RT8008 1.5MHz, 600mA, High Efficiency PWM Step-Down DC/DC Converter General Description Features The RT8008 is a high-efficiency pulse-width-modulated (PWM) step-down DC/DC converter. Capable of delivering 600mA output current over a wide input voltage range from 2.5V to 5.5V, the RT8008 is ideally suited for portable electronic devices that are powered from 1-cell Li-ion battery or from other power sources within the range such as cellular phones, PDAs and handy-terminals. z 2.5V to 5.5V Input Range z Adjustable Output From 0.6V to VIN 1.0V, 1.2V, 1.5V, 1.8V, 2.5V and 3.3V Fixed/ Adjustable Output Voltage 600mA Output Current, 1A Peak Current 95% Efficiency No Schottky Diode Required 1.5MHz Fixed Frequency PWM Operation Small SOT-23-5 and TSOT-23-5 Package RoHS Compliant and 100% Lead (Pb)-Free Internal synchronous rectifier with low RDS(ON) dramatically reduces conduction loss at PWM mode. No external Schottky diode is required in practical application. The RT8008 automatically turns off the synchronous rectifier while the inductor current is low and enters discontinuous PWM mode. This can increase efficiency at light load condition. The RT8008 enters Low-Dropout mode when normal PWM cannot provide regulated output voltage by continuously turning on the upper P-MOSFET. RT8008 enter shutdown mode and consumes less than 0.1μA when EN pin is pulled low. z z z z z z z Applications z z z z z Cellular Telephones Personal Information Appliances Wireless and DSL Modems MP3 Players Portable Instruments Ordering Information RT8008(- Package Type B : SOT-23-5 J5 : TSOT-23-5 The switching ripple is easily smoothed-out by small package filtering elements due to a fixed operation frequency of 1.5MHz. This along with small SOT-23-5 and TSOT-23-5 package provides small PCB area application. Other features include soft start, lower internal reference voltage with 2% accuracy, over temperature protection, and over current protection. Lead Plating System P : Pb Free G : Green (Halogen Free and Pb Free) Output Voltage Default : Adjustable 10 : 1.0V 12 : 1.2V 15 : 1.5V 18 : 1.8V 25 : 2.5V 33 : 3.3V Pin Configurations (TOP VIEW) FB/VOUT VIN 5 ) 4 2 3 EN GND LX Note : Richtek products are : ` SOT-23-5/TSOT-23-5 Marking Information RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020. ` Suitable for use in SnPb or Pb-free soldering processes. For marking information, contact our sales representative directly or through a Richtek distributor located in your area. DS8008-07 March 2011 www.richtek.com 1 RT8008 Typical Application Circuit 4 VIN 2.2V to 5.5V VIN CIN 4.7µF 3 LX L 2.2µH VOUT RT8008 1 EN COUT 5 VOUT 10µF GND 2 Figure 1. Fixed Voltage Regulator 4 VIN 2.2V to 5.5V LX 1 EN FB GND 2 R1 ⎞ ⎛ = V REF x ⎜ 1 + ⎟ R2 ⎠ ⎝ 3 VOUT C1 RT8008 4.7µF V OUT VIN CIN L 2.2µH R1 COUT 5 10µF IR2 R2 with R2 = 300kΩ to 60kΩ so the IR2 = 2μA to 10μA, and (R1 x C1) should be in the range between 3x10-6 and 6x10-6 for component selection. Figure 2. Adjustable Voltage Regulator Layout Guide VIN CIN VIN 4 GND COUT 3 LX 2 GND 1 EN VIN VOUT L CIN VIN 4 GND COUT 3 LX 2 GND 1 EN VOUT L C1 VOUT 5 FB R1 VOUT GND 5 R2 GND Figure 3 Layout note: 1. The distance that CIN connects to VIN is as close as possible (Under 2mm). 