RT9185 Triple, Ultra-Fast CMOS LDO Regulator General Description Features The RT9185 series are efficient, precise triple-channel CMOS LDO regulators specifically designed for motherboard application. The device is intended to powering the standby voltage in which 3.3V_PCI, 2.5V_Clock and 1.8V_ICH2 or 1.5V_ICH4 core voltage of the PC based computer system. Moreover, it is also optimized for CD/ DVD-ROM, CD/RW, XDSL Router or IA equipments applications. The regulator outputs are capable of sourcing 1.5A, 0.8A and 0.3A of output current respectively. z Fixed Output Voltages : 3.35V at 1.5A, 2.55V at 0.8A and 1.5V or 1.8V at 0.3A z Low Quiescent Current (Typically 0.4mA) Operating Voltage Ranges : 3.5V to 5.5V Ultra-Fast Transient Response Tight Load and Line Regulation Current Limiting Protection Thermal Shutdown Protection Only Low-ESR Ceramic Capacitors Required for Stability Custom Voltage Available RoHS Compliant and 100% Lead (Pb)-Free The RT9185 also works with low-ESR ceramic capacitors, reducing the amount of board space necessary for power applications. The other features include faster transient response, low dropout voltage, high output accuracy, current limiting and thermal shutdown protections. z z z z z z z z Applications z The RT9185 regulators are available in fused SOP-8, 5-lead TO-252 and 5-lead TO-263 packages. Ordering Information z z z z Mother-board Power Supply CD/DVD-ROM, CD/RW XDSL Router IA Equipments Cable Modems RT9185 Package Type S : SOP-8 L5 : TO-252-5 M5 : TO-263-5 Operating Temperature Range P : Pb Free with Commercial Standard G : Green (Halogen Free with Commercial Standard) VOUT3 A : 1.8V B : 1.5V Other voltage versions please contact RichTek for detail. Pin Configurations (TOP VIEW) VOUT1 8 GND VDD 2 7 GND VOUT2 3 6 GND VOUT3 4 5 GND SOP-8 Note : 5 VOUT3 4 3 2 VOUT2 RichTek Pb-free and Green products are : `RoHS compliant and compatible with the current require- GND (TAB) VDD VOUT1 TO-252-5 ments of IPC/JEDEC J-STD-020. `Suitable for use in SnPb or Pb-free soldering processes. 5 VOUT3 `100%matte tin (Sn) plating. 4 VOUT2 3 GND (TAB) 2 VDD VOUT1 TO-263-5 DS9185-11 March 2007 www.richtek.com 1 RT9185 Typical Application Circuit VOUT1 VOUT1 (3.35V/1.5A) VOUT3 VOUT3 (1.5V or 1.8V/0.3A) C4 1uF C2 4.7uF RT9185 VDD VDD (5VSB) VOUT2 VOUT2 (2.55V/0.8A) GND C1 2.2uF C3 4.7uF Function Block Diagram Current Limiting VDD + - Thermal Sensor VOUT1 + Error Amplifier Reference VDD Current Limiting Current Limiting + - Error Amplifier VOUT3 VDD + - + + Error Amplifier VOUT2 GND Functional Pin Description Pin Name Pin Function VOUT1 Channel 1 Output Voltage VDD Supply Input GND Common Ground VOUT2 Channel 2 Output Voltage VOUT3 Channel 3 Output Voltage www.richtek.com 2 DS9185-11 March 2007 RT9185 Absolute Maximum Ratings z z z z z z z (Note 1) Supply Input Voltage -------------------------------------------------------------------------------------------------- 7V Power Dissipation, PD @ TA = 25°C SOP-8 -------------------------------------------------------------------------------------------------------------------- 0.625W TO-252-5 ----------------------------------------------------------------------------------------------------------------- 1.471W TO-263-5 ----------------------------------------------------------------------------------------------------------------- 2.222W Package Thermal Resistance (Note 6) SOP-8, θJA -------------------------------------------------------------------------------------------------------------- 160°C/W TO-252-5, θJA ----------------------------------------------------------------------------------------------------------- 68°C/W TO-263-5, θJA ----------------------------------------------------------------------------------------------------------- 45°C/W Lead Temperature (Soldering, 10 sec.) --------------------------------------------------------------------------- 260°C Junction Temperature ------------------------------------------------------------------------------------------------- 150°C Storage Temperature Range ---------------------------------------------------------------------------------------- −65°C to 150°C ESD Susceptibility (Note 2) HBM (Human Body Mode) ------------------------------------------------------------------------------------------ 