RT9047 1A, Low Voltage, Low Dropout LDO General Description Features The RT9047 is a 1A linear low dropout (LDO) voltage regulator which uses an N-MOSFET pass element in a voltage follower. The topology is relatively insensitive to output capacitor value and ESR, allowing a wide variety of load configurations. The N-MOSFET topology also allows very low dropout. Current consumption, when not enabled, is under 1μA and ideal for portable applications. z Stable with Ceramic Capacitor z Input Voltage Range : 2.2V to 5.5V Ultra Low Dropout Voltage : 130mV (typ.) at 1A Low Reverse Leakage Current Low Quiescent (<1μ μA) in Shutdown Mode Thermal Shutdown and Current Limit Available in Multiple Output Voltage Versions Custom Outputs Available Using Factory RoHS Compliant and Halogen Free This device is protected by thermal shutdown and foldback current limit. The RT9047 is available an SOT-223-5 package. Ordering Information RT9047 Package Type G5 : SOT-223-5 Lead Plating System G : Green (Halogen Free and Pb Free) z z z z z z z Applications z z z z z z Telecom/Networking Cards Motherboards/Peripheral Cards Wireless Infrastructure Notebook Computers Battery Powered Systems Set Top Boxes Note : Richtek products are : ` RoHS compliant and compatible with the current require- Pin Configurations (TOP VIEW) ments of IPC/JEDEC J-STD-020. 2 3 4 5 FB 1 EN Marking Information GND(TAB) Suitable for use in SnPb or Pb-free soldering processes. VOUT ` RT9047 GG5YMDNN YMDNN : Date Code VIN RT9047GG5 : Product Number SOT-223-5 DS9047-03 November 2011 www.richtek.com 1 RT9047 Typical Application Circuit 1 VIN RT9047 VIN VOUT CIN 4.7µF Chip Enable 2 R1 VOUT COUT 4.7µF FB 4 5 EN R2 GND 3 VOUT = VFB × (1 + R1 ) Volts R2 Note : Where VFB is the reference voltage with a typical value of 1.2V. Functional Pin Description Pin No. Pin Name Pin Function 1 VIN Supply Voltage Input. 2 3 4 VOUT GND FB Output Voltage. Ground. Output Feedback Pin. Connect the external resistor divider. 5 EN Chip Enable (Active-High). Function Block Diagram 4MHz Oscilator Charge Pump Current Limit VIN Thermal Shutdown Bandgap EN www.richtek.com 2 + ERROR AMP FB GND VOUT DS9047-03 November 2011 RT9047 Absolute Maximum Ratings z z z z z z z z (Note 1) Input Voltage, VIN ---------------------------------------------------------------------------------------------------------Output Voltage, VOUT ----------------------------------------------------------------------------------------------------Power Dissipation, PD @ TA = 25°C SOT-223-5 -----------------------------------------------------------------------------------------------------------------Package Thermal Resistance (Note 2) SOT-223-5, θJA ------------------------------------------------------------------------------------------------------------SOT-223-5, θJC ------------------------------------------------------------------------------------------------------------Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------------Junction Temperature ----------------------------------------------------------------------------------------------------Storage Temperature Range -------------------------------------------------------------------------------------------ESD Susceptibility (Note 3) HBM (Human Body Mode) ---------------------------------------------------------------------------------------------MM (Machine Mode) ------------------------------------------------------------------------------------------------------ Recommended Operating Conditions z z z 6V 5.5V 1.282W 78°C/W 15°C/W 260°C 150°C −65°C to 150°C 2kV 200V (Note 4) Input Voltage, VIN ---------------------------------------------------------------------------------------------------------- 2.2V to 5.5V Junction Temperature Range -------------------------------------------------------------------------------------------- −40°C to 125°C Ambient Temperature Range -------------------------------------------------------------------------------------------- −40°C to 85°C Electrical Characteristics (VIN = VOUT(NOM) + 1V, IOUT = 1mA, VEN = 2.2V, and COUT = 4.7μF ,TA = 25°C, unless otherwise specified) Parameter