RT9018A/B Maximum 3A, Ultra Low Dropout Regulator General Description Features The RT9018A/B is a high performance positive voltage regulator designed for use in applications requiring very low Input voltage and very low dropout voltage at up to 3A(Peak). It operates with a VIN as low as 1.4V and VDD voltage 3V with output voltage programmable as low as 0.8V. The significant feature includes ultra low dropout, ideal for applications where VOUT is very close to VIN. Additionally, there is an enable pin to further reduce power dissipation while shutdown. The RT9018A/B provides excellent regulation over variations in line, load and temperature. and provides a power OK signal to indicate if the voltage level of Vo reaches 90% of its rating value. z Ordering Information RT9018A/BPackage Type SP : SOP-8 (Exposed Pad-Option 1) QW : WDFN-10L 3x3 Operating Temperature Range P : Pb Free with Commercial Standard G : Green (Halogen Free with Commercial Standard) Z : ECO (Ecological Element) Output Voltage 10 : 1V/Adj 1K : 1.05V/Adj 12 : 1.2V/Adj 15 : 1.5V/Adj 18 : 1.8V/Adj 25 : 2.5V/Adj Typically 220mV Dropout at 3A z Power Good Output z Output Voltage Pull Low Resistance when Disable z Thermal and Over Current Protection z RoHS Compliant and 100% Lead (Pb)-Free z Applications Front Side Bus VTT (1.2V/3A) z NoteBook PC Applications z Motherboard Applications z 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. Pin Configurations (TOP VIEW) 8 PGOOD EN 2 VIN 3 VDD 4 GND 7 ADJ GND 6 9 5 VOUT NC SOP-8 (Exposed Pad) VOUT 1 VOUT 2 VOUT 3 ADJ 4 PGOOD 5 GND 11 10 9 8 7 9 The RT9018A/B is available in the SOP-8 (Exposed Pad) and WDFN-10L 3x3 packages with 1V, 1.05V, 1.2V, 1.5V, 1.8V and 2.5V internally preset outputs that are also adjustable using external resistors. Maximum 3A Low-Dropout Voltage Regulator z High Accuracy Output Voltage ± 1.5% VDD VIN VIN VIN EN WDFN-10L 3x3 Enable Pin Function A : Internal Pull High B : Internal Pull Low Note : Richtek Green products are : ` RoHS compliant and compatible with the current require- ments of IPC/JEDEC J-STD-020. ` Suitable for use in SnPb or Pb-free soldering processes. DS9018A/B-07 September 2010 www.richtek.com 1 RT9018A/B Pin Description Pin No. Pin Name Pin Function PSOP-8 WDFN 3x3 3 7, 8, 9 VIN Supply Input Voltage. 2 6 EN Chip Enable (Active-High). 4 10 VDD Supply Voltage of Control Circuitry. 1 5 PGOOD Power Good Open Drain Output. 7 4 ADJ Set the output voltage by the internal feedback resistors when ADJ is grounded. If external feedback resistors is used, VOUT = 0.8V x (R1 + R2)/R2. 6 1, 2, 3 VOUT Output Voltage. 5 -- NC No Internal Connection. 8, Exposed Pad (11) GND Exposed Pad (9) Ground. The exposed pad must be soldered to a large PCB and connected to GND for maximum power dissipation. Typical Application Circuit VOUT = 0.8 × R1 + R2 R2 VIN 10µF Chip Enable VOUT VOUT RT9018 VDD VDD 10µF 10µF Chip Enable ADJ EN VIN VIN PGOOD GND R1 10µF ADJ EN R2 PGOOD VDD GND 100k 1µF CDummy RT9018A/B VDD VOUT VOUT 100k 1µF VOUT VOUT Figure 1. Fixed Voltage Regulator Figure 2. Adjustable Voltage Regulator Function Block Diagram VOUT VIN OCP Driver Error Amplifier EN VDD - + OTP POR Mode 0.8V ADJ PGOOD 0.72V + GND www.richtek.com 2 DS9018A/B-07 September 2010 RT9018A/B Absolute Maximum Ratings (Note 1) Supply Voltage, VIN ------------------------------------------------------------------------------------------------- 1V to 6V Control Voltage, VDD ------------------------------------------------------------------------------------------------ 3V to 6V z Output Voltage, VOUT ----------------------------------------------------------------------------------------------- 0.8 to 6V z Power Dissipation, PD @ TA = 25°C SOP-8 (Exposed Pad) ---------------------------------------------------------------------------------------------- 1.33W WDFN-10L 3x3 ------------------------------------------------------------------------------------------------------- 1.67W z 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 -------------------------------------------------------------------------------------------------- 