2. COUT should be placed near RT8008. www.richtek.com 2 DS8008-07 March 2011 RT8008 Functional Pin Description Pin Number 1 2 3 4 5 Pin Name Pin Function EN GND LX VIN FB/VOUT Chip Enable (Active High, do not leave EN pin floating, and VEN < VIN + 0.6V). Ground. Pin for Switching. Power Input. Feedback Input Pin. Function Block Diagram VIN EN RS1 OSC & Shutdown Control Slope Compensation FB/VOUT Error Amplifier Current Limit Detector Current Sense Control Logic PWM Comparator Driver LX RC COMP UVLO & Power Good Detector Zero Detector RS2 VREF GND DS8008-07 March 2011 www.richtek.com 3 RT8008 Absolute Maximum Ratings (Note 1) Supply Input Voltage -----------------------------------------------------------------------------------------------------Enable, FB Voltage ------------------------------------------------------------------------------------------------------Power Dissipation, PD @ TA = 25°C SOT-23-5, TSOT-23-5 ----------------------------------------------------------------------------------------------------Package Thermal Resistance (Note 2) SOT-23-5, TSOT-23-5, θJA ----------------------------------------------------------------------------------------------SOT-23-5, TSOT-23-5, θJC ----------------------------------------------------------------------------------------------Junction Temperature Range -------------------------------------------------------------------------------------------Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------------Storage Temperature Range -------------------------------------------------------------------------------------------ESD Susceptibility (Note 3) HBM (Human Body Mode) ---------------------------------------------------------------------------------------------MM (Machine Mode) ------------------------------------------------------------------------------------------------------ Recommended Operating Conditions 6.5V VIN + 0.6V 0.4W 250°C/W 130°C/W 150°C 260°C −65°C to 150°C 2kV 200V (Note 4) Supply Input Voltage ------------------------------------------------------------------------------------------------------ 2.5V to 5.5V Junction Temperature Range -------------------------------------------------------------------------------------------- −40°C to 125°C Ambient Temperature Range -------------------------------------------------------------------------------------------- −40°C to 85°C Electrical Characteristics (VIN = 3.6V, VOUT = 2.5V, VREF = 0.6V, L = 2.2μH, CIN = 4.7μF, COUT = 10μF, TA = 25°C, IMAX = 600mA unless otherwise specified) Parameter Symbol Test Conditions Min Typ Max Unit 2.5 -- 5.5 V Input Voltage Range VIN Quiescent Current IQ IOUT = 0mA, VFB = VREF + 5% -- 50 100 μA Shutdown Current I SHDN EN = GND -- 0.1 1 μA Reference Voltage VREF For adjustable output voltage 0.588 0.6 0.612 V Adjustable Output Range VOUT VREF -- VIN − 0.2 V −3 -- 3 % −3 -- 3 % −3 -- 3 % −3 -- 3 % ΔVOUT ΔVOUT ΔVOUT Fix Output Voltage Accuracy ΔVOUT VIN = 2.2 to 5.5V, VOUT = 1.0V 0A < IOUT < 600mA VIN = 2.2 to 5.5V, VOUT = 1.2V 0A < IOUT < 600mA VIN = 2.2 to 5.5V, VOUT = 1.5V 0A < IOUT < 600mA VIN = 2.2 to 5.5V, VOUT = 1.8V 0A < IOUT < 600mA ΔVOUT VIN = 2.8 to 5.5V, VOUT = 2.5V 0A < IOUT < 600mA −3 -- 3 % ΔVOUT VIN = 3.5 to 5.5V, VOUT = 3.3V 0A < IOUT < 600mA −3 -- 3 % −3 -- 3 % −3 -- 3 % VIN = VOUT + 0.2V to 5.5V, VIN ≧ 3.5V Adjustable ΔVOUT 0A < IOUT < 600mA VIN = VOUT + 0.4V to 5.5V, VIN ≧ 2.2V 0A < IOUT < 600mA To be continued www.richtek.com 4 DS8008-07 March 2011 RT8008 Parameter Symbol Test Conditions Min Typ Max Unit −50 -- 50 nA VIN = 3.6V -- 0.3 -- VIN = 2.5V -- 0.4 -- VIN = 3.6V -- 0.25 -- VIN = 2.5V -- 0.35 -- FB Input Current IFB PMOSFET RON PRDS(ON) I OUT = 200mA NMOSFET RON NRDS(ON) I OUT = 200mA P-Channel Current Limit IP(LM) VIN = 2.5V to 5.5 V 1 -- 1.8 A EN High-Level Input Voltage VENH VIN = 2.5V to 5.5V 1.5 -- -- V EN Low-Level Input Voltage VENL VIN = 2.5V to 5.5V -- -- 0.4 V Under Voltage Lockout Threshold -- 1.8 -- V Hysteresis -- 0.1 -- V 1.2 1.5 1.8 MHz -- 160 -- °C -- 50 -- ns 100 -- -- % −1 -- 1 μA Oscillator Frequency fOSC Thermal Shutdown Temperature TSD VFB = VIN VIN = 3.6V, I OUT = 100mA Min. On Time