fp6181

FP6181 2A, 23V, 380KHz Step-Down Converter This datasheet contains new product information. Feeling Technology reserves the rights to modify the product specification without notice. No liability is assumed as a result of the use of this product. No rights under any patent accompany the sales of the product. Website: http://www.feeling-tech.com.tw Rev. 0.63 1/14 General Description The FP6181 is a buck regulator with a built in internal power MOSFET. It achieves 2A continuous output current over a wide input supply range with excellent load and line regulation. Current mode operation provides fast transient response and eases loop stabilization. The device includes cycle-by-cycle current limiting and thermal shutdown protection. Adjustable soft-start reduced the stress on the input source at power-on. The regulator only consumes 23µA supply current in shutdown mode. The FP6181 requires a minimum number of readily available external components to complete a 2A buck regulator solution. Features  2A Output Current  Adjustable Soft-Start  0.18Ω Internal Power MOSFET Switch  Stable with Low ESR Output Ceramic Capacitors  Up to 95% Efficiency  23μA Shutdown Mode Current  Fixed 380KHz frequency  Thermal Shutdown  Cycle-by-Cycle Over Current Protection  Wide 4.75 to 23V Operating Input Range  Output Adjustable From 0.92 to 16V  Available MSOP-10L (EP)  Under Voltage Lockout. Applications  Distributed Power Systems  Battery Charger  Pre-Regulator for Linear Regulators  DSL Modems Typical Application Circuit FP6181 This datasheet contains new product information. Feeling Technology reserves the rights to modify the product specification without notice. No liability is assumed as a result of the use of this product. No rights under any patent accompany the sales of the product. Website: http://www.feeling-tech.com.tw Rev. 0.63 2/14 Function Block Diagram Oscillator 240/380KHz Slope Compensation Control Logic 0.92V FB BS IN SW GND Internal Regulator UVLO Current Sense EN COMP Enable Control 0.4V 1µA 5V Current Comparator Frequency Foldback Comparator Error Amplifier SS 1.8V Pin Descriptions MSOP-10L (EP) Name No. I / O Description NC 1 No connect BS 2 O Bootstrap NC 3 No connect IN 4 P Supply Voltage SW 5 O Switch GND 6 P Ground FB 7 I Feedback COMP 8 O Compensation EN 9 I Enable / UVLO SS 10 O Programmable Soft Start FP6181 This datasheet contains new product information. Feeling Technology reserves the rights to modify the product specification without notice. No liability is assumed as a result of the use of this product. No rights under any patent accompany the sales of the product. Website: http://www.feeling-tech.com.tw Rev. 0.63 3/14 Marking Information MSOP-10L (EP) Halogen Free: Halogen free product indicator Lot Number: Wafer lot number’s last two digits For Example: 132386TB  86 Internal ID: Internal Identification Code Per-Half Month: Production period indicated in half month time unit For Example: January → A (Front Half Month), B (Last Half Month) February → C (Front Half Month), D (Last Half Month) Year: Production year’s last digit FP6181 This datasheet contains new product information. Feeling Technology reserves the rights to modify the product specification without notice. No liability is assumed as a result of the use of this product. No rights under any patent accompany the sales of the product. Website: http://www.feeling-tech.com.tw Rev. 0.63 4/14 Ordering Information Part Number Operating Temperature Package MOQ Description FP6181gR-G1 -40°C ~ +85°C MSOP-10L (EP) 3000EA Tape & Reel Absolute Maximum Ratings Parameter Symbol Conditions Min. Typ. Max. Unit Supply Voltage VIN -0.3 24 V Switch Voltage VSW -1 VIN+0.3 V Boost Voltage VBS VSW -0.3 VSW +6 V All Other Pins -0.3V 6 V θJA +105 °C / W Thermal Resistance θJC MSOP-10L (EP) +19 °C / W Junction Temperature +150 °C Storage Temperature -65 +150 °C Operating Temperature -40 +85 °C Lead Temperature (soldering, 10 