RT9043 High PSRR, Low Dropout, 400mA Adjustable LDO Regulator General Description Features The RT9043 is a high-performance, 400mA LDO regulator, offering high PSRR and low dropout. The quiescent current is as low as 35μA, further prolonging the battery life. The RT9043 also works with low-ESR ceramic capacitors, reducing the amount of board space necessary for power applications, critical in handheld wireless devices. z Adjustable Output Voltage z Enable/Shutdown Control Wide Operating Voltage Range : 2.2V to 5.5V Low Dropout : 230mV at 400mA Low-Noise for RF Application Ultra-Fast Response in Line/Load Transient Current Limit Protection High Power Supply Rejection Ratio Output Only 1μ μF Capacitor Required for Stability RoHS Compliant and Halogen Free z z z z z The RT9043 consumes typical 0.7μA in shutdown mode. The other features include low dropout voltage, high output accuracy, current limit protection, and enable/shutdown control. The RT9043 is available in the SOT-23-5 package. z z z Applications Ordering Information z RT9043 - z Package Type B : SOT-23-5 z z Lead Plating System G : Green (Halogen Free and Pb Free) z Note : z Richtek products are : z ` RoHS compliant and compatible with the current require- Pin Configurations ments of IPC/JEDEC J-STD-020. ` Mega SIM Card CDMA/GSM Cellular Handsets Portable Information Appliances Laptop, Palmtops, Notebook Computers Hand-Held Instruments Mini PCI & PCI-Express Cards PCMCIA & New Cards Suitable for use in SnPb or Pb-free soldering processes. (TOP VIEW) Marking Information VOUT FB 5 4 For marking information, contact our sales representative directly or through a Richtek distributor located in your area. 2 3 VIN GND EN SOT-23-5 Typical Application Circuit 1 VIN Chip Enable CIN 1µF VOUT 5 EN VOUT COUT 1µF RT9043 3 R3 10k DS9043-02 April 2011 VIN FB GND R1 4 2 R2 www.richtek.com 1 RT9043 Function Block Diagram Functional Pin Description Pin No. EN Current Limit POR OTP VIN VREF FB + MOSFET Driver VOUT Pin Nam e Pin Function 1 VIN Voltage Input. 2 GND Ground. 3 EN Chip Enable (Active High). 4 FB Output Voltage Feedback. 5 VOUT Voltage Output. GND Absolute Maximum Ratings z z z z z z z z (Note 1) Supply Input Voltage, VIN ------------------------------------------------------------------------------------------------ 6V EN Input Voltage ----------------------------------------------------------------------------------------------------------Power Dissipation, PD @ TA = 25°C SOT-23-5 -------------------------------------------------------------------------------------------------------------------Package Thermal Resistance (Note 2) SOT-23-5, θJA --------------------------------------------------------------------------------------------------------------Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------------Junction Temperature ----------------------------------------------------------------------------------------------------Storage Temperature Range -------------------------------------------------------------------------------------------ESD Susceptibility (Note 3) HBM -------------------------------------------------------------------------------------------------------------------------MM ---------------------------------------------------------------------------------------------------------------------------- Recommended Operating Conditions z z 6V 0.4W 250°C/W 260°C 150°C −65°C to 150°C 2kV 200V (Note 4) Junction Temperature Range -------------------------------------------------------------------------------------------- −40°C to 125°C Ambient Temperature Range -------------------------------------------------------------------------------------------- −40°C to 85°C www.richtek.com 2 DS9043-02 April 2011 RT9043 Electrical Characteristics (VIN = 3.7V, CIN = COUT = 1μF, IOUT = 20mA, TA = 25°C, unless otherwise specified) Parameter Symbol Test Conditions Min Typ Max Unit 2.2 1.188 -1.200 5.5 1.212 V V Input Voltage Range Reference Voltage VIN VREF Quiescent Current IQ IOUT = 0mA -- 35 50 μA Shutdown Current ISHDN VEN = 0V -- 0.7 1.5 μA Current Limit ILIM RLOAD = 0Ω, 2.2V ≤ VIN < 5.5V 400 650 -- mA Dropout Voltage VDROP IOUT = 400mA -- 230 350 mV Load Regulation ΔVLOAD -- -- 1 % Line Regulation ΔVLINE -- 0. 