Max. Duty Cycle LX Leakage Current VIN = 3.6V, VLX = 0V or VLX = 3.6V Ω Ω 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 low effective single layer thermal conductivity test board of JEDEC 51-3 thermal measurement standard. Pin 2 of SOT-23-5/TSOT-23-5 packages is the case position for θJC measurement. Note 3. Devices are ESD sensitive. Handling precaution recommended. Note 4. The device is not guaranteed to function outside its operating conditions. DS8008-07 March 2011 www.richtek.com 5 RT8008 Typical Operating Characteristics Efficiency vs. Input Voltage Efficiency vs. Load Current 100 100 VIN = 3.3V 90 80 Efficiency (%) Efficiency (%) 90 VIN = 5V 70 60 IOUT = 300mA 80 IOUT = 600mA 70 60 50 50 VOUT = 1.2V VOUT = 1.2V 40 0.01 0.11 0.21 0.31 0.41 0.51 40 2.5 0.61 3 3.5 4 4.5 5 5.5 Input Voltage (V) Load Current (A) Output Voltage vs. Load Current Current Limit vs. Input Voltage 2.5 1.220 2.0 1.210 VIN = 3.3V VIN = 5V 1.205 1.200 VIN = 2.5V 1.195 1.190 Current Limit (A) Output Voltage (V) 1.215 1.5 1.0 0.5 1.185 VOUT = 1.2V VOUT = 1.2V 0.0 1.180 0 0.1 0.2 0.3 0.4 0.5 2.5 0.6 3 3.5 4.5 5 5.5 Frequency vs. Temperature Frequency vs. Input Voltage 1.50 1.50 1.48 1.48 Frequency (MHz) Frequency (MHz) 4 Input Voltage (V) Load Current (A) 1.45 1.43 1.40 VOUT = 1.2V, IOUT = 300mA 1.45 1.43 1.40 1.38 1.38 VOUT = 1.2V, IOUT = 300mA 1.35 2.5 3 3.5 4 4.5 Input Voltage (V) www.richtek.com 6 5 5.5 1.35 -50 -25 0 25 50 75 100 125 Temperature (°C) DS8008-07 March 2011 RT8008 Output Voltage vs. Temperature Reference Voltage vs. Input Voltage 1.25 1.23 0.6005 Output Voltage (V) Reference Voltage (V) 0.6010 0.6000 0.5995 1.21 1.19 1.17 VOUT = 1.2V VIN = 3.3V, IOUT = 0A 1.15 0.5990 2.5 3 3.5 4 4.5 5 -50 5.5 -25 0 25 50 75 100 Input Voltage (V) Temperature (°C) Load Transient Response Load Transient Response VIN = 3.3V, VOUT = 1.2V, IOUT = 200mA to 600mA 125 VIN = 3.3V, VOUT = 1.2V, IOUT = 300mA to 600mA VOUT (20mV/Div) VOUT (20mV/Div) IOUT (500mA/Div) IOUT (500mA/Div) Time (50μs/Div) Time (50μs/Div) Output Ripple Power On VIN = 3.3V, VOUT = 1.2V, IOUT = 600mA VIN = 3.3V, VOUT = 1.2V, IOUT = 600mA VOUT (5mV/Div) VEN (2V/Div) VLX (5V/Div) VOUT (500mV/Div) I IN (200mA/Div) ILX (500mA/Div) Time (500ns/Div) DS8008-07 March 2011 Time (100μs/Div) www.richtek.com 7 RT8008 Power Off VIN = 3.3V, VOUT = 1.2V, IOUT = 600mA VEN (2V/Div) VOUT (500mV/Div) I IN (200mA/Div) Time (100μs/Div) www.richtek.com 8 DS8008-07 March 2011 RT8008 Applications Information The basic RT8008 application circuit is shown in Typical Application Circuit. External component selection is determined by the maximum load current and begins with the selection of the inductor value and operating frequency followed by CIN and COUT. Inductor Selection For a given input and output voltage, the inductor value and operating frequency determine the ripple current. The ripple current ΔIL increases with higher VIN and decreases with higher inductance. ⎡V ⎤⎡ V ⎤ ΔIL = ⎢ OUT ⎥ ⎢1 − OUT ⎥ VIN ⎦ ⎣ f × L ⎦⎣ Having a lower ripple current reduces the ESR losses in the output capacitors and the output voltage ripple. Highest efficiency operation is achieved at low frequency with small ripple current. This, however, requires a large inductor. A reasonable starting point for selecting the ripple current is ΔIL = 0.4(IMAX). The largest ripple current occurs at the highest VIN. To guarantee that the ripple current stays below a specified maximum, the inductor value should be chosen according to the following equation : ⎡ VOUT ⎤ ⎡ VOUT ⎤ L=⎢ ⎥ ⎥ ⎢1 − V f I × Δ L(MAX) IN(MAX) ⎦ ⎦⎣ ⎣ Inductor Core Selection Once the value for L is known, the type of inductor must be selected. High efficiency converters