® RT8547 1.6A Flash LED Driver General Description Features The RT8547 is a high efficiency, high current, Boost-type flash LED driver capable of 1.6A maximum output current. It is an ideal power solution for LED photo flash applications in all single cell Lithium-ion/polymer battery operated products. Input Voltage Range : 2.8V to 5.5V Current Accuracy within 5% Up to 1.6A Regulated Output Current Up to 88% Efficiency with Small Magnetics 2MHz Switching Frequency Separate Strobe and Torch Mode Current Programmable Safety Timer Input Current Limit Over Voltage Protection for LED Open Over Temperature Protection True Load Disconnect Shutdown Current : <2μ μA The RT8547 maintains output current regulation by switching the internal high side and low power switches switch transistors. The power switches are pulse width modulated at a fixed frequency of 2MHz. The high switching frequency allows the use of small inductor and output capacitor that makes the RT8547 being ideally suited for small battery powered applications. One-wire dimming control function is designed to set the strobe mode current level through the FLSET pin for the flash LEDs. Applications The RT8547 contains over voltage protection, over current protection and over temperature protection functions to protect the device from output open circuit and short-circuit conditions. An internal soft- start control circuit is built-in to prevent excessive inrush current during start-up. In shutdown mode, the supply current is reduced to 2μA. Cellular Phones Digital Cameras PDAs and Smart Phones Probable Instruments Point of Load Regulation for High-Performance DSPs, FPGAs, and ASICs Simplified Application Circuit L VIN C1 VIN SW RT8547 FLSET VOUT C2 Control FLED FLEN PGND AGND Copyright © 2016 Richtek Technology Corporation. All rights reserved. DS8547-01 February 2016 FLGND is a registered trademark of Richtek Technology Corporation. www.richtek.com 1 RT8547 Pin Configurations Ordering Information Package Type QW : WDFN-14L 3x2 (W-Type) (Exposed Pad-Option 1) Lead Plating System G : Green (Halogen Free and Pb Free) Note : Richtek products are : AGND FLSET FLED FLEN AGND VIN PGND 1 2 3 4 5 6 7 PGND (TOP VIEW) RT8547 15 14 13 12 11 10 9 8 NC FLGND NC Control SW SW VOUT WDFN-14L 3x2 RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020. Suitable for use in SnPb or Pb-free soldering processes. Marking Information 00 : Product Code W : Date Code 00W Functional Pin Description Pin No. Pin Name Pin Function 1, 5 AGND Analog Ground. Connect AGND to PGND at a single point. 2 FLSET Flash Set Function. 3 FLED Output for Flash LED Current Sink. Connect cathode of Flash LED to FLED. 4 FLEN On/Off Control Input. 6 VIN Power Input. Connect VIN to the input power supply voltage. Connect a 2.2F or larger ceramic capacitor from VIN to ground and place the capacitor as close as possible to the VIN pin. 7, 15 (Exposed pad) PGND Power Ground. The Exposed pad should be soldered to a large PCB and connected to PGND for maximum thermal dissipation. 8 VOUT Power Output of the LED Driver. Connect a 4.7F or larger ceramic capacitor from VOUT to ground. Connect the VOUT pin to the anode of flash LED. SW Switch Node. Connect an inductor between the SW and VIN pins. Control ON/Off Control Input. NC No Internal Connection. Please connect this pin to GND or floating. Don't pull high voltage to this pin. FLGND Ground for Flash LED Current. Connect this pin to a strong ground pad for better thermal performance. 