RT8562 High Voltage 8 Channel LED Driver General Description Features The RT8562 is a 40V 8-channel LED driver capable of delivering 30mA to each channel with 10 LEDs (3.6V per diode), total of 80 LEDs with one driver. The RT8562 is a current mode boost converter opearated at 1MHz, wide VIN range covers from 6V to 24V and the on-chip current z High Voltage : VIN up to 24V, VOUT up to 40V, Driving up to 80 x 3.6V LEDs (10 each channel) z switch is rated at 2.5A. z Channel Current Programmabe 10mA to 30mA and Matched to 1.5% Current Mode PWM 1MHz Boost Converter Easy Analog and Digital Dimming Control Programmable Soft Start Automatic Detecting Unconnected and/or Broken Channel Programmable Over Voltage Protection Disconnects LED in Shutdown Providing High Accuracy Digital Dimming by PWM Signal VIN Under Voltage Lockout Over Temperature Protection Current Limiting Protection Small 24-Lead WQFN Package RoHS Compliant and Halogen Free The PWM output voltage loop regulates the LED pins to 0.6V with an auto-adjustment circuit allowing voltage mismatches between LED strings. The RT8562 automatically detects and disconnects any unconnected and/or broken strings during operation from PWM loop to prevent VOUT from over voltage. The 1.5% matched LED currents on all channels are simply programmed with a resistor or a current sink. Both analog dimming and digitally controlled PWM dimming are supported by RT8562. Analog dimming is linearly controlled by an external voltage. A very high contrast ratio true digital PWM dimming can be achieved by driving PWM pin with a PWM signal. Other protecting features include programmable output over voltage protection, LED curren limit, PWM switch current limit and thermal shutdown. The RT8562 is packaged with a tiny footprint package of WQFN-24L 4x4 packages. z z z z z z z z z z z Applications z z z UMPC and Notebook Computer Backlight GPS, Portable DVD Backlight Desk Lights and Room Lighting Pin Configurations ` Suitable for use in SnPb or Pb-free soldering processes. COMP NC LX2 LX1 19 EN 18 PGND2 NC 2 17 PGND1 SS 3 16 OVP NC 4 15 CH1 GND 5 14 CH2 PWM 6 13 CH3 GND 25 7 8 9 10 11 12 CH4 ments of IPC/JEDEC J-STD-020. 20 CH5 RoHS compliant and compatible with the current require- 21 ISET ` 22 CH6 Richtek products are : 23 CH7 Note : Lead Plating System G : Green (Halogen Free and Pb Free) 24 1 CH8 Package Type QW : WQFN-24L 4x4 (W-Type) VIN RT8562 VDC (TOP VIEW) Ordering Information WQFN-24L 4x4 Marking Information For marking information, contact our sales representative directly or through a Richtek distributor located in your area. DS8562-01 April 2011 www.richtek.com 1 RT8562 Typical Application Circuit VIN 6V to 24V C5 10µF : : : : RT8562 C6 1µF R5 1k 1 EN LX2 20 15 CH1 14 CH2 5V R6 1k 6 PWM 22 COMP 24 VDC 3 SS PWM Signal R1 1.8k CH7 CH8 8 C7 ... :: : : : : 10 LED String : : 7 R2 OVP 16 ISET 11 GND 5, Exposed Pad (25) C4 0.1µF R7 : : : : ... VIN LX1 19 23 C3 4.7µF D1 C1 10µF R4 10 C2 3.9nF VOUT 40V MAX L 10µH VOUT R3 RISET 4.75k ILED (mA) = 20 x 4.75 RISET (kΩ) Figure 1. 1MHz, 20mA Full Scale Current PWM Dimming Control VIN 6V to 24V 23 C6 1µF 5V R5 1k R1 1.8k C2 3.9nF VIN EN 6 PWM 22 COMP 24 VDC 3 SS C3 4.7µF C4 0.1µF : : : : RT8562 LX1 19 LX2 20 15 CH1 14 CH2 CH7 CH8 8 R7 C7 : : : : ... :: : : : : 10 LED String : : ... R6 1k 1 D1 C5 10µF C1 10µF R4 10 Analog Dimming VOUT 40V MAX L 10µH 7 R2 OVP 16 ISET 11 GND 5, Exposed Pad (25) VOUT R3 RISET 4.75k ILED (mA) = 20 x 4.75 RISET (kΩ) Figure 2. 