RT8479CGSP

® RT8479C Two-Stage Hysteretic LED Driver with Internal MOSFETs General Description Features The RT8479C is a two-stage controller with dual MOSFETs and consists of a Boost converter (first stage) and a Buck converter (second stage). The advantage of two-stage topology is highly compatible with ET (Electronic Transformer) and extremely high Power Factor performance in MR16 / AR111 lighting market fields applications.  Two-Stage Topology (Boost + Buck)  Dual MOSFETs Inside Wide Input Voltage Range : 4.5V to 36V Excellent Power Factor Programmable Boost Output Voltage Independent Dual Stage Function Programmable LED Current with ±5% LED Current Accuracy Input Under-Voltage Lockout Detection Thermal Shutdown Protection The first stage is a Boost converter for constant voltage output with inductor peak current over-current protection. The second stage is a Buck converter for constant output current by typical constant peak current regulation.        Ordering Information The RT8479C is equipped with dual output gate drivers for internal power MOSFETs. RT8479C Package Type SP : SOP-8 (Exposed Pad-Option 2) The RT8479C is available in the SOP-8 (Exposed Pad) package. Note : Applications        Lead Plating System G : Green (Halogen Free and Pb Free) Richtek products are : MR16 Lighting Signage and Decorative LED Lighting Architectural Lighting High Power LED Lighting Low Voltage Industrial Lighting Indicator and Emergency Lighting Automotive LED Lighting  RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020.  Suitable for use in SnPb or Pb-free soldering processes. Simplified Application Circuit L1 D1 D5 R1 D2 VL AC 12V VCC RT8479C VCC OVP ISN CIN C1 To Dimming Copyright © 2014 Richtek Technology Corporation. All rights reserved. DS8479C-04 August 2014 LED- C2 VCOMP D4 ACTL D6 C3 CREG LX1 D3 RSENSE LED+ R2 VN COUT L2 LX2 GND is a registered trademark of Richtek Technology Corporation. www.richtek.com 1 RT8479C Marking Information Pin Configurations RT8479CGSP : Product Number RT8479C GSPYMDNN (TOP VIEW) YMDNN : Date Code 8 LX1 OVP 2 ACTL 3 VCOMP 4 GND LX2 7 CREG 6 VCC 5 ISN 9 SOP-8 (Exposed Pad) Functional Pin Description Pin No. Pin Name Pin Function 1 LX1 Switch Node. The first stage internal MOSFET Drain. 2 OVP Over-Voltage Protection Sense Input. 3 ACTL Analog / PWM Dimming Control Input. Connect to CREG if not used. 4 VCOMP Compensation Node. A compensation network between VCOMP and GND is needed. 5 ISN LED Negative Current Sense Input. 6 VCC Supply Voltage Input. For good bypass, place a ceramic capacitor near the VCC pin. 7 CREG Internal Regulator Output. Place an 1F capacitor between the CREG and GND pins. 8 LX2 Switch Node. The second stage internal MOSFET Drain. 9 (Exposed Pad) GND Ground. The exposed pad must be soldered to a large PCB and connected to GND for maximum power dissipation. Function Block Diagram ISN VCC ACTL ACTL Logic -130mV V Regulator VCC + - UV/OV CREG LX2 OVP Core Logic EN2 EN2 EN1 LX1 EN1 VCOMP + - Copyright © 2014 Richtek Technology Corporation. All rights reserved. www.richtek.com 2 GND is a registered trademark of Richtek Technology Corporation. DS8479C-04 August 2014 RT8479C Operation The RT8479C VCC is supplied from the first stage Boost output. The first stage is a constant output voltage Boost topology and senses the peak inductor current for over-current protection with excellent Power Factor. The second stage is a constant output current Buck topology. The current sense voltage threshold between the VCC and ISN pins is only 130mV to reduce power loss. Copyright © 2014 Richtek