fp6185

FP6185 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. 0.62 1/14 FP6185 BS IN GND SS FB VIN EN SW COMP 1 2 3 4 VOUT 5 6 7 8 EN General Description The FP6185 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 reduces the stress on the input source during power-on. The regulator only consumes 23μA supply current in shutdown mode. The FP6185 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 High Side 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 Package: SOP-8L  Under Voltage Lockout Applications  Distributed Power Systems  Battery Charger  Pre-Regulator for Linear Regulators  DSL Modems Typical Application Circuit FP6185 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. 0.62 2/14 Function Block Diagram Pin Descriptions SOP-8L 1 2 3 4 8 7 6 5 BS IN SW GND SS EN COMP FB FP6185 9Fa-86L Top View Name No. I / O Description BS 1 O Bootstrap IN 2 P Supply Voltage SW 3 O Switch GND 4 P Ground FB 5 I Feedback COMP 6 O Compensation EN 7 I Enable / UVLO SS 8 O Programmable Soft Start FP6185 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. 0.62 3/14 Marking Information Halogen Free Lot Number Internal ID Per-Half Month Year FP6185 - 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 FP6185 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. 0.62 4/14 Ordering Information Part Number Operating Temperature Package MOQ Description FP6185DR-G1 -40°C ~ +85°C SOP-8L 2500 EA 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 Thermal Resistance θJA SOP-8L 175 °C / W Thermal Resistance θJC SOP-8L 55 °C / W Junction Temperature TJ 110 °C Storage Temperature -65 150 °C Lead Temperature (soldering, 10 sec) SOP-8L 260 °C Allowable Power Dissipation (TA≦+25°C) SOP-8L 570 mW IR Re-flow Soldering Curve FP6185 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. 0.62 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=12V, unless otherwise noted) Parameter Symbol Conditions Min. Typ. Max. Unit Standby Current IST VEN≧3V,VFB>1V 0.3 0.5 0.7 mA Operating Current ICC VEN≧3V 3.2 4.2 6.1 mA Shutdown Supply Current ISH VEN=0 15 23 36 µA Feedback Voltage VFB VIN=12V,VCOMP<2V 0.892 0.92 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 △ICOMP=±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 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 100 ns Under Voltage Lockout Threshold VUVLO 2.37 2.5 2.62 V Under Voltage Lockout Threshold Hysteresis VHYS 210 mV EN Threshold Voltage VEN ICC＞100μA 0.7 1 1.3 V Enable Pin Pull Up Current IEN VEN=0V 1 µA Soft-Start Pin Equivalent Output Resistance RSS 9 kΩ Thermal Shutdown TTS +150 °C Thermal Shutdown Reset Hysteresis THYS +40 °C FP6185 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. 0.62 6/14 Typical Operating Characteristics (TA= 25°C, VIN=12V, unless otherwise noted) Figure 1: Power on Figure 2: Power off Figure 3: EN Pin Enable Figure 4: EN Pin Disable Figure 5: Load 2A Figure 6: Load 2A Ripple FP6185 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. 0.62 7/14 Figure 7: SCP Figure 9: Load Step Figure 8: OCP 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 % Figure 10: Efficiency VIN=12V VOUT=3.3V FP6185 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. 0.62 8/14 Function Description The FP6185 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 FP6185 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 pin where a frequency compensation network stabilizes the regulation 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 the 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 100kΩ, but a typical value is 10kΩ. Shutdown Mode Drive ENABLE pin to ground to shut down the FP6185. Shutdown forces the internal power MOSFET off, turns off all internal circuitry, and reduces the VIN supply current to 23μA (typ.). The ENABLE pin rising threshold is 1V (typ.). Before any operation begins, the voltage at ENABLE pin must exceed 1V (typ.). 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 during SW pin pulled to ground period. FP6185 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. 0.62 9/14 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 off and the BST capacitor voltage provides the necessary enhancement voltage to turn on the high-side switch. Thermal Shutdown Protection The FP6185 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. FP6185 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. 0.62 10/14 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. When using electrolytic or tantalum capacitors, a small high quality 0.1μF ceramic capacitor should be placed closely 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 required CIN to suppress input voltage ripple 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 sometimes 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 )D1( fI VVL O DO   Where  is the ripple current ratio,  =△IL / ILOAD 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 FP6185 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. 0.62 11/14 capacitance. The output voltage ripple is mainly decided by the capacitance value. Choose the capacitor value with following equation.      IN OUT OUT 2 OUT OUT V V 1 VLf8 V C In the case of tantalum or electrolytic capacitors, the ESR dominates the impedance at the switching frequency. Choose the capacitor with suitable ESR calculated following.  OUTINOUT INOUT VVV VLfV ESR   PC Board Layout Checklist The power traces, consisting of the GND trace, the SW trace and the VIN trace should be kept short, direct and wide. Place CIN near IN Pin as closely as possible to maintain input voltage steady and filter out the pulsing input current. The resistive divider R2 and R4 must be connected to FB pin directly as close as possible. 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 switching EMI radiation to disturb the DC-DC converter’s own voltage feedback trace. FP6185 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. 0.62 12/14 Suggested Layout FP6185 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. 0.62 13/14 Typical Application FP6185 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. 0.62 14/14 Package Outline SOP-8L UNIT:mm Note: 1. Package dimensions are in compliance with JEDEC Outline: MS-012 AA. 2. Dimension “D” does not include molding flash, protrusions gate burrs. 3. Dimension “E” does not include inter-lead flash, or protrusions. Symbols Min. (mm) Max. (mm) A 1.346 1.752 A1 0.101 0.254 A2 1.498 D 4.800 4.978 E 3.810 3.987 H 5.791 6.197 L 0.406 1.270 θ° 0° 8°