generally cannot afford the core loss found in low cost powdered iron cores, forcing the use of more expensive ferrite or mollypermalloy cores. Actual core loss is independent of core size for a fixed inductor value but it is very dependent on the inductance selected. As the inductance increases, core losses decrease. Unfortunately, increased inductance requires more turns of wire and therefore copper losses will increase. Ferrite designs have very low core losses and are preferred at high switching frequencies, so design goals can concentrate on copper loss and preventing saturation. Ferrite core material saturates “hard”, which means that inductance collapses abruptly when the peak design DS8008-07 March 2011 current is exceeded. This results in an abrupt increase in inductor ripple current and consequent output voltage ripple. Do not allow the core to saturate! Different core materials and shapes will change the size/ current and price/current relationship of an inductor. Toroid or shielded pot cores in ferrite or permalloy materials are small and don’ t radiate energy but generally cost more than powdered iron core inductors with similar characteristics. The choice of which style inductor to use mainly depends on the price vs size requirements and any radiated field/EMI requirements. CIN and COUT Selection The input capacitance, C IN, is needed to filter the trapezoidal current at the source of the top MOSFET. To prevent large ripple voltage, a low ESR input capacitor sized for the maximum RMS current should be used. RMS current is given by : IRMS = IOUT(MAX) VOUT 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. Note that ripple current ratings from capacitor manufacturers are often based on only 2000 hours of life which makes it advisable to further derate the capacitor, or 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. The selection of COUT is determined by the effective series resistance (ESR) that is required to minimize voltage ripple and load step transients, as well as the amount of bulk capacitance that is necessary 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 ⎤ ΔVOUT ≤ ΔIL ⎢ESR + ⎥ 8fC OUT ⎦ ⎣ The output ripple is highest at maximum input voltage since ΔIL increases with input voltage. Multiple capacitors placed in parallel may be needed to meet the ESR and RMS current handling requirements. Dry tantalum, special www.richtek.com 9 RT8008 polymer, aluminum electrolytic and ceramic capacitors are all available in surface mount packages. Special polymer capacitors offer very low ESR but have lower capacitance density than other types. Tantalum capacitors have the highest capacitance density but it is important to only use types that have been surge tested for use in switching power supplies. Aluminum electrolytic capacitors have significantly higher ESR but can be used in cost-sensitive applications provided that consideration is given to ripple current ratings and long term reliability. 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. Using Ceramic Input and Output Capacitors 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 the 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. Efficiency Considerations The efficiency of a switching regulator is equal to the output power divided by the input power times 100%. It is often useful to analyze individual losses to determine what is limiting the efficiency and which change would produce the most improvement. Efficiency can be expressed as : Efficiency = 100% − (L1+ L2+ L3+ ...) where L1, L2, etc. are the individual losses as a percentage of input power. Although all dissipative elements in the circuit produce losses, two main sources usually account for most of the losses : VIN quiescent current and I2R losses. The VIN quiescent current loss dominates the efficiency loss at very low load currents whereas the I2R loss dominates the efficiency loss at medium to high load currents. In a typical efficiency plot, the efficiency curve at very low load currents can be misleading since the actual power lost is of no consequence. 