FAN8841MPX

Is Now Part of To learn more about ON Semiconductor, please visit our website at www.onsemi.com Please note: As part of the Fairchild Semiconductor integration, some of the Fairchild orderable part numbers will need to change in order to meet ON Semiconductor’s system requirements. Since the ON Semiconductor product management systems do not have the ability to manage part nomenclature that utilizes an underscore (_), the underscore (_) in the Fairchild part numbers will be changed to a dash (-). This document may contain device numbers with an underscore (_). Please check the ON Semiconductor website to verify the updated device numbers. The most current and up-to-date ordering information can be found at www.onsemi.com. Please email any questions regarding the system integration to Fairchild_questions@onsemi.com. ON Semiconductor and the ON Semiconductor logo are trademarks of Semiconductor Components Industries, LLC dba ON Semiconductor or its subsidiaries in the United States and/or other countries. ON Semiconductor owns the rights to a number of patents, trademarks, copyrights, trade secrets, and other intellectual property. A listing of ON Semiconductor’s product/patent coverage may be accessed at www.onsemi.com/site/pdf/Patent-Marking.pdf. ON Semiconductor reserves the right to make changes without further notice to any products herein. ON Semiconductor makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does ON Semiconductor assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages. Buyer is responsible for its products and applications using ON Semiconductor products, including compliance with all laws, regulations and safety requirements or standards, regardless of any support or applications information provided by ON Semiconductor. “Typical” parameters which may be provided in ON Semiconductor data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each customer application by customer’s technical experts. ON Semiconductor does not convey any license under its patent rights nor the rights of others. ON Semiconductor products are not designed, intended, or authorized for use as a critical component in life support systems or any FDA Class 3 medical devices or medical devices with a same or similar classification in a foreign jurisdiction or any devices intended for implantation in the human body. Should Buyer purchase or use ON Semiconductor products for any such unintended or unauthorized application, Buyer shall indemnify and hold ON Semiconductor and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that ON Semiconductor was negligent regarding the design or manufacture of the part. ON Semiconductor is an Equal Opportunity/Affirmative Action Employer. This literature is subject to all applicable copyright laws and is not for resale in any manner. FAN8841 Dual Half-Bridge Piezoelectric Driver with Step-up DC-DC Converter Features Description Step-up DC-DC Converter The FAN8841 is a single-chip piezoelectric actuator driver consisting of a step-up DC-DC converter with integrated 36 V boost switch and the dual half-bridge output stages. The step-up DC-DC converter operates in Critical Conduction Mode (CRM) in order to reduce switching loss at the DC-DC converter for high efficiency. It is optimized to work in a coupled-inductor configuration to provide output voltages in excess of 60 V. The step-up DC-DC converter has a soft-start capability that limits the inrush current during startup. Over-voltage protection and over-current protection are included. Under-voltage protection is used to disable the dual half-bridge gate driver when the step-up DC-DC converter output voltage is lower than the specified threshold voltage. The boost voltage is set using external resistors and analog voltage at the VCON pin and step-up current limit is programmable via the external resistor at the OCP pin. The output Half-bridge is integrated with 75 V P- and N-channel for the piezoelectric actuator driving. An open drain Fault-out (FO) signal indicates if an abnormal over-voltage has occurred.        