® RT8299 3A, 24V, 500kHz Synchronous Step-Down Converter General Description Features The RT8299 is a high efficiency, monolithic synchronous step-down DC/DC converter with internal power MOSFETs. It achieves 3A of continuous output current over a wide input supply range from 3V to 24V with excellent load and line regulation. Current mode operation provides fast transient response and eases loop stabilization. Cycleby-cycle current limit provides protection against shorted outputs and soft-start eliminates input current surge during start-up. Thermal shutdown provides reliable, fault tolerant operation. The low current shutdown mode provides output disconnection, enabling easy power management in battery powered systems. 3V to 24V Input Voltage Range 3A Output Current Internal N-MOSFETs Current Mode Control Fixed Frequency Operation : 500kHz Output Adjustable from 0.8V to 15V Up to 95% Efficiency Stable with Low ESR Ceramic Output Capacitors Cycle-by-Cycle Over Current Protection Input Under Voltage Lockout Output Under Voltage Protection Thermal Shutdown Protection SOP-8 (Exposed Pad) and 10-Lead WDFN Packages RoHS Compliant and Halogen Free Ordering Information RT8299 Package Type SP : SOP-8 (Exposed Pad-Option 1) QW: WDFN-10L 3x3 (W-Type) Lead Plating System G : Green (Halogen Free and Pb Free) Z : ECO (Ecological Element with Halogen Free and Pb free) Note : Richtek products are : RoHS compliant and compatible with the current require- Applications Industrial and Commercial Low Power Systems Computer Peripherals LCD Monitors and TVs Green Electronics/Appliances Point of Load Regulation for High Performance DSPs, FPGAs, and ASICs Pin Configurations (TOP VIEW) ments of IPC/JEDEC J-STD-020. Suitable for use in SnPb or Pb-free soldering processes. BOOT VIN 2 SW 3 GND 4 GND 8 VCC 7 PGOOD 6 EN 5 FB 9 FB PGOOD EN VCC BOOT 1 2 3 4 5 GND SOP-8 (Exposed Pad) 11 10 9 8 7 6 GND SW SW VIN VIN WDFN-10L 3x3 Copyright © 2014 Richtek Technology Corporation. All rights reserved. DS8299-04 October 2014 is a registered trademark of Richtek Technology Corporation. www.richtek.com 1 RT8299 Marking Information RT8299GSP RT8299GQW RT8299GSP : Product Number RT8299 GSPYMDNN 56= : Product Number YMDNN : Date Code YMDNN : Date Code 56=YM DNN RT8299ZSP RT8299ZQW RT8299ZSP : Product Number RT8299 ZSPYMDNN 56 : Product Number YMDNN : Date Code YMDNN : Date Code 56 YM DNN Typical Application Circuit RT8299 VIN CIN 10µF x 2 VIN BOOT CBOOT L1 Chip Enable SW EN VCC CVCC 1µF GND VOUT R1 RT FB PGODD COUT R2 Power Good Table 1. Recommended Component Selection VOUT (V) 1.2 R1 (k) R2 (k) RT (k) 15 30 50 2.5 25.5 12 40 3.6 22 x 2 3.3 16 5.1 30 4.7 22 x 2 5 27 5.1 18 6.8 22 x 2 Copyright © 2014 Richtek Technology Corporation. All rights reserved. www.richtek.com 2 L (H) COUT (F) 2 22 x 2 is a registered trademark of Richtek Technology Corporation. DS8299-04 October 2014 RT8299 Functional Pin Description Pin No. SOP-8 WDFN-10L 3x3 (Exposed Pad) 1 5 2 6, 7 3 4, 9 (Exposed Pad) Pin Name Pin Function Bootstrap for High Side Gate Driver. Connect a 0.1F or greater ceramic capacitor from BOOT to SW pin. Supply Input Voltage. Must bypass with a suitably large ceramic capacitor. Switch Node. Connect to external LC filter. Ground. The exposed pad must be soldered to a large PCB and connected to GND for maximum power dissipation. BOOT VIN 8, 9 SW 10, 11 GND (Exposed Pad) 5 1 FB 6 3 EN 7 2 PGOOD Feedback Input. This pin is connected to the converter output. It is used to regulate the output of the converter to a desired value via an internal resistive voltage divider. For an adjustable output, an external resistive voltage divider is connected to this pin. Enable Input. A logic high enables the converter; a logic low forces the RT8299 into shutdown mode, reducing the supply current to less than 3A. Attach this pin to VIN with a 100k pull up resistor for automatic startup. Power Good Output. The output of this pin is open drain. 