/div 100us/div 200us/div 200usidiv Start-up through enable Shut-down through enable Shut-down through Enable lOuT 1A Resistive Load No load OUT =1A Resistive load V 5V/dⅳv. 5∨/div OUT V OUT OUT 1V/div 2V/dⅳv SW 10V/div 10V/div SW 10V/di lAdy 1A/diy 1A/div 200us/div 200us/dⅳV 200us/div P2359Rev.1.21 ww. MonolithicPower com 5 7/18/2011 MPS Proprietary Information Patent Protected. Unauthorized Photocopy and duplication Prohibited C 2011 MPS. All Rights Reserved 』5 MP2359-1.2A. 24V.1. 4MHz STEP-DOWN CONVERTER INA TSOT23-6 OPERATION The MP2359 is a current mode buck regulator If the sum of the current Sense amplifier output That is, the ea output voltage is proportional to and the Slope Compensation signal does not the peak inductor current exceed the ea output for a whole cycle, then At the beginning of a cycle, M1 is off. The EA the falling edge of the ClK resets the Flip-Flop output voltage is higher than the current sense The output of the Error amplifier integrates the amplifier output, and the current comparator's voltage difference between the feedback and output is low. The rising edge of the 1.4MHZ the 0. 81V bandgap reference. The polarity is CLK signal sets the Rs Flip-Flop. Its output such that a Fb pin voltage lower than 0. 81V turns on M1 thus connecting the sw pin and increases the ea output voltage. since the EA inductor to the input supply output voltage is proportional to the peak inductor current, an increase in its voltage also The increasing inductor current is sensed and amplified by the current Sense amplifier. Ramp increases current delivered to the output compensation is summed to the current sense Amplifier output and compared to the Error Amplifier output by the PWM Comparator When the sum of the Current Sense amplifier output and the Slope Compensation signal exceeds the EA output voltage, the Rs Flip Flop is reset and M1 is turned off. The external Schottky rectifier diode (D1)conducts the inductor current CURRENT SENSE AMPLIFIER RSEN RAMP 25mQ lllln D GENERATOR REGULATOR BST EN REGULATOR OSCILLATOR 1. 4MHz/460KHZ s Q DRIVER M1 SW 1pF CURRENT COMPARATOR REFERENCE 27pF 400kQ PWM ERROR COMPARATOR AMPLIFIER Figure 1-Functional Block Diagram P2359Rev.1.21 ww. MonolithicPower com 6 7/18/2011 MPS Proprietary Information Patent Protected. Unauthorized Photocopy and duplication Prohibited C 2011 MPS. All Rights Reserved 』5 MP2359-1.2A. 24V.1. 4MHz STEP-DOWN CONVERTER INA TSOT23-6 APPLICATION INFORMATION Setting Output Voltage Selecting the Input Capacitor The external resistor divider is used to set the The input capacitor reduces the surge current output voltage (see the schematic on front drawn from the input supply and the switching page). Table 1 shows a list of resistor selection noise from the device. The input capacitor for common output voltages. The feedback impedance at the switching frequency should be resistor R1 also sets the feedback loop less than the input source impedance to prevent bandwidth with the internal compensation high frequency switching current from passing capacitor(see Figure 1). R2 can be determined through the input ceramic capacitors with X5R or XTR dielectrics are highly recommended because R1 of their low Esr and small temperature R2= OUT coefficients. For most applications a 4.7uF 0.81V capacitor is sufficient Table 1-Resistor Selection for Common Selecting the Output Capacitor Output Voltages The output capacitor keeps the output voltage ripple small and ensures feedback loop stability VOUT (V R1(k) R2(kQ2 The output capacitor impedance should be low 1.8 806(1%) 649(1%) at the switching frequency. Ceramic capacitors 2.5 49.9(1%) 237(1%) with x5r or xr dielectrics are recommended for their low esr characteristics. For most 3.3 49.9(1%) 162(1%) applications,a22μ ceramic capacitor wil‖lbe 49.9(1%) 9.53(1%) sufficient Selecting the Inductor PCB Layout Guide A 1HH to 10WH inductor with a dc current rating PCB layout is very important to achieve stable of at least 25% percent higher than the operation. Please follow these guidelines and maximum load current is recommended for take Figure2 for references most applications. For highest efficiency, the 1)Keep the path of switching