01 0.2 %/V 1mA < IOUT < 400mA 2.2V ≤ V IN < 5.5V VIN = (V OUT + 0.5V) to 5.5V, IOUT = 1mA Logic-Low Voltage VIL 0 -- 0.6 Logic-High Voltage VIH 1.6 -- 5.5 EN Pin Current IEN -- 0.1 1 μA FB Pin Current IFB -- 0.1 1 μA Power Supply Rejection Ratio PSRR f = 1kHz, IOUT = 10mA -- 67 -- dB f = 10kHz, IOUT = 10mA -- 56 -- dB Output Noise Voltage VON VOUT = 1.5V, COUT = 1μF, IOUT = 0mA -- 30 -- μVRMS Thermal Shutdown Temperature TSD -- 160 -- °C -- 110 -- °C EN Threshold Thermal Shutdown Recovery Temperature V 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 thermal conductivity test board of JEDEC 51-3 thermal measurement standard. Note 3. Devices are ESD sensitive. Handling precaution is recommended. Note 4. The device is not guaranteed to function outside its operating conditions. DS9043-02 April 2011 www.richtek.com 3 RT9043 Typical Operating Characteristics Quiescent Current vs. Temperature Reference Voltage vs. Temperature 36 1.215 34 Quiescent Current (uA) Reference Voltage (V) 1.210 1.205 1.200 1.195 1.190 32 30 28 26 24 22 VIN = VEN = 3.3V, No Laod 1.185 -40 -25 -10 5 20 35 50 65 80 VIN = VEN = 3.3V, VOUT = 2.5V, No Laod 20 -40 -25 -10 95 110 125 5 50 65 80 95 110 125 EN Threshold vs. Temperature Dropout Voltage vs. Load Current 1.6 350 TA = 125°C 300 1.5 1.4 TA = 25°C 250 200 150 TA = −40°C 100 EN Threshold (V) Dropout Voltage (mV) 35 Temperature (°C) Temperature (°C) 1.3 1.2 1.1 1 Rising 0.9 Falling 0.8 50 0.7 VIN = VEN = 3.3V, VOUT = 2.5V 0 0 50 100 150 200 250 300 350 VIN = 3.3V, No Laod 0.6 -40 400 -20 0 20 40 60 80 100 Temperature (°C) Load Current (mA) Current Limit vs. Input Voltage Current Limit vs. Temperature 700 700 675 675 650 650 Current Limit (mA) Current Limit (mA) 20 625 600 575 550 525 VOUT = 1.8V 500 2 2.5 3 3.5 4 Input Voltage (V) www.richtek.com 4 4.5 5 5.5 625 600 575 550 525 500 475 VIN = 3.3V, VOUT = 1.8V 450 -50 -25 0 25 50 75 100 125 Temperature (°C) DS9043-02 April 2011 RT9043 0 Line Transient Response PSRR ILOAD = 10mA, CIN = COUT = 1μF/X7R VIN = 4V to 5V, VOUT = 2.5V, ILOAD = 1mA, COUT = 1μF/X7R -10 PSRR(dB) -20 5 VIN (V/Div) 4 -30 -40 -50 VOUT (20mV/Div) -60 -70 -80 10 100 1K 1000 10K 10000 100K 100000 Time (50μs/Div) 1M 1000000 Frequency (Hz) Load Transient Response Load Transient Response VIN = 3.3V, VOUT = 2.5V, ILOAD = 1mA to 400mA, CIN = COUT = 1μF/X7R VIN = 3.3V, VOUT = 2.5V, ILOAD = 200mA to 400mA, CIN = COUT = 1μF/X7R VOUT (10mV/Div) VOUT (10mV/Div) IOUT (200mA/Div) IOUT (200mA/Div) Time (100μs/Div) Time (100μs/Div) Power On from EN Enable/Shutdown Response VIN = 5V, VOUT = 2.5V, ILOAD = 10mA VIN = 3.3V, VOUT = 2.5V, No Load VEN (5V/Div) VEN (5V/Div) VOUT (1V/Div) VOUT (1V/Div) Time (5μs/Div) DS9043-02 April 2011 Time (500μs/Div) www.richtek.com 5 RT9043 Application Information Input Capacitor Selection Output Voltage Setting Like any low-dropout linear regulator, the external capacitors used with the RT9043 must be carefully selected for stability and performance. The input capacitance is recommended to be at least 1μF, and can be increased without limit. The input capacitor must be located at a distance of less than 0.5 inch from the input pin of the IC and returned to a clean ground plane. Any high-quality ceramic capacitor or tantalum capacitor can be used for the input capacitor. Using input capacitor with larger capacitance and lower ESR (equivalent series resistance) can obtain better PSRR and line transient response. The output voltage divider R1 and R2 allows to adjust the output voltage for various application as shown in Figure 2. Output