8 4 VCC Bias Supply. Function Block Diagram VIN EN Comparator Regulator + 5k 3V Current Sense Amplifier - Ramp Generator + BOOT Oscillator 500kHz 2V VCC FB PGOOD - + Error Amplifier PGOOD Generator 300k 30pF 1pF Copyright © 2014 Richtek Technology Corporation. All rights reserved. DS8299-04 October 2014 Q R Q Driver + Reference S PWM Comparator SW OC Limit Clamp GND is a registered trademark of Richtek Technology Corporation. www.richtek.com 3 RT8299 Absolute Maximum Ratings (Note 1) Supply Input Voltage, VIN ---------------------------------------------------------------------------------- −0.3 to 26V Switching Voltage, SW ------------------------------------------------------------------------------------ −0.6 to (VIN + 0.3V) < 20ns ---------------------------------------------------------------------------------------------------------- −5V to 30V Boot Voltage, BOOT ---------------------------------------------------------------------------------------- (VSW − 0.3V) to (VSW + 6V) All Other Pins ------------------------------------------------------------------------------------------------ −0.3 to 6V Power Dissipation, PD @ TA = 25°C SOP-8 (Exposed Pad) ------------------------------------------------------------------------------------- 1.333W WDFN-10L 3x3 ----------------------------------------------------------------------------------------------- 1.429W Package Thermal Resistance (Note 2) SOP-8 (Exposed Pad), θJA -------------------------------------------------------------------------------- 75°C/W SOP-8 (Exposed Pad), θJC ------------------------------------------------------------------------------- 15°C/W WDFN-10L 3x3, θJA ----------------------------------------------------------------------------------------- 70°C/W WDFN-10L 3x3, θJC ----------------------------------------------------------------------------------------- 8.2°C/W Lead Temperature (Soldering, 10 sec.) ----------------------------------------------------------------- 260°C Junction Temperature -------------------------------------------------------------------------------------- 150°C Storage Temperature Range ------------------------------------------------------------------------------ −65°C to 150°C ESD Susceptibility (Note 3) HBM (Human Body Model) --------------------------------------------------------------------------------- 2kV MM (Machine Model) ---------------------------------------------------------------------------------------- 200V Recommended Operating Conditions (Note 4) Supply Voltage, VIN ----------------------------------------------------------------------------------------- 3V to 24V Junction Temperature Range ------------------------------------------------------------------------------ −40°C to 125°C Ambient Temperature Range ------------------------------------------------------------------------------ 40°C to 85°C Electrical Characteristics (VIN = 12V, TA = 25°C, unless otherwise specified) Parameter Shutdown Current Symbol Min -- Typ -- Max 3 Unit A -- 1 -- mA Upper Switch On Resistance -- 100 -- m Lower Switch On Resistance -- 100 -- m V EN = 0V, VSW = 0V or 12V -- 0 10 A -- 5.5 -- A 425 500 575 kHz -- 150 -- kHz I SHDN Supply Current Test Conditions V EN = 0V V EN = 3V, VFB = 1V Switch Leakage Current Limit I LIM V BOOT VSW = 4.8V Oscillator Frequency f OSC V FB = 0.75V Short Circuit Frequency V FB = 0V Maximum Duty Cycle DMAX Minimum On-Time t ON Feedback Voltage VFB Logic-High EN Input Threshold Voltage Logic-Low V FB = 0.8V -- 93 -- % -- 100 -- ns 788 800 812 mV VIH 2 -- 5.5 VIL -- -- 0.4 4.5V VIN 24V Copyright © 2014 Richtek Technology Corporation. All rights reserved. www.richtek.com 4 V is a registered trademark of Richtek Technology Corporation. DS8299-04 October 2014 RT8299 Parameter Under Voltage Lockout Threshold Under Voltage Lockout Threshold Hysteresis Symbol VUVLO Test Conditions Min Typ Max Unit -- 2.8 -- V -- 300 -- mV VOUT Rising, with Respect to VFB -- 90 -- VOUT Falling, with Respect to VFB -- 70 -- -- 5 -- V 4 -- 4 % VIN Rising VUVLO Power Good Threshold VCC Regulator VCC Load Regulation