RT8016 1.5MHz, 1A, High Efficiency PWM Step-Down DC/DC Converter General Description Features The RT8016 is a high-efficiency Pulse-Width-Modulated (PWM) step-down DC-DC converter. Capable of delivering 1A output current over a wide input voltage range from 2.5V to 5.5V, the RT8016 is ideally suited for portable electronic devices that are powered from 1-cell Li-ion battery or from other power sources such as cellular phones, PDAs and hand-held devices. Two operating modes are available including : PWM/LowDropout autoswitch and shut-down modes, the Internal synchronous rectifier with low RDS(ON) dramatically reduces conduction loss at PWM mode. No external Schottky diode is required in practical application. The RT8016 enters Low-Dropout mode when normal PWM cannot provide regulated output voltage by continuously turning on the upper PMOS. The RT8016 enters shutdown mode and consumes less than 0.1uA when EN pin is pulled low. The RT8016 also offers a range of 1V to 3.3V with 0.1V per step or adjustable output voltage by two external resistor. +2.5V to +5.5V Input Range Adjustable Output From 0.6V to VIN 1A Output Current 95% Efficiency No Schottky Diode Required 1.5MHz Fixed-Frequency PWM Operation Small 6-Lead WDFN Package RoHS Compliant and 100% Lead (Pb)-Free Applications Mobile Phones Personal Information Appliances Wireless and DSL Modems MP3 Players Portable Instruments Ordering Information RT8016Package Type QW : WDFN-6L 2x2 (W-Type) Operating Temperature Range P : Pb Free with Commercial Standard G : Green (Halogen Free with Commercial Standard) The switching ripple is easily smoothed-out by small package filtering elements due to a fixed operating frequency of 1.5MHz. This along with small WDFN-6L 2x2 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. Pin Configurations (TOP VIEW) GND EN VIN 1 6 2 5 3 7 4 FB/VOUT GND LX Output Voltage Default : Adjustable 10 : 1.0V 11 : 1.1V : 32 : 3.2V 33 : 3.3V Note : Richtek Pb-free and Green products are : RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020. Suitable for use in SnPb or Pb-free soldering processes. WDFN-6L 2x2 Marking Information For marking information, contact our sales representative directly or through a Richtek distributor located in your area, otherwise visit our website for detail. DS8016-01 October 2008 www.richtek.com 1 RT8016 Typical Application Circuit VIN 2.5V to 5.5V 3 CIN 4.7uF VIN LX 4 L 2.2uH VOUT RT8016 2 EN VOUT 6 COUT 10uF GND 1, 5 Figure 1. Fixed Voltage Regulator VIN 2.5V to 5.5V 3 VIN CIN LX 4 L 2.2uH C1 RT8016 4.7uF 2 EN FB VOUT R1 COUT 6 10uF GND 1, 5 IR2 R2 VOUT = VREF x 1 + R1 R2 with R2 = 300k to 60k so the IR2 = 2A to 10A, 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 RT8016_ADJ RT8016_FIX GND 1 6 VOUT EN 2 5 GND VIN 3 L1 Output capacitor must be near RT8016 4 LX GND 1 6 FB EN 2 5 GND VIN 3 4 LX L1 COUT COUT CIN LX should be connected CIN must be placed to Inductor by wide and between VDD and short trace, keep sensitive compontents GND as close as away from this trace possible Output capacitor must be near RT8016 CIN CIN must be placed between VDD and GND as close as possible LX should be connected to Inductor by wide and short trace, keep sensitive compontents away from this trace R1 R2 Layout note: 1. The distance that CIN connects to VIN is as close as possible (Under 2mm). 2. COUT should be placed near RT8016. Figure 3. Layout Guide for RT8016 www.richtek.com 2 DS8016-01 October 2008 RT8016 Functional Pin Description Pin No. Pin Name Pin Function 2 EN Chip Enable (Active High). 