2kV MM (Machine Mode) -------------------------------------------------------------------------------------------------- 200V Recommended Operating Conditions z z (Note 3) Supply Input Voltage -------------------------------------------------------------------------------------------------- 3.5V to 5.5V Junction Temperature Range ---------------------------------------------------------------------------------------- −40°C to 125°C Electrical Characteristics (VDD = 5V, CIN = 1μF, TA = 25°C, for each LDO unless otherwise specified) Parameter Output Voltage Accuracy Symbol Line Regulation (triple LDOs) Load Regulation (Note 4) Typ Max Units IOUT1 = 1mA 3.315 3.35 3.415 VOUT2 IOUT2 = 1mA 2.525 2.55 2.60 RT9185A 1.782 1.8 1.836 1.485 1.5 1.530 RT9185B IOUT3 = 1mA V ILIM1 RLOAD = 1Ω 1.5 1.9 -- ILIM2 R LOAD = 1Ω 0.8 1.3 -- ILIM3 R LOAD = 1Ω 0.3 0.5 -- IOUT = 0mA -- 0.4 0.8 mA ΔVDROP1 IOUT1 = 1.5A -- 600 1085 mV ΔVDROP2 IOUT2 = 0.8A -- 700 -- mV ΔVLINE IOUT = 1mA, VDD = 4V to 6V -- 2 10 mV ΔVLOAD1 VOUT1, 1mA < IOUT1 <1.5A -- 30 55 ΔVLOAD2 VOUT2, 1mA < IOUT2 <0.8A -- 30 55 ΔVLOAD3 VOUT3, 1mA < IOUT3 < 0.3A -- 20 45 Quiescent Current (triple LDOs) IDD (Note 5) Dropout Voltage Min VOUT1 VOUT3 Current Limiting Test Conditions A mV Temperature Coefficient TC -- 30 -- PPM Thermal Shutdown TSD 125 165 -- °C DS9185-11 March 2007 www.richtek.com 3 RT9185 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 recommended. Note 3. The device is not guaranteed to function outside its operating conditions. Note 4. Regulation is measured at constant junction temperature by using a 20ms current pulse. Devices are tested for load regulation in the load range from 1mA to 1.5A, 0.8A and 0.3A for each LDO respectively. Note 5. 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 6. θJA is measured in the natural convection at T A = 25°C on a low effective thermal conductivity test board of JEDEC 51-3 thermal measurement standard. The pad size is 100mm2 on TO-252 packages, 125mm2 on TO-263 packages. www.richtek.com 4 DS9185-11 March 2007 RT9185 Typical Operating Characteristics Quiescient Current Temperature Stability 600 4.2 3.8 500 Iq (uA) Output Voltage (V) VOUT1 = 3.35V 3.4 3 VOUT2 = 2.55V 2.6 VDD = 5V VDD = 6V 400 2.2 VDD = 4V 300 VOUT3 = 1.8V/1.5V 1.8 200 -40 -35 1.4 -35 -40 -15 5 25 45 65 85 105 125 -15 5 25 Temperature (°C) Current Limit vs. Temperature 65 85 105 125 PSRR -10 2.5 VDD = 5V V OUT1 -20 V OUT2 -30 PSRR (dB) 2 Current Limit (A) 45 Temperature (°C) 1.5 1 TA = 25°C -40 -50 -60 V OUT3 VDD = 5V C1 = 2.2uF, C2 = 4.7uF C3 = 4.7uF, C4 = 1uF IO1, IO2, IO3 = 10mA V OUT3 V OUT2 0.5 -70 V OUT1 -80 0 -40 -35 -15 5 25 45 65 85 105 10 125 100 1K 1000 10K 10000 100K 100000 1M 1000000 Frequency (Hz) Temperature (°C) Dropout Valtage vs. Temperature Short Thermal Shutdown 1 0.8 TA = 25°C VDD = 5V C1 = 2.2uF VOUT2 = 2.55V ILoad1 (A) Dropout Valtage (V) VDD = 5V VOUT1 = 3.35V 0.6 0.4 0.2 -40 -35 -15 5 25 45 65 85 Temperature (°C) DS9185-11 March 2007 105 125 Time (25ms/Div) www.richtek.com 5 RT9185 Load Transient Response Output Voltage Deviation (mV) TA = 25°C 50 0 -50 Load Current (A) VDD = 5V, VOUT1 = 3.35V C1 = 2.2uF, C2 = 4.7uF 100 100 VDD = 5V, VOUT2 = 2.55V C1 = 2.2uF, C3 = 4.7uF ≈ 1 0 50 0 ≈ ≈ 1 0 Time (500μs/Div) Time (500μs/Div) Line Transient Response 0 ≈ ≈ 400 200 0 5 TA = 25°C IOUT1 = 500mA 0 ≈ ≈ 5.5 4.5 Time (500μs/Div) Time (100μs/Div) Line Transient Response Line Transient Response VDD = 4.5V to 5.5V 20 VOUT2 = 2.55V C1 = 2.2uF, C3 = 4.7uF 10 TA = 25°C IOUT1 = 400mA 0 ≈ ≈ 5.5 4.5 Time (100μs/Div) www.richtek.com 6 VDD = 4.5V to 5.5V VOUT1 = 3.35V C1 = 2.2uF, C2 = 4.7uF 10 -5 Output Voltage Deviation (mV) Load Current (mA) Output Voltage Deviation (mV) Output Voltage Deviation (mV) 50 -50 Input Voltage Deviation (V) TA = 25°C Input Voltage Deviation (V) VDD = 5V, VOUT3 = 1.5V 100 C1 = 2.2uF, C4 = 1uF 20 10 VDD = 4.5V to 5.5V VOUT1 = 1.5V C1 = 2.2uF, C2 = 4.7uF TA = 25°C IOUT1 = 150mA 0 -10 Input Voltage Deviation (V) Output Voltage Deviation (mV) Load Transient Response -10 TA = 25°C -50 ≈ Load Current (A) Output Voltage Deviation (mV) Load Transient Response ≈ ≈ 5.5 4.5 Time (100μs/Div) DS9185-11 March 2007 RT9185 Power Dissipation vs. Copper Area