ICC = 5mA % Soft-Start Period tSS -- 2 -- ms Thermal Shutdown TSD -- 150 -- C 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. DS8299-04 October 2014 is a registered trademark of Richtek Technology Corporation. www.richtek.com 5 RT8299 Typical Operating Characteristics Efficiency vs. Output Current Reference Voltage vs. Input Voltage 100 0.820 90 0.815 Reference Voltage (V) Efficiency (%) 80 70 VIN VIN VIN VIN VIN VIN 60 50 40 30 = = = = = = 5V, VOUT = 3.3V 12V, VOUT = 3.3V 23V, VOUT = 3.3V 5V, VOUT = 1.2V 3V, VOUT = 1.2V 12V, VOUT = 1.2V 20 0.810 0.805 0.800 0.795 0.790 10 0.785 0 0.780 VOUT = 3.3V, IOUT = 0A 0 0.5 1 1.5 2 2.5 3 4 6 8 10 Output Current (A) 14 16 18 20 22 24 Input Voltage (V) Output Voltage vs. Output Current Reference Voltage vs. Temperature 0.820 3.360 0.815 3.355 0.810 3.350 Output Voltage (V) Reference Voltage (V) 12 0.805 0.800 0.795 0.790 0.785 3.345 3.340 3.335 3.330 VIN = 5V VIN = 12V VIN = 23V 3.325 VIN = 12V, VOUT = 3.3V VOUT = 3.3V 0.780 3.320 -50 -25 0 25 50 75 100 125 0 0.3 0.6 Temperature (°C) 0.9 1.2 1.5 1.8 2.1 2.4 2.7 3 Output Current (A) Frequency vs. Input Voltage Output Voltage vs. Output Current 570 1.240 560 1.235 Frequency (kHz)1 Output Voltage (V) 550 1.230 1.225 1.220 1.215 VIN VIN VIN VIN 1.210 1.205 VOUT = 1.2V = 3V = 5VV = 4.5V = 12V 540 530 520 510 500 490 480 VOUT = 1.2V, IOUT = 0.5A 470 1.200 0 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7 Output Current (A) Copyright © 2014 Richtek Technology Corporation. All rights reserved. www.richtek.com 6 3 3 5 7 9 11 13 15 17 19 21 23 Input Voltage (V) is a registered trademark of Richtek Technology Corporation. DS8299-04 October 2014 RT8299 Frequency vs. Temperature Current Limit vs. Temperature 570 8 560 7 540 Current Limit (A) Frequency (kHz)1 550 530 520 510 500 VIN VIN VIN VIN 490 480 = 23V = 12VV = 5V = 3V 6 5 VIN = 12V VIN = 5VV VIN = 3V 4 3 VOUT = 1.2V, IOUT = 0.5A 470 VOUT = 1.2V 2 -50 -25 0 25 50 75 100 125 -50 0 25 50 75 100 Temperature (°C) Load Transient Response Load Transient Response VOUT (100mV/Div) VOUT (100mV/Div) IOUT (2A/Div) IOUT (2A/Div) Time (100μs/Div) Time (100μs/Div) Switching Switching VOUT (5mV/Div) VOUT (5mV/Div) VSW (10V/Div) VSW (10V/Div) IL (2A/Div) IL (2A/Div) VIN = 12V, VOUT = 1.2V, IOUT = 3A Time (1μs/Div) Copyright © 2014 Richtek Technology Corporation. All rights reserved. October 2014 125 VIN = 12V, VOUT = 1.2V, IOUT = 1.5A to 3A VIN = 12V, VOUT = 1.2V, IOUT = 0A to 3A DS8299-04 -25 Temperature (°C) VIN = 12V, VOUT = 1.2V, IOUT = 1.5A Time (1μs/Div) is a registered trademark of Richtek Technology Corporation. www.richtek.com 7 RT8299 Power On from VIN Power Off from VIN VIN (10V/Div) VIN (10V/Div) VOUT (1V/Div) VOUT (1V/Div) IL (2A/Div) IL (2A/Div) VIN = 12V, VOUT =1.2V, IOUT = 3A Time (2.5ms/Div) Time (2.5ms/Div) Power On from EN Power Off from EN VEN (5V/Div) VEN (5V/Div) VOUT (1V/Div) VOUT (1V/Div) IL (2A/Div) IL (2A/Div) VIN = 12V, VOUT = 1.2V, IOUT = 3A Time (2.5ms/Div) Copyright © 2014 Richtek Technology Corporation. All rights reserved. www.richtek.com 8 VIN = 12V, VOUT = 1.2V, IOUT = 3A VIN = 12V, VOUT = 1.2V, IOUT = 3A Time (2.5ms/Div) is a registered trademark of Richtek Technology Corporation. DS8299-04 October 2014 RT8299 Application Information The RT8299 is a synchronous high voltage buck converter that can support the input voltage range from 3V to 24V and the output current can be up to 3A. Output Voltage Setting The resistive divider allows the FB pin to sense the output voltage as shown in Figure 1. VOUT R1 FB RT8299 R2 GND Figure 1. Output Voltage Setting Chip Enable Operation The EN pin is the chip enable input. Pulling the EN pin low (<0.4V) will shutdown the device. During shutdown mode, the RT8299 quiescent current drops to lower than 3μA. Driving the EN pin high (>2V, < 5.5V) will turn on the device again. For external timing control (e.g.RC), the EN pin can also be externally pulled high by adding a REN* resistor and CEN* capacitor from the VIN pin (see Figure 5). An external