sec) +260 °C Allowable Power Dissipation (TA≦+25°) 800 mW IR Re-flow Soldering Curve FP6181 This datasheet contains new product information. Feeling Technology reserves the rights to modify the product specification without notice. No liability is assumed as a result of the use of this product. No rights under any patent accompany the sales of the product. Website: http://www.feeling-tech.com.tw Rev. 0.63 5/14 Recommended Operating Conditions Parameter Symbol Conditions Min. Typ. Max. Unit Supply Voltage VIN 4.75 23 V Operating Temperature -40 +85 °C DC Electrical Characteristics (TA= 25°C, VIN=3.6V, unless otherwise noted) Parameter Symbol Conditions Min. Typ. Max. Unit Standby Current IST VEN≧3V,VFB>1V 0.6 mA Shutdown Supply Current IST VEN=0 23 36 µA Feedback Voltage VFB VIN=12V,VCOMP<2V 0.892 0.920 0.948 V Current Sense Tran conductance Output Current to Comp Pin Voltage TCS 2.1 A / V Error Amplifier Voltage Gain GEA 400 V / V Error Amplifier Tran conductance TEA △IC=±10µA 830 µA / V High Side Switch ON Resistance RON-HS 0.18 Ω Low Side Switch ON Resistance RON-LS 10 Ω High Side Switch Leakage Current IIL VEN=0,VSW=0V 0.1 10 µA Current Limit ICL 2.8 3.4 A Oscillation Frequency fOSC 380 KHz Short Circuit Oscillation Frequency fSC VFB=0V 240 KHz Maximum Duty Cycle DMAX VFB=0.8V 90 % Minimum On Time tON VFB=1.5V 100 ns Under Voltage Lockout Threshold VUVLO VEN Rising 2.37 2.50 2.62 V Under Voltage Lockout Threshold Hysteresis VHYS 210 mV EN Threshold Voltage VEN ICC＞100μA 0.7 1.0 1.3 V Enable Pull Up Current IEN VEN=0V 1.0 µA Soft-Start Pin Equivalent Output Resistance RSS 9 kΩ Thermal Shutdown TTS 150 °C Thermal Shutdown Reset Hysteresis THYS 40 °C FP6181 This datasheet contains new product information. Feeling Technology reserves the rights to modify the product specification without notice. No liability is assumed as a result of the use of this product. No rights under any patent accompany the sales of the product. Website: http://www.feeling-tech.com.tw Rev. 0.63 6/14 Typical Operating Characteristics (TA= 25°C, VIN=12V, unless otherwise noted) Figure1: Power on Figure2: Power off Figure3: EN Pin Enable Figure4: EN Pin Disable Figure5: Load 2A Figure6: Load 2A Ripple FP6181 This datasheet contains new product information. Feeling Technology reserves the rights to modify the product specification without notice. No liability is assumed as a result of the use of this product. No rights under any patent accompany the sales of the product. Website: http://www.feeling-tech.com.tw Rev. 0.63 7/14 0 10 20 30 40 50 60 70 80 90 0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 A % Figure7: SCP Figure8: OCP Figure9: Load Step Figure10: Efficiency VIN=12V VOUT=3.3V FP6181 This datasheet contains new product information. Feeling Technology reserves the rights to modify the product specification without notice. No liability is assumed as a result of the use of this product. No rights under any patent accompany the sales of the product. Website: http://www.feeling-tech.com.tw Rev. 0.63 8/14 Function Description The FP6181 is a current-mode buck regulator. It regulates input voltages from 4.75V to 23V down to an output voltage as low as 0.92V, and is able to supply up to 2A of load current. The FP6181 uses current-mode control to regulate the output voltage. The output voltage is measured at FB through a resistive voltage divider and amplified through the internal error amplifier. The output current of the Tran conductance error amplifier is presented at COMP where a network compensates the regulation control system. The voltage at COMP is compared to the switch current measured internally to control the output voltage. The converter uses an internal n-channel MOSFET switch to step-down the input voltage to the regulated output voltage. Since the MOSFET requires a gate voltage greater than the input voltage, a boost capacitor connected between SW and BS drives the gate. The capacitor is