Integrated Step-up Power Switch up to 36 V Wide Operating Voltage Range of 2.7 to 5.5 V Adjustable Step-up Output Voltage by VCON Adjustable Step-up Switch Current Limit Zero Current Detector (ZCD) Internal Soft-Start Built-in Protection Circuit - Under-Voltage Protection (UVP) - Over-Voltage Protection (OVP) Piezo Actuator Driver    Integrated Half-Bridge Switches (VDS=75 V)  Small 4.0 mm × 4.0 mm MLP Dual Half-Bridge Piezoelectric Driver Built-in Shutdown Function Package Information Applications  Piezoelectric Actuator Ordering Information Part Number Operating Temperature Range Package Packing Method FAN8841MPX -40°C to +125°C 24-Lead, 4.0 mm × 4.0 mm Molded Leadless Package (MLP) Tape & Reel © 2015 Fairchild Semiconductor Corporation FAN8841 • Rev. 1.0 www.fairchildsemi.com FAN8841 — Dual Half-Bridge Piezoelectric Driver with Step-up DC-DC Converter June 2015 VDRV N1 N2 2.7 V ~5.5 V PGND1 PGND1 VDD SGND ZCD FB COMP LX LX FO FO NC EN EN IN1 IN1 OUT2 IN2 IN2 NC FAN8841 OUT1 PGND2 VDRV VDRV AGND VCON SD CONTROLLER OCP SD VCON Figure 1. Typical Application Circuit for Piezo Actuator Driver Block Diagram IN1 VDRV_UVP VDRV UNDER VOLTAGE IN2 VDRV HPO1 CONTROL LOGIC HIN1 HPO2 HIN2 SD LIN2 AGND LIN1 GATE DRIVER OUT1 LNO2 OUT2 LNO1 PGND2 VDD VOLTAGE MONITOR AND LOGIC EN SGND VDD ICON ZCD CLAMP VCON VREF TIMER Q VZCD COMP DRIVER S ZCD FB LX PWM R OVP VOVP PGND1 RAMP GENERATOR FO FAULT [tFO=20us] CURRENT LIMIT Figure 2. © 2015 Fairchild Semiconductor Corporation FAN8841 • Rev. 1.0 RLIMIT OCP Block Diagram www.fairchildsemi.com 2 FAN8841 — Dual Half-Bridge Piezoelectric Driver with Step-up DC-DC Converter Typical Application FAN8841 — Dual Half-Bridge Piezoelectric Driver with Step-up DC-DC Converter Pin Configuration PGND1 PGND1 VDD SGND ZCD FB COMP LX OCP LX FO NC FAN8841 EN OUT1 OUT2 IN2 NC VDRV VDRV AGND VCON SD Figure 3. PGND2 IN1 Pin Assignment Pin Definitions Pin # Name 1, 2 PGND1 Description Power Ground 1. It is connected to the source of the step-up switch. 3 VDD 4 SGND Power supply of step-up DC-DC converter. 5 ZCD 6 FB 7 COMP 8 OCP 9 FO Fault Output. 10 EN Enable pin to turn on and off the overall system. (Active Low Shutdown Mode). 11 IN1 Logic input for Half-Bridge 1 12 IN2 Logic input for Half-Bridge 2 13 SD Shutdown input for H-Bridge 1 and 2. (Active Low Shutdown Mode). Signal Ground. The signal ground for step-up DC-DC converter circuitry. The input of the Zero Current Detection Step-up DC-DC converter output voltage feedback input. Output of the transconductance error amplifier. Sets Step-up DC-DC converter current limit 14 VCON 15 AGND Control input for output voltage of step-up DC-DC converter 16, 17 VDRV 18 PGND2 19 NC 20 OUT2 Output for Half-bridge 2 21 OUT1 Output for Half-bridge 1 22 NC Not Connected 23, 24 LX Switch Node. This pin is connected to the inductor. Analog Ground. The signal ground for H-bridge driver circuitry Power supply of each H-bridge driver Power Ground 2. The power ground for Half-bridge driver Not Connected © 2015 Fairchild Semiconductor Corporation FAN8841 • Rev. 1.0 www.fairchildsemi.com 3 Stresses exceeding the absolute maximum ratings may damage the device. The device may not function or be operable above the recommended operating conditions and stressing the parts to these levels is not recommended. In addition, extended exposure to stresses above the recommended operating conditions may affect device reliability. The absolute maximum ratings are stress ratings only. Symbol Parameter Min. VDRV DC Link Input Voltage Drain-Source Voltage of each MOSFET VDD Max. Unit 75 V DC Supply Voltage for DC-DC Converter -0.3 5.5 V VINPUT EN, SD, IN1, IN2, FB and COMP to SGND and AGND -0.3 VDD +0.3 V VCON VCON to SGND -0.3 VDD +0.3 V 40 V VLX LX to PGND -0.3 (2) 1S0P with thermal vias (3) 0.98 1S2P with thermal vias (4) 2.9 1S0P with thermal vias (3) 127 1S2P with thermal vias (4) 43 PD Power Dissipation θJA Thermal Resistance Junction-Air TA Operating Ambient Temperature Range -40 125 °C TJ Operating Junction Temperature -55 150 °C -55 150 °C 2 KV 500 V TSTG (1) Storage Temperature Range Human Body Model, JESD22-A114 ESD Electrostatic Discharge Capability Charged Device Model, JESD22-C101 W °C/W Notes: 1. All voltage values, except differential voltages, are given with respect to SGND, AGND and PGND pin. 2. JEDEC standard: JESD51-2, JESD51-3. Mounted on 76.2 x 114.3 x1.6 mm PCB (FR-4 glass epoxy material). 3. 1S0P with thermal via: one signal layer with zero power plane and thermal via. 4. 1S2P with thermal via: one signal layer with two power plane and thermal via. Recommended Operating Conditions The Recommended Operating Conditions table defines the conditions for actual device operation. Recommended operating conditions are specified to ensure optimal performance. Fairchild does not recommend exceeding them or designing to Absolute Maximum Ratings. Symbol VDRV VLX Parameter Supply Voltage for Half-Bridge Driver Min. Max. Unit 13 60 V 36 V Boost Switch Voltage Output Voltage Control of DC-DC Converter 0.1 VDD V VDD Operating Voltage for DC-DC Converter 2.8 5.0 V ROCP Current Limit Control Resistor 3.3 150 kΩ VCON © 2015 Fairchild Semiconductor Corporation FAN8841 • Rev. 1.0 www.fairchildsemi.com 4 FAN8841 — Dual Half-Bridge Piezoelectric Driver with Step-up DC-DC Converter Absolute Maximum Ratings VDD=3.0 V, VDRV=60 V, and TA= -40°C to +125°C. Typical values TA=25°C, unless otherwise specified. Symbol Parameter Conditions Min. Typ. Max. Unit 800 1200 µA 400 800 µA 1 µA 8 15 µA 2.8 V Power Supply Section (5) IQ,DD Quiescent Current for VDD I Q,DRV Quiescent Current for VDRV ISD,DD Shutdown Current for VDD ISD,DRV Shutdown Current for VDRV VEN=VCOMP=VDD, VFB=1.0 V, VIN1=VIN2=0 V VEN=0 V, VDD= VDRV =3 V VDDSTART Start Threshold Voltage 2.6 2.7 VDDUVHYS VDD UVLO Hysteresis Voltage 0.10 0.2 0.99 1.00 V Error Amplifier Section VFB Feedback Reference Voltage IFB FB pin Bias Current VFB1 Gm TA=25°C VFB=0 V ~ 2 V Feedback Voltage Line Regulation (6) Transconductance 2.7 V < VDD < 5 V, 0.5 TA=25°C 800 1.01 V 1 µA 1.5 %/V µmho Zero Current Detect Section VZCD Input Voltage Threshold (7) 1.65 VCLAMPH Input High Clamp Voltage IDET=2.3 mA VCLAMPL Input Low Clamp Voltage IDET= -2.3 mA IZCD,SR Source Current Capability IZCD,SK Sink Current Capability tZCD,D Delay From ZCD to Output Turn-On 1.83 2.00 V 3.0 3.5 4.0 V -0.30 0.12 0.50 V -2.3 mA 2.3 mA 50 200 ns 15 25 35 µs 16 28 40 ms 15 25 35 µs 900 1000 KHz (7) Maximum On-Time Section tON,MAX Maximum On-Time Soft-Start Timer Section tSS Internal Soft-Start Restart / Maximum Switching Frequency Limit Section tRST fMAX Restart Timer Maximum Switching Frequency (7) Notes: 5. This is only the VDD current consumption with no switching condition. It does not include gate-drive current. VOUT 1  . VIN VOUT 6. The line regulation is calculated based on 7. This parameter, although guaranteed by design, is not tested in production. © 2015 Fairchild Semiconductor Corporation FAN8841 • Rev. 1.0 www.fairchildsemi.com 5 FAN8841 — Dual Half-Bridge Piezoelectric Driver with Step-up DC-DC Converter Electrical Characteristics VDD=3.0 V, VDRV=60 V, and TA= -40°C to +125°C. Typical values TA=25°C, unless otherwise specified. Symbol Parameter Conditions Min. Typ. Max. Unit ROCP=3.3 KΩ, VDD=3.3 V 1.85 2.00 2.15 A ROCP=22 KΩ,VDD=3.3 V 0.9 1.0 1.1 A 80 130 180 ns 9.0 10 11 µA Current Limit Comparator Section IOCP tCS_BLANK OCP Trip Current (8) Comparator Leading-Edge Blanking Time Step-up Output Control Section ICON VCON+ VCON- Internal Current Source for VCON Pin Positive Going Threshold Voltage (8) Negative Going Threshold Voltage TA=25°C (8) 1.0 V 0.1 V Step-up Switch Section RDSON N-Channel On Resistance VDD=3.3 V, TA=25°C ILK_LX LX Leakage Current VLX=36 V 0.2 0.5 Ω 1.0 µA