current short inductors dc resistance should be less than and minimize the loop area formed by Input 200mQ2. Refer to Table 2 for suggested surface cap, high-side MOSFET and schottky diode mount inductors. For most designs, the required inductance value can be derived from the 2)Keep the connection of schottky diode following equation between sw pin and input power ground as short and wide as possible UT OUT VN×△ IL X fsw 3) Ensure all feedback connections are short and direct. place the feedback resistors Where AlL is the inductor ripple current and compensation components as close to the chip as possible Choose the inductor ripple current to be 30% of the maximum load current The maximum 4)Route sw away from sensitive analog inductor peak current is calculated from areas such as Fb 5 Connect IN, sW, and especially GND L(MAX LOAD respectively to a large copper area to cool the chip to improve thermal performance Under light load conditions below 100mA,a and long-term reliability. For single layer larger inductance is recommended for improved PCB, exposed pad should not be soldered efficiency. See Table 2 for suggested inductors Also note that the maximum recommended load current is 1A if the duty cycle exceeds 35% P2359Rev.1.21 ww. MonolithicPower com 7/18/2011 MPS Proprietary Information Patent Protected. Unauthorized Photocopy and duplication Prohibited C 2011 MPS. All Rights Reserved 』5 MP2359-1.2A. 24V.1. 4MHz STEP-DOWN CONVERTER INA TSOT23-6 [R2 IRI External Bootstrap Diode An external bootstrap diode may enhance the SGND efficiency of the regulator, the applicable conditions of external bst diode are VouT=5V or 3.3V; and 艺艺 Duty cycle is high: D=OUT>65% In these cases, an external bst diode is recommended from the output of the voltage regulator to BST pin, as shown in Fig 3 Extemal bst Diode 4148 DI c BST PGND MP2359 01~1pF SW 5V or 3.3V Figure 2-PCB Layout Figure 3-Add optional External Bootstrap Diode to Enhance Efficiency The re ended external bst diode IN4148, and the bst cap is 0.1-luF Table 2-Suggested Surface Mount Inductors Current Dimensions Manufacturer Part Number Inductance(HH) Max DCR(Q2 Rating(A)LXWXH(mma) Toko A921CY-4R7M 0.027 1.66 6X6.3X3 Sumida CDRH4D28C/LD 0.036 5.1X5.1X3 Wurth Electronics 7440530047 4.7 0.038 2.0 58X58×28 P2359Rev.1.21 ww. MonolithicPower com 8 7/18/2011 MPS Proprietary Information Patent Protected. Unauthorized Photocopy and duplication Prohibited C 2011 MPS. All Rights Reserved 』5 MP2359-1.2A. 24V.1. 4MHz STEP-DOWN CONVERTER INA TSOT23-6 TYPICAL APPLICATION CIRCUITS 1N4148 (Optional 10uF 25√10k9 1N4148 22nF 4.7H/1.66A (Optional) EN MP2359 SW 6 OFFON O VOUT C2 o3.3y B230A-13-F 224F 6.3V 1)D3 can be installed if VIN 5V 2)D2 can be installed if VOUT 5V 3 3)No need for both d2 and d3 FB GND R2 R1 U1 62kg49.9kg2 Figure 4-1.4MHZ, 3. 3V Output at 1A Step-Down Converter V BST 6V-12V C3 4.7uF inf L1 16V 3R3 6 10uH SW 100k MP2359 D1 仝N5819HW7 10uF ED1 vol 16V OFFON EN FB GND LED2 200k R2 LED3 OUT Figure 5-White LED Driver Application P2359Rev.1.21 ww. MonolithicPower com 7/18/2011 MPS Proprietary Information Patent Protected. Unauthorized Photocopy and duplication Prohibited C 2011 MPS. All Rights Reserved 』5 MP2359-1.2A. 24V.1. 4MHz STEP-DOWN CONVERTER INA TSOT23-6 PACKAGE INFORMATION TSOT23-6 0.60 2.80 TYP BSC 3.00 4 TYP See Note 7 EXAMPLE TOP MARK AAAA 2.60 2.60 TYP PIN 1 TOP VIEW RECOMMENDED LAND PATTERN 0.84 1.00MA SEATING PLANE 0.30 -0.95BsC 0.00 0.50 0.10 SEE DETAILA FRONT VIEW SIDE VIEW NOT 1ALL DIMENSIONS ARE IN MILLIMETERS GAUGE PLANE 2) PACKAGE LENGTH DOES NOT INCLUDE MOLD FLASH, 0.25 BSC PROTRUSION OR GATE BURR 3)PACKAGE WIDTH DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSION 4)LEAD COPLANARITY(BOTTOM OF LEADS AFTER FORMING) 0.30 SHALL BE.10 MILLIMETERS MAX 0.50 5)DRAWING CONFORMS TO JEDEC MO-193, VARIATION AB 6)DRAWING IS NOT TO SCALE DETAIL“A” 7)PIN 1 IS LOWER LEFT PIN WHEN READING TOP MARK FROM LEFT TO RIGHT, (SEE EXAMPLE TOP MARK) P2359Rev.1.21 ww. MonolithicPower com 10 7/18/2011 MPS Proprietary Information Patent Protected. Unauthorized Photocopy and duplication Prohibited o 2011 MPS. All Rights Reserved

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