1MHz, 20mA Full Scale Current Analog Dimming Control www.richtek.com 2 DS8562-01 April 2011 RT8562 VIN 4V to 36V VAVDD 6V to 24V 5V C7 1µF C1 10µF R4 10 R5 1k 23 C6 2.2µF C5 10µF R6 1k 6 22 24 LX1 19 VIN LX2 20 15 CH1 14 CH2 C4 0.1µF 8 PWM CH7 COMP CH8 VDC OVP 16 ISET 11 3 SS C3 4.7µF : : : : RT8562 1 EN R1 1.8k C2 3.9nF D1 R7 C8 : : : : ... :: : : : : 10 LED String : : ... Analog Dimming VOUT 40V MAX L 10µH 7 GND 5, Exposed Pad (25) R2 VOUT R3 RISET 4.75k ILED (mA) = Note : 20 x 4.75 RISET (kΩ) 1. Due to the limitaion of maximum duty, 5V input can support typically to VOUT = 33V. 2. Due to the limitaion of maximum duty, 4V input can support typically to VOUT = 26V. Figure 3. Wide Range VIN Application by Connecting VCC Pin to LCD Driver Power AVDD Function Block Diagram LX1, LX2 OSC VIN 5.6V CH1 S + R OVP 1.6V + + - - 1.2V - R + EN VDC + CH2 Shutdown + - 5V LDO VOUT Regulation Unit COMP . . . CH7 5V + - 5uA SS CH8 PWM + + - - ISET DS8562-01 April 2011 www.richtek.com 3 RT8562 Functional Pin Description Pin No. Pin Name Pin Function 1 EN Chip enable pin, when pulled low, chip is in shutdown mode. 2, 4, 21 NC No Internal Connection. 3 SS Soft Start Pin, a capacitor of at least 10nF is required for soft start. 5, GND 25 (Exposed Pad) 6 PWM 11 ISET Ground pin of the chip. The exposed pad must be soldered to a large PCB and connected to GND for maximum power dissipation. Analog/Digital dimming control. When using analog dimming, ILED (mA) = 20 x 4.75 for VPWM ≥ 1.2V. RISET (kΩ) A resistor or a current from DAC on this pin programs the full LED current. 10, 9, 8, 7 CH5 to CH8 Channel 5 to Channel 8 LED current sink. Leave the pin unconnected if not used. 15, 14, 13, 12 CH1 to CH4 Channel 1 to Channel 4 LED current sink. Leave the pin unconnected if not used. Over Voltage Protection. PWM boost converter turns off when V OVP goes OVP higher than 1.2V. PGND1, Power Ground (LX1/LX2 power return). PGND2 LX1, LX2 PWM boost converter switch node. 16 17, 18 19, 20 22 COMP PWM boost converter loop compensation node. 23 VIN Power supply of the chip. For good bypass, a low ESR capacitor is required. 24 VDC Put 1μF capacitor on this pin to stabilize the 5V output of the internal regulator. This regulator is for chip internal use only. Absolute Maximum Ratings z z z z z z z z z z (Note 1) Supply Voltage, VIN -----------------------------------------------------------------------------------------------------LX1, LX2 Pin Voltage at Switching Off -------------------------------------------------------------------------------CH1 to CH8 Pin -----------------------------------------------------------------------------------------------------------PWM, EN, OVP Pin Voltage ------------------------------------------------------------------------------------------Power Dissipation, PD @ TA = 25°C WQFN-24L 4x4 -----------------------------------------------------------------------------------------------------------Package Thermal Resistance (Note 2) WQFN-24L 4x4, θJA ------------------------------------------------------------------------------------------------------WQFN-24L 4x4, θJC -----------------------------------------------------------------------------------------------------Junction Temperature ----------------------------------------------------------------------------------------------------Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------------Storage Temperature Range -------------------------------------------------------------------------------------------ESD Susceptibility (Note 3) HBM (Human Body Mode) ---------------------------------------------------------------------------------------------MM (Machine Mode) ------------------------------------------------------------------------------------------------------ Recommended Operating Conditions z z z 28V 45V 35V −0.3V to 5.5V 1.923W 52°C/W 7°C/W 150°C 260°C −65°C to 150°C 2kV 200V (Note 4) Supply Input Voltage, VIN ----------------------------------------------------------------------------------------------- 6V to 24V Junction Temperature Range -------------------------------------------------------------------------------------------- −40°C to 125°C Ambient Temperature Range -------------------------------------------------------------------------------------------- −40°C to 85°C www.richtek.com 4 DS8562-01 April 2011 RT8562 Electrical Characteristics (VIN = 17V, TA = 25°C, unless otherwise specified) Parameter Symbol Supply Current VIN Under Voltage Lockout Threshold IVIN Shutdown Current EN Pin Input Current ISHDN IEN EN Logic Input PWM Logic Input VUVLO Test Conditions Min Typ Max Unit COMP ≤ 0.2V (Switching off) V IN Rising V IN Falling ---- 3 5.6 4.9 5 5.95 -- mA V EN ≤ 0.7V V EN ≤ 5V --- --- 10 0.1 μA μA V High Level Low Level High Level VEN_H VEN_L VPWM_H 1.6 -1.3 ---- 5 1 5 Low Level VPWM_L -- -- 0.15 2V > VCHx > 0.6V, RISET = 4.75kΩ, V PWM > 1.2V 19 20 21 mA 2V > VCHx > 0.6V, RISET = 4.75kΩ, V PWM > 1.2V, Calculating (I(MAX) − I(MIN)) / IAverage x 100% -- -- 1.5 % 1.17 -- 1.2 1 1.23 2 V μA --- 0.2 0.1 --- V V 0.8 -- 1 100 1.2 -- MHz ns 0.5 -0.1 0.6 ±15 0.2 0.7 --- V μA V V V LED Current Programming LED Current ICHx LEDs Current Matching ISET Pin Voltage Input Current of PWM VISET IPWM 3.6kΩ ≤ R ISET ≤ 9.6kΩ, V PWM > 1.2V 0.3V ≤ VPW M ≤ 1.2V Threshold of PWM VCHx Threshold VPWM LED Current Off Un-connection PWM Boost Converter Switching Frequency Minimum On Time Regulated VCHx Amplifier (gm) Output Current COMP Threshold Highest Voltage LED String 2.4V > COMP > 0.2V PWM Switch Off -- 0.3 0.5 Ω ILIM 2.5 -- -88 --- A % OVP Threshold VOVP 1.1 1.2 1.3 V OVP Input Current Soft Start Current IOVP ISS -3 -5 50 8 nA μA Thermal Shutdown Temperature T SD -- 150 -- °C -- 20 -- °C LX1, LX2 RDS(ON) LX1, LX2 Current Limit SW Maximum Duty OVP & Soft Start V OVP ≤ 3V V SS ≤ 2.5V Thermal Shutdown Hysteresis Note 1. Stresses listed as the above “Absolute Maximum Ratings” may cause permanent damage to the device. These are for stress ratings. 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 for extended periods may remain possibility to affect device reliability. Note 2. θJA is measured in the natural convection at TA = 25°C on a high effective four layers thermal conductivity test board of JEDEC 51-7 thermal measurement standard. The case point of θJC is on the expose pad for the WQFN package. Note 3. Devices are ESD sensitive. Handling precaution is recommended. Note 4. The device is not guaranteed to function outside its operating conditions. DS8562-01 April 2011 www.richtek.com 5 RT8562 Typical Operating Characteristics Efficiency vs. Input Voltage LED Current vs. Input Voltage 100 26 90 24 80LEDs LED Current (mA) Efficiency (%) 80 70 60 50 40 30 20 22 20 CH1 CH2 CH3 CH4 CH5 CH6 CH7 CH8 18 16 14 12 10 0 10 8 10 12 14 16 18 20 22 24 8 10 12 Input Voltage (V) LED Current vs. Temperature 18 20 22 24 1.24 23 1.22 22 1.20 21 VISET (V) LED Current (mA) 16 VISET vs. Temperature 24 20 19 1.18 1.16 1.14 18 1.12 17 VIN = 12V 16 VIN = 12V 1.10 -40 -15 10 35 60 85 110 135 -40 -15 Temperature (°C) 10 35 60 85 110 135 Temperature (°C) LED Current vs. PWM Duty Cycle VISET vs. Input Voltage 25 1.25 1.24 20 LED Current (mA) 1.23 VISET (V) 14 Input Voltage (V) 1.22 1.21 1.20 1.19 15 PWM = 200Hz PWM = 1kHz PWM = 10kHz PWM = 30kHz 10 5 1.18 VPWM = 0V to 3V, VIN = 12V 0 1.17 8 10 12 14 16 18 Input Voltage (V) www.richtek.com 6 20 22 24 0 0 0.1 10 0.2 1 20 0.3 30 0.4 40 0.5 50 0.6 60 0.7 70 0.8 80 0.9 90 100 Duty Cycle (%) DS8562-01 April 2011 RT8562 LED Current vs. PWM Analog Voltage Frequency vs. Input Voltage 28 1100 24 Frequency (kHz) LED Current (mA) 1060 20 16 12 8 1020 980 940 4 VIN = 12V 900 0 0 0.25 0.5 0.75 1 1.25 8 1.5 10 12 14 16 18 20 22 24 Input Voltage (V) PWM Analog Voltage(V) Shutdown Current vs. Input Voltage Switch Off Current vs. Input Voltage 4.0 10 8 Switch Off Current (mA) Shutdown Current (uA) 3.9 6 4 2 VEN = 0V 0 