60°C/W z Junction Temperature ----------------------------------------------------------------------------------------------- 150°C z Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------- 260°C z Storage Temperature Range --------------------------------------------------------------------------------------- −65°C to 150°C z ESD Susceptibility (Note 3) HBM (Human Body Mode) ----------------------------------------------------------------------------------------- 2kV MM (Machine Mode) ------------------------------------------------------------------------------------------------ 200V z z Recommended Operating Conditions (Note 4) Supply Voltage, VIN ------------------------------------------------------------------------------------------------- 1.4V to 5.5V Control Voltage, VDD (VDD P VOUT + 1.5V) --------------------------------------------------------------------- 3V to 5.5V z Junction Temperature Range -------------------------------------------------------------------------------------- −40°C to 125°C z Ambient Temperature Range -------------------------------------------------------------------------------------- −40°C to 85°C z z Electrical Characteristics (VIN = VOUT + 500mV, VEN = VDD = 5V, CIN = COUT = 10μF, TA = TJ = 25°C, unless otherwise specified) Parameter Min Typ Max Unit POR Threshold 2.4 2.7 3 V POR Hysteresis 0.15 0.2 -- V IOUT = 1mA -- 0.2 0.4 V IOUT = 1mA 0.788 0.8 0.812 V −1.5 0 +1.5 % -- 0.2 0.6 % -- 0.2 1 % IOUT = 2A -- 150 250 mV IOUT = 3A -- 210 350 mV VDD = 5.5V -- 0.6 1.2 mA 3.2 4.5 -- A Adjustable Pin Threshold Symbol VTH_ADJ Reference Voltage (ADJ Pin Voltage) VADJ Fixed Output Voltage Range ΔVOUT Line Regulation (VIN) ΔVLINE_IN Load Regulation ΔVLOAD (Note 7) Dropout Voltage (Note 5) VDROP Quiescent Current (Note 6) IQ Current Limit ILIM Test Conditions VIN = VOUT + 0.5V to 5V, IOUT = 1mA VIN = VOUT + 1V, IOUT = 1mA to 3A Short Circuit Current VOUT < 0.2V 0.5 1.8 -- A In-rush Current COUT = 10μF, Enable Start-up -- 0.6 -- A VOUT Pull Low Resistance VEN = 0V -- 150 -- Ω To be continued DS9018A/B-07 September 2010 www.richtek.com 3 RT9018A/B Parameter Symbol Test Conditions Min Typ Max Unit --- 12 10 -20 μA --- 1 0.2 Chip Enable EN Input Bias Current VDD Shutdown RT9018A Current RT9018B I EN VEN = 0V I SHDN VEN = 0V Logic-Low Voltage VENL Logic-High Voltage VENH VDD = 5V --- VDD = 5V 1.2 -- -- Power Good PGOOD Rising Threshold -- 90 93 % PGOOD Hysteresis 3 10 -- % -- 0.2 0.4 V 0.5 1.5 5 ms EN Threshold PGOOD Sink Capability IPGOOD = 10mA PGOOD Delay Thermal Protection μA V Thermal Shutdown Temperature TSD -- 160 -- °C Thermal Shutdown Hysteresis ΔTSD -- 30 -- °C -- 110 -- °C Thermal Shutdown Temperature Fold-back VOUT < 0.4V 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 high effective thermal conductivity test board (4 Layers, 2S2P) of JEDEC 51-7 thermal measurement standard. The case point of θJC is on the expose pad for SOP-8 (Exposed Pad) package. Note 3. Devices are ESD sensitive. Handling precaution recommended. Note 4. The device is not guaranteed to function outside its operating conditions. Note 5. The dropout voltage is defined as VIN -VOUT, which is measured when VOUT is VOUT(NORMAL) - 100mV. Note 6. Quiescent, or ground current, is the difference between input and output currents. It is defined by IQ = IIN - IOUT under no load condition (IOUT = 0mA). The total current drawn from the supply is the sum of the load current plus the ground pin current. Note 7. Regulation is measured at constant junction temperature by using a 2ms current pulse. Devices are tested for load regulation in the load range from 1mA to 3A. www.richtek.com 4 DS9018A/B-07 September 2010 RT9018A/B Typical Operating Characteristics Load Transient Response Load Transient Response VDD = 5V, VIN = 1.8V, VOUT = 1.2V VDD = 5V, VIN = 1.8V, VOUT = 1.2V VOUT (20mV/Div) VOUT (20mV/Div) IOUT (1A/Div) IOUT (1A/Div) Time (2.5ms/Div) Time (2.5ms/Div) VIN Line Transient Response VIN Line Transient Response VDD = 5V, VOUT = 1.2V, IOUT = 0A VIN 3 VDD = 5V, VOUT = 1.2V, IOUT = 2A VIN 2 3 2 VOUT (20mV/Div) VOUT (20mV/Div) Time (250μs/Div) Time (250μs/Div) VDD Line Transient Response VDD Line Transient Response VIN = 1.8V, VOUT = 1.2V, IOUT = 0A VDD 5 VIN = 1.8V, VOUT = 1.2V, IOUT = 2A VDD 4 5 4 VOUT (20mV/Div) VOUT (20mV/Div) Time (250μs/Div) DS9018A/B-07 September 2010 Time (250μs/Div) www.richtek.com 5 RT9018A/B Dropout Voltage vs. Load Current Start Up from Enable 400 IOUT = 3A Dropout Voltage (mV) 350 125°C 300 250 EN (1V/Div) 25°C VOUT (1V/Div) 200 150 PGOOD (1V/Div) -40°C 100 I IN (2A/Div) 50 0 0 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7 3 Time (500μs/Div) Load Current (A) Start Up from VDD Start Up from VIN IOUT = 3A IOUT = 3A VIN (1V/Div) VDD (5V/Div) VOUT (1V/Div) VOUT (1V/Div) PGOOD (1V/Div) PGOOD (1V/Div) I IN (2A/Div) I IN (2A/Div) Time (500μs/Div) Time (1ms/Div) Short Circuit Current vs. Temperature Short Circuit Protection IOUT (1A/Div) Short Circuit Current Ishort (A) VDD = 5V, VIN = 1.8V, VOUT = 1.2V 2.6 2.4 2.2 2.0 1.8 1.6 1.4 1.2 1.0 Time (100μs/Div) -40 -20 0 20 40 60 80 100 Temperature (°C) www.richtek.com 6 DS9018A/B-07 September 2010 RT9018A/B 28 VDD Standby Current vs. Temperature Quiescent Current vs. Temperature 1200 1.2 VIN = 3.3V, VEN = 0V, VDD = 5V 24 20 16 RT9018A 12 8 4 VIN = 1.8V, VOUT = 1.2V, IOUT = 0A 1100 1.1 QuiescentCurrent Current(mA) (uA) Quiescent VDD Standby Current (μA)1 32 RT9018B 0 1000 1.0 900 0.9 800 0.8 700 0.7 600 0.6 500 0.5 400 0.4 300 0.3 200 0.2 100 0.1 0 -4 -50 -25 0 25 50 75 100 -40 -25 -10 125 5 50 65 80 95 110 125 Output Voltage vs. Temperature Reference Voltage vs. Temperature 1.25 0.84 1.24 0.83 VIN = 1.8V, VADJ = 0V, IOUT = 0A 1.23 0.82 Output Voltage (V) Reference Voltage (V) 35 Temperature (°C) Temperature (°C) 0.81 0.80 0.79 0.78 1.22 1.21 1.20 1.19 1.18 1.17 0.77 1.16 0.76 1.15 -40 -25 -10 5 20 35 50 65 80 95 110 125 -40 -25 -10 5 Temperature (°C) ADJ Threshold Voltage Range (V) 2.95 2.90 Rising 2.80 2.75 2.70 2.65 Falling 2.60 35 50 65 80 95 110 125 ADJ Threshold Voltage vs. Temperature VDD POR Threshold Voltage vs. Temperature 2.85 20 Temperature (°C) 3.00 POR Voltage (V) 20 2.55 2.50 2.45 2.40 0.30 0.28 0.26 0.24 0.22 0.20 0.18 0.16 0.14 0.12 0.10 -40 -25 -10 5 20 35 50 65 Temperature (°C) DS9018A/B-07 September 2010 80 95 110 125 -40 -25 -10 5 20 35 50 65 80 95 110 125 Temperature (°C) www.richtek.com 7 RT9018A/B Over Current Protection Fold Back Output Voltage VOUT (V) 3 VIN = VEN = 3.3V, VDD = 5V 2.5 2 1.5 1 0.5 0 0 0.5 1 1.5 2 2.5 3 3.5 4 Loading Current I OUT (A) www.richtek.com 8 DS9018A/B-07 September 2010 RT9018A/B Application Information Adjustable Mode Operation Power Good The output voltage of RT9018A/B is adjustable from 0.8V to (VIN - VDROP) by external voltage divider resisters as shown in Typical Application Circuit (Figure 2). The value of resisters R1 and R2 should be more than 10kΩ to reduce the power loss. The VDD must be greater than (VOUT + 1.5V). The power good function is an open-drain output. Connects 100kΩ pull up resistor to VOUT to obtain an output voltage. The PGOOD pin will output high immediately after the output voltage arrives 90% of normal output voltage. The PGOOD pin will output high with typical 1.5ms delay time. Thermal-Shutdown Protection Enable The RT9018A/B goes into shutdown mode when the EN pin is in the logic low condition. During this condition, the pass transistor, error amplifier, and band gap are turned off, reducing the supply current to 10μA typical. The RT9018A/B goes into operation mode when the EN pin is in the logic high condition. If the EN pin is floating, NOTE that the RT9018A/B internal initial logic level. For RT9018A, the EN pin function pulls high level internally. So the regulator will be turn on when EN pin is floating. For RT9018B, the EN pin function pulls low level internally. So the regulator will be turn off when EN pin is floating. Output Capacitor The RT9018A/B is specifically designed to employ ceramic output capacitors as low as 10μF. The ceramic capacitors offer significant cost and space savings, along with high frequency noise filtering. Input Capacitor Good bypassing is recommended from input to