® RT7321 Linear LED Driver for High-Voltage LED Lamps General Description Features The RT7321 is a simple and robust constant-current regulator designed to provide a cost-effective solution for driving high-voltage LEDs in LED lamp applications. The RT7321 is equipped with a proprietary control mechanism to improve the utilization of high-voltage LEDs. The RT7321 allows users to set the regulated current levels (WQFN20L 5x5 Package) for various LED lamps. It also provides low pin-count SOP-8 (Exposed Pad) package with customized current setting to meet various application requirements. In addition, the RT7321 also provides a thermal regulation protection, instead of traditional thermal shutdown, to suppress the rise of the temperatures in LED lamps and prevent the LED lamps from flicker. AC Input Voltage Range : 200 to 240VRMS No Electrolytic Capacitor and Transformer Required Improved LED Utilization Programmable LED Current Thermal Regulation Protection High Power Efficiency High Power Factor Easy EMI Solution Minimized BOM Cost and Space Required RoHS Compliant and Halogen Free Applications High-Voltage LED Lamps Simplified Application Circuit For SOP-8 (Exposed Pad) Package For WQFN-20L 5x5 Package RT7321 AC RT7321 AC HV1 HV S3 S1 S4 S2 GND Copyright © 2014 Richtek Technology Corporation. All rights reserved. DS7321-02 July 2014 HV1 HV S3 S1 S4 S2 GND I11 I32 I12 I31 I13 I33 I23 I21 I22 is a registered trademark of Richtek Technology Corporation. www.richtek.com 1 RT7321 Ordering Information Marking Information RT7321 RT7321AEGSP Package Type SP : SOP-8 (Exposed Pad-Option 2) QW : WQFN-20L 5x5 (W-Type) RT7321AEGSP : Product Number RT7321AE GSPYMDNN YMDNN : Date Code Lead Plating System G : Green (Halogen Free and Pb Free) RT7321BFGSP RT7321 Version Table (Only for SOP-8 (Exposed Pad)) RT7321BFGSP : Product Number RT7321BF GSPYMDNN Note : YMDNN : Date Code Richtek products are : RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020. RT7321CGGSP Suitable for use in SnPb or Pb-free soldering processes. RT7321CGGSP : Product Number RT7321CG GSPYMDNN RT7321 Version Table YMDNN : Date Code RT7321XYGSP Parallel Current (IP_S1/2 and IP_S3/4) Code (X) Series Current (IS_S3/4) Code (Y) 10mA A 10mA A 15mA B 15mA B 20mA C 20mA C 25mA D 25mA D 30mA E 30mA E 35mA F 40mA G 45mA H 50mA I Copyright © 2014 Richtek Technology Corporation. All rights reserved. www.richtek.com 2 RT7321CHGSP RT7321CHGSP : Product Number RT7321CH GSPYMDNN YMDNN : Date Code RT7321GQW RT7321GQW : Product Number RT7321 GQW YMDNN YMDNN : Date Code is a registered trademark of Richtek Technology Corporation. DS7321-02 July 2014 RT7321 Pin Configurations GND 4 GND 6 S2 5 NC 9 S2 I11 I12 I13 16 15 I23 14 I22 13 I21 NC 2 HV1 3 NC 4 12 GND NC 5 11 I33 GND 21 6 7 8 9 10 I31 3 S1 1 17 I32 S4 7 HV 18 S4 2 HV 19 S3 S3 8 20 NC HV1 S1 (TOP VIEW) SOP-8 (Exposed Pad) WQFN-20L 5x5 Functional Pin Description For SOP-8 (Exposed Pad) Package Pin No. Pin Name Pin Function HV1 Controlled High-Voltage Output. A built-in high-voltage transistor, connected between the HV and HV1 pins, controls the ON or OFF of the supply voltage to the external high-voltage LED connected with HV1 pin. 2 S3 Output of the S3 Current Regulator. The regulated sinking current is set by the internal bounding wires and depends on the requests of users. In the “Parallel operation”, the current (IP_S3) can be set from 10mA to 30mA; in the “Series operation”, the current (IS_S3) can be set from the IP_S3 to 50mA. 3 S4 Output of the S4 Current Regulator. Like the S3 pin, the typical regulated currents (IP_S3 and IP_S4; IS_S3 and IS_S4) of S3 and S4 pins are the same, respectively. 