Output Voltage Symbol VOUT Test Conditions VIN = 3.3V, VFB = VOUT, I OUT = 10mA, Over Temperature Min Typ Max Unit −3 -- 3 % -- 0.5 1 %/A -- 0.1 0.2 %/V -- 130 200 mV 1.05 1.6 2.2 A VDROP VIN = 3.3V, VFB = VOUT, I OUT = 10mA to 1A VIN = 2.2V to 5.5V, VFB = VOUT, I OUT = 10mA I OUT = 1A Output Current Limit ILIM VIN = 3.3V Short Circuit Current ISC VIN = 3.3V, VOUT = 0 -- 500 -- mA FB Pin Current IFB VIN = 3.3V -- -- 1 μA Load Regulation (Note 5) ΔVLOAD ΔVLINE Line Regulation Dropout Voltage (Note 6) f = 100Hz, I OUT = 1A -- 55 -- f = 10kHz, I OUT = 1A -- 35 -- VON COUT = 10μF -- tSTR VOUT = 3V, RL = 30Ω Logic-High VIH Logic-Low Power Supply Rejection Rate PSRR Output Noise Voltage BW = 10Hz − 100kHz Startup Time EN Threshold Voltage EN Pin Current dB -- μVRMS -- 27 x VOUT 500 -- μs VIN = 3.3V 1.7 -- -- VIL VIN = 3.3V -- -- 0.5 IEN_H VIN = VEN = 5.5V -- -- 1 V μA To be continued DS9047-03 November 2011 www.richtek.com 3 RT9047 Parameter Symbol Test Conditions Feedback Voltage VFB VIN = 3.3V, VFB = VOUT, I OUT = 1mA Output Impedance in ZO_DROP 2.2V < VIN < VOUT + VDO Dropout Reverse Leakage Current I Leakage VEN = 0V, 0 ≦ VIN ≦ VOUT Thermal Shutdown TSD Temperature VIN = 3.3V, IOUT = 1mA Quiescent Current I GND VIN = 3.3V, IOUT = 1A Shutdown Current I SHDN VEN = 0V Min Typ Max Unit 1.190 1.200 1.216 V -- 0.25 -- Ω -- -- 1 μA 140 -- 160 °C -- 600 -- -- 800 -- μA -- -- 1 μA 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 natural convection at TA = 25°C on a high effective thermal conductivity four-layer test board of JEDEC 51-7 thermal measurement standard. The measurement case position of θJC is on 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. Note 5. Regulation is measured at constant junction temperature by using 2ms current pulse. Devices are tested for load regulation in the load range from 10mA to 1A. Note 6. The dropout voltage is defined as VIN − VOUT, which is measured when VOUT is VOUT (NORMAL) − 100mV. www.richtek.com 4 DS9047-03 November 2011 RT9047 Typical Operating Characteristics Quiescent Current vs. Temperature 700 1.23 650 Quiescent Current (µA) Output Voltage (V) Output Voltage vs. Temperature 1.24 1.22 1.21 1.20 1.19 1.18 600 550 500 450 400 1.17 VIN = 2.5V, VOUT = 1.2V, IOUT = 0mA VIN = 2.5V, VOUT = 1.2V, IOUT = 0mA 1.16 350 -50 -25 0 25 50 75 100 125 -50 -25 0 Temperature (°C) 50 75 100 125 Temperature (°C) Current Limit vs. Temperature Dropout Voltage vs. Load Current 3.1 300 2.8 250 Dropout Voltage (mV) Current Limit (A) 25 2.5 2.2 1.9 125°C 200 25°C 150 100 −40°C 50 1.6 VIN = 4.2V, VOUT = 3.3V VOUT = 2.5V 0 1.3 -50 -25 0 25 50 75 100 0.0 125 0.2 0.4 0.6 0.8 1.0 Load Current (A) Temperature (°C) UVLO vs. Temperature EN Threshold Voltage vs. Temperature 2.3 1.5 EN Threshold Voltage (V) 1.4 UVLO (V) 2.1 1.9 Rising 1.7 Falling 1.5 1.3 VEN = 5V 1.1 1.2 1.1 Rising 1.0 0.9 Falling 0.8 0.7 0.6 VEN = 3.3V, VOUT = 2.5V 0.5 -50 -25 0 25 50 Temperature (°C) DS9047-03 1.3 November 2011 75 100 125 -50 -25 0 25 50 75 100 125 Temperature (°C) www.richtek.com 5 RT9047 Load Transient Response Line Transient Response VOUT (10mV/Div) VIN (2V/Div) VOUT (10mV/Div) IOUT (500mA/Div) VIN = 4.2V to 5.2V, VOUT = 3.3V, IOUT = 1A VIN = 3.3V, VOUT = 2.5V, IOUT = 10mA to 1A Time (100μs/Div) Time (500μs/Div) Power On from EN Power Off from EN VEN (5V/Div) VEN (5V/Div) VOUT (1V/Div) VOUT (1V/Div) I IN (1A/Div) I IN (1A/Div) VIN = 3.3V, VOUT = 1.2V, IOUT = 1A Time (100μs/Div) VIN = 3.3V, VOUT = 1.2V, IOUT = 1A Time (5μs/Div) PSRR 0 IOUT = 1mA IOUT = 100mA IOUT = 300mA PSRR (dB) -20 -40 -60 VIN = 4.1V to 4.2V, VOUT = 3V -80 0.01 10 0.1 100 1 1000 10 10000 100 100000 1000 1000000 Frequency (kHz) www.richtek.com 6 DS9047-03 November 2011 RT9047 Application Information Output Voltage Setting The RT9047 output voltage is adjustable from 1.2V to 5.2V via the external resistive voltage divider. The voltage divider resistors can have values of up to 800kΩ because of the very high impedance and low bias current of the sense comparator. The output voltage is set according to the following equation : VOUT = VFB × ⎛⎜ 1+ R1 ⎞⎟ ⎝ R2 ⎠ where VFB is the reference