® RT8476 Two-Stage Hysteretic LED Driver Controller General Description Features The RT8476 is a two-stage controller with dual gate drivers consist of a Boost converter (first stage) and a Buck converter (second stage). The advantage of the two-stage topology is highly compatible with ET (Electronic Transformer) in MR16 / AR111 lighting market field applications. Two-Stage Topology (Boost + Buck) Wide Input Voltage Range : 4.5V to 40V Adjustable Peak Input Current Control Adjustable Boost Output Voltage Independent Dual Stage Function Adjustable LED Current with ± 5% LED Current Accuracy Input Under Voltage Lockout Detection Thermal Shutdown Protection SOP-8 and SOP-8 (Exposed Pad) Packages RoHS Compliant and Halogen Free 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. The RT8476 is equipped with dual output gate drivers for external power MOSFETs, suitable for higher power applications. Ordering Information RT8476 The RT8476 is available in the SOP-8 and SOP-8 (Exposed pad) packages. Package Type S : SOP-8 SP : SOP-8 (Exposed Pad-Option 1) Applications Lead Plating System G : Green (Halogen Free and Pb Free) Note : MR16 Lighting Signage and Decorative LED Lighting Architectural Lighting High Power LED Lighting Low Voltage Industrial Lighting Indicator and Emergency Lighting Automotive LED Lighting Richtek products are : RoHS compliant and compatible with the current require- Suitable for use in SnPb or Pb-free soldering processes. ments of IPC/JEDEC J-STD-020. Simplified Application Circuit L1 D6 RSENSE COUT D1 D2 VL AC 12V RT8476 OVP VCC R5 CIN VN M1 GATE1 D3 ISN CREG CS D4 R6 Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS8476-01 March 2015 R4 LED+ C3 M2 D7 C6 L2 LED- GATE2 GND is a registered trademark of Richtek Technology Corporation. www.richtek.com 1 RT8476 Marking Information Pin Configurations RT8476GS (TOP VIEW) RT8476GS : Product Number RT8476 GSYMDNN 8 GATE1 YMDNN : Date Code GATE2 CS 2 7 CREG OVP GND 3 6 VCC 4 5 ISN 8 GATE2 RT8476GSP SOP-8 RT8476GSP : Product Number RT8476 GSPYMDNN YMDNN : Date Code GATE1 CS 2 OVP GND 3 GND 7 CREG 6 VCC 5 ISN 9 4 SOP-8 (Exposed Pad) Functional Pin Description Pin No. Pin Name Pin Function SOP-8 SOP-8 (Exposed Pad) 1 1 GATE1 Gate Driver Output for External MOSFET Switch in the First Stage. 2 2 CS Current Sense Input for External MOSFET Switch. 3 3 OVP Over Voltage Protection Sense Input. 4 4, 9 (Exposed Pad) GND Ground. The exposed pad must be soldered to a large PCB and connected to GND for maximum power dissipation. 5 5 ISN LED Current Sense Amplifier Negative Input. 6 6 VCC Supply Voltage Input. For good bypass, place a ceramic capacitor near the VCC pin. 7 7 CREG Internal Regulator Output. Place an 1F capacitor between the CREG and GND pins. 8 8 GATE2 Gate Driver Output for External MOSFET Switch in the Second Stage. Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 2 is a registered trademark of Richtek Technology Corporation. DS8476-01 March 2015 RT8476 Function Block Diagram ISN VCC -130mV Regulator V CREG VCC + - UV OVP Core Logic EN2 CREG EN1 CS GATE2 EN2 EN1 GATE1 + - V 240mV GND Operation The VCC of the RT8476 is supplied from the first stage Boost output. The first stage is a constant output voltage Boost topology. The CS pin senses the peak inductor current for over current protection. The peak inductor current level can be adjusted by the sense resistor between MOSFET Source and GND pins. Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS8476-01 March 2015 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. is a registered trademark of Richtek Technology Corporation. www.richtek.com 3 RT8476 Absolute Maximum Ratings (Note 1) Supply Input Voltage, VCC to GND ----------------------------------------------------------------------------------- −0.3V to 45V CS, GATE1, GATE2, CREG, OVP to GND -------------------------------------------------------------------------- −0.3V to 6V VCC to ISN ----------------------------------------------------------------------------------------------------------------- −1V to 3V Power Dissipation, PD @ TA = 25°C SOP-8 -----------------------------------------------------------------------------------------------------------------------SOP-8 (Exposed Pad) --------------------------------------------------------------------------------------------------Package Thermal Resistance (Note 2) SOP-8, θJA -----------------------------------------------------------------------------------------------------------------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) ----------------------------------------------------------------------------------------------------- Recommended Operating Conditions 0.53W 3.44W 188°C/W 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 = 10V, No Load, CLOAD = 1nF, TA = 25°C, unless otherwise specified) Parameter Symbol Test Conditions Min Typ Max Unit Supply Voltage CREG UVLO_ ON V UVOL_ON CS/OVP = 0V 4 4.3 4.6 V CREG UVLO_ OFF V UVOL_OFF CS/OVP = 0V -- 4.2 -- V VCC Shutdown Current ISHDN Before Start-Up, VCC = 3.5V -- 10 -- A VCC Quiescent Current IQ After Start-Up, VCC = 5V, GATE1 and GATE2 Stand Still -- 1.5 -- mA Internal Reference Voltage V CREG -- 5 -- V -- 4.9 -- V Supply Current Internal Reference Voltage ICREG = 20mA Current Sense Comparator CS Threshold Voltage V CS 215 240 265 mV CS Pin Leakage Current ICS -- 1 -- A Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 4 is a registered trademark of Richtek Technology Corporation. DS8476-01 March 2015 RT8476 Parameter Symbol Test Conditions Min Typ Max Unit OVP Threshold OVP High Level VOVP_H 1.71 1.9 2.09 V OVP Low Level VOVP_L 1.44 1.6 1.76 V OVP Pin Leakage Current IOVP -- 1 -- A -- 1.5 -- s Gate Driver GATE1 Duty Off-Time UGATE1 Drive Sink RUGATE1sk Sink = 50mA -- 2 -- LGATE1 Drive Source RLGATE1sr Source = 50mA -- 1.25 -- -- 90 -- k 123.5 130 136.5 mV GATE1 Default Pull Down Resistor Buck Converter ISN Threshold VISN ISN Hysteresis VISN 10 15 20 % ISN Pin Leakage Current IISN -- 1 -- A UGATE2 Drive Sink RUGATE2sk Sink = 50mA -- 2 -- LGATE2 Drive Source RLGATE2sr Source = 50mA -- 1.25 -- -- 90 -- k 140 155 170 C -- 35 -- C GATE2 Default Pull Down Resistor Temperature Protection Thermal Shutdown Temperature T SD Thermal Shutdown Hysteresis TSD 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. Note 3. Devices are ESD sensitive. Handling precaution is recommended. Note 4. The device is not guaranteed to function outside its operating conditions. Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS8476-01 March 2015 is a registered trademark of Richtek Technology Corporation. www.richtek.com 5 RT8476 Typical Application Circuit L1 22µH D1 R4 D2 VL AC 12V CIN 1µF VN D3 D4 RSENSE 280m D6 R5 GATE1 CREG CS R6 120m COUT LED+ ISN M1 Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 6 RT8476 VCC OVP C3 4.7µF M2 D7 L2 120µH C6 4.7µF LED- GATE2 GND is a registered trademark of Richtek Technology Corporation. DS8476-01 March 2015 RT8476 Typical Operating Characteristics Quiescent Current vs. Temperature 4.0 1.7 3.5 Quiescent Current (mA) Quiescent Current (mA) Quiescent Current vs. VCC 1.8 1.6 1.5 1.4 1.3 1.2 1.1 3.0 2.5 2.0 1.5 1.0 0.5 VCC = 4.5V to 30V, Gate Capacitor = 100pF VCC = 24V, Gate Capacitor = 100pF 1.0 0.0 4 9.2 14.4 19.6 24.8 -50 30 -25 0 VCC (V) Operating Current vs. VCC 75 100 125 Operating Current vs. Temperature 4.0 2.5 3.5 Operating Current (mA) Operating Current (mA) 50 Temperature (°C) 2.8 2.2 1.9 1.6 1.3 3.0 2.5 2.0 1.5 VCC = 4.5V to 30V, Gate Capacitor = 100pF VCC = 24V, Gate Capacitor = 100pF 1.0 1.0 4 9.2 14.4 19.6 24.8 30 -50 -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 5 ICREG = 0mA ICREG = -20mA 4 3 5.2 5.1 ICREG = 0mA ICREG = -20mA 5.0 4.9 VCC = 10V VCC = 4.5V to 30V 2 4.8 4.5 9.6 14.7 19.8 24.9 VCC (V) Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS8476-01 March 2015 30 -50 -25 0 25 50 75 100 125 Temperature (°C) is a registered trademark of Richtek Technology Corporation. www.richtek.com 7 RT8476 CS Threshold vs. Temperature 280 250 260 CS Threshold (mV) CS Threshold (mV) CS Threshold vs. VCC 260 240 230 220 240 220 200 210 180 4.5 9.6 14.7 19.8 24.9 30 -50 -25 0 50 75 150 140 140 ISN Theshold (V) 150 130 120 110 100 125 130 120 110 100 VCC = 4.5V to 40V VCC = 30V 90 90 4 8 12 16 20 24 28 32 36 40 -50 -25 0 25 50 75 100 125 Temperature (°C) VCC (V) OVP Hi/Low Level