Technology Corporation. All rights reserved. DS8479C-04 August 2014 is a registered trademark of Richtek Technology Corporation. www.richtek.com 3 RT8479C Absolute Maximum Ratings           (Note 1) Supply Voltage, VCC to GND -----------------------------------------------------------------------------------------ACTL, CREG, OVP, VCOMP to GND -------------------------------------------------------------------------------LX1, LX2 to GND ----------------------------------------------------------------------------------------------------------VCC to ISN ----------------------------------------------------------------------------------------------------------------Power Dissipation, PD @ TA = 25°C −0.3V to 45V −0.3V to 6V −0.3V to 40V −0.3V to 3V SOP-8 (Exposed Pad) --------------------------------------------------------------------------------------------------Package Thermal Resistance (Note 2) SOP-8 (Exposed Pad), θJA ---------------------------------------------------------------------------------------------SOP-8 (Exposed Pad), θJC --------------------------------------------------------------------------------------------Junction Temperature ----------------------------------------------------------------------------------------------------Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------------Storage Temperature Range -------------------------------------------------------------------------------------------ESD Susceptibility (Note 3) HBM (Human Body Model) ---------------------------------------------------------------------------------------------MM (Machine Model) ----------------------------------------------------------------------------------------------------- 3.44W Recommended Operating Conditions    29°C/W 2°C/W 150°C 260°C −65°C to 150°C 2kV 200V (Note 4) Supply Input Voltage, VCC ---------------------------------------------------------------------------------------------- 4.5V to 40V Junction Temperature Range -------------------------------------------------------------------------------------------- −40°C to 125°C Ambient Temperature Range -------------------------------------------------------------------------------------------- −40°C to 85°C Electrical Characteristics (VCC = 10VDC, No Load, CLOAD = 1nF, TA = 25°C, unless otherwise specified) Parameter Symbol Test Conditions Min Typ Max Unit Supply Voltage CREG UVLO_ ON VUVLO_ ON OVP = 0V -- 4.2 -- V CREG UVLO_ OFF VUVLO_ OFF OVP = 0V -- 3.9 -- V VCC Shutdown Current I SHDN VCC = 3.5V -- 10 -- A VCC Quiescent Current IQ VCC = 10V -- 1.5 -- mA Internal Reference Voltage VCREG -- 5 -- V -- 4.9 -- V -- 5 -- s Supply Current Internal Reference Voltage (ICREG = 20mA) ICREG = 20mA Stage 1 Max On-Time High-Lev el VOVP_H 1.85 1.94 2.04 Low-Level VOVP_L 1.52 1.6 1.68 Stage 1 OVP V OVP Pin Leakage Current I OVP -- 1 -- A ACTL Turn On Threshold VACTL_ON -- 240 -- mV ACTL Turn Off Threshold VACTL_OFF -- 60 -- mV Copyright © 2014 Richtek Technology Corporation. All rights reserved. www.richtek.com 4 is a registered trademark of Richtek Technology Corporation. DS8479C-04 August 2014 RT8479C Parameter Symbol Test Conditions Min Typ Max Unit 94 97 100 % -- -- 1 A 123.5 130 136.5 mV (dV1 + dV2) / 2 -- 15 -- % Sense threshold percentage at VACTL = 2.7V ACTL Sense Threshold High ACTL Input Bias Current ISN Threshold VISN Stage 2 Peak to Peak Sense Voltage VACTL = 3V LX1 Internal Switch RDS(ON) RDS(ON)_1 Sink = 100mA -- 0.15 --  LX2 Internal Switch RDS(ON) RDS(ON) _2 Sink = 100mA -- 0.2 --  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. Copyright © 2014 Richtek