® 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 Lead Plating System P : Pb Free G : Green (Halogen Free and Pb Free) Z : ECO (Ecological Element with Halogen Free and Pb free) 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 z z z z z Applications z z z Front Side Bus VTT (1.2V/3A) NoteBook PC Applications Motherboard Applications Marking Information For marking information, contact our sales representative directly or through a Richtek distributor located in your area. 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 VOUT VOUT ADJ PGOOD 1 2 3 4 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. z Maximum 3A Low-Dropout Voltage Regulator High Accuracy Output Voltage ±1.5% Typically 210mV Dropout at 3A Power Good Output Output Voltage Pull Low Resistance when Disable Thermal and Over Current Protection RoHS Compliant and 100% Lead (Pb)-Free VDD VIN VIN VIN EN WDFN-10L 3x3 Enable Pin Function A : Internal Pull High B : Internal Pull Low Note : Richtek 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. Copyright © 2012 Richtek Technology Corporation. All rights reserved. DS9018A/B-09 April 2012 is a registered trademark of Richtek Technology Corporation. www.richtek.com 1 RT9018A/B Typical Application Circuit VOUT = 0.8 × R1 + R2 R2 VIN VIN 10µF Chip Enable VOUT VOUT 10µF RT9018A/B VDD VDD 10µF Chip Enable ADJ EN PGOOD GND VIN VIN 100k R1 10µF ADJ EN R2 PGOOD VDD GND 1µF CDummy RT9018A/B VDD VOUT VOUT 100k 1µF VOUT VOUT Figure 1. Fixed Voltage Regulator Figure 2. Adjustable Voltage Regulator Function Pin Description Pin No. SOP-8 WDFN-10L 3x3 (Exposed Pad) Pin Name Pin Function 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 6 1, 2, 3 Set the output voltage by the internal feedback resistors when ADJ is grounded. If external feedback resistors is used, V OUT = 0.8V x (R1 + R2)/R2. Output Voltage. VOUT 5 -NC 8, 11 (Exposed Pad) GND 9 (Exposed Pad) No Internal Connection. Ground. The exposed pad must be soldered to a large PCB and connected to GND for maximum power dissipation. Function Block Diagram VOUT VIN OCP Driver Error Amplifier + - OTP EN VDD POR Mode 0.8V ADJ PGOOD 0.72V + GND Copyright © 2012 Richtek Technology Corporation. All rights reserved. www.richtek.com 2 is a registered trademark of Richtek Technology Corporation. DS9018A/B-09 April 2012 RT9018A/B Absolute Maximum Ratings z z z z z z z z z (Note 1) Supply Voltage, VIN -----------------------------------------------------------------------------------------------------Control Voltage, VDD ----------------------------------------------------------------------------------------------------Output Voltage, VOUT --------------------------------------------------------------------------------------------------Power Dissipation, PD @ TA = 25°C SOP-8 (Exposed Pad) --------------------------------------------------------------------------------------------------WDFN-10L 3x3 ------------------------------------------------------------------------------------------------------------Package Thermal Resistance (Note 2) SOP-8 (Exposed Pad), θJA ---------------------------------------------------------------------------------------------SOP-8 (Exposed Pad), θJC --------------------------------------------------------------------------------------------WDFN-10L 3x3, θJA ------------------------------------------------------------------------------------------------------Junction Temperature ----------------------------------------------------------------------------------------------------Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------------Storage Temperature Range -------------------------------------------------------------------------------------------ESD Susceptibility (Note 3) HBM (Human Body Mode) ---------------------------------------------------------------------------------------------MM (Machine Mode) ------------------------------------------------------------------------------------------------------ Recommended Operating Conditions z z z z z 1V to 6V 3V to 6V 0.8 to 6V 1.33W 1.67W 75°C/W 15°C/W 60°C/W 150°C 260°C −65°C to 150°C 2kV 200V (Note 4) Supply Voltage, VIN ------------------------------------------------------------------------------------------------------Control Voltage, VDD (VDD > VOUT + 1.5V) -------------------------------------------------------------------------Control Voltage with PGOOD, VDD (Note 8) ----------------------------------------------------------------------Junction Temperature Range -------------------------------------------------------------------------------------------Ambient Temperature Range -------------------------------------------------------------------------------------------- 1.4V to 5.5V 3V to 5.5V 4.5V to 5.5V −40°C to 125°C −40°C to 85°C 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 IOUT = 3A -- 210 350 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 5) Dropout