Power Dissipation vs. Copper Area 500 500 TJ = 125°C Copper Area (mm 2 ) 400 400 2 2 Copper Area (mm 2 ) TJ = 125°C 300 200 100 TA = 65°C TA = 50°C 300 200 100 TA = 65°C TA = 25°C TA = 50°C TA = 25°C SOP-8 TO-252 0 0 1 1.5 2 2.5 3 Power Dissipation (W) 2 2.5 3 3.5 4 4.5 5 Power Dissipation (W) Power Dissipation vs. Copper Area 300 2 Copper Area (mm 2 ) TJ = 125°C 250 TA = 65°C TA = 50°C TA = 25°C 200 150 TO-263-5 100 2.5 3.5 4.5 5.5 6.5 7.5 8.5 Power Dissipation (W) DS9185-11 March 2007 www.richtek.com 7 RT9185 Application Information Like any low-dropout regulator, the RT9185 requires input and output decoupling capacitors. The device is specifically designed for portable applications requiring minimum board space and smallest components. These capacitors must be correctly selected for good performance (see Capacitor Characteristics Section). Please note that linear regulators with a low dropout voltage have high internal loop gains which require care in guarding against oscillation caused by insufficient decoupling capacitance. Input Capacitor An input capacitance of ≅2.2μF is required between the device input pin and ground directly (the amount of the capacitance may be increased without limit). The input capacitor MUST be located less than 1 cm from the device to assure input stability (see PCB Layout Section). A lower ESR capacitor allows the use of less capacitance, while higher ESR type (like aluminum electrolytic) require more capacitance. Capacitor types (aluminum, ceramic and tantalum) can be mixed in parallel, but the total equivalent input capacitance/ ESR must be defined as above to stable operation. There are no requirements for the ESR on the input capacitor, but tolerance and temperature coefficient must be considered when selecting the capacitor to ensure the capacitance will be ≅2.2μF over the entire operating temperature range. Output Capacitor The RT9185 is designed specifically to work with very small ceramic output capacitors. The recommended minimum capacitance (temperature characteristics X7R, X5R, Z5U, or Y5V) are 2.2μF to 4.7μF range with 10mΩ to 50mΩ range ceramic capacitors between each LDO output and GND for transient stability, but it may be increased without limit. Higher capacitance values help to improve transient. The output capacitor's ESR is critical because it forms a zero to provide phase lead which is required for loop stability. www.richtek.com 8 No Load Stability The device will remain stable and in regulation with no external load. This is specially important in CMOS RAM keep-alive applications. Input-Output (Dropout) Voltage A regulator's minimum input-to-output voltage differential (dropout voltage) determines the lowest usable supply voltage. In battery-powered systems, this determines the useful end-of-life battery voltage. Because the device uses a PMOS, its dropout voltage is a function of drain-to-source on-resistance, RDS(ON), multiplied by the load current: VDROPOUT = VDD − VOUT = RDS(ON) x IOUT Current Limit The RT9185 monitors and controls the PMOS’ gate voltage, limiting the output current to 1.9A, 1.3A and 0.5A (typ.) respectively. The outputs can be shorted to ground for an indefinite period of time without damaging the part. Short-Circuit Protection The device is short circuit protected and in the event of a peak over-current condition, the short-circuit control loop will rapidly drive the output PMOS pass element off. Once the power pass element shuts down, the control loop will rapidly cycle the output on and off until the average power dissipation causes the thermal shutdown circuit to respond to servo the on/off cycling to a lower frequency. Please refer to the section on thermal information for power dissipation calculations. Capacitor Characteristics It is important to note that capacitance tolerance and variation with temperature must be taken into consideration when selecting a capacitor so that the minimum required amount of capacitance is provided over the full operating temperature range. In general, a good tantalum capacitor will show very little capacitance variation with temperature, but a ceramic may not be as good (depending on dielectric type). Aluminum electrolytics also typically have large temperature