ground to help improve AC performance. A 10μF input capacitor or greater located as close as possible to the IC is recommended. Current Limit The RT9018A/B contains an independent current limit and the short circuit current protection to prevent unexpected applications. The current limit monitors and controls the pass transistor’ s gate voltage, limiting the output current to higher than 4.5A typical. When the output voltage is less than 0.4V, the short circuit current protection starts the current fold back function and maintains the loading current 1.8A. The output can be shorted to ground indefinitely without damaging the part. DS9018A/B-07 September 2010 Thermal protection limits power dissipation to prevent IC over temperature in RT9018A/B. When the operation junction temperature exceeds 160°C, the over-temperature protection circuit starts the thermal shutdown function and turns the pass transistor off. The pass transistor turn on again after the junction temperature cools by 30°C. RT9018A/B lowers its OTP trip level from 160°C to 110°C when output short circuit occurs (VOUT < 0.4V). It limits IC case temperature under 100°C and provides maximum safety to customer while output short circuit occurring. Power Dissipation For continuous operation, do not exceed absolute maximum operation junction temperature 125°C. The power dissipation definition in device is: PD = (VIN − VOUT) x IOUT + VIN x IQ The maximum power dissipation depends on the thermal resistance of IC package, PCB layout, the rate of surroundings airflow and temperature difference between junctions 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 125°C, TA is the ambient temperature and the θJA is the junction to ambient thermal resistance. For recommended operating conditions specification of RT9018A/B, 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 for SOP-8 (Exposed Pad) package is 75°C/W on the standard JEDEC 51-7 (4 layers, 2S2P) thermal test board. The copper thickness is 2oz. The maximum power dissipation at TA = 25°C can be calculated by www.richtek.com 9 RT9018A/B following formula: PD (MAX) = (125°C − 25°C) / (75°C/W) = 1.33W (SOP-8 Exposed Pad on the minimum layout) Layout Considerations The thermal resistance θJA of SOP-8 (Exposed Pad) 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) package. As shown in Figure 3, the amount of copper area to which the SOP-8 (Exposed Pad) is mounted affects thermal performance. When mounted to the standard SOP-8 (Exposed Pad) pad (Figure 3.a), θJA is 75°C/W. Adding copper area of pad under the SOP-8 (Exposed Pad) Figure 3.b) reduces the θJA to 64°C/W. Even further, increasing the copper area of pad to 70mm2 (Figure 3.e) reduces the θJA to 49°C/W. Figure 3 (d). Copper Area = 50mm2, θJA = 51°C/W Figure 3 (e). Copper Area = 70mm2, θJA = 49°C/W Figure 3. Thermal Resistance vs. Different Cooper Area Layout Design The maximum power dissipation depends on operating ambient temperature for fixed T J(MAX) and thermal resistance θJA . For RT9018A/B packages, the Figure 4 of de-rating curves allows the designer to see the effect of rising ambient temperature on the maximum power allowed. Figure 3 (a). Minimum Footprint, θJA = 75°C/W 2.2 Copper Area Figure 3 (b). Copper Area = 10mm2, θJA = 64°C/W Power Dissipation (W) 2 70mm2 1.8 50mm2 1.6 30mm2 1.4 10mm2 Minimum Layout 1.2 1 0.8 0.6 0.4 0.2 0 JEDEC 4-Layers PCB 0 20 40 60 80 100 120 140 Ambient Temperature (°C) Figure 4. De-rating Curves Figure 3 (c). Copper Area = 30mm2, θJA = 54°C/W www.richtek.com 10 DS9018A/B-07 September 2010 RT9018A/B Outline Dimension H A M EXPOSED THERMAL PAD (Bottom of Package) Y J X B F C I D Dimensions In Millimeters Symbol Dimensions In Inches 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 DS9018A/B-07 September 2010 www.richtek.com 11 RT9018A/B D2 D L E E2 1 SEE DETAIL A 2 e 2 1 b DETAIL A Pin #1 ID and Tie Bar Mark Options A A1 1 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 0.180 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 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 12 DS9018A/B-07 September 2010