Voltage vs. Temperature OVP Hi/Low Level Voltage vs. VCC 2.1 2.2 2.0 High 1.9 1.8 1.7 Low 1.6 1.5 VCC = 4.5V to 30V OVP Hi/Low Level Voltage (V) OVP Hi/Low Level Voltage (V) 100 ISN Threshold vs. Temperature ISN Threshold vs. VCC ISN Threshold (mV) 25 Temperature (°C) VCC (V) 2.1 2.0 High 1.9 1.8 1.7 Low 1.6 1.5 1.4 VCC = 10V 1.3 1.4 4.5 9.6 14.7 19.8 24.9 VCC (V) Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 8 30 -50 -25 0 25 50 75 100 125 Temperature (°C) is a registered trademark of Richtek Technology Corporation. DS8476-01 March 2015 RT8476 LED Current vs. Input Voltage LED Current vs. Output Voltage 450 440 437 440 LED Current (mA) LED Current (mA) 434 430 420 410 400 431 428 425 422 419 416 390 413 VCC = 4.5V to 20V, Load = 4LED 380 Load = 1LED to 6LED 410 4.5 7.6 10.7 13.8 16.9 20 4.5 7.6 Input Voltage (V) 13.8 16.9 20 Output Voltage (V) GATE1 Duty Off-Time vs. Temperature GATE1 Rising/Falling Time vs. VCC 3.1 60 2.8 2.5 2.2 1.9 1.6 1.3 VCC = 10V 1.0 GATE1 Rising/Falling Time (ns) GATE1 Duty Off-Time (µs) 10.7 55 50 Rising 45 40 35 Falling 30 25 VCC = 4.5V to 30V 20 -50 -25 0 25 50 75 100 125 4.5 9.6 14.7 19.8 24.9 Temperature (°C) VCC (V) Power On From VCC Power Off From VCC IOUT (500mA/Div) IOUT (500mA/Div) I IN (2A/Div) I IN (2A/Div) VOUT (10V/Div) V CC (20V/Div) VOUT (10V/Div) V CC (20V/Div) VCC = 10V, 4LEDs Time (5ms/Div) Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS8476-01 March 2015 30 VCC = 10V, 4LEDs Time (5ms/Div) is a registered trademark of Richtek Technology Corporation. www.richtek.com 9 RT8476 Power On From AC-IN Power Off From AC-IN IOUT (500mA/Div) IOUT (500mA/Div) VOUT (10V/Div) VOUT (10V/Div) V CC (20V/Div) AC-IN (50V/Div) V CC (20V/Div) AC-IN (50V/Div) AC = 12V, 4LEDs Time (5ms/Div) Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 10 AC = 12V, 4LEDs Time (10ms/Div) is a registered trademark of Richtek Technology Corporation. DS8476-01 March 2015 RT8476 Application Information The RT8476 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 800kHz 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. 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 R SENSE is shown below : IOUT = 130mV RSENSE LED Current Ripple Reduction Under Voltage Lockout (UVLO) The RT8476 includes an under voltage lookout function with 100mV hysteresis. The internal MOSFET turns off when VCC falls below 4.2V (typ.). 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. 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 RT8476 from excessive onchip power dissipation. The CREG pin has set the output to 4.3V (typ.) to protect the external FETs from excessive power dissipation caused by not being fully enhanced. If the CREG pin is used to drive extra circuits beside RT8476, the extra loads should be limited to less than 10mA. 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 Gate Driver There are two gate drivers, GATE1 and GATE2, in the RT8476. The Gate driver consists of a CMOS buffer designed to drive the external power MOSFET. It features unbalanced source and 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 Gate Driver is pulled low. The RT8476 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] Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS8476-01 March 2015 is a registered trademark of Richtek Technology Corporation. www.richtek.com 11 RT8476 where where fsw is switching frequency (Hz). tOFF is Off-Time. The typical value is 1.5μs. RDS2(ON) is the low side switch on-resistance of external MOSFET (M2). The typical value is 0.35Ω. ILIM is the input current. The typical value is 2A for MR16 application. D is the duty cycle = VOUT / VIN VCC is the supply input voltage (V) IOUT is the required LED current (A) VIN is the input voltage after bridge diodes (V) ΔIOUT is the inductor peak-peak ripple current (internally set to 0.3 x IOUT) VF is the forward voltage (V) VCC is the supply input voltage (V) D = 1 − (VIN / VOUT) VOUT is the total LED forward voltage (V) fSW = (1 − D) / tOFF VISN is the voltage cross current sense resistor (V) where L2 is the inductance (H) D is the operation duty 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. fSW is the switching frequency