variation of capacitance value. DS9185-11 March 2007 RT9185 Equally important to consider is a capacitor's ESR change with temperature: this is not an issue with ceramics, as their ESR is extremely low. However, it is very important in tantalum and aluminum electrolytic capacitors. Both show increasing ESR at colder temperatures, but the increase in aluminum electrolytic capacitors is so severe they may not be feasible for some applications. Ceramic : For values of capacitance in the 10μF to 100μF range, ceramics are usually larger and more costly than tantalums but give superior AC performance for by-passing high frequency noise because of very low ESR (typically less than 10mΩ). However, some dielectric types do not have good capacitance characteristics as a function of voltage and temperature. Z5U and Y5V dielectric ceramics have capacitance that drops severely with applied voltage. A typical Z5U or Y5V capacitor can lose 60% of its rated capacitance with half of the rated voltage applied to it. The Z5U and Y5V also exhibit a severe temperature effect, losing more than 50% of nominal capacitance at high and low limits of the temperature range. X7R and X5R dielectric ceramic capacitors are strongly recommended if ceramics are used, as they typically maintain a capacitance range within ±20% of nominal over full operating ratings of temperature and voltage. Of course, they are typically larger and more costly than Z5U/Y5U types for a given voltage and capacitance. Tantalum : Solid tantalum capacitors are recommended for use on the output because their typical ESR is very close to the ideal value required for loop compensation. They also work well as input capacitors if selected to meet the ESR requirements previously listed. Tantalums also have good temperature stability: a good quality tantalum will typically show a capacitance value that varies less than 10~15% across the full temperature range of 125°C to -40°C. ESR will vary only about 2X going from the high to low temperature limits. DS9185-11 March 2007 The increasing ESR at lower temperatures can cause oscillations when marginal quality capacitors are used (if the ESR of the capacitor is near the upper limit of the stability range at room temperature). Aluminum : This capacitor type offers the most capacitance for the money. The disadvantages are that they are larger in physical size, not widely available in surface mount, and have poor AC performance (especially at higher frequencies) due to higher ESR and ESL. Compared by size, the ESR of an aluminum electrolytic is higher than either Tantalum or ceramic, and it also varies greatly with temperature. A typical aluminum electrolytic can exhibit an ESR increase of as much as 50X when going from 25°C down to -40°C. It should also be noted that many aluminum electrolytics only specify impedance at a frequency of 120Hz, which indicates they have poor high frequency performance. Only aluminum electrolytics that have an impedance specified at a higher frequency (between 20kHz and 100kHz) should be used for the device. Derating must be applied to the manufacturer's ESR specification, since it is typically only valid at room temperature. Any applications using aluminum electrolytics should be thoroughly tested at the lowest ambient operating temperature where ESR is maximum. Thermal Considerations The RT9185 is a triple channel CMOS regulator designed to provide two output voltage from one package. Each output pin the RT9185 can deliver a current of up to 1.5A, 0.8A and 0.3A respectively over the full operating junction temperature range. However, the maximum output current must be derated at higher ambient temperature to ensure the junction temperature does not exceed 125°C. With all possible conditions, the junction temperature must be within the range specified under operating conditions. Each regulator contributes power dissipation to the overall power dissipation of the package. Power dissipation can be calculated based on the output current and the voltage drop across each regulator. www.richtek.com 9 RT9185 PD = (VDD - VOUT1) IOUT1 + (VDD - VOUT2) IOUT2 + (VDD VOUT3) IOUT3 + VIN IGND Although the device is rated for 1.5A, 0.8A and 0.3A of output current, the application