6 8 10 12 14 16 18 20 22 3.8 3.7 3.6 3.5 3.4 3.3 3.2 3.1 COMP = 0V 3.0 8 24 10 12 14 16 18 20 22 24 Input Voltage (V) Input Voltage (V) SS Current vs. Temperature SS Current vs. Input Voltage 9 8.0 7.6 8 6.8 SS Current (uA) SS Current (uA) 7.2 6.4 6.0 5.6 5.2 7 6 5 4 4.8 3 4.4 VIN = 12V, CSS = 0.1μF 4.0 -40 -15 10 35 60 85 Temperature (°C) DS8562-01 April 2011 110 135 CSS = 0.1μF 2 8 10 12 14 16 18 20 22 24 Input Volatge (V) www.richtek.com 7 RT8562 OVP Voltage vs. Input Volatge OVP Voltage vs. Temperature 1.3 1.30 1.28 1.2 1.24 OVP Voltage (V) OVP Voltage (V) 1.26 1.22 1.20 1.18 1.16 1.1 1.0 0.9 1.14 1.12 VIN = 12V 1.10 -40 -15 10 35 60 85 110 0.8 8 135 Temperature (°C) 12 14 16 18 20 22 24 Input Voltage (V) PWM SW-OFF Threshold Voltage vs. Temperature PWM SW-OFF Threshold Voltage (V) 10 Line Transient Response 0.22 VIN = 10.8V to 13.2V 0.21 0.20 0.19 VIN (5V/Div) 0.18 0.17 0.16 0.15 VIN = 12V IOUT (100mA/Div) 0.14 -40 -15 10 35 60 85 110 Time (50ms/Div) 135 Temperature (°C) Power On from EN VIN (10V/Div) VEN (2V/Div) VOUT (50V/Div) VOUT (20V/Div) I IN (500mADiv) LX1, LX2 (50V/Div) VIN = 12V, CSS = 0.1μF Time (10ms/Div) www.richtek.com 8 OVP VIN = 12V, All LED Pin Open Time (2.5ms/Div) DS8562-01 April 2011 RT8562 Applications Information The RT8562 is a current mode boost converter operating at 1MHz to power up to 80 white LEDs with a programmable current for uniform intensity. The part integrates current sources, soft-start, and easy analog and digital dimming control. The protection block provides the circuitry for over-temperature, over-voltage and currentlimit protection features. UVLO PWM EN VIN must be turned off early than EN and PWM signal VIN must be turned on late than EN and PWM signal No Soft-Start If PWM turns on late Soft-Start The input operating voltage range of the RT8562 is 6V to 24V. An input capacitor at the VIN pin can reduce ripple voltage. It is recommended to use a ceramic 10uF or larger capacitance as the input capacitor. This IC provides an under voltage lockout (UVLO) function to enhance the stability when startup. The UVLO threshold of input rising voltage is set at 5.6V typically with a 0.7V hysteresis. Power Sequence VOUT Figure 5. Power-On Sequence Control by VIN EN and/or VIN should be pulled low once PWM pull low for over 10 ms EN/VIN PWM Please refer to the below Figure 4 and 5. The recommended power-on sequence is that the PWM ready before EN and/or VIN ready. If not, the Soft-Start function will be disabled. As to power-off sequence, the EN/VIN must be pulled low within 10ms to prevent “Hard-Start” shown as Figure 6. Power-off sequence Abnormal Poweron sequence VIN UVLO PWM EN Abnormal Poweron sequence VIN Input UVLO Power-on sequence Power-off sequence Power-on sequence EN must be turned on late than VIN and PWM signal Soft-Start VOUT EN must be turned off early than VIN and PWM signal 10ms Figure 6. To Prevent “Hard-Start” Sequence Soft Start The RT8562 employs a soft start feature to limit the inrush current. The soft-start circuit prevents the excessive inrush current and input voltage droop. The soft-start time is determined by capacitor CSS connected to SS pin with 5uA constant current to charge CSS. The value of capacitor CSS is user-defined to satisfy the designer's requirement. The recommended soft-start capacitor is 0.1uF. LED connection No Soft-Start If PWM turns on late Figure 4. Power-On Sequence Control by EN The RT8562 equips 8 channel LED drivers and each channel supports up to 10 LEDs. The 8 LED strings are connected from VOUT to pin 7, 8, 9, 10, 12, 13, 14, and 15 respectively. If one of the LED channel is not used, the LED pin should be opened directly. Setting and Regulation of LED current The LED current can be calculated by the following equation : ILED (mA) = 20 x 4.75 