3 VIN Power Input. 4 LX Pin for Switching. GND Ground Pin. FB/VOUT Feedback/Output Voltage Pin. 1, 5 6 7 (Exposed Pad) No Internal Connection. The exposed pad must be soldered to a large PCB and NC connected to GND for maximum power dissipation. Function Block Diagram EN VIN RS1 OSC & Shutdown Control Current Limit Detector Slope Compensation Current Sense FB/VOUT Error Amplifier Control Logic PWM Comparator UVLO & Power Good Detector LX Mux Current Source Controller RC COMP Driver Current Detector VREF RS2 GND DS8016-01 October 2008 www.richtek.com 3 RT8016 Absolute Maximum Ratings (Note 1) Supply Input Voltage -----------------------------------------------------------------------------------------------------EN, FB Pin Voltage ------------------------------------------------------------------------------------------------------Power Dissipation, PD @ TA = 25C WDFN-6L 2x2 -------------------------------------------------------------------------------------------------------------Package Thermal Resistance (Note 4) WDFN-6L 2x2, JA --------------------------------------------------------------------------------------------------------WDFN-6L 2x2, JC -------------------------------------------------------------------------------------------------------Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------------Storage Temperature Range -------------------------------------------------------------------------------------------Junction Temperature ----------------------------------------------------------------------------------------------------ESD Susceptibility (Note 2) HBM (Human Body Mode) ---------------------------------------------------------------------------------------------MM (Machine Mode) ------------------------------------------------------------------------------------------------------ Recommended Operating Conditions 6.5V -0.3V to VIN 0.606W 165C/W 20C/W 260C -65C to 150C 150C 2kV 200V (Note 3) Supply Input Voltage ------------------------------------------------------------------------------------------------------ 2.5V to 5.5V Junction Temperature Range -------------------------------------------------------------------------------------------- -40C to 125C Ambient Temperature Range -------------------------------------------------------------------------------------------- -40C to 85C Electrical Characteristics (VIN = 3.6V, VOUT = 2.5V, VREF = 0.6V, L = 2.2uH, CIN = 4.7uF, COUT = 10uF, TA = 25C, IMAX = 1A unless otherwise specified) Parameter Symbol Test Conditions Min Typ Max Units 2.5 -- 5.5 V Input Voltage Range V IN Quiescent Current IQ IO UT = 0mA, VFB = VREF + 5% -- 50 70 uA Shutdown Current I SHDN EN = GND -- 0.1 1 uA Reference Voltage V RE F For Adjustable Output Voltage 0.588 0.6 0.612 V Adjustable Output Range V OUT (Note 6) VREF -- V IN - 0.2V V V OUT V IN = (VOUT + V) to 5.5V or V IN > 2.5V which ever is larger. (Note 5) -3 -- +3 % V IN = VOUT + V to 5.5V 0A < IOUT < 1A -3 -- +3 % -50 -- 50 nA V IN = 3.6V -- 0.28 -- V IN = 2.5V -- 0.38 -- V IN = 3.6V -- 0.25 -- V IN = 2.5V -- 0.35 -- 1.4 1.5 -- A 1.5 -- VIN V Fix Output Voltage Accuracy Adjustable V OUT FB Input Current I FB PMOSFET RON R DS(ON)_P IOUT = 200mA NMOSF ET RON R DS(ON)_N IOUT = 200mA P-Channel Current Limit I LIM_P EN High-Level Input Voltage V EN_H VFB = VIN V IN = 2.5V to 5.5 V (Note 5) To be continued www.richtek.com 4 DS8016-01 October 2008 