Logic (EN, IN1,IN2, SD) Section VINPUT+ Input Logic High Threshold Voltage VINPUT- Input Logic Low Threshold Voltage 1.34 IINPUT- Input Low Current VEN=0 V IINPUT+ Input High Current VEN=VDD RINPUT Input Logic Pull-Down Resistance VEN=VINPUT=3 V 16 V 24 0.5 V 1 µA 32 µA 125 KΩ Full-Bridge Switch Section RDS,ONP Output Upper-Side On Resistance RDS,ONN Output Low-Side On Resistance tON Turn-on Propagation Delay Time tOFF Turn-off Propagation Delay Time TA=25°C VDRV=30 V, TA=25°C 3.0 5.0 Ω 3.0 5.0 Ω 300 ns 330 ns Protection (UVP, and OVP ) VUVP HYUVP Under-Voltage Threshold of DC-DC Con. 11 12 1.05 1.10 Under-Voltage Hysteresis 13 1.0 V V VOVP OVP Threshold Voltage HYOVP OVP Hysteresis Voltage 0.1 Fault Output Duration 20 30 µs 0.1 0.4 V tFO VFOL Fault Output Low Level voltage RPU=50 KΩ, VPU=3 V 1.15 V V Note: 8. This parameter, although guaranteed by design, is not tested in production. © 2015 Fairchild Semiconductor Corporation FAN8841 • Rev. 1.0 www.fairchildsemi.com 6 FAN8841 — Dual Half-Bridge Piezoelectric Driver with Step-up DC-DC Converter Electrical Characteristics Figure 4 shows the timing chart for overall system. EN VCON,MAX = 1.0 V VCON VCON,MIN = 0.1 V VDRV VUVP = 12 V SD IN1 IN2 Skip by UV condition of VDRV OUT1 Skip by UV condition of VDRV Skip by SD signal OUT2 A C D E D A B D B Figure 4. Table 1. C Timing Chart of Overall System Operating Modes Input Output Mode IN1 IN2 EN SD OUT1 OUT2 State X X L X L L A X X H L L L E L L H H L H L H H L L H H L H L H D H DC-DC H-Bridge Whole System Disable Active Disable Normal Operation Notes: 9. X: Don’t care (L or H). 10. EN: Whole system is disable mode when EN is LOW state. 11. Soft-start duration: C, under-voltage condition of VDRV: B. © 2015 Fairchild Semiconductor Corporation FAN8841 • Rev. 1.0 www.fairchildsemi.com 7 FAN8841 — Dual Half-Bridge Piezoelectric Driver with Step-up DC-DC Converter Design Consideration Information Figure 5. Figure 7. Figure 9. Figure 11. Reference Voltage vs. Temperature Figure 6. Shutdown Current for VDD & VDRV vs. Temperature VDD Threshold vs. Temperature Figure 8. VCON Current vs. Temperature Quiescent Current for VDD & VDRV vs. Temperature Figure 10. OCP Current vs. Temperature Operating Current for VDD, VDRV, & VIN © 2015 Fairchild Semiconductor Corporation FAN8841 • Rev. 1.0 Figure 12. ZDC Clamp Voltage vs. Temperature www.fairchildsemi.com 8 FAN8841 — Dual Half-Bridge Piezoelectric Driver with Step-up DC-DC Converter Typical Performance Characteristics Typical Performance Characteristics (Continued) Figure 13. Maximum On-Time vs. Temperature Figure 15. Figure 17. Figure 19. Figure 14. Restart-Time vs. Temperature Figure 16. Soft-Start Time vs. Temperature Figure 18. Enable(EN) Threshold Voltage vs. Temperature © 2015 Fairchild Semiconductor Corporation FAN8841 • Rev. 1.0 OVP (FB) vs. Temperature INPUT Threshold vs. Temperature INPUT Logic Current vs. Temperature Figure 20. VDRV UVP Threshold Voltage vs. Temperature www.fairchildsemi.com 9 FAN8841 — Dual Half-Bridge Piezoelectric Driver with Step-up DC-DC Converter vs. Temperature Figure 21. Half-Bridge Switch RDSON vs. Temperature Figure 23. Figure 22. OUT1/2 Delay vs. VDRV Figure 25. © 2015 Fairchild Semiconductor Corporation FAN8841 • Rev. 1.0 Boost Switch RDSON vs. Temperature Figure 24. % of OUT Amplitude vs. VCON IOCP vs. ROCP www.fairchildsemi.com 10 FAN8841 — Dual Half-Bridge Piezoelectric Driver with Step-up DC-DC Converter Typical Performance Characteristics (Continued) The FAN8841 has a basic PWM controller for Step-up DC-DC converter topology in Critical Conduction Mode (CRM) and integrated Dual half–bridge drivers. To increase efficiency of the DC-DC converter, FAN8841 has a Zero Current Detection (ZCD) function for CRM control. It can reduce Step-up DC-DC converter switching loss at MOSFET turn on time. The FAN8841 Step-up DC-DC converter supports output voltage up to 36 V with the use of a commercial inductor since the