1 4, GND 9 (Exposed Pad) Ground. Connect this pin to system ground with lowest impedance. The exposed pad must be soldered to a large PCB and connected to GND for maximum power dissipation. 5 NC No Internal Connection. 6 S2 Output of the S2 Current Regulator. This pin only regulates the sinking current (IP_S2) in the “Parallel operation”. The current (IP_S2), set by the internal bounding wires, is in the range of 10mA to 30mA and depends on the requests of users. 7 S1 Output of the S1 Current Regulator. Like the S2 pin, the typical regulated currents (IP_S1 and IP_S2) of S1 and S2 pins are the same. 8 HV High-Voltage and Bias Voltage Input. Connect this pin to the rectified voltage from AC input. Copyright © 2014 Richtek Technology Corporation. All rights reserved. DS7321-02 July 2014 is a registered trademark of Richtek Technology Corporation. www.richtek.com 3 RT7321 For WQFN-20L 5x5 Package Pin No. Pin Name Pin Function 1 HV High-Voltage Input. Connect this pin to the rectified voltage from AC input. 2, 4, 5, 6 NC No Internal Connection. 3 HV1 Controlled High Voltage Output. A built-in high-voltage transistor, connected between the HV and HV1 pins, controls the ON or OFF of the supply voltage to the external high-voltage LED connected with HV1 pin. 7 S3 Output of the S3 Current Regulator. The regulated sinking currents (IP_S3 and IS_S3) are easily programmed by users. In the “Parallel operation”, the current (IP_S3) can be set from 10mA to 30mA by using the I21 to I23 pins; in the “Series operation”, the current (IS_S3) can be set from the IP_S3 to 50mA by using the I31 to I33 pins. To directly connect the I21/I31, I22/I32 or I23/I33 pin to GND pin, respectively increases the sinking current by 5mA, 10mA or 20mA. The initial IP_S3 is 10mA if the I21 to I23 pins are open. 8 S4 Output Pin of the S4 Current Regulator. Like the S3 pin, the typical regulated currents (IP_S3 and IP_S4; IS_S3 and IS_S4) of S3 and S4 pins are the same and easily programmed by using the I21 to I23 pins and I31 to I33 pins, respectively. 9 I32 Current Setting Input for S3 and S4 pins. If this pin is directly connected to GND, the regulated currents (IS_S3 and IS_S4) increase 10mA (typ.). 10 I31 Current Setting Input for S3 and S4 pins. If this pin is directly connected to GND, the regulated currents (IS_S3 and IS_S4) increase 5mA (typ.). 11 I33 Current Setting Input Pin for S3 and S4 pins. If this pin is directly connected to GND, the regulated currents (IS_S3 and IS_S4) increase 20mA (typ.). 12, GND 21 (Exposed Pad) Ground. The exposed pad must be soldered to a large PCB and connected to GND for maximum power dissipation. 13 I21 Current Setting Input for S3 and S4 pins. If this pin is directly connected to GND, the regulated currents (IP_S3/4 and IS_S3/4) increase 5mA (typ.). 14 I22 Current Setting Input for S3 and S4 pins. If this pin is directly connected to GND, the regulated currents (IP_S3/4 and IS_S3/4) increase 10mA (typ.). 15 I23 Current Setting Input Pin for S3 and S4 pins. If this pin is directly connected to GND, the regulated currents (IP_S3/4 and IS_S3/4) increase 20mA (typ.). 16 I13 Current Setting Input for S1 and S2 pins. If this pin is directly connected to GND, the regulated currents (IP_S1 and IP_S2) increase 20mA (typ.). 17 I12 Current Setting Input for S1 and S2 pins. If this pin is directly connected to GND, the regulated currents (IP_S1 and IP_S2) increase 10mA (typ.). 18 I11 Current Setting Input for S1 and S2 pins. If this pin is directly connected to GND, the regulated currents (IP_S1 and IP_S2) increase 5mA (typ.). 19 S2 Output of the S2 Current Regulator. This pin only regulates the sinking current (IP_S2) in the “Parallel operation”. To open or directly connect the I11, I12 or I13 pin to GND pin can easily program the sinking current from 10mA to 30mA by users. 