internally charged while the switch is off. An internal 10Ω switch from SW to GND is used to insure that SW is pulled to GND when the switch is off to fully charge the BS capacitor. Output Voltage (VOUT) The output voltage is set using a resistive voltage divider from the output voltage to FB. The voltage divider divides the output voltage down by the ratio: 42 4 OUTFB RR R VV  Thus the output voltage is: 4 42 FBOUT R RR VV  A typical value for R4 can be as high as 100k, but a typical value is 10K. Shutdown Mode Drive enable Pin to ground to shut down the FP6181. Shutdown forces the internal power MOSFET off, turns off all internal circuitry, and reduces the VIN supply current to 20μA (type). The enable Pin rising threshold is 1.2V (type). Before any operation begins, the voltage at Enable Pin must exceed 1.2V (type). The Enable Pin input has 100mV hysteresis. Boost High-Side Gate Drive (BST) Since the MOSFET requires a gate voltage greater than the input voltage ,connect a flying bootstrap capacitor between SW and BS to provide the gate-drive voltage to the high-side n-channel MOSFET switch. The capacitor is alternately charged from the internally regulator. On startup, an internal low-side switch connects SW to ground and charges the BST capacitor to internally regulator voltage. Once the BST capacitor is charged, the internal low-side switch is turned FP6181 This datasheet contains new product information. Feeling Technology reserves the rights to modify the product specification without notice. No liability is assumed as a result of the use of this product. No rights under any patent accompany the sales of the product. Website: http://www.feeling-tech.com.tw Rev. 0.63 9/14 off and the BST capacitor voltage provides the necessary enhancement voltage to turn on the high-side switch. Thermal Shutdown Protection The FP6181 features integrated thermal shutdown protection. Thermal shutdown protection limits allowable power dissipation (PD) in the device, and protects the device in the event of a fault condition. When the IC junction temperature exceeds +150°C, an internal thermal sensor signals the shutdown logic, turning off the internal power MOSFET and allowing the IC to cool down. The thermal sensor turns the internal power MOSFET back on after the IC junction temperature cools down to + 110°C, resulting in a pulsed output under continuous thermal overload conditions. Application Information Input Capacitor Selection The input current to the step-down converter is discontinuous, therefore a capacitor is required to supply the AC current to the step-down converter while maintaining the DC input voltage. Use low ESR capacitors for the best performance. Ceramic capacitors are preferred, but tantalum or low-ESR electrolytic capacitors may also suffice. The input capacitor can be electrolytic, tantalum or ceramic. When using electrolytic or tantalum capacitors, a small, high quality ceramic capacitor, i.e. 0.1μF, should be placed as close to the IC as possible. When using ceramic capacitors, make sure that they have enough capacitance to provide sufficient charge to prevent excessive voltage ripple at input. The input voltage ripple caused by capacitance can be estimated by )D1(D Vf I C IN O IN  Inductor Selection The inductor is required to supply constant current to the output load while being driven by the switched input voltage. A larger value inductor will result in less ripple current that will result in lower output ripple voltage. However, the larger value inductor will have a larger physical size, higher series resistance, and / or lower saturation current. A good rule for determining the inductance to use is to allow the peak-to-peak ripple current in the inductor to be approximately 30% of the maximum switch current limit. Also, make sure that the peak inductor current is below the maximum switch current limit. The inductance value can be calculated by FP6181 This datasheet