RISET (kΩ) DS8562-01 April 2011 www.richtek.com 9 RT8562 Where, the RISET is the resister between ISET pin and GND. This setting is the reference for the LED current at CH1 to CH8 and represents the sensed LED current for each string. The DC/DC converter regulates the LED current according to the setting. If VIN is close to VOUT and smaller than VOUT, the control loop may turn on the power switch with minimum on time and then skip cycles to maintain LED current regulation. Brightness Control The RT8562 features both analog and digital dimming control. Analog dimming is linearly controlled by an external voltage (0.3V to 1.2V) at PWM pin. A very high contrast ratio true digital PWM dimming can be achieved by driving PWM pin with a PWM signal and the recommended PWM frequency is 100Hz to 10kHz. Dimming frequency can be sufficiently adjusted from 100Hz to 30kHz. However, LED current cannot be 100% proportional to duty cycle especially for high frequency and low duty ratio because of physical limitation caused by inductor rising time. Refer to Figure 7, the minimum dimming duty can be as low as 1% for the frequency range from 100Hz to 300Hz. For the dimming frequency from 300Hz to 1kHz, the duty is about 5%. If the frequency is increased to 1kHz to 30kHz, the duty will be about 10%. LED Current vs. PWM Duty Cycle 25 LED Current (mA) 20 Over Voltage Protection The RT8562 equips over voltage protection (OVP) function. When the voltage at the OVP pin reaches a threshold of approximately1.2V, the MOSFET driver output (LX1, LX2) will be turned “OFF”. The MOSFET driver output (LX1, LX2) will be turned “ON” again once the voltage at OVP drops below the threshold voltage 1.2V. So, the output voltage can be clamped at a certain voltage level and it can be calculated by the following equation : VOUT, OVP = VOVP × ⎛⎜ 1+ R2 ⎞⎟ ⎝ R3 ⎠ Where R2 and R3 are the voltage divider connected to OVP pin. VOVP is typically 1.2V. If at least one string is in normal operation, the controller will automatically ignore the open strings and continue to regulate the current for the string(s) in normal operation. Current Limit Protection The RT8562 can limit the peak current to achieve over current protection. RT8562 senses the inductor current through LX1, LX2 pins in the switch-on period. The duty cycle depends on the current sense signal summing with the internal slope compensation compared to the COMP signal. The internal N-MOSFET will be turned off when the current signal is larger than the COMP signal. In the off period, the inductor current will descend. The internal MOSFET is turned on by the oscillator in the next begining cycle. Over Temperature Protection 15 PWM = 200Hz PWM = 1kHz PWM = 10kHz PWM = 30kHz 10 5 VPWM = 0V to 3V, VIN = 12V 0 0 0 0.1 10 0.2 20 0.3 1 30 0.4 40 0.5 50 0.6 60 0.7 70 0.8 80 0.9 90 100 Duty Cycle (%) Figure 7. LED Current vs. PWM Dimming Duty Cycle www.richtek.com 10 The RT8562 has over temperature protection (OTP) function to prevent the excessive power dissipation from overheating. The OTP will shut down switching operation while the junction temperature exceeds 150°C. Main converter starts switching when junction temperature cooling down approximately 20°C. Inductor Selection The value of the output inductor (L), where the transition from discontinuous to continuous mode occurs is approximated by the following equation : (VOUT − VIN ) × VIN2 L= 2 × IOUT × f × VOUT 2 DS8562-01 April 2011 RT8562 ` Pin22 is the compensation point to adjust system stability. Place the compensation components to pin22 as close as possible. The input capacitor reduces current spikes from the input supply and minimizes noise injection to the converter. For most applications, a 10uF ceramic capacitor is sufficient. A value higher or lower may be used