Voltage (Note 6) VDROP Quiescent Current (Note 7) IQ Current Limit ILIM Copyright © 2012 Richtek Technology Corporation. All rights reserved. DS9018A/B-09 April 2012 Test Conditions VIN = VOUT + 0.5V to 5V, IOUT = 1mA VIN = VOUT + 1V, IOUT = 1mA to 3A mV is a registered trademark of Richtek Technology Corporation. www.richtek.com 3 RT9018A/B Parameter Symbol Test Conditions Min Typ Max Unit 0.5 1.8 -- A Short Circuit Current VOUT < 0.2V In-rush Current COUT = 10μF, Enable Start-up -- 0.6 -- A VOUT Pull Low Resistance VEN = 0V -- 150 -- Ω μA Chip Enable EN Input Bias Current IEN VDD Shutdown RT9018A Current RT9018B VEN = 0V -- 12 -- -- 10 20 -- -- 1 μA ISHDN VEN = 0V Logic-Low VENL VDD = 5V -- -- 0.7 Logic-High VENH VDD = 5V 1.2 -- -- PGOOD Rising Threshold -- 90 93 % PGOOD Hysteresis 3 10 -- % -- 0.2 0.4 V 0.5 1.5 5 ms EN Threshold Voltage V Power Good PGOOD Sink Capability IPGOOD = 10mA PGOOD Delay Thermal Protection 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 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 recommended. Note 4. The device is not guaranteed to function outside its operating conditions. Note 5. 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. Note 6. The dropout voltage is defined as VIN -VOUT, which is measured when VOUT is VOUT(NORMAL) - 100mV. Note 7. 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 8. The control voltage must within 4.5V to 5.5V when using PGOOD function. Copyright © 2012 Richtek Technology Corporation. All rights reserved. www.richtek.com 4 is a registered trademark of Richtek Technology Corporation. DS9018A/B-09 April 2012 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 4 VOUT (20mV/Div) VOUT (20mV/Div) Time (250μs/Div) Copyright © 2012 Richtek Technology Corporation. All rights reserved. DS9018A/B-09 April 2012 5 Time (250μs/Div) is a registered trademark of Richtek Technology Corporation. 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) Copyright © 2012 Richtek Technology Corporation. All rights reserved. www.richtek.com 6 is a registered trademark of Richtek Technology Corporation. DS9018A/B-09 April 2012 RT9018A/B Quiescent Current vs. Temperature VDD Standby 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 28 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 00 -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 80 95 110 125 Temperature (°C) Copyright © 2012 Richtek Technology Corporation. All rights reserved. DS9018A/B-09 April 2012 -40 -25 -10 5 20 35 50 65 80 95 110 125 Temperature (°C) is a registered trademark of Richtek Technology Corporation. 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) Copyright © 2012 Richtek Technology Corporation. All rights reserved. www.richtek.com 8 is a registered trademark of Richtek Technology Corporation. DS9018A/B-09 April 2012 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. Copyright © 2012 Richtek Technology Corporation. All rights reserved. DS9018A/B-09 April 2012 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, where TJ (MAX) is the maximum junction temperature of the die (125°C) and T A 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 following is a registered trademark of Richtek Technology Corporation. www.richtek.com 9 RT9018A/B 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 . The Figure 4 of de-rating curves allows the designer to see the effect of rising ambient temperature on the maximum power allowed. 2.2 Power Dissipation (W) Figure 3 (b). Copper Area = 10mm2, θJA = 64°C/W Copper Area 2 Figure 3 (a). Minimum Footprint, θJA = 75°C/W 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 Copyright © 2012 Richtek Technology Corporation. All rights reserved. www.richtek.com 10 is a registered trademark of Richtek Technology Corporation. DS9018A/B-09 April 2012 RT9018A/B Outline Dimension H A M EXPOSED THERMAL PAD (Bottom of Package) Y J B X 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 © 2012 Richtek Technology Corporation. All rights reserved. DS9018A/B-09 April 2012 is a registered trademark of Richtek Technology Corporation. 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. 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 5F, No. 20, Taiyuen Street, Chupei City Hsinchu, Taiwan, R.O.C. Tel: (8863)5526789 Richtek products are sold by description only. Richtek reserves the right to change the circuitry and/or specifications without notice at any time. Customers should obtain the latest relevant information and data sheets before placing orders and should verify that such information is current and complete. Richtek cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Richtek product. Information furnished by Richtek is believed to be accurate and reliable. However, no responsibility is assumed by Richtek or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Richtek or its subsidiaries. www.richtek.com 12 DS9018A/B-09 April 2012