voltage with a typical value of 1.2V. Chip Enable Operation The RT9047 goes into sleep mode when the EN pin is in a logic low condition. In this condition, the pass transistor, error amplifier, and band gap are all turned off, reducing the supply current to only 1μA (max.). The EN pin can be directly tied to VIN to keep the part on. Current Limit The RT9047contains an independent current limit circuitry, which monitors and controls the pass transistor's gate voltage, limiting the output current to 1.6A (typ.). CIN and COUT Selection Like any low dropout regulator, the external capacitors of the RT9047 must be carefully selected for regulator stability and performance. Using a capacitor of at least 4.7μF is suitable. The input capacitor must be located at a distance of not more than 0.5 inch from the input pin of the IC. Any good quality ceramic capacitor can be used. However, a capacitor with larger value and lower ESR (Equivalent Series Resistance) is recommended since it will provide better PSRR and line transient response. The RT9047 is designed specifically to work with low ESR ceramic output capacitor for space saving and performance consideration. Using a ceramic capacitor with capacitance of at least 4.7μF and ESR larger than 1mΩ on the RT9047 DS9047-03 November 2011 output ensures stability. Nevertheless, the RT9047 can still work well with other types of output capacitors due to its wide range of stable ESR. Figure 1 shows the allowable ESR range as a function of load current for various output capacitance. Output capacitors with larger capacitance can reduce noise and improve load transient response, stability, and PSRR. The output capacitor should be located at a distance of not more than 0.5 inch from the output pin of the RT9047. Region of Stable COUT ESR vs. Load Current 100 Unstable Range 10 COUT ESR (Ω) The RT9047 is a low voltage, low dropout linear regulator with an external bias supply input capable of supporting an input voltage range from 2.2V to 5.5V with a fixed output voltage from 1V to 2V in 0.1V increments. 1 Stable Range 0.1 0.01 VIN = 2.5V, VOUT = 1.2V, COUT = 4.7μF / X7R 0.001 0.0 0.3 0.5 0.8 1.0 Load Current (A) Figure 1 Thermal Considerations For continuous operation, do not exceed absolute maximum junction temperature. The maximum power dissipation depends on the thermal resistance of the IC package, PCB layout, rate of surrounding airflow, and difference between junction and ambient temperature. The maximum power dissipation can be calculated by the following formula : PD(MAX) = (TJ(MAX) − TA) / θJA where TJ(MAX) is the maximum junction temperature, TA is the ambient temperature, and θJA is the junction to ambient thermal resistance. For recommended operating condition specifications of the RT9047, the maximum junction temperature is 125°C and TA is the ambient temperature. The junction to ambient thermal resistance, θJA, is layout dependent. For SOT223-5 packages, the thermal resistance, θJA, is 78°C/W www.richtek.com 7 RT9047 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 formula : PD(MAX) = (125°C − 25°C) / (78°C/W) = 1.282W for SOT-223-5 package Maximum Power Dissipation (W)1 The maximum power dissipation depends on the operating ambient temperature for fixed T J(MAX) and thermal resistance, θJA. For the RT9047 package, the derating curve in Figure 2 allows the designer to see the effect of rising ambient temperature on the maximum power dissipation. 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 0 25 50 75 100 125 Ambient Temperature (°C) Figure 2. Derating Curves for the RT9047 Package www.richtek.com 8 DS9047-03 November 2011 RT9047 Outline Dimension Symbol Dimensions In Millimeters Dimensions In Inches Min Max Min Max A 1.400 1.800 0.055 0.071 A1 0.020 0.100 0.001 0.004 b 0.410 0.530 0.016 0.021 B 3.300 3.700 0.130 0.146 C 6.700 7.300 0.264 0.287 D 6.300 6.700 0.248 0.264 b1 2.900 3.100 0.114 0.122 e 1.270 0.050 H 0.230 0.350 0.009 0.014 L 1.500 2.000 0.059 0.079 L1 0.800 1.100 0.031 0.043 5-Lead SOT-223 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. DS9047-03 November 2011 www.richtek.com 9