Technology Corporation. All rights reserved. DS8479C-04 August 2014 is a registered trademark of Richtek Technology Corporation. www.richtek.com 5 RT8479C Typical Application Circuit L1 10µH D1 D5 VCC R1 130k D2 VL AC 12V R2 10k CIN 1µF VN D3 D4 For Dimming Signal C1 0.47µF COUT 4.7µF RT8479C 2 OVP VCC 6 RSENSE 250m LED+ C5 ISN 5 CREG 7 1 LX1 4 VCOMP 3 ACTL COUT_EC 220µF C3 4.7µF C2 4.7µF LX2 8 GND 9 (Exposed Pad) ACTL can be connected to CREG if not used. 4LED D6 LED- L2 68µH D1,D2, D3, D4, D5, D6 = PMEG4020 C5 depends on PCB layout and noise immunity. Figure 1. Typical MR16 LED Lamp for 5W Application Sense Threshold vs. ACTL Voltage 150 Sense Threshold (mV) 135 120 105 90 75 60 45 30 15 VCC = 20V, Temp = 25°C 0 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 ACTL Voltage(V) Copyright © 2014 Richtek Technology Corporation. All rights reserved. www.richtek.com 6 is a registered trademark of Richtek Technology Corporation. DS8479C-04 August 2014 RT8479C Typical Operating Characteristics Quiescent Current vs. Temperature 3.5 1.6 3.0 Quiescent Current (mA) Quiescent Current (mA) Quiescent Current vs.VCC 1.7 1.5 1.4 1.3 1.2 2.5 2.0 1.5 1.0 0.5 OVP = 5V VCC = 4.5V to 30V, OVP = 5V 0.0 1.1 4 9.2 14.4 19.6 24.8 -50 30 -25 0 Operating Current vs. VCC 75 100 125 Operating Current vs. Temperature 4.0 Operating Current (mA) 3.6 Operating Current (mA) 50 Temperature (°C) VCC (V) 3.2 2.8 2.4 2.0 VCC = 4.5V to 30V, LX1/LX2 Capacitor = 1nF, OVP = 0V 3.5 3.0 2.5 2.0 1.5 VCC = 10V, LX1/LX2 Capacitor = 1nF, OVP = 0V 1.0 1.6 4 9.2 14.4 19.6 24.8 -50 30 -25 0 VCC (V) 25 50 75 100 125 Temperature (°C) CREG Voltage vs. VCC CREG Voltage vs. Temperature 7 5.4 5.3 CREG Voltage (V) 6 CREG Voltage (V) 25 ICREG = 0mA 5 ICREG = −20mA 4 3 5.2 ICREG = 0mA 5.1 ICREG = −20mA 5.0 4.9 VCC = 4.5V to 30V 2 VCC = 10V 4.8 4.5 9.6 14.7 19.8 24.9 VCC (V) Copyright © 2014 Richtek Technology Corporation. All rights reserved. DS8479C-04 August 2014 30 -50 -25 0 25 50 75 100 125 Temperature (°C) is a registered trademark of Richtek Technology Corporation. www.richtek.com 7 RT8479C ISN Threshold vs. Temperature ISN Threshold vs. VCC 150 150 140 ISN Threshold (V) ISN Threshold (mV) 140 130 120 110 130 120 110 100 VCC = 4.5V to 30V VCC = 10V 100 90 4 9.2 14.4 19.6 24.8 30 -50 -25 0 50 75 100 125 Temperature (°C) VCC (V) OVP Hi/Low Level Voltage vs. VCC OVP Hi/Low Level Voltage vs. Temperature 2.2 2.0 Hi 1.9 1.8 1.7 Low 1.6 1.5 VCC = 4.5V to 30V OVP Hi/Low Level Voltage (V) 2.1 OVP Hi/Low Level Voltage (V) 25 1.4 2.1 2.0 Hi 1.9 1.8 1.7 Low 1.6 1.5 1.4 VCC = 10V 1.3 4.5 9.6 14.7 19.8 24.9 30 -50 -25 0 VCC (V) 25 50 75 100 125 Temperature (°C) LX2_RDS(ON) vs. Temperature LX1_RDS(ON) vs. Temperature 0.30 0.25 0.25 LX2 RDS(ON) (Ω) LX1 RDS(ON) (Ω) 0.20 0.15 0.10 0.05 0.20 0.15 0.10 0.05 VCC = 10V 0.00 -50 -25 0 25 50 75 100 Temperature (°C) Copyright © 2014 Richtek Technology Corporation. All rights reserved. www.richtek.com 8 125 VCC = 10V 0.00 -50 -25 0 25 50 75 100 125 Temperature (°C) is a registered trademark of Richtek Technology Corporation. DS8479C-04 August 2014 RT8479C ACTL Threshold Voltage vs. Temperature ACTL Threshold Voltage vs. VCC 270 240 ACTL Threshold Voltage (mV) ACTL Threshold Voltage (mV) 270 On 210 180 150 120 90 Off 60 30 On 240 210 180 150 120 90 Off 60 30 4 8 12 16 20 24 28 32 -50 -25 0 VCC (V) 50 75 100 125 LED Current vs. Input Voltage LED Current vs. ACTL Voltage 800 450 700 440 IOUT = 756mA LED Current (mA) LED Current (mA) 25 Temperature (°C) 600 500 IOUT = 382mA 400 300 IOUT = 185mA 430 420 410 400 200 100 390 0 380 VCC = 7V to 20V, IOUT = 