contains new product information. Feeling Technology reserves the rights to modify the product specification without notice. No liability is assumed as a result of the use of this product. No rights under any patent accompany the sales of the product. Website: http://www.feeling-tech.com.tw Rev. 0.63 10/14 )D1( fI VV L O DO   Where r is the ripple current ratio RMS current in inductor 12 1II 2 OLrms  Output Capacitor Selection The output capacitor is required to maintain the DC output voltage. Ceramic, tantalum, or low ESR electrolytic capacitors are recommended. Low ESR capacitors are preferred to keep the output voltage ripple low. The output voltage ripple can be estimated by:         OUTIN OUTINOUT OUT Cf8 1ESR* VLf VVV V In the case of ceramic capacitors, the impedance at the switching frequency is dominated by the capacitance. The output voltage ripple is mainly caused by the capacitance. In the case of tantalum or electrolytic capacitors, the ESR dominates the impedance at the switching frequency. Ⅰ.In the case of ceramic capacitors      IN OUT OUT 2 OUT OUT V V 1 VLf8 V C Ⅱ.In the case of tantalum or electrolytic capacitors  OUTINOUT INOUT VVV VLfV ESR   PC Board Layout Checklist 1. The power traces, consisting of the GND trace, the SW trace and the VIN trace should be kept short, direct and wide. 2. Place CIN near IN Pin as closely as possible. To maintain input voltage steady and filter out the pulsing input current. 3. The resistive divider R2and R4 must be connected to FB pin directly as closely as possible. 4. FB is a sensitive node. Please keep it away from switching node, SW. A good approach is to route the feedback trace on another layer and to have a ground plane between the top layer and the layer on which the feedback trace is routed. This reduces EMI radiation on to the DC-DC converter’s own voltage feedback trace. FP6181 This datasheet contains new product information. Feeling Technology reserves the rights to modify the product specification without notice. No liability is assumed as a result of the use of this product. No rights under any patent accompany the sales of the product. Website: http://www.feeling-tech.com.tw Rev. 0.63 11/14 Suggested Layout FP6181 This datasheet contains new product information. Feeling Technology reserves the rights to modify the product specification without notice. No liability is assumed as a result of the use of this product. No rights under any patent accompany the sales of the product. Website: http://www.feeling-tech.com.tw Rev. 0.63 12/14 Typical Application NC BS NC IN SW SS EN COMP FB GND 1 2 3 4 5 10 9 8 7 6 FP6181 C1 22nF C3 NA R1 16K C6 1000pF C2 10nF C5 22µF C4 0.1µF R2 16K R4 6.2K C9 47µF C8 0.1µF VIN 12V VOUT 3.3V D1 SM340A L1 10µH FP6181 This datasheet contains new product information. Feeling Technology reserves the rights to modify the product specification without notice. No liability is assumed as a result of the use of this product. No rights under any patent accompany the sales of the product. Website: http://www.feeling-tech.com.tw Rev. 0.63 13/14 Package Outline MSOP-10L (EP) UNIT: mm Symbols Min. (mm) Max. (mm) A 1.100 A1 0.000 0.150 A2 0.750 0.950 b 0.170 0.270 c 0.080 0.230 D 3.000 BSC. E 4.900 BSC. E1 3.000 BSC. e 0.500 BSC. L 0.400 0.800 L1 0.950 REF. θ° 0° 8° FP6181 This datasheet contains new product information. Feeling Technology reserves the rights to modify the product specification without notice. No liability is assumed as a result of the use of this product. No rights under any patent accompany the sales of the product. Website: http://www.feeling-tech.com.tw Rev. 0.63 14/14 MSOP-10L (EP) continued Exposed PAD Dimensions: Note: 1. Package dimensions are in compliance with JEDEC outline: MO-187 BA-T. 2. Dimension “D” does not include molding flash, protrusions or gate burrs. 3. Dimension “E1” does not include inter-lead flash or protrusions. Symbols Min. (mm) Max. (mm) E2 1.715 REF D1 1.600 REF