may limit the amount of output current based on the total power dissipation and the ambient temperature. The final operating junction temperature for any set of conditions can be estimated by the following thermal equation: PD (MAX) = ( TJ (MAX) - TA ) / θJA Where TJ (MAX) is the maximum junction temperature of the die (125° C) and T A is the maximum ambient temperature. θJA is the thermal resistance from the junction to the surrounding environment which is combined with θJC + θCA. Where θJC is junction to case thermal resistance which for fused SOP-8 is 20°C/W, TO-252-5 is 10°C/W and TO-263-5 is 5.5°C/W, θCA is case to ambient thermal resistance which depend on PCB board area and air flow. PCB Layout The RT9185 is a fixed output voltage regulator which the voltage are sensed at the output pin. A long PCB trace to load will cause a voltage drop between load and RT9185. Be careful with PCB layout which minimum the output trace length and maximum the trace width. Good board layout practices must be used or instability can be induced because of ground loops and voltage drops. The input and output capacitors MUST be directly connected to the input, output, and ground pins of the device using traces which have no other currents flowing through them. The best way to do this is to layout CIN and COUT near the device with short traces to the VDD, VOUT, and ground pins. The regulator ground pin should be connected to the external circuit ground so that the regulator and its capacitors have a “single point ground”. It should be noted that stability problems have been seen in applications where “vias” to an internal ground plane were used at the ground points of the device and the input and output capacitors. This was caused by varying ground potentials at these nodes resulting from current flowing through the ground plane. Using a single point ground technique for the regulator and it's capacitors fixed the problem. Since high current flows through the traces going into VIN and coming from VOUT, Kelvin connect the capacitor leads to these pins so there is no voltage drop in series with the input and output capacitors. Optimum performance can only be achieved when the device is mounted on a PC board according to the diagram below: TRACE RESISTANCE RT9185 VDD RP VOUT1 IO + + VOUT3 VOUT2 DROP = IO * RP LOAD GND GND PLANE The GND pin of the RT9185 performs the dual function of providing an electrical connection to ground and channeling heat away. Connect the GND pin to ground using a large pad or ground plane. www.richtek.com 10 DS9185-11 March 2007 RT9185 GND + + VOUT1 VOUT3 + GND + VDD GND VOUT2 SOP-8 Board Layout GND + + VOUT1 VOUT3 + GND + VDD VOUT2 GND TO-252-5/TO-263-5 Board Layout DS9185-11 March 2007 www.richtek.com 11 RT9185 Outline Dimension H A M J B 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 3.988 0.150 0.157 C 1.346 1.753 0.053 0.069 D 0.330 0.508 0.013 0.020 F 1.194 1.346 0.047 0.053 H 0.170 0.254 0.007 0.010 I 0.050 0.254 0.002 0.010 J 5.791 6.200 0.228 0.244 M 0.400 1.270 0.016 0.050 8-Lead SOP Plastic Package www.richtek.com 12 DS9185-11 March 2007 RT9185 E C2 R b3 L3 T V S D H L b P L2 A Symbol Dimensions In Millimeters Dimensions In Inches Min Max Min Max A 2.184 2.388 0.086 0.094 b 0.381 0.889 0.015 0.035 b3 4.953 5.461 0.195 0.215 C2 0.457 0.889 0.018 0.035 D 5.334 6.223 0.210 0.245 E 6.350 6.731 0.250 0.265 H 9.000 10.414 0.354 0.410 L 0.508 1.780 0.020 0.070 L2 L3 0.508 Ref. 0.889 2.032 0.020 Ref. 0.035 0.080 P 1.270 Ref. 0.050 Ref. V 5.200 Ref. 0.205 Ref. R 0.200 1.500 0.008 0.059 S 2.500 3.400 0.098 0.134 T 0.500 0.850 0.020 0.033 5-Lead TO-252 Surface Mount Package DS9185-11 March 2007 www.richtek.com 13 RT9185 C D U B V E L1 L2 b e b2 A Symbol Dimensions In Millimeters Dimensions In Inches Min Max Min Max A 4.064 4.826 0.160 0.190 B 1.143 1.676 0.045 0.066 b 0.660 0.914 0.026 0.036 b2 0.305 0.584 0.012 0.023 C 1.143 1.397 0.045 0.055 D 9.652 10.668 0.380 0.420 E 8.128 9.652 0.320 0.380 e 1.524 1.829 0.060 0.072 L1 14.605 15.875 0.575 0.625 L2 2.286 2.794 0.090 0.110 U 6.223 Ref. 0.245 Ref. V 7.620 Ref. 0.300 Ref. 5-Lead TO-263 Surface Mount 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: [email protected] www.richtek.com 14 DS9185-11 March 2007