420mA, Load = 4LED 0 0.5 1 1.5 2 2.5 3 6 8 10 LED Current vs. Output Voltage 14 16 18 20 PK-Current vs. Temperature 2500 440 435 2000 PK-Current (mA) LED Current (mA) 12 Input Voltage (V) ACTL Voltage (V) 430 425 420 VC = 5V 1500 1000 VC = 0V 500 415 VCC = 10V Load = 1LED to 6LED 410 0 4.5 7.6 10.7 13.8 16.9 Output Voltage (V) Copyright © 2014 Richtek Technology Corporation. All rights reserved. DS8479C-04 August 2014 20 -50 -25 0 25 50 75 100 125 Temperature (°C) is a registered trademark of Richtek Technology Corporation. www.richtek.com 9 RT8479C Power On from VIN CREG UVLO vs. Temperature 5.0 IOUT (500mA/Div) 4.5 UVLO-H LX2 (50V/Div) UVLO (V) 4.0 UVLO-L 3.5 VOUT (10V/Div) 3.0 VIN (10V/Div) 2.5 VIN = 10V, 4LEDs 2.0 -50 -25 0 25 50 75 100 Time (25ms/Div) 125 Temperature (°C) Power Off from VIN Power On from AC-IN IOUT (500mA/Div) IOUT (200mA/Div) LX2 (50V/Div) VOUT (10V/Div) VOUT (10V/Div) VIN (10V/Div) VIN = 10V, 4LEDs Time (25ms/Div) V CC (20V/Div) AC-IN (50V/Div) Time (10ms/Div) Power Off from AC-IN IOUT (200mA/Div) VOUT (10V/Div) V CC (20V/Div) AC-IN (50V/Div) Time (10ms/Div) Copyright © 2014 Richtek Technology Corporation. All rights reserved. www.richtek.com 10 is a registered trademark of Richtek Technology Corporation. DS8479C-04 August 2014 RT8479C Application Information The RT8479C consists of a constant output current Buck controller and a fixed off-time controlled Boost controller. The Boost controller is based on a peak current, fixed offtime control architecture and designed to operate up to 1MHz to use a very small inductor for space constrained applications. A high-side current sense resistor is used to set the output current of the Buck controller. A 1% sense resistor performs a ±5% LED current accuracy for the best performance. Under-Voltage Lockout (UVLO) The RT8479C includes an under-voltage lockout function with 100mV hysteresis. The internal MOSFET turns off when VCC falls below 4.2V (typ.). CREG Regulator The CREG pin requires a capacitor for stable operation and to store the charge for the large GATE switching currents. Choose a 10V rated low ESR, X7R or X5R, ceramic capacitor for best performance. A 4.7μF capacitor will be adequate for many applications. Place the capacitor close to the IC to minimize the trace length to the CREG pin and to the IC ground. An internal current limit on the CREG output protects the RT8479C from excessive on-chip power dissipation. The CREG pin has set the output to 4.3V (typ.) to protect the internal FETs from excessive power dissipation caused by not being fully enhanced. If the CREG pin is used to drive extra circuits beside RT8479C, the extra loads should be limited to less than 10mA. Internal MOSFET There are two drivers, LX1 and LX2, in the RT8479C. The driver consists of a CMOS buffer designed to drive the internal power MOSFET. It features great sink capabilities to optimize switch on and off performance without additional external components. Whenever the IC supply voltage is lower than the under voltage threshold, the internal MOSFET is turned off. Copyright © 2014 Richtek Technology Corporation. All rights reserved. DS8479C-04 August 2014 Average Output Current Setting The output current that flows through the LED string is set by an external resistor, RSENSE, which is connected between the VCC and ISN terminal. The relationship between output current, IOUT, and RSENSE is shown below: IOUT = 130mV / RSENSE LED Current Ripple Reduction Higher LED current ripple will shorten the LED life time and increase heat accumulation of LED. To reduce the LED current ripple, an