absolute maximum voltage of internal switching FET VDS is 40 V. If the use requires a driving voltage higher than 36 V, it is recommended to use a coupled inductor, since the internal half-bridge absolute maximum voltage is 75 V. recommended that the VCON pin is connected with VDD voltage. Zero Current Detection (ZCD) The Step-up DC-DC converter of the FAN8841 operates in CRM method with ZCD function. The ZCD is detected instantly when the inductor current goes to zero voltage switching operation. Once the boost inductor current becomes zero, the output capacitor of the main FET (COSS) and the magnetizing inductor of the coupled inductor (L1) resonate together, and the drain voltage of the main switch decreases, as shown in Figure 26. Since the ZCD pin can be connected to the switching diode anode, the FAN8841 detects when the diode anode voltage reaches its minimum value directly. The threshold voltage to detect the anode voltage inside the ZCD pin is typically 1.83 V. Therefore, the next switching begins after the anode voltage reaches 1.83 V, and has a 200 ns maximum delay to the next gate turn-on. The device architecture is that of a current mode controller with an internal sensing resistor connected in series with the NMOS switch. The voltage at the feedback pin tracks the output voltage at the cathode of the external Schottky diode. The internal error amplifier amplifies the difference between the feedback voltage and the internal reference voltage. Its error signal is applied to the input of a compensator and is compared to the current of the main switch which produces the appropriate duty cycle of the main switch in the inner loop. The amplified error voltage serves as a reference voltage to the internal PWM comparator. The PWM comparator resets the latch when the RAMP generator signal meets the error amp output level. The ZCD signal sets the latch and the SR latch turns on the FET switch. Since the comparator input contains information about the output voltage and the control loop is arranged to form a negative feedback loop, the value of the peak inductor current is adjusted to the driving power. iL1 vLX VO + nVBAT 1+n VBAT Every time the latch is reset, the FET is turned off and the current flow through the switch is terminated. The latch can be reset by other events as well. Over-current condition is monitored by the current limit comparator which resets the latch and turns off the switch instantaneously within each clock cycle. vZCD 3.5V 1.83V Soft Startup vgate The FAN8841 has a Soft Startup function to prevent inrush current during the Step-up DC-DC converter startup. When the EN pin voltage goes HIGH from LOW, the Step-up DC-DC converter is turned on, the COMP is pre-charged, and inverting input of the internal error amplifier reference voltage starts up gradually with regular slope. This time is typically 28 ms at the maximum VCON. ZCD delay time 200 ns Turn on t Figure 26. Waveforms for ZCD The resistor RZCD is obtained as follows: RZCD  Adjustable VDRV Voltage (VCON Control) The FAN8841 can control the Step-up DC-DC converter output voltage without changing the resistive feedback divider using the VCON pin. The VCON is controlled directly by the external DC voltage or external resistance value. VCON control range is fixed from 0.1 to 1.0 V. If VCON voltage decreases below 0.1 V or increases higher than 1.0 V, VDRV voltage fixed on minimum or maximum voltage due to the internal clamp level. If the user wants a fixed VDRV voltage, it is © 2015 Fairchild Semiconductor Corporation FAN8841 • Rev. 1.0 0.12V (VDRV  0.7)  VCLAMPH I ZCD (1) Over-Current Protection (OCP) The Over-Current Protection (OCP) function of the FAN8841 limits the inductor peak current of the Step-up DC-DC converter via an external resistor ROCP. The adjustable current limit should be less than the rated saturation limit of the inductor by the user to avoid the damage to both the inductor and