9,10 11 12,14 13 Copyright © 2016 Richtek Technology Corporation. All rights reserved. www.richtek.com 2 is a registered trademark of Richtek Technology Corporation. DS8547-01 February 2016 RT8547 Function Block Diagram VIN VOUT Prodio UVLO One-Wire Dimming Controller FLSET OVP, OCP OTP High Side ZC Sense VREF1 Soft-Start Control Error Amp PWM Oscillator 2MHz 70%MAX Duty FLEN VIN Ibias Bandgap Reference Back Gate Control SW PGND Current Sense Internal Compensation Control LOGIC Control, UGATE Min On-Time, Current Source & UGATE/LGATE LGATE Driver PWM Comp FLED VOUT + AGND VIN LVP Low Drop-out N-MOSFET Current Source Thermal Regulation FLGND Operation UVLO OSC The UVLO detects VIN voltage to generate UVLO signal. Generates 2MHz clock. LVP VREF1, Bandgap Reference The LVP detects VIN voltage to protect battery. These blocks provide reference voltages for error amplifier and other bias circuits. OTP OTP checks the junction temperature to generate OT signal. Error Amplifier The error amplifier generates COMP signal by the difference between FB and VREF1. One-Wire Dimming Controller The One-wire dimming control is used to set the operation mode. PWM Comp The PWM comparator compares COMP signal with current feedback signal to trigger PWM signal. OVP/OCP Output over voltage protection and over current protection limit the output voltage and inductor current during operation. LOGIC Control According to OVP, OCP, ZC and PWM signal to decide the on/off states for power switches. High Side ZC sense The zero-current detection for high side power switch. Copyright © 2016 Richtek Technology Corporation. All rights reserved. DS8547-01 February 2016 is a registered trademark of Richtek Technology Corporation. www.richtek.com 3 RT8547 Absolute Maximum Ratings (Note 1) Supply Voltage, VIN -----------------------------------------------------------------------------------------------------Boost Output Voltage, VOUT ------------------------------------------------------------------------------------------Switching Voltage, SW -------------------------------------------------------------------------------------------------Current Source Voltage, FLED ----------------------------------------------------------------------------------------Other Pins (FLEN, FLSET, Control) ----------------------------------------------------------------------------------Power Dissipation, PD @ TA = 25°C WDFN-14L 3x2 ------------------------------------------------------------------------------------------------------------Package Thermal Resistance (Note 2) WDFN-14L 3x2, θJA ------------------------------------------------------------------------------------------------------WDFN-14L 3x2, θJC ------------------------------------------------------------------------------------------------------Junction Temperature Range -------------------------------------------------------------------------------------------Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------------Storage Temperature Range -------------------------------------------------------------------------------------------ESD Susceptibility (Note 3) HBM (Human Body Model) ---------------------------------------------------------------------------------------------MM (Machine Model) ----------------------------------------------------------------------------------------------------- Recommended Operating Conditions −0.3V to 6V −0.3V to 6.5V −0.3V to 6.5V −0.3V to 6.5V −0.3V to 6V 2.71W 36.9°C/W 10.9°C/W 150°C 260°C −65°C to 150°C 2kV 200V (Note 4) Supply Voltage, VIN ------------------------------------------------------------------------------------------------------ 2.8V to 5.5V Junction Temperature Range -------------------------------------------------------------------------------------------- −40°C to 125°C Ambient Temperature Range -------------------------------------------------------------------------------------------- −40°C to 85°C Electrical Characteristics (VIN = 3.6V, CIN = 2.2μF, COUT = 4.7μF, TA = 25°C, unless otherwise specified) Parameter Symbol Test Conditions Min Typ Max Unit -- 2.4 -- V IFLED = 1.6A -- TBD -- mA IFLED = 300mA -- 300 -- A VIN = 5V, FLSET = VIN, FLEN = 0 -- 55 -- A VIN = 5V, FLSET = FLEN = 0 -- 2 -- A Power Supply UVLO VIN Supply Current VIN Shutdown Current UVLO IQ ISHDN Current Source of LED Current Accuracy of Output Current (Flash) IFL1 IFLED = 300mA 5 -- 5 % IFL2 IFLED = 1A 5 -- 5 % FLED Sense Voltage VFLEDS FLED Sense Voltage, IFLED = 300mA -- 150 -- mV Start-Up Current IST FLED to VOUT -- 96 -- A Oscillator and Timer Operating Frequency fOSC 1.6 2 2.4 MHz Maximum Duty Cycle DMAX -- 70 -- % Copyright © 2016 Richtek Technology Corporation. All rights reserved. www.richtek.com 4 is a registered trademark of Richtek Technology Corporation. DS8547-01 February 2016 RT8547 Parameter Symbol Test Conditions Min Typ Max Unit Power Switch N-MOSFET On-Resistance RDS(ON)_N VOUT = 3.6V -- 0.2 -- P-MOSFET On-Resistance RDS(ON)_P VOUT = 3.6V -- 0.2 -- N-MOSFET Current Limit IOCP 2.16 2.7 3.24 A Over Voltage Protection VOVP 5.1 5.5 5.9 V Thermal Shutdown TSH -- 150 -- C -- 20 -- C Protection Function Thermal Shutdown Hysteresis TSH_Hys Logic Control FLEN Control FLSET Logic-High VFLEN_H 1.4 -- -- Logic-Low VFLEN_L -- -- 0.4 Logic-High VCEN_H 1.4 -- -- Logic-Low VCEN_L -- -- 0.4 Logic-High VFLSET_H 1.4 -- -- Logic-Low VFLSET_L -- -- 0.4 V V V High Time set to Logic-High tH_SH 2x TL_HB -- 180 s Low Time set to Logic-High tL_SH 4 -- 360 s High Time set to Logic-Low tH_SL 4 -- 180 s Low Time set to Logic-Low tL_SL 2x TH_LB -- 360 s FLEN Pull Low Resistance RFLEN -- 400 -- k Control Pull Low Resistance RCEN -- 400 -- k FLSET Pull Low Resistance RFLSET -- 400 -- k Shutdown Delay tSHD 1.5 -- -- ms FLSET = 0 (Note 5) Note 1. Stresses beyond those listed “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions may affect device reliability. Note 2. θJA is measured at TA = 25°C on a high effective thermal conductivity four-layer test board per JEDEC 51-7. θJC is measured at the exposed pad of the package. Note 3. Devices are ESD sensitive. Handling precaution is recommended. Note 4. The device is not guaranteed to function outside its operating conditions. Note 5. FLSET H L for 1.5ms to turn off the chip. Copyright © 2016 Richtek Technology Corporation. All rights reserved. DS8547-01 February 2016 is a registered trademark of Richtek Technology Corporation. www.richtek.com 5 RT8547 Typical Application Circuit L 1µH VIN C1 2.2µF 6 9, 10 SW VIN RT8547 2 FLSET 11 Control 4 FLEN VOUT AGND C2 4.7µF FLED 3 PGND 1, 5 8 FLGND 7, 15 (Exposed Pad) 13 Timing Diagram MIN 10µs for 1st falling Shutdown delay 1.5ms TH(MIN 4µs) TH FLSET TL TL(MIN 4µs) TH > 2 x TL Logic High Copyright © 2016 Richtek Technology Corporation. All rights reserved. www.richtek.com 6 TL > 2 x TH Logic Low is a registered trademark of Richtek Technology Corporation. DS8547-01 February 2016 RT8547 Table 1. Flash Configuration Registers Address : 10011001 0x01 NA 7 : 4 NA Default (Reset value) 0000 0x01 Low Vin Protection 3 : 0 LVP 0110 [0000] 3.0V, [0001] 3.1V, [0010] 3.2V, [0011]3.3V, [0100] 3.4V, [0101] 3.5V, [0110] 3.6V, [0111] 3.7V, [1000 to 1111] 3.8V 0x02 Timeout Current Level 7 : 5 TimeI 000 [000] 100mA, [001] 150mA, [010] 200mA, [011] 250mA, [100] 300mA, [101] 350mA, [110 to 111] 400mA 4 : 0 Isled1_fl 10010 [00000] 100mA, [00001] 150mA, [00010] 200mA, [00011] 250mA, [00100] 300mA, [00101] 350mA, [00110] 400mA, [00111] 450mA, [01000] 500mA, [01001] 550mA, [01010] 600mA, [01011] 650mA, [01100] 700mA, [01101] 750mA, [01110] 800mA, [01111] 850mA, [10000] 900mA, [10001] 950mA, [10010] 1000mA, [10011] 1050mA, [10100] 1100mA, [10101] 1150mA, [10110] 1200mA, [10111] 1250mA, [11000] 1300mA, [11001] 1350mA, [11010] 1400mA, [11011] 1450mA, [11100] 1500mA, [11101] 1550mA, [11110] 1600mA, [11111] 1600mA 7 : 6 NA 00 Address 0x02 0x03 0x03 0x03 Address Name FLED LED1 Strobe Current NA Software Reset Strobe Select BIT LABEL 5 Sreset 0 [0] Normal, [1] Software Reset 4 Selstr 0 [0] Strobe, [1] Torch 0010 [0000] 25mA, [0001] 50mA, [0010] 75mA, [0011] 100mA, [0100] 125mA, [0101] 150mA, [0110] 175mA, [0111] 200mA, [1000] 225mA, [1001] 250mA, [1010] 275mA, [1011] 300mA, [1100] 325mA, [1101] 350mA, [1110] 375mA, [1111] 400mA 001111 [000000] 64ms, [000001] 96ms, [000010] 128ms, [000011] 192ms,.....