output capacitor in parallel with the LED should be added. The typical value of output capacitor is 4.7μF. VCC Voltage Setting The VCC voltage setting is equipped with an Over-Voltage Protection (OVP) function. When the voltage at the OVP pin exceeds threshold approximately 1.9V, the power switch is turned off. The power switch can be turned on again once the voltage at the OVP pin drops below 1.6V. For Boost applications, the output voltage can be set by the following equation : VCC(MAX) = 1.9 x (1 + R4 / R5) R4 and R5 are the voltage divider resistors from VOUT to GND with the divider center node connected to the OVP pin. For MR16 LED lamp application, the minimum voltage of VCC should maintain above 25V for stable operation. Step-Down Converter Inductor Selection The RT8479C implemented a simple high efficiency, continuous mode inductive step-down converter. The inductance L2 in Buck converter is determined by the following factors : inductor ripple current, switching frequency, VOUT/VIN ratio, internal MOSFET, topology specifications, and component parameter. The inductance L2 is calculated according to the following equation : L2 ≥ [VCC(MAX) − VOUT − VISN − (RDS2(ON) x IOUT)] x D / [fSW x ΔIOUT] where fsw is switching frequency (Hz). is a registered trademark of Richtek Technology Corporation. www.richtek.com 11 RT8479C RDS2(ON) is the low-side switch on-resistance of external MOSFET (M2). The typical value is 0.35Ω. Check the ILIM setting satisfied the output LED current request by the following equation : D is the duty cycle = VOUT / VIN (IOUT + ΔIOUT) < [2 x L1 x ILIM + tOFF x (VIN − VOUT − VF)] x VIN / [2 x L1 x (VCC)] IOUT is the required LED current (A) ΔIOUT is the inductor peak-peak ripple current (internally set to 0.3 x IOUT) VCC is the supply input voltage (V) VOUT is the total LED forward voltage (V) VISN is the voltage cross current sense resistor (V) Diode Selection To obtain better efficiency, the Schottky diode is recommended for its low reverse leakage current, low recovery time and low forward voltage. With its low power dissipation, the Schottky diode outperforms other silicon diodes and increases overall efficiency. L2 is the inductance (H) The selected inductor must have saturation current higher than the peak output LED current and continuous current rating above the required average output LED current. In general, the inductor saturation current should be 1.5 times the LED current. In order to minimize output current ripple, higher values of inductance are recommended at higher supply voltages. Because high values of inductance has high line resistance, it will cause lower efficiency. Input Capacitor selection Input capacitor has to supply peak current to the inductor and flatten the current ripple on the input. The low ESR condition is required to avoid increasing power loss. The ceramic capacitor is recommended due to its excellent high frequency characteristic and low ESR, which is suitable for the RT8479C. For maximum stability over the entire operating temperature range, capacitors with better dielectric are suggested. Step-Up Converter Inductor Selection The RT8479C uses a constant off-time control to provide high efficiency step-up converter. Thermal Protection where A thermal protection feature is to protect the RT8479C from excessive heat damage. When the junction temperature exceeds 150°C, the thermal protection will turn off the LX terminal. When the junction temperature drops below 125°C, the RT8479C will turn on the LX terminal and return to normal operation. tOFF is Off-Time. The typical