FAN8841. www.fairchildsemi.com 11 FAN8841 — Dual Half-Bridge Piezoelectric Driver with Step-up DC-DC Converter Functional Description D The driving voltage of the internal dual Half-bridge is received from the VDRV pin. The internal 5 V LDO for driving the internal gate driver is also received from the VDRV pin. For supplying a stable power to the internal gate driver, VDRV has an under-voltage protection function. If the VDRV voltage is less than 11 V typically, during normal operation, the internal gate driver is turned off. When the VDRV voltage exceeds 12 V typically, the internal gate driver is turned on. L1 (N1) VLX RO CO VO Q Figure 28. The FAN8841 features a unique VDRV monitoring to maximize the safety when the feedback voltage is higher than the specified threshold voltage. The OVP comparator shuts down the output drive block when the voltage of the FB pin is higher than 1.1 V. Schematic of Coupled Inductor Boost Converter VLX is determined by the output voltage, input voltage and coupled inductor turn ratio. The VLX voltage is calculated as follows: At the normal operating condition, Fault Out signal maintains on VDD voltage, but the abnormal over-voltage has occurred at VDRV, Fault Out signal goes low during typ. 20 µs. VLX  VINPUT  VO  VINPUT VO  nVINPUT  n 1 n 1 (3) Therefore, the turn’s ratio can be easily obtained as the following equations: n Application information Setting the Output Voltage VO  VLX VLX  VINPUT (4) To determine the turn’s ratio, the input voltage variation has to be considered as well. The internal reference is 1.0 V (Typical) and it controlled by the VCON voltage. The output voltage is divided by the external resistor divider, RFB1 and RFB2 to the FB pin. The output voltage is given by: RFB1 ) RFB 2 iD VINPUT Over-Voltage Protection (OVP) VDRV  VREF (1  L2 (N2) The inductor parameters are directly related to the device performance, saturation current and DC resistance. The lower the DC resistance, the higher efficiency. Usually a trade-off between inductor size, cost and overall efficiency is needed to make the optimum choice. (2) The inductor saturation current should be rated around 2 A at maximum power in the FAN8841. If to use a low saturation current inductor under 2 A due to inductor size, it is possible using the OCP level control. VDRV FAN8841 RFB1 iL1 RFB2 IPK n+1 IPK FB ID,PK IOUT tOFF = (1-d)TS tON = dTS Figure 27. TS Feedback Circuit Inductor Selection Figure 29. To prevent the absolute maximum voltage in the operating condition, the switching voltage VLX should be lower than 36 V, as shown in Figure 28. Current Waveform In CRM operation, the inductance can be obtained from the slope of the inductor current, as shown in Figure 29. During FET turn off period, the inductor current flows through the diode. The diode peak current is expressed as follows: I D , PK  © 2015 Fairchild Semiconductor Corporation FAN8841 • Rev. 1.0 t 2 I OUT 1 d (5) www.fairchildsemi.com 12 FAN8841 — Dual Half-Bridge Piezoelectric Driver with Step-up DC-DC Converter VDRV Under-Voltage Protection I PK  V 2 I OUT (1  n) , or I PK  INPUT dTS 1 d L1 Vripple, pp (6) VINPUT dTS VINPUT d (1  d )TS  I PK 2 I OUT (1  n) (7)  (1  d ) 2   2d    I OUT  TS 2  CO   2Vripple, pp If a user wants a commercial inductor at output voltage under 35 V condition, n(turns ratio at using coupled inductor) should be substituted the value zero, (turns ratio at using coupled inductor). (9) Diode Selection Output Capacitor Selection The external diode used for the rectification is usually a Schottky diode. It’s average forward current and reverse voltage maximum ratings should exceed the load current and the voltage at the output of the converter respectively. The value of the output capacitor can be selected based on the output voltage ripple requirements. Without consideration of the effect of Equivalent Series Resistance (ESR) as output capacitors, the output voltage ripple in a peak-to-peak