20 S1 Output of the S1 Current Regulator. Like the S2 pin, the typical regulated currents (IP_S1 and IP_S2) of S1 and S2 pins are the same. Copyright © 2014 Richtek Technology Corporation. All rights reserved. www.richtek.com 4 is a registered trademark of Richtek Technology Corporation. DS7321-02 July 2014 RT7321 Function Block Diagram S1 S2 S3 S4 S1 Current Regulator S2 Current Regulator S3 Current Regulator S4 Current Regulator ON_S1 ON_S2 ON_S3 ON_S4 For SOP-8 (Exposed Pad) Package HV GND VS4 VREF VS2 VREF1 Thermal Regulation Protection Voltage Regulator VREG M5 Parallel ON/OFF and Parallel/Series Controls D1 HV1 S1 S2 S3 S4 S1 Current Regulator S2 Current Regulator S3 Current Regulator S4 Current Regulator ON_S1 ON_S2 ON_S3 ON_S4 For WQFN-20L 5x5 Package HV GND IS2 VS4 IS1 VREF VS2 VREF1 Thermal Regulation Protection IS3 IS4 I11 I12 I13 I10 5mA 10mA 20mA 10mA I11 I12 I13 Copyright © 2014 Richtek Technology Corporation. All rights reserved. DS7321-02 July 2014 VREG M5 Parallel ON/OFF and Parallel/Series Controls Current Setting for S1 and S2 Voltage Regulator D1 HV1 Parallel Current Setting for S3 and S4 : I20, I21 to I23 are used in Parallel operation I20, I21 to I23, I31 to I33 are used in Series operation I21 I22 I23 5mA 10mA 20mA I21 I22 I23 I20 I31 10mA 5mA I31 I32 I33 10mA 20mA I32 I33 is a registered trademark of Richtek Technology Corporation. www.richtek.com 5 RT7321 Operation Constant-Current Regulator 4 x VF In Figure 1, each constant-current regulator in the RT7321 consists of an output high-voltage MOSFET, programmable current-sense resistors, an error amplifier and a reference voltage (VREF). 3 x VF 2 x VF VF VHV t0 t1 t2 t3 Sx VREG t4 t5 t6 t7 t8 t9 Figure 2. Timing Chart + VREF Error Amplifier M1 VCS Programmable Current-sense Resistors … Ix3 Ix1 Figure 1 The error amplifier, designed with high DC gain, compares the current signal (VCS) on the current-sense resistors and the VREF to generate an amplified error signal. The error signal regulates the output MOSFET (M1) to control the sinking current on Sx pin at the programmed current level. In addition, the operating Sx voltage (VSx) must be higher than the minimum Sx voltage (VSx_MIN). Otherwise, the output current might not be regulated at the programmed level (ISx_SET). The VSx_MIN is approximately calculated by the following equation: VSx_MIN = 3000 x ISx_SET2 + 4 (V) For the SOP-8 (Exposed Pad) package, the Sx regulated currents are set by the internal bounding wires and depends on the requests of users. For the WQFN-20L 5x5 package, the regulated currents are easily programmed by users. Parallel and Series Operations For improving the utilization of high-voltage LEDs, the RT7321 is equipped with a proprietary control mechanism which switches the operating mode in either “parallel operation” or “series operation”. Copyright © 2014 Richtek Technology Corporation. All rights reserved. www.richtek.com 6 Figure 3 shows the current paths in parallel operation. In this operation (during t1 to t3 and t6 to t8), an internal MOSFET are turned on to provide a current path from HV to HV1 pins. In this operation, the S1 and S3 regulators is turned on when the input voltage (VHV) is greater than the LED forward voltage (VF) and smaller than 2 x VF (during t1 to t2 and t7 to t8); the S2 and S4 regulators take over the current regulations when the VHV is approximately larger then 2 x VF and smaller than 3 x VF (during t2 to t3 and t6 to t7). The typical regulated currents are calculated by the following equations: IP_S1/2 = I10 + I11 (if I11 = GND) + I12 (if I12 = GND) + I13 (if I13 = GND) IP_S3/4 = I20 + I21 (if I21 = GND) + I22 (if I22 = GND) + I23 (if I23 = GND) VHV HV1 HV IP_S3 VHV HV1 HV IP_S1 S1 S3 S1 S3 IP_S4 