[100100] to [111111] 1216ms 0x03 FLED LED1 Torch Current 3 : 0 Itled1_fl 0x04 NA 7 : 6 NA 0x04 FLED Strobe Timeout 5 : 0 Tstrobe Copyright © 2016 Richtek Technology Corporation. All rights reserved. DS8547-01 February 2016 Description is a registered trademark of Richtek Technology Corporation. www.richtek.com 7 RT8547 Typical Operating Characteristics Efficiency vs. Input Voltage Efficiency vs. Input Voltage 100 100 IOUT = 25mA IOUT = 100mA IOUT = 200mA IOUT = 300mA IOUT = 400mA 80 90 Efficiency (%) Efficiency (%) 90 70 60 50 IOUT = 400mA IOUT = 200mA IOUT = 100mA 80 70 60 50 Troch Mode Strobe Mode 40 40 2.8 3.2 3.6 4 4.4 4.8 5.2 5.6 2.8 3.2 3.6 Input Voltage (V) 4.8 5.2 5.6 VIN Supply Current vs. Input Voltage 450 380 425 VIN Supply Current (µA) 390 370 360 350 340 330 400 375 350 325 300 275 VIN = 3.6V, IFLED = 300mA VIN = 3.6V, IFLED = 300mA 320 250 -50 -25 0 25 50 75 100 125 2.8 3.2 3.6 Temperature (°C) 4 4.4 4.8 5.2 5.6 Input Voltage (V) Oscillator Frequency vs. Temperature Oscillator Frequency vs. Temperature 1.16 2.25 Oscillator Frequency (MHz)1 Oscillator Frequency (MHz)1 4.4 Input Voltage (V) VIN Supply Currnet vs. Temperature VIN Supply Currnet (µA) 4 1.12 1.08 1.04 1.00 0.96 2.20 2.15 2.10 2.05 2.00 1.95 Troch Mode, VIN = 3.6V, IFLED = 300mA 0.92 Strobe Mode, VIN = 3.6V, IFLED = 300mA 1.90 -50 -25 0 25 50 75 100 Temperature (°C) Copyright © 2016 Richtek Technology Corporation. All rights reserved. www.richtek.com 8 125 -50 -25 0 25 50 75 100 125 Temperature (°C) is a registered trademark of Richtek Technology Corporation. DS8547-01 February 2016 RT8547 FLED Sense Voltage vs. Temperature 170 155 160 FLED Sense Voltage (mV) FLED Sense Voltage (mV) FLED Sense Voltage vs. Input Voltage 160 150 145 140 135 150 140 130 120 110 IFLED = 300mA VIN = 3.6V, IFLED = 300mA 100 130 2.8 3.2 3.6 4 4.4 4.8 5.2 -50 5.6 -25 0 50 75 FLED Torch Current vs. Register Step 125 FLED Strobe Current vs. Register Step 450 1800 400 FLED Strobe Current (mA) Spec 350 300 Results 250 200 150 100 50 1600 Results 1400 1200 Spec 1000 800 600 400 200 VIN = 3.6V VIN = 3.6V 0 0 0 3 6 9 12 15 0 4 8 Register Step 12 16 20 24 28 32 Register Step VIN Shutdown Current vs. Input Voltage Low Input Voltage Protection vs. Register Step 3.0 4.50 2.5 2.0 1.5 1.0 0.5 FLSET = FLEN = Control = 0 0.0 Low Input Voltage Protection (V) VIN Shutdown Current (µA)1 100 Temperature (°C) Input Voltage (V) FLED Torch Current (mA) 25 Test Result 3.75 Spec 3.00 2.25 1.50 0.75 0.00 2.8 3.2 3.6 4 4.4 4.8 5.2 Input Voltage (V) Copyright © 2016 Richtek Technology Corporation. All rights reserved. DS8547-01 February 2016 5.6 0 3 6 9 12 15 Register Step is a registered trademark of Richtek Technology Corporation. www.richtek.com 9 RT8547 Power On in Torch Mode Power Off in Torch Mode VFLEN (5V/Div) VOUT (5V/Div) VFLEN (5V/Div) VOUT (5V/Div) VFLED (1V/Div) VFLED (1V/Div) I IN (500mA/Div) VIN = 3.6V, ILED = 400mA I IN (500mA/Div) Time (50μs/Div) Time (50ms/Div) Power On in Strobe Mode Power Off in Strobe Mode VFLEN (5V/Div) VOUT (5V/Div) VFLEN (5V/Div) VOUT (5V/Div) VFLED (2V/Div) VFLED (2V/Div) I IN (1A/Div) I IN (1A/Div) VIN = 3.6V, ILED = 1A Time (100μs/Div) Copyright © 2016 Richtek Technology Corporation. All rights reserved. www.richtek.com 10 VIN = 3.6V, ILED = 400mA VIN = 3.6V, ILED = 1A Time (50ms/Div) is a registered trademark of Richtek Technology Corporation. DS8547-01 February 2016 RT8547 Application Information Soft-Start Low Input Voltage Protection The RT8547 employs a soft-start feature