MOSFET can be added to implement digital control on the EN pin when no system voltage above 2.5V is available, as shown in Figure 3. In this case, a 100kΩ pull-up resistor, REN, is connected between VIN and the EN pin. MOSFET Q1 will be under logic control to pull down the EN pin. The output voltage is set by an external resistive voltage divider according to the following equation : VOUT = VFB 1 R1 R2 BOOT VIN VIN REN 100k CIN Chip Enable SW EN R1 Q1 GND External Bootstrap Diode It is recommended to add an external bootstrap diode between an external 5V and BOOT pin for efficiency improvement when input voltage is lower than 5.5V or duty ratio is higher than 65% .The bootstrap diode can be a low cost one such as IN4148 or BAT54. The external 5V can be a 5V fixed input from system or a 5V output of the RT8299. Note that the external boot voltage must be lower than 5.5V 5V R2 VCC VIN 12V BOOT VIN CIN 10µF RT8299 0.1µF Figure 2. External Bootstrap Diode Copyright © 2014 Richtek Technology Corporation. All rights reserved. VOUT 8V CBOOT L SW R1 REN2 SW October 2014 R 100k To prevent enabling circuit when VIN is smaller than the VOUT target value, a resistive voltage divider can be placed between the input voltage and ground and connected to the EN pin to adjust IC lockout threshold, as shown in Figure 4. For example, if an 8V output voltage is regulated from a 12V input voltage, the resistor REN2 can be selected to set input lockout threshold larger than 8V. EN RT8299 PGOOD Figure 3. Enable Control Circuit for Logic Control with Low Voltage REN 100k BOOT COUT FB VCC C Connect a 100nF low ESR ceramic capacitor between the BOOT pin and SW pin. This capacitor provides the gate driver voltage for the high side MOSFET. VOUT L where VFB is the feedback reference voltage (0.8V typ.). DS8299-04 CBOOT RT8299 VCC C GND FB PGOOD R 100k VCC COUT R2 Figure 4. The Resistors can be Selected to Set IC Lockout Threshold is a registered trademark of Richtek Technology Corporation. www.richtek.com 9 RT8299 Under Voltage Protection CIN and COUT Selection Hiccup Mode For the RT8299, it provides Hiccup Mode Under Voltage Protection (UVP). When the FB voltage drops below half of the feedback reference voltage, VFB, the UVP function will be triggered and the RT8299 will shut down for a period of time and then recover automatically. The Hiccup Mode UVP can reduce input current in short-circuit conditions. Inductor Selection The inductor value and operating frequency determine the ripple current according to a specific input and output voltage. The ripple current ΔIL increases with higher VIN and decreases with higher inductance. V V IL = OUT 1 OUT f L VIN Having a lower ripple current reduces not only the ESR losses in the output capacitors but also the output voltage ripple. High frequency with small ripple current can achieve highest efficiency operation. However, it requires a large inductor to achieve this goal. For the ripple current selection, the value of ΔIL = 0.24(IMAX) will be a reasonable starting point. The largest ripple current occurs at the highest VIN. To guarantee that the ripple current stays below the specified maximum, the inductor value should be chosen according to the following equation : VOUT VOUT L = 1 VIN(MAX) f I L(MAX) V IRMS = IOUT(MAX) OUT VIN VIN 1 VOUT This formula has a maximum at VIN = 2VOUT, where IRMS = IOUT / 2. This simple worst case condition is commonly used for design because even significant deviations do not offer much relief. Choose a capacitor rated at a higher temperature than required. Several capacitors may also be paralleled to meet size or height requirements in the design. For the input capacitor, two 10μF low ESR ceramic capacitors are recommended. The selection of COUT is determined by the required ESR to minimize voltage ripple. Moreover, the amount of bulk capacitance is also a key for COUT selection to ensure that the control loop is stable. Loop stability can be checked by viewing the load transient response as described