S2 S4 GND IP_S2 S2 S4 GND (a) (b) Figure 3. Current Paths in Parallel Operation As the VHV is approximately larger then 3 x VF (during t3 to t6), the series operation is active. Figure 4 shows the current paths in series operation. In this operation, the internal MOSFET is turned off and a built-in high-voltage diode provides a current path from S2 to HV1 pins. In this operation, the S3 regulator is turned on when the VHV is approximately greater than 3 x VF and smaller than 4 x VF (during t3 to t4 and t5 to t6); the S4 regulator takes over is a registered trademark of Richtek Technology Corporation. DS7321-02 July 2014 RT7321 the current regulation when the VHV is approximately larger then 4 x VF (during t4 to t5). The typical regulated currents are calculated by the following equations : IS_S3/4 = IP_S3/4 + I31 (if I31 = GND) + I32 (if I32 = GND) + I33 (if I33 = GND) VHV HV1 VHV HV HV1 HV S1 S3 S1 IS_S3 S3 IS_S4 S2 S4 GND S2 S4 GND (a) (b) Figure 4. Current Paths in Series Operation Thermal Regulation Protection When a LED lamp operates in high ambient temperature conditions, it needs a thermal protection to limit the temperatures for protecting LED lamps and ensuring system reliability. The RT7321 provides a thermal regulation protection, instead of traditional thermal shutdown, to suppress the rise of temperatures. When the IC junction temperature rise above 140°C (typ.), this function starts to gradually reduce the regulated LED current (IS_S3 and IS_S4), depending on the rise of the junction temperature. Meanwhile, the system power dissipation is also reduced. Finally, the temperatures in the system will be well controlled and enter their steadystates. The function can achieve both of the two targets : to protect LED lamps and to prevent them from flicker. Copyright © 2014 Richtek Technology Corporation. All rights reserved. DS7321-02 July 2014 is a registered trademark of Richtek Technology Corporation. www.richtek.com 7 RT7321 Absolute Maximum Ratings (Note 1) HV to GND Voltage, VHV -----------------------------------------------------------------------------------------------HV1 to GND Voltage ----------------------------------------------------------------------------------------------------HV1 to HV Voltage ------------------------------------------------------------------------------------------------------S1, S2 to GND Voltage (at off-state) --------------------------------------------------------------------------------S3, S4 to GND Voltage (at off-state) --------------------------------------------------------------------------------S1, S2, S3, S4 to GND Voltage (at on-state) ---------------------------------------------------------------------I11, I12, I13, I21, I22, I23, I31, I32, I33 to GND Voltage ---------------------------------------------------------Typical Value of Programmed Parallel Current --------------------------------------------------------------------Typical Value of Programmed Series Current ---------------------------------------------------------------------Power Dissipation, PD @ TA = 25°C SOP-8 (Exposed Pad) -------------------------------------------------------------------------------------------------WQFN-20L 5x5 ----------------------------------------------------------------------------------------------------------Package Thermal Resistance (Note 2) SOP-8 (Exposed Pad), θJA --------------------------------------------------------------------------------------------SOP-8 (Exposed Pad), θJC -------------------------------------------------------------------------------------------WQFN-20L 5x5, θJA -----------------------------------------------------------------------------------------------------WQFN-20L 5x5, θJC ----------------------------------------------------------------------------------------------------Junction Temperature ---------------------------------------------------------------------------------------------------Lead Temperature (Soldering, 10 sec.) -----------------------------------------------------------------------------Storage Temperature Range ------------------------------------------------------------------------------------------ESD Susceptibility (Note 3) HBM (Human Body Model), All pins except HV and HV1 -----------------------------------------------------MM (Machine Model) ---------------------------------------------------------------------------------------------------- Recommended Operating Conditions www.richtek.com 8 3.44W 3.54W 29°C/W 2°C/W 28.2°C/W 7.1°C/W 150°C 260°C −65°C to 150°C 2kV 200V (Note 4) HV Supply Voltage, VHV -----------------------------------------------------------------------------------------------S1, S2 Input DC Voltage (at on-state) ------------------------------------------------------------------------------(at off-state) ------------------------------------------------------------------------------S3, S4 Input DC Voltage (at on-state) ------------------------------------------------------------------------------(at off-state) ------------------------------------------------------------------------------Typical Value of Programmed S1, S2 Current --------------------------------------------------------------------Typical Value of Programmed S3, S4 Current --------------------------------------------------------------------Ambient Temperature Range ------------------------------------------------------------------------------------------Junction Temperature Range ------------------------------------------------------------------------------------------- Copyright © 2014 Richtek Technology Corporation. All rights reserved. −0.3V to 500V −0.3V to 500V −0.3V to 300V −0.3V to 450V −0.3V to 300V −0.3V to 150V −0.3V to 5V 35mA 70mA 1V to 400V 1V to 100V 1V to 450V 1V to 100V 1V to 300V 10mA to 30mA 10mA to 50mA −40°C to 85°C −40°C to 125°C is a registered trademark of Richtek Technology Corporation. DS7321-02 July 2014 RT7321 Electrical Characteristics (TA = 25°C, unless otherwise specification) Parameter Symbol Test Conditions Min Typ Max Unit mA Output Current Section I10, I20 VS1, VS2, VS3, or VS4 = 30V, I11 to I33 = Open 9.5 10 10.5 I11 VS1 or VS2 = 30V, I11 = GND, I12 = I13 = Open 4.75 5 5.25 Increment of S1, S2 Regulated I12 Current VS1 or VS2 = 30V, I12 = GND, I11 = I13 = Open 9.5 10 10.5 I13 VS1 or VS2 = 30V, I13 = GND, I11 = I12 = Open 19 20 21 I21 VS3 or VS4 = 30V, I21 = GND, I22 = I23 = Open 4.75 5 5.25 I22 VS3 or VS4 = 30V, I22 = GND, I21 = I23 = Open 9.5 10 10.5 I23 VS3 or VS4 = 30V, I23 = GND, I21 = I22 = Open 19 20 21 I31 VS3 or VS4 = 30V, I31 = GND, I32 = I33 = Open 4.75 5 5.25 I32 VS3 or VS4 = 30V, I32 = GND, I31 = I33 = Open 9.5 10 10.5 I33 VS3 or VS4 = 30V, I33 = GND, I31 = I32 = Open 19 20 21 S1 Leakage Current VS2 = 20V, VS1 = 300V -- -- 300 A S2 Leakage Current VS2 = 300V -- -- 300 A S3 Leakage Current VS4 = 20V, VS3 = 200V -- -- 300 A HV-to-HV1 Current VHV = 5V, VHV1 = 0V 80 -- -- mA S2-to-HV1 Current VS2 = 1.2V, VHV1 = 0V 60 -- -- mA Initial S1 to S4 Regulated Current Increment of S3, S4 Regulated Current mA mA Off-State Leakage Currents Current Capability 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. DS7321-02 July 2014 is a registered trademark of Richtek Technology Corporation. www.richtek.com 9 RT7321 Typical Application Circuit RT7321 X-cap AC RRSE HV 8 1 HV1 MOV 7N391U 2 S3 S1 3 S4 4, GND 9 (Exposed Pad) 7 S2 6 Figure 5. For SOP-8 (Exposed Pad) Package RT7321 X-cap AC 3 MOV 7N391U 7 RRSE 8 12, 21 (Exposed Pad) 9 10 11 13 1 HV1 HV S3 S1 S4 GND S2 19 18 I11 I32 I12 I31 I13 I33 I23 I21 I22 20 17 16 15 14 Figure 6. For WQFN-20L 5x5 Package RT7321 RT7321 HV1 HV HV1 HV S3 S1 S3 S1 S4 S2 S4 S2 GND GND RT7321 X-cap AC MOV 7N391U RRSE RT7321 HV1 HV HV1 HV S3 S1 S3 S1 S4 S2 S4 S2 GND GND Figure 7. 