to limit the inrush current. The soft-start circuit prevents the excessive inrush current and input voltage drop. When the input voltage is lower than a specified value, the converter will stop switching. Until the input voltage rises above the low input voltage protection threshold plus hysteresis voltage value, the converter resumes switching. The low input voltage protection can be programmed with 9 different levels (3V to 3.8V). Input UVLO The input voltage range of the LED driver is from 2.8V to 5.5V. The RT8547 provides an Under Voltage Lockout (UVLO) function to prevent it from unstable issue during startup. The UVLO threshold of input rising voltage is set at 2.4V typically. Over Voltage Protection (Open LED, Open Circuit) The RT8547 provides an internal over voltage protection to limit its output voltage. The OVP function prevents the RT8547 from damaging while open LED or open circuit condition occurs. Once the open circuit condition is removed, and the RT8547 will return to normal operation. Over Temperature Protection The RT8547 provides an over temperature protection to prevent the IC from overheating. When the junction temperature rises above 150°C, the OTP function will be triggered and then the LED driver will be shut down. The OTP of RT8547 comes with a hysteresis of 20°C. Once the junction temperature reduces below the over temperature protection threshold by 20°C, the IC will enter normal operation again. Inductor Selection The recommended value of inductor for LED photo flash applications is 1μH. Small size and better efficiency are the major concerns for portable devices which is used for single cell Lithium-ion/polymer battery applications. The inductor should have low core loss at 2MHz and low DCR for better efficiency. The inductor saturation current rating should be considered to cover the inductor peak current. When VIN is larger than forward voltage of flash LED at set current. The RT8547 will enter bypass mode. ILED_MAX is maximum LED current, which is usually equal to flash mode current. For normal operation, we suggest customers to reconfirm RDC of inductor as below formula. When VIN_operation > VF (ILED_MAX) : Please make sure VIN − VOUT on PCB is smaller than 205mV in bypass mode. 205mV 150 (m) = Suggested Inductor RDC (m ) ILED_MAX (A) Torch mode and Strobe Mode Operation The RT8547 is designed for LED driving for torch and strobe applications, it provides an One-wire dimming control function through the FLSET pin for flash LED. Moreover, the strobe and torch mode current level can be chosen by the FLSET pin. Over Current Protection Capacitor Selection Input ceramic capacitor of 2.2μF and output ceramic capacitor of 4.7μF are recommended for the RT8547 applications. For better voltage filtering, ceramic capacitors with low ESR are recommended. X5R and X7R types are suitable because of their wider voltage and temperature ranges. The current through the inductor is monitored by current sense circuit. If the value exceeds the current limit threshold, the N-MOSFET will be turned off to leave the charging stage. Copyright © 2016 Richtek Technology Corporation. All rights reserved. DS8547-01 February 2016 is a registered trademark of Richtek Technology Corporation. www.richtek.com 11 RT8547 Thermal Considerations Layout consideration For continuous operation, do not exceed absolute maximum junction temperature. The maximum power dissipation depends on the thermal resistance of the IC package, PCB layout, rate of surrounding airflow, and difference between junction and ambient temperature. The maximum power dissipation can be calculated by the following formula : For best performance of the RT8547, the following PCB layout guidelines should be strictly followed. PD(MAX) = (TJ(MAX) − TA) / θJA where TJ(MAX) is the maximum junction temperature, TA