depending on the noise level from the input supply and the input current to the converter. GND LX1 23 D1 LX2 24 COUT2 L CVC2 22 21 20 19 COUT1 VOUT EN 1 18 PGND2 NC 2 17 PGND1 16 OVP 15 CH1 14 CH2 13 CH3 SS 3 NC 4 GND 5 PWM 6 GND 25 7 8 9 10 11 12 CH4 Capacitor Selection C1 R1 C6 Locate the CVIN2 as close to VIN pin as possible. Place power components as close as possible. C2 R4 Diode Selection Schottky diode is a good choice for an asynchronous Boost converter due to the small forward voltage. However, for power dissipation, reverse voltage rating and pulsating peak current are the important parameters of Schottky diode consideration. Choose a suitable diode whose reverse voltage rating is greater than the maximum output voltage. VIN Locate the compensation components to COMP pin as close as possible. ISET IPEAK = VOUT × IOUT + VIN × T ⎛⎜ VOUT − VIN ⎞⎟ η × VIN 2 × L ⎝ VOUT ⎠ ` It is recommend to place C6 close to VIN pin. COMP The inductor must be selected with a saturation current rating greater than the peak current provided by the following equation : ` Place L and D1 connected to LX pin as close as possible. The trace should be short and wide as possible. NC The boost converter operates in discontinuous mode over the entire input voltage range when the L1 inductor value is less than this value L. With an inductance greater than L, the converter operates in continuous mode at the minimum input voltage and may be discontinuous at higher voltages. CH5 η is the efficiency of the power converter. VIN IOUT = sum of current from all LED strings. ` The power components L, D1, C1, COUT1 and COUT2 must be placed as close as possible to reduce the ac current loop. The PCB trace between power components must be short and wide as possible due to large current flow through these trace during operation. CH6 f = operating frequency. VDC VIN = minimum input voltage. PCB layout is very important to design power switching converter circuits. The following layout guide lines should be strictly followed for best performance of the RT8562. CH7 VOUT = maximum output voltage. Layout Guideline CH8 Where, Figure 8 It is recommended to choose a ceramic capacitor bases on the output voltage ripple requirements. The minimum value of the output capacitor COUT is approximately given by the following equation : (VOUT − VIN ) × IOUT COUT = η × VRIPPLE × VOUT × f DS8562-01 April 2011 www.richtek.com 11 RT8562 Outline Dimension D2 D SEE DETAIL A L 1 E E2 e b 1 1 2 2 DETAIL A Pin #1 ID and Tie Bar Mark Options A A3 A1 Note : The configuration of the Pin #1 identifier is optional, but must be located within the zone indicated. Dimensions In Millimeters Dimensions In Inches Symbol 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 0.180 0.300 0.007 0.012 D 3.950 4.050 0.156 0.159 D2 2.300 2.750 0.091 0.108 E 3.950 4.050 0.156 0.159 E2 2.300 2.750 0.091 0.108 e L 0.500 0.350 0.020 0.450 0.014 0.018 W-Type 24L QFN 4x4 Package Richtek Technology Corporation Richtek Technology Corporation Headquarter Taipei Office (Marketing) 5F, No. 20, Taiyuen Street, Chupei City 5F, No. 95, Minchiuan Road, Hsintien City Hsinchu, Taiwan, R.O.C. Taipei County, Taiwan, R.O.C. Tel: (8863)5526789 Fax: (8863)5526611 Tel: (8862)86672399 Fax: (8862)86672377 Email: [email protected] Information that is provided by Richtek Technology Corporation is believed to be accurate and reliable. Richtek reserves the right to make any change in circuit design, specification or other related things if necessary without notice at any time. No third party intellectual property infringement of the applications should be guaranteed by users when integrating Richtek products into any application. No legal responsibility for any said applications is assumed by Richtek. www.richtek.com 12 DS8562-01 April 2011