Capacitor Selection The output capacitor must meet both the requirements for minimum capacitance and minimum ESR value in all applications. The RT9043 is designed specifically to work with low ESR ceramic output capacitor to save board space and have better performance. Figure 1 shows the allowable ESR range for stable operation as a function of load current and output capacitance value. Use at least 1μF ceramic output capacitor which ESR is within the stable operation range to ensure stability. Larger capacitance can reduce noise and improve load transient response, stability, and PSRR. The RT9043 can operate with other types of output capacitor due to its wide stable operation range. The output capacitor should be placed less than 0.5 inch from the VOUT and returned to a clean ground plane. Region StableC COUT ESR (ohm) (Ω) Region ofof Stable OUT ESR Region of Stable COUT ESR vs. Load Current 100.00 COUT = 1μF Unstable Region 10.00 V OUT R1 FB R9043 R2 GND Figure 2. Output Voltage Setting The output voltage is set according to the following equation: R1 ⎞ ⎛ VOUT = VFB ⎜ 1 + ⎟ R2 ⎝ ⎠ Where VFB is the feedback reference voltage (1.2V typical). Enable Function The RT9043 features enable/shutdown function. The voltage at the EN pin determines the enable/shutdown state of the regulator. To ensure the regulator will switch on, the enable control voltage must be greater than 1.6V. The regulator will enter shutdown mode when the voltage at EN pin falls below 0.6 volt. If the enable function is not needed, EN pin should be pulled high or simply tied to VIN to keep the regulator in on state. PSRR RT9043 features high power supply rejection ratio (PSRR), which is defined as the ratio of output voltage change against input voltage change. ⎛ ΔVOUT ⎞ PSRR = 20 × log ⎜ ⎟ ⎝ ΔV IN ⎠ A low-dropout regulator with higher PSRR can provide better line transient performance. 1.00 Current Limit 0.10 Stable Region 0.01 Unstable Region (Simulation Verity) 0.00 0 50 100 150 200 250 Load Current (mA) Figure 1 www.richtek.com 6 300 350 400 The RT9043 implements an independent current limit circuit, which monitors and controls the pass element’s gate voltage to limit the output current at 650mA (typ.). If the current limit condition lasts for a long time, the regulator temperature may increase high enough to damage the regulator itself. There fore, RT9043 implements current limit function and thermal protection function to prevent DS9043-02 April 2011 RT9043 Thermal Considerations For continuous operation, do not exceed absolute maximum operation junction temperature. 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 ) / θJA Where T J(MAX) is the maximum operation junction temperature, TA is the ambient temperature and the θJA is the junction to ambient thermal resistance. 0.50 Maximum Power Dissipation (W) the regulator from damaging when the output is shorted to ground. Single Layer PCB 0.45 0.40 0.35 SOT-23-5 0.30 0.25 0.20 0.15 0.10 0.05 0.00 0 25 50 75 100 125 Ambient Temperature (°C) Figure 3. Derating Curves for RT9043 Packages For recommended operating conditions specification of RT9043, the maximum junction temperature is 125°C. The junction to ambient thermal resistance θJA is layout dependent. For SOT-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 : P D(MAX) = (125°C − 25°C) / (250°C/W) = 0.4W for SOT-23-5 packages The maximum power dissipation depends on operating ambient temperature for fixed T J(MAX) and thermal resistance θJA. For RT9043 packages, the Figure 3 of derating curves allows the designer to see the effect of rising ambient temperature on the maximum power allowed. DS9043-02 April 2011 www.richtek.com 7 RT9043 Outline Dimension H D L B C b A A1 e Dimensions In Millimeters Dimensions In Inches Symbol 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 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 8 DS9043-02 April 2011