in a later section. The output ripple, ΔVOUT , is determined by : 1 VOUT IL ESR 8fCOUT The output ripple will be highest at the maximum input The inductor's current rating (caused a 40°C temperature rising from 25°C ambient) should be greater than the maximum load current and its saturation current should be greater than the short circuit peak current limit. Please see Table 2 for the inductor selection reference. Table 2. Suggested Inductors for Typical Application Circuit Component Supplier Series Dimensions (mm) TDK VLF10045 10 x 9.7 x 4.5 TDK TAIYO YUDEN SLF12565 12.5 x 12.5 x 6.5 NR8040 8x8x4 Copyright © 2014 Richtek Technology Corporation. All rights reserved. www.richtek.com 10 The input capacitance, C IN, is needed to filter the trapezoidal current at the source of the high side MOSFET. To prevent large ripple current, a low ESR input capacitor sized for the maximum RMS current should be used. The RMS current is given by : voltage since ΔIL increases with input voltage. Multiple capacitors placed in parallel may be needed to meet the ESR and RMS current handling requirement. Dry tantalum, special polymer, aluminum electrolytic and ceramic capacitors are all available in surface mount packages. Special polymer capacitors offer very low ESR value. However, it provides lower capacitance density than other types. Although Tantalum capacitors have the highest capacitance density, it is important to only use types that pass the surge test for use in switching power supplies. Aluminum electrolytic capacitors have significantly higher ESR. However, it can be used in cost-sensitive applications is a registered trademark of Richtek Technology Corporation. DS8299-04 October 2014 RT8299 for ripple current rating and long term reliability considerations. Ceramic capacitors have excellent low ESR characteristics but can have a high voltage coefficient and audible piezoelectric effects. The high Q of ceramic capacitors with trace inductance can also lead to significant ringing. a load step occurs, VOUT immediately shifts by an amount equal to ΔILOAD (ESR) also begins to charge or discharge COUT generating a feedback error signal for the regulator to return VOUT to its steady-state value. During this recovery time, VOUT can be monitored for overshoot or ringing that would indicate a stability problem. Higher values, lower cost ceramic capacitors are now becoming available in smaller case sizes. Their high ripple current, high voltage rating and low ESR make them ideal for switching regulator applications. However, care must be taken when these capacitors are used at input and output. When a ceramic capacitor is used at the input and the power is supplied by a wall adapter through long wires, a load step at the output can induce ringing at the input, VIN. At best, this ringing can couple to the output and be mistaken as loop instability. At worst, a sudden inrush of current through the long wires can potentially cause a voltage spike at VIN large enough to damage the part. EMI Consideration Since parasitic inductance and capacitance effects in PCB circuitry would cause a spike voltage on SW pin when high side MOSFET is turned-on/off, this spike voltage on SW may impact on EMI performance in the system. In order to enhance EMI performance, there are two methods to suppress the spike voltage. One is to place an R-C snubber between SW and GND and make them as close as possible to the SW pin (see Figure 5). Another method is adding a resistor RBOOT* in series with the bootstrap capacitor, CBOOT. But this method will decrease the driving capability to the high side MOSFET. It is strongly recommended to reserve the R-C snubber during PCB layout for EMI improvement. Moreover, reducing the SW trace area and keeping the main power in a small loop will be helpful on EMI performance. For detailed PCB layout guide, please refer to the section of Layout Consideration. Checking Transient Response The regulator loop response can be checked by looking at the load transient