value is 1.5μs. Analog Dimming Control ILIM is the input current. The typical value is 2A for MR16 application. The ACTL terminal is driven by an external voltage, VACTL, to adjust the output current to an average value set by RSENSE. The voltage range for VACTL to adjust the output current is from 0.24V to 2.5V. If VACTL becomes larger than 2.5V, the output current value will just be determined by the external/resistor, RSENSE. Following the constant off-time mechanism, the inductance L1 is calculated according to the following equation : L1 > tOFF x (VCC(MAX) − VIN(MIN) + VF) / ILIM VCC is the supply input voltage (V) VIN is the input voltage after bridge diodes (V) VF is the forward voltage (V) L1 is the inductance (H) D = 1 - (VIN / VOUT) V  0.24 IOUT avg = 0.13V  ACTL RSENSE 2.5 fsw = (1 - D) / tOFF ACTL Control where The ACTL pin is the dimming function pin with the DC level proportional to the output LED current until ACTL clamp voltage that is the max output current (100%). D is the operation duty fsw is the switching frequency of Boost controller. Copyright © 2014 Richtek Technology Corporation. All rights reserved. www.richtek.com 12 is a registered trademark of Richtek Technology Corporation. DS8479C-04 August 2014 RT8479C Thermal Considerations 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 5W MR16 LED Lamp application in Figure 1, the typical PCB size is 2x2 mm2 with two-layer layout plane. Under 25°C room temperature, the case temperature of RT8479C is around 65°C. If RT8479C is operated in higher output power or smaller PCB size, the thermal plane for heat dissipation should be concerned seriously. 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 SOP-8 (Exposed Pad) package, the thermal resistance, θJA, is 29°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 : P D(MAX) = (125°C − 25°C) / (29°C/W) = 3.44W for SOP-8 (Exposed Pad) 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 2 allows the designer to see the effect of rising ambient temperature on the maximum power dissipation. Maximum Power Dissipation (W)1 3.6 Four-Layer PCB 3.0 2.4 1.8 1.2 0.6 0.0 0 25 50 75 100 125 Ambient Temperature (°C) Figure 2. Derating Curve of Maximum Power Dissipation Copyright © 2014 Richtek Technology Corporation. All rights reserved. DS8479C-04 August 2014 is a registered trademark of Richtek Technology Corporation. www.richtek.com 13 RT8479C Layout Consideration Locate input capacitor as close to the VCC as possible. D5 L1 VCC R1 OVP R2 RSENSE COUT C15 D6 C3 GND D1 D2 CIN L2 VN C7 D3 8 LX1 VL D4 OVP 2 ACTL 3 VCOMP 4 GND LX2 7 CREG 6 VCC 5 ISN 9 ISN LED+ C8 C5 LED- C2 C5: VCC-ISN bypass capacitor; noise interference like inductive and magnetic pick up will be rejected by C5. C1 GND Figure 3. PCB Layout Guide Copyright © 2014 Richtek Technology Corporation. All rights reserved. www.richtek.com 14 is a registered trademark of Richtek Technology Corporation. DS8479C-04 August 2014 RT8479C Outline Dimension H A M EXPOSED THERMAL PAD (Bottom of Package) Y J X B F C I D Dimensions In Millimeters Dimensions In Inches Symbol Min Max Min Max A 4.801 5.004 0.189 0.197 B 3.810 4.000 0.150 0.157 C 1.346 1.753 0.053 0.069 D 0.330 0.510 0.013 0.020 F 1.194 1.346 0.047 0.053 H 0.170 0.254 0.007 0.010 I 0.000 0.152 0.000 0.006 J 5.791 6.200 0.228 0.244 M 0.406 1.270 0.016 0.050 X 2.000 2.300 0.079 0.091 Y 2.000 2.300 0.079 0.091 X 2.100 2.500 0.083 0.098 Y 3.000 3.500 0.118 0.138 Option 1 Option 2 8-Lead SOP (Exposed Pad) Plastic 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. DS8479C-04 August 2014 www.richtek.com 15