RT8016 Parameter Min Typ Max Units VE N_L -- -- 0.4 V Under Voltage Lock Out threshold UVLO -- 1.8 -- V Hysteresis -- 0.1 -- V 1.2 1.5 1.8 MHz -- 160 -- C 100 -- -- % 1 -- 100 uA EN Low-Level Input Voltage Symbol Oscillator Frequency fOSC Thermal Shutdown Temperature TSD Test Conditions VIN = 3.6V, IOUT = 100mA Max. Duty Cycle LX Current Source VIN = 3.6V, VLX = 0V or VL X = 3.6V 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. Devices are ESD sensitive. Handling precaution is recommended. Note 3. The device is not guaranteed to function outside its operating conditions. Note 4. JA is measured in the natural convection at TA = 25C on a low effective single layer thermal conductivity test board of JEDEC 51-3 thermal measurement standard. The case point of JC is on the expose pad for the QFN package. Note 5. V = IOUT x PRDS(ON) Note 6. Guarantee by design. DS8016-01 October 2008 www.richtek.com 5 RT8016 Typical Operating Characteristics Efficiency vs. Output Current Output Voltage vs. Output Current 100 1.220 90 1.218 VIN = 3.6V 1.216 VIN = 5V 70 Output Voltage (V) Efficiency (%) 80 60 50 40 30 VIN = 3.6V 1.214 1.212 VIN = 5V 1.210 1.208 1.206 1.204 20 10 1.202 VOUT = 1.2V, COUT = 10uF, L = 2.2H 0 0.001 0.01 0.1 1.200 0 1 0.1 0.2 0.3 Output Voltage vs. Temperature 0.6 0.7 0.8 0.9 1 UVLO Threshold vs. Temperature 1.25 2.1 1.24 2.0 1.23 1.22 Input Voltage (V) Output Voltage (V) 0.5 Output Current (A) Output Current (A) 1.21 1.20 1.19 1.18 1.17 Rising 1.9 1.8 1.7 Falling 1.6 1.5 1.4 1.16 VIN = 3.6V, IOUT = 0A 1.15 -50 -25 0 25 50 75 100 VOUT = 1.2V, IOUT = 0A 1.3 -50 125 -25 0 EN Threshold vs. Input Voltage 1.5 1.5 1.4 1.4 1.3 1.3 EN Voltage (V) 1.6 1.2 1.1 Rising 0.9 0.8 Falling 1.0 0.8 0.6 VOUT = 1.2V, IOUT = 0A 2.8 3.1 3.4 3.7 4 4.3 4.6 Input Voltage (V) www.richtek.com 6 125 4.9 5.2 5.5 Rising 0.9 0.6 2.5 100 1.1 0.7 0.4 75 1.2 0.7 0.5 50 EN Threshold vs. Temperature 1.6 1.0 25 Temperature (C) Temperature (C) EN Voltage (V) 0.4 Falling 0.5 VIN = 3.6V, VOUT = 1.2V, IOUT = 0A 0.4 -40 -15 10 35 60 85 110 135 Temperature (C) DS8016-01 October 2008 RT8016 Frequency vs. Temperature 1.60 1.55 1.55 1.50 1.50 Frequency (MHz) Frequency (MHz) Frequency vs. Input Voltage 1.60 1.45 1.40 1.35 1.30 1.25 1.45 1.40 1.35 1.30 1.25 VIN = 3.6V, VOUT = 1.2V, IOUT = 300mA 1.20 2.5 2.8 3.1 3.4 3.7 4 4.3 4.6 4.9 5.2 VIN = 3.6V, VOUT = 1.2V, IOUT = 300mA 1.20 5.5 -40 -15 10 Input Voltage (V) Current Limit vs. Input Voltage 85 110 135 Current Limit vs. Temperature 2.2 2.1 2.1 2.0 2.0 Output Current (A) Output Current (A) 60 Temperature (C) 2.2 1.9 1.8 1.7 1.6 1.5 VIN = 3.6V 1.9 VIN = 5V 1.8 1.7 1.6 VIN = 3.3V 1.5 1.4 1.4 1.3 VOUT = 1.2V 1.2 2.5 2.8 3.1 3.4 3.7 4 4.3 4.6 4.9 5.2 1.3 -40 5.5 10 35 60 85 110 135 Output Ripple Voltage VIN = 3.6V, VOUT = 1.2V, IOUT = 1A VIN = 5V, VOUT = 1.2V, IOUT = 1A VOUT (10mV/Div) VOUT (10mV/Div) VLX (5V/Div) VLX (5V/Div) October 2008 -15 Temperature (C) Output Ripple Voltage Time (500ns/Div) VOUT = 1.2V 1.2 Input Voltage (V) DS8016-01 35 Time (500ns/Div) www.richtek.com 7 RT8016 Power On from EN Power On from EN VIN = 3.6V, VOUT = 1.2V, IOUT = 10mA VIN = 3.6V, VOUT = 1.2V, IOUT = 1A VEN (2V/Div) VEN (2V/Div) VOUT (1V/Div) VOUT (1V/Div) I IN (500mA/Div) I IN (500mA/Div) Time (100us/Div) Time (100us/Div) Power On from VIN Power Off from EN VIN = 3.6V, VOUT = 1.2V, IOUT = 1A VEN = 3.6V, VOUT = 1.2V, IOUT = 1A VEN (2V/Div) VIN (2V/Div) VOUT (1V/Div) VOUT (1V/Div) I IN (500mA/Div) I IN (500mA/Div) Time (250us/Div) Time (100us/Div) Load Transient Response Load Transient Response VIN = 3.6V, VOUT = 1.2V IOUT = 50mA to 1A VIN = 3.6V, VOUT = 1.2V IOUT = 50mA to 0.5A VOUT (50mV/Div) VOUT (50mV/Div) IOUT (500mA/Div) IOUT (500mA/Div) Time (50us/Div) www.richtek.com 8 Time (50us/Div) DS8016-01 October 2008 RT8016 Load Transient Response Load Transient Response VIN = 5V, VOUT = 1.2V IOUT = 50mA to 1A VIN = 5V, VOUT = 1.2V IOUT = 50mA to 0.5A VOUT (50mV/Div) VOUT (50mV/Div) IOUT (500mA/Div) IOUT (500mA/Div) Time (50us/Div) DS8016-01 October 2008 Time (50us/Div) www.richtek.com 9 RT8016 Applications Information The basic RT8016 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. 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! Inductor Selection 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. For a given input and output voltage, the inductor value and operating frequency determine the ripple current. The ripple current IL increases with higher VIN and decreases with higher inductance. V V IL = OUT x 1 - OUT VIN f xL 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 IL = 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= x 1 - f x IL(MAX) VIN(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 www.richtek.com 10 Different core materials and shapes will change the size/ current and price/current relationship of an inductor. 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 I RMS = I OUT/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, VOUT, is determined by : 1 VOUT IL ESR + 8fCOUT DS8016-01 October 2008 RT8016 The output ripple is highest at maximum input voltage since IL increases with input voltage. Multiple capacitors placed in parallel may be needed to meet the ESR and RMS current handling requirements. Dry tantalum, special 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. For adjustable voltage mode, the output voltage is set by an external resistive divider according to the following equation : VOUT = VREF (1 + R1) R2 where VREF is the internal reference voltage (0.6V typ.) Using Ceramic Input and Output Capacitors 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. 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. Output Voltage Programming The resistive divider allows the FB pin to sense a fraction of the output voltage as shown in Figure 4. V OUT R1 FB RT8016 R2 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. 1. The VIN quiescent current appears due to two factors including : 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 Q moves from VIN to ground. The resulting Q/t is the current out of VIN that is typically larger than the DC bias current. In continuous mode, IGATECHG = f(QT+QB) 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. GND Figure 4. Setting the Output Voltage DS8016-01 October 2008 www.richtek.com 11 RT8016 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 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. For RT8016 packages, the Figure 5 of derating curves allows the designer to see the effect of rising ambient temperature on the maximum power allowed. 