response. Switching regulators take several cycles to respond to a step in load current. When RBOOT* VIN REN* CIN 10µF x 2 BOOT VIN CBOOT L RT8299 SW VOUT EN RS* CEN* R1 CS* VCC FB GND PGOOD C R 100k COUT R2 VCC * : Optional Figure 5. Reference Circuit with Snubber and Enable Timing Control Copyright © 2014 Richtek Technology Corporation. All rights reserved. DS8299-04 October 2014 is a registered trademark of Richtek Technology Corporation. www.richtek.com 11 RT8299 Maximum Power Dissipation (W)1 Thermal Considerations For continuous operation, do not exceed the maximum operation junction temperature 125°C. The maximum power dissipation depends on the thermal resistance of IC package, PCB layout, the rate of surroundings airflow and temperature difference between junction to ambient. The maximum power dissipation can be calculated by following formula : PD(MAX) = (TJ(MAX) − TA ) / θJA Where T J(MAX) is the maximum operation junction temperature , TA is the ambient temperature and the 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 75°C/W on a standard JEDEC 51-7 four-layer thermal test board. For WDFN-10L 3x3 packageS, the thermal resistance, θJA, is 70°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 formulas : PD(MAX) = (125°C − 25°C) / (75°C/W) = 1.333W for SOP-8 (Exposed Pad) package PD(MAX) = (125°C − 25°C) / (70°C/W) = 1.429W for WDFN-10L 3x3 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 6 allow the designer to see the effect of rising ambient temperature on the maximum power dissipation. Copyright © 2014 Richtek Technology Corporation. All rights reserved. www.richtek.com 12 1.5 1.4 1.3 1.2 1.1 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 Four-Layer PCB WDFN-10L 3x3 SOP-8 (Exposed Pad) 0 25 50 75 100 125 Ambient Temperature (°C) Figure 6. Derating Curve of Maximum Power Dissipation Layout Consideration Follow the PCB layout guidelines for optimal performance of the RT8299. Keep the traces of the main current paths as short and wide as possible. Put the input capacitor as close as possible to the device pins (VIN and GND). SW node is with high frequency voltage swing and should be kept at small area. Keep analog components away from the SW node to prevent stray capacitive noise pickup. Connect feedback network behind the output capacitors. Keep the loop area small. Place the feedback components near the RT8299. An example of PCB layout guide is shown in Figure 6 for reference. is a registered trademark of Richtek Technology Corporation. DS8299-04 October 2014 RT8299 The CVCC component must be connected as close to the device as possible. GND Input capacitor must be placed as close to the IC as possible. VIN SW GND CVCC CIN BOOT VOUT CS* VIN 2 SW 3 GND 4 GND 8 VCC 7 PGOOD 6 EN 5 FB 9 RS* RPG REN R1 R2 VOUT VCC VIN The REN component must be connected to VIN. COUT SW should be connected to inductor by wide and short trace. Keep sensitive components away from this trace. GND The feedback components must be connected as close to the device as possible. Figure 7. PCB Layout Guide Copyright © 2014 Richtek Technology Corporation. All rights reserved. DS8299-04 October 2014 is a registered trademark of Richtek Technology Corporation. www.richtek.com 13 RT8299 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 Copyright © 2014 Richtek Technology Corporation. All rights reserved. www.richtek.com 14 is a registered trademark of Richtek Technology Corporation. DS8299-04 October 2014 RT8299 D2 D L E E2 1 e SEE DETAIL A b 2 1 2 1 A A1 A3 DETAIL A Pin #1 ID and Tie Bar Mark Options Note : The configuration of the Pin #1 identifier is optional, but must be located within the zone indicated. Dimensions In Millimeters 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 2.950 3.050 0.116 0.120 D2 2.300 2.650 0.091 0.104 E 2.950 3.050 0.116 0.120 E2 1.500 1.750 0.059 0.069 e L 0.500 0.350 0.020 0.450 0.014 0.018 W-Type 10L DFN 3x3 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. DS8299-04 October 2014 www.richtek.com 15