is the ambient temperature, and θJA is the junction to ambient thermal resistance. For recommended operating condition specifications, the maximum junction temperature is 125°C. The junction to ambient thermal resistance, θJA, is layout dependent. For WDFN-14L 3x2 package, the thermal resistance, θJA, is The AGND and PGND of the IC should be connected to the ground plane of the PCB. Input and output capacitors should be connected to a strong ground plane for heat sinking and noise protection. SW node of DC/DC converter is with high frequency voltage swing. It should be kept at a small area. Keep the main current traces as short and wide as possible. It is recommended to add additional PCB exposed pad area or the flash LED for maximized heat-sinking ability. This is necessary for high current application and long flash duration application. 36.9°C/W on a standard JEDEC 51-7 four-layer thermal test board. The maximum power dissipation at TA = 25°C can be calculated by the following formula : PD(MAX) = (125°C − 25°C) / (36.9°C/W) = 2.71W for WDFN-14L 3x2 package The maximum power dissipation depends on the operating ambient temperature for fixed T J(MAX) and thermal resistance, θJA. The derating curve in Figure 1 allows the designer to see the effect of rising ambient temperature on the maximum power dissipation. Maximum Power Dissipation (W)1 3.5 Four-Layer PCB 3.0 2.5 2.0 1.5 1.0 0.5 0.0 0 25 50 75 100 125 Ambient Temperature (°C) Figure 1. Derating Curve of Maximum Power Dissipation Copyright © 2016 Richtek Technology Corporation. All rights reserved. www.richtek.com 12 is a registered trademark of Richtek Technology Corporation. DS8547-01 February 2016 RT8547 Input capacitor must be placed between GND and VIN to reduce noise. GND 1 2 3 4 5 6 7 PGND FLED node copper area should be AGND minimized FLSET FLED FLEN AGND VIN CIN2 PGND VOUT 15 14 13 12 11 10 9 8 NC FLGND NC Control SW SW VOUT CIN1 VIN COUT GND Input capacitor must be placed between GND and VIN to reduce noise. Output capacitor must be placed between GND and VOUT to reduce noise. The inductor should be placed as close as possible to the switch pin to minimize the noise coupling into other circuits. SW node copper area should be minimized for reducing EMI. Figure 2. PCB Layout Guide Copyright © 2016 Richtek Technology Corporation. All rights reserved. DS8547-01 February 2016 is a registered trademark of Richtek Technology Corporation. www.richtek.com 13 RT8547 Outline Dimension 2 1 2 1 DETAIL A Pin #1 ID and Tie Bar Mark Options Note : The configuration of the Pin #1 identifier is optional, but must be located within the zone indicated. Dimensions In Millimeters Symbol Dimensions In Inches Min. Max. Min. Max. A 0.700 0.800 0.028 0.031 A1 0.000 0.050 0.000 0.002 A3 0.175 0.250 0.007 0.010 b 0.150 0.250 0.006 0.010 D 2.950 3.050 0.116 0.120 Option1 2.450 2.550 0.096 0.100 Option2 2.550 2.650 0.100 0.104 1.950 2.050 0.077 0.081 Option1 0.750 0.850 0.030 0.033 Option2 0.850 0.950 0.033 0.037 D2 E E2 e 0.400 0.300 L 0.016 0.400 0.012 0.016 W-Type 14L DFN 3x2 Package Richtek Technology Corporation 14F, No. 8, Tai Yuen 1st Street, Chupei City Hsinchu, Taiwan, R.O.C. Tel: (8863)5526789 Richtek products are sold by description only. Richtek reserves the right to change the circuitry and/or specifications without notice at any time. Customers should obtain the latest relevant information and data sheets before placing orders and should verify that such information is current and complete. Richtek cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Richtek product. Information furnished by Richtek is believed to be accurate and reliable. However, no responsibility is assumed by Richtek or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Richtek or its subsidiaries. www.richtek.com 14 DS8547-01 February 2016