700 Maximum Power Dissipation (mW) 2. I2R losses are calculated from the resistances of the internal switches, RSW 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 : Single Layer PCB 600 500 WDFN-6L 2x2 400 300 200 100 0 0 20 40 60 80 100 120 140 Ambient Temperature (C) Figure 5. Derating Curves for RT8016 Package Thermal Considerations 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 ) / JA Where T J(MAX) is the maximum operation junction temperature, TA is the ambient temperature and the JA is the junction to ambient thermal resistance. For recommended operating conditions specification of RT8016 DC/DC converter, where TJ(MAX) is the maximum junction temperature of the die and TA is the maximum ambient temperature. The junction to ambient thermal resistance JA is layout dependent. For WDFN-6L 2x2 packages, the thermal resistance JA is 165C/W on the standard JEDEC 51-7 four layers thermal test board. 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 a load step occurs, VOUT immediately shifts by an amount equal to ILOAD (ESR), where ESR is the effective series resistance of COUT. ILOAD 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. Layout Considerations Follow the PCB layout guidelines for optimal performance of RT8016. For the main current paths as indicated in bold lines in Figure 6, keep their traces short and wide. The maximum power dissipation at TA = 25C can be calculated by following formula : Put the input capacitor as close as possible to the device pins (VIN and GND). PD(MAX) = (125C - 25C) / 165C/W = 0.606W for WDFN-6L 2x2 packages 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. The maximum power dissipation depends on operating ambient temperature for fixed T J(MAX) and thermal resistance JA. www.richtek.com 12 Connect feedback network behind the output capacitors. Keep the loop area small. Place the feedback components near the RT8016. DS8016-01 October 2008 RT8016 Connect all analog grounds to a command node and then connect the command node to the power ground behind the output capacitors. An example of 2-layer PCB layout is shown in Figure 7 to Figure 8 for reference. VIN 3 VIN VOUT L1 RT8016 LX 4 C2 FB/VOUT 2 C1 EN GND Figure 7. Top Layer R1 6 C3 1, 5 R2 VIN R3 Figure 6. EVB Schematic Figure 8. Bottom Layer Table 1. Recommended Inductors Inductance Current Rating (mA) (uH) Supplier DCR (m) Dimensions (mm) Series TAIYO YUDEN 2.2 1480 60 3.00 x 3.00 x 1.50 NR 3015 GOTREND 2.2 1500 58 3.85 x 3.85 x 1.80 GTSD32 Sumida 2.2 1500 75 4.50 x 3.20 x 1.55 CDRH2D14 Sumida 4.7 1000 135 4.50 x 3.20 x 1.55 CDRH2D14 TAIYO YUDEN 4.7 1020 120 3.00 x 3.00 x 1.50 NR 3015 GOTREND 4.7 1100 146 3.85 x 3.85 x 1.80 GTSD32 Table 2. Recommended Capacitors for CIN and COUT DS8016-01 Supplier Capacitance (uF) Package Part Number TDK 4.7 603 C1608JB0J475M MURATA 4.7 603 GRM188R60J475KE19 TAIYO YUDEN 4.7 603 JMK107BJ475RA TAIYO YUDEN 10 603 JMK107BJ106MA TDK 10 805 C2012JB0J106M MURATA 10 805 GRM219R60J106ME19 MURATA 10 805 GRM219R60J106KE19 TAIYO YUDEN 10 805 JMK212BJ106RD October 2008 www.richtek.com 13 RT8016 Outline Dimension D2 D L E E2 1 e 2 b A A1 SEE DETAIL A 1 2 1 DETAIL A Pin #1 ID and Tie Bar Mark Options A3 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 0.200 0.350 0.008 0.014 D 1.950 2.050 0.077 0.081 D2 1.000 1.450 0.039 0.057 E 1.950 2.050 0.077 0.081 E2 0.500 0.850 0.020 0.033 e L 0.650 0.300 0.026 0.400 0.012 0.016 W-Type 6L DFN 2x2 Package Richtek Technology Corporation Richtek Technology Corporation Headquarter Taipei Office (Marketing) 5F, No. 20, Taiyuen Street, Chupei City 8F, No. 137, Lane 235, Paochiao Road, Hsintien City Hsinchu, Taiwan, R.O.C. Taipei County, Taiwan, R.O.C. Tel: (8863)5526789 Fax: (8863)5526611 Tel: (8862)89191466 Fax: (8862)89191465 Email: marketing@richtek.com 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 DS8016-01 October 2008