1. The VIN quiescent current is due to two components : the DC bias current as given in the electrical characteristics and the internal main switch and synchronous switch gate charge currents. The gate charge current results from switching the gate capacitance of the internal power MOSFET switches. Each time the gate is switched from high to low to high again, a packet of charge ΔQ moves from VIN to ground. The resulting ΔQ/Δt is the current out of VIN that is typically larger than the DC bias current. In continuous mode, IGATECHG = f(QT+QB) Output Voltage Programming The resistive divider allows the VFB pin to sense a fraction of the output voltage as shown in Figure 4. VOUT R1 FB RT8008 R2 GND Figure 4. Setting the Output Voltage For adjustable about voltage mode, the output voltage is set by an external resistive divider according to the following equation : V R1) OUT = VREF (1 + R2 where VREF is the internal reference voltage (0.6V typ.) www.richtek.com 10 where QT and QB are the gate charges of the internal top and bottom switches. Both the DC bias and gate charge losses are proportional to VIN and thus their effects will be more pronounced at higher supply voltages. 2. I2R losses are calculated from the resistances of the internal switches, R SW and external inductor RL. In continuous mode the average output current flowing through inductor L is “chopped” between the main switch and the synchronous switch. Thus, the series resistance looking into the LX pin is a function of both top and bottom MOSFET RDS(ON) and the duty cycle (DC) as follows : RSW = RDS(ON)TOP x DC + RDS(ON)BOT x (1−DC) The RDS(ON) for both the top and bottom MOSFETs can be obtained from the Typical Performance Characteristics DS8008-07 March 2011 RT8008 curves. Thus, to obtain I2R losses, simply add RSW to RL and multiply the result by the square of the average output current. Other losses including CIN and COUT ESR dissipative losses and inductor core losses generally account for less than 2% of the total loss. Where TC is the package case (Pin 2 of package leads) temperature measured by thermal sensor, PD is the power dissipation defined by user's function and the θJC is the junction to case thermal resistance provided by IC manufacturer. Therefore it's easy to estimate the junction temperature by any condition. Thermal Considerations Checking Transient Response 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 : 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 a load step occurs, VOUT immediately shifts by an amount PD(MAX) = ( TJ(MAX) - TA ) / θJA Where T J(MAX) is the maximum operation junction temperature 125°C, TA is the ambient temperature and the θJA is the junction to ambient thermal resistance. equal to ΔILOAD (ESR), where ESR is the effective series resistance of COUT. ΔILOAD also begins to charge or discharge COUT generating a feedback error signal used by 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. For recommended operating conditions specification of RT8008 DC/DC converter, where TJ (MAX) is the maximum junction temperature of the die (125°C) and TA is the maximum ambient temperature. The junction to ambient thermal resistance θ JA is layout dependent. For SOT-23-5/TSOT-23-5 packages, the thermal resistance θJA is 250°C/W on the standard