24W to 25W Output Power Application Copyright © 2014 Richtek Technology Corporation. All rights reserved. www.richtek.com 10 is a registered trademark of Richtek Technology Corporation. DS7321-02 July 2014 RT7321 Application Information Thermal Considerations Maximum Power Dissipation (W)1 4.0 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 (Exposed Pad) package, the thermal resistance, θJA, is 29°C/W on a standard JEDEC 51-7 four-layer thermal test board. For WQFN-20L 5x5 package, the thermal resistance, θJA, is 28.2°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 : WQFN-20L 5x5 3.0 2.5 SOP-8 (Exposed Pad) 2.0 1.5 1.0 0.5 0.0 0 25 50 75 100 125 Ambient Temperature (°C) Figure 8. Derating Curve of Maximum Power Dissipation Layout Considerations The thermal resistance θJA of SOP-8 (Exposed Pad) or WQFN-20L 5x5 is determined by the package design and the PCB design. However, the package design had been designed. If possible, it's useful to increase thermal performance by the PCB design. The thermal resistance θJA can be decreased by adding a copper under the exposed pad of SOP-8 (Exposed Pad) or WQFN-20L 5x5 package. The Exposed Pad can be connected the ground or an isolated plane on the PCB. The used current setting pins (I11 to I33) must be directly connect to GND pin with shortest copper paths. Notused current setting pins (I11 to I33) must be kept open. P D(MAX) = (125°C − 25°C) / (29°C/W) = 3.44W for SOP-8 (Exposed Pad) package PD(MAX) = (125°C − 25°C) / (28.2°C/W) = 3.54W for WQFN-20L 5x5 package Four-Layer PCB 3.5 The maximum power dissipation depends on the operating ambient temperature for fixed T J(MAX) and thermal resistance, θJA. The derating curve in Figure 8 allows the designer to see the effect of rising ambient temperature on the maximum power dissipation. Copyright © 2014 Richtek Technology Corporation. All rights reserved. DS7321-02 July 2014 is a registered trademark of Richtek Technology Corporation. www.richtek.com 11 RT7321 Selection Guide of the RT7321 in the SOP-8 (Exposed Pad) Package The S1 to S4 sinking current of the RT7321 in the SOP-8 (Exposed Pad) package depends on the requests of users and set by the internal bounding wires. In the “Parallel operation”, the LED current range can be set from 10mA to 30mA; in the “Series operation”, the LED current range can be set from 10mA to 50mA. The following table shows the selection guide of the RT7321 in the SOP-8 (Exposed Pad) package for the applications with input power from 5W to 8W. Input Power Parallel Current Series Current Ordering Information 5W 10mA 30mA RT7321AEGSP 6W 15mA 35mA RT7321BFGSP 7W 20mA 40mA RT7321CGGSP 8W 20mA 45mA RT7321CHGSP Copyright © 2014 Richtek Technology Corporation. All rights reserved. www.richtek.com 12 is a registered trademark of Richtek Technology Corporation. DS7321-02 July 2014 RT7321 Outline Dimension 1 1 2 2 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. Symbol Dimensions In Millimeters 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 0.250 0.350 0.010 0.014 D 4.900 5.100 0.193 0.201 D2 3.100 3.200 0.122 0.126 E 4.900 5.100 0.193 0.201 E2 3.100 3.200 0.122 0.126 0.650 e L 0.500 0.026 0.600 0.020 0.024 W-Type 20L QFN 5x5 Package Copyright © 2014 Richtek Technology Corporation. All rights reserved. DS7321-02 July 2014 is a registered trademark of Richtek Technology Corporation. www.richtek.com 13 RT7321 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 14 DS7321-02 July 2014