manner is obtained as follows: © 2015 Fairchild Semiconductor Corporation FAN8841 • Rev. 1.0 (8) where Vripple,pp is the output voltage ripple in peak-topeak manner. Therefore, the output capacitance can be selected with the given output voltages ripple specification as follows: The inductance value obtained as follows: L1   (1  d ) 2   2d    I OUT  TS 2    2CO A care should be taken to avoid any short circuit of V OUT to GND, even with the IC disabled, since the diode can be instantly damaged by the excessive current. www.fairchildsemi.com 13 FAN8841 — Dual Half-Bridge Piezoelectric Driver with Step-up DC-DC Converter And then, the peak current of the main switch is obtained as follows: 4.00 2.80 18 0.05 C 4.00 13 A B 2X 19 12 4.00 2.80 4.00 24 7 0.80 PIN 1 QUADRANT 0.05 C 2X TOP VIEW 1 6 0.30 24X RECOMMENDED LAND PATTERN 0.10 C 0.08 C SIDE VIEW C SEATING PLANE BOTTOM VIEW PIN ONE OPTIONS PIN #1 IDENT (0.635) 4X 1 6 NOTES: 24 7 A. CONFORMS TO JEDEC REGISTRATION MO-220, VARIATION WGGD-6. B. DIMENSIONS ARE IN MILLIMETERS. C. DIMENSIONS AND TOLERANCES PER ASME Y14.5M, 2009. 19 (0.650) 4X 12 (0.495) 4X 18 0.50 E. DRAWING FILENAME: MKT-MLP24Erev5. 13 0.10 0.05 BOTTOM VIEW D. LAND PATTERN IPC REFERENCE : QFN50P400X400X80-25W6N. 24X C A B C 0.20 ON Semiconductor and are trademarks of Semiconductor Components Industries, LLC dba ON Semiconductor or its subsidiaries in the United States and/or other countries. ON Semiconductor owns the rights to a number of patents, trademarks, copyrights, trade secrets, and other intellectual property. A listing of ON Semiconductor’s product/patent coverage may be accessed at www.onsemi.com/site/pdf/Patent−Marking.pdf. ON Semiconductor reserves the right to make changes without further notice to any products herein. ON Semiconductor makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does ON Semiconductor assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages. Buyer is responsible for its products and applications using ON Semiconductor products, including compliance with all laws, regulations and safety requirements or standards, regardless of any support or applications information provided by ON Semiconductor. “Typical” parameters which may be provided in ON Semiconductor data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each customer application by customer’s technical experts. ON Semiconductor does not convey any license under its patent rights nor the rights of others. ON Semiconductor products are not designed, intended, or authorized for use as a critical component in life support systems or any FDA Class 3 medical devices or medical devices with a same or similar classification in a foreign jurisdiction or any devices intended for implantation in the human body. Should Buyer purchase or use ON Semiconductor products for any such unintended or unauthorized application, Buyer shall indemnify and hold ON Semiconductor and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that ON Semiconductor was negligent regarding the design or manufacture of the part. ON Semiconductor is an Equal Opportunity/Affirmative Action Employer. This literature is subject to all applicable copyright laws and is not for resale in any manner. PUBLICATION ORDERING INFORMATION LITERATURE FULFILLMENT: Literature Distribution Center for ON Semiconductor 19521 E. 32nd Pkwy, Aurora, Colorado 80011 USA Phone: 303−675−2175 or 800−344−3860 Toll Free USA/Canada Fax: 303−675−2176 or 800−344−3867 Toll Free USA/Canada Email: orderlit@onsemi.com © Semiconductor Components Industries, LLC N. American Technical Support: 800−282−9855 Toll Free USA/Canada Europe, Middle East and Africa Technical Support: Phone: 421 33 790 2910 Japan Customer Focus Center Phone: 81−3−5817−1050 www.onsemi.com 1 ON Semiconductor Website: www.onsemi.com Order Literature: http://www.onsemi.com/orderlit For additional information, please contact your local Sales Representative www.onsemi.com