JEDEC 51-3 single-layer thermal test board. The maximum power dissipation at TA = 25°C can be calculated by following formula : Maximum Power Dissipation (mW) 450 PD(MAX) = ( 125°C - 25°C ) / 250 = 0.4 W for SOT-23-5/ TSOT-23-5 packages The maximum power dissipation depends on operating ambient temperature for fixed T J(MAX) and thermal resistance θJA. For RT8008 packages, the Figure 5 of derating curves allows the designer to see the effect of rising ambient temperature on the maximum power allowed. The value of junction to case thermal resistance θJC is popular for users. This thermal parameter is convenient for users to estimate the internal junction operated temperature of packages while IC operating. It's independent of PCB layout, the surroundings airflow effects and temperature difference between junction to ambient. The operated junction temperature can be calculated by following formula : Single Layer PCB 400 350 SOT-23-5, TSOT-23-5 Packages 300 250 200 150 100 50 0 0 20 40 60 80 100 120 140 Ambient Temperature (°C) Figure 5. Derating Curves for RT8008 Package Layout Considerations Follow the PCB layout guidelines for optimal performance of RT8008. ` For the main current paths as indicated in bold lines in Figure 6, keep their traces short and wide. ` Put the input capacitor as close as possible to the device pins (VIN and GND). ` LX node is with high frequency voltage swing and should be kept small area. Keep analog components away from LX node to prevent stray capacitive noise pick-up. TJ = TC + PD x θJC DS8008-07 March 2011 www.richtek.com 11 RT8008 VIN } Connect feedback network behind the output capacitors. 4 Keep the loop area small. Place the feedback components near the RT8008. } VOUT L1 RT8008 VIN LX 3 C1 1 Connect all analog grounds to a command node and then connect the command node to the power ground behind the output capacitors. EN FB GND C3 5 2 C2 R1 R2 C4 10uF VIN } An example of 2-layer PCB layout is shown in Figure 7 to Figure 8 for reference. J1 Figure 6. EVB Schematic Figure 7. Top Layer Figure 8. Bottom Layer Suggested Inductors Component Supplier Series Inductance DCR Current Rating Dimensions (µH) (mΩ) (mA) (mm) TAIYO YUDEN NR 3015 2.2 60 1480 3 x 3 x 1.5 TAIYO YUDEN NR 3015 4.7 120 1020 3 x 3 x 1.5 Sumida CDRH2D14 2.2 75 1500 4.5 x 3.2 x 1.55 Sumida CDRH2D14 4.7 135 1000 4.5 x 3.2 x 1.55 GOTREND GTSD32 2.2 58 1500 3.85 x 3.85 x 1.8 GOTREND GTSD32 4.7 146 1100 3.85 x 3.85 x 1.8 Suggested Capacitors for CIN and COUT Component Supplier Part No. Capacitance (µF) Case Size TDK C1608JB0J475M 4.7 0603 TDK C2012JB0J106M 10 0805 MURATA GRM188R60J475KE19 4.7 0603 MURATA GRM219R60J106ME19 10 0805 MURATA GRM219R60J106KE19 10 0805 TAIYO YUDEN JMK107BJ475RA 4.7 0603 TAIYO YUDEN JMK107BJ106MA 10 0603 TAIYO YUDEN JMK212BJ106RD 10 0805 www.richtek.com 12 DS8008-07 March 2011 RT8008 Outline Dimension H D L B C b A A1 e Symbol Dimensions In Millimeters Dimensions In Inches Min Max Min Max A 0.889 1.295 0.035 0.051 A1 0.000 0.152 0.000 0.006 B 1.397 1.803 0.055 0.071 b 0.356 0.559 0.014 0.022 C 2.591 2.997 0.102 0.118 D 2.692 3.099 0.106 0.122 e 0.838 1.041 0.033 0.041 H 0.080 0.254 0.003 0.010 L 0.300 0.610 0.012 0.024 SOT-23-5 Surface Mount Package DS8008-07 March 2011 www.richtek.com 13 RT8008 H D L B C b A A1 e Symbol Dimensions In Millimeters Dimensions In Inches Min Max Min Max A 0.700 1.000 0.028 0.039 A1 0.000 0.100 0.000 0.004 B 1.397 1.803 0.055 0.071 b 0.300 0.559 0.012 0.022 C 2.591 3.000 0.102 0.118 D 2.692 3.099 0.106 0.122 e 0.838 1.041 0.033 0.041 H 0.080 0.254 0.003 0.010 L 0.300 0.610 0.012 0.024 TSOT-23-5 Surface Mount 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 14 DS8008-07 March 2011