of Boost controller. Step-Up Converter Inductor Selection The RT8476 uses a constant off-time control to provide high efficiency step-up converter. The resistor, R6, between the Source of the external N-MOSFET and GND should be selected to provide adequate switch maximum current to drive the application. The current limit threshold on the CS pin of the RT8476 is 240mV (typ.). When the CS pin voltage is higher than the 240mV reference, the comparator will disable the power section. The GATE1 will pull low after fixed delay time 1.5μs (typ.) and then turn on again after OVP operation is removed. This cycle repeats, keeping the output voltage within a small window. Following the constant off-time mechanism, the inductance L1 is calculated according to the following equation : L1 is the inductance (H) Check the ILIM setting satisfied the output LED current request by the following equation : (IOUT + ΔIOUT) < [2 x L1 x ILIM + tOFF x (VIN − VOUT − VF)] x VIN / [2 x L1 x (VCC)] 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. 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 are suitable for the RT8476. For maximum stability over the entire operating temperature range, capacitors with better dielectric are suggested. L1 > tOFF x (VCC(MAX) − VIN(MIN) + VF) / ILIM Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 12 is a registered trademark of Richtek Technology Corporation. DS8476-01 March 2015 RT8476 Thermal Protection Maximum Power Dissipation (W)1 4.0 A thermal protection feature is to protect the RT8476 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 RT8476 will turn on the LX terminal and return to normal operation. 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 : 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 package, the thermal resistance, θ JA , is 188°C/W on a standard JEDEC 51-7 four-layer thermal test board. 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 : PD(MAX) = (125°C − 25°C) / (188°C/W) = 0.53W for SOP-8 package P D(MAX) = (125°C − 25°C) / (29°C/W) = 3.44W for SOP-8 (Exposed Pad) package Four-Layer PCB SOP-8 (Exposed Pad) 3.5 3.0 2.5 2.0 1.5 1.0 SOP-8 0.5 0.0 0 25 50 75 100 125 Ambient Temperature (°C) Figure 1. Derating Curve of Maximum Power Dissipation Layout Consideration PCB layout is very important to design power switching converter circuits. Some recommended layout guidelines are suggested as follows : The power components L1, D6, M1, CIN, and COUT must be placed as close to each other as possible to reduce the ac current loop area. The power components L2, D7, and M2 must be placed as close to each other as possible to reduce the ac current loop area. The PCB trace between power components must be as short and wide as possible due to large current flow through these traces during operation. The capacitor COUT, C6 and external resistor, RSENSE, must be placed as close as possible to the VIN and SENSE pins of the device respectively. The GND should be connected to a strong ground plane. Keep the main current traces as short and wide as possible. 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. Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS8476-01 March 2015 is a registered trademark of Richtek Technology Corporation. www.richtek.com 13 RT8476 D6 L1 VIN VCC R4 OVP R5 COUT RSENSE C15 D7 D1 D2 GATE1 VL VN R11 D3 D4 L2 CIN M1 R6 LED+ C6 GND L3 C8 8 GATE2 CS 2 7 CREG OVP 3 6 VCC GND 4 5 ISN LED- M2 C5 C3 GND Figure 2. PCB Layout Guide for SOP-8 Package Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 14 is a registered trademark of Richtek Technology Corporation. DS8476-01 March 2015 RT8476 Outline Dimension H A M J 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 3.988 0.150 0.157 C 1.346 1.753 0.053 0.069 D 0.330 0.508 0.013 0.020 F 1.194 1.346 0.047 0.053 H 0.170 0.254 0.007 0.010 I 0.050 0.254 0.002 0.010 J 5.791 6.200 0.228 0.244 M 0.400 1.270 0.016 0.050 8-Lead SOP Plastic Package Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS8476-01 March 2015 is a registered trademark of Richtek Technology Corporation. www.richtek.com 15 RT8476 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. www.richtek.com 16 DS8476-01 March 2015