Preliminary RT9166/A 300/500mA, Ultra-Fast Transient Response LDO Regulator General Description The RT9166/A series are CMOS low dropout regulators optimized for ultra-fast transient response. The devices are capable of supplying 300mA or 500mA of output current with a dropout voltage of 230mV or 430mV respectively. The RT9166/A’s performance is optimized for CD/DVD-ROM, CD/RW or wireless communication supply applications. The RT9166/A regulators are stable with output capacitors as low as 1µF. The other features include ultra low dropout voltage, high output accuracy, current limiting protection, and high ripple rejection ratio. The devices are available in fixed output voltages range of 1.2V to 4.5V with 0.1V per step. The RT9166/A regulators are available in 3-lead SOT-23, SOT-89, SOT-223 and TO-92 packages. Ordering Information Features Low Quiescent Current (Typically 220µA) Guaranteed 300/500mA Output Current Low Dropout Voltage: 230/430mV at 300/500mA Wide Operating Voltage Ranges: 3V~5.5V Ultra-Fast Transient Response Tight Load and Line Regulation Current Limiting Protection Thermal Shutdown Protection Only low-ESR Ceramic Capacitor Required for Stability Custom Voltage Available Applications CD/DVD-ROM, CD/RW Wireless LAN Card/Keyboard/Mouse Battery-Powered Equipment XDSL Router PCMCIA Card Marking Information RT9166/APackage Type VL : SOT-23 X : SOT-89 XL : SOT-89 L type G : SOT-223 GL : SOT-223 L type Z : TO-92 For marking information, contact our sales representative directly or through a RichTek distributor located in your area, otherwise visit our website for detail. Operating Temperature Range C: Commercial Standard Output Voltage 12 : 1.2V 13 : 1.3V : 45 : 4.5V 500mA Output Current 300mA Output Current DS9166A-03 July 2003 www.richtek.com 1 RT9166/A Preliminary Pin Configurations Part Number Typical Application Circuit Pin Configurations RT9166CVL (Plastic SOT-23) VIN 1. GND 2. VOUT 3. VIN 2 1 RT9166/A TOP VIEW 3 RT9166/ACG (Plastic SOT-223) 1µF C IN VOUT VOUT VIN + _ GND + 1µF _ C OUT TOP VIEW 1 2 3 RT9166/ACGL (Plastic SOT-223) 1. VOUT 2. GND (TAB) 3. VIN TOP VIEW Note: To prevent oscillation, a 1µF minimum X7R or X5R ceramic is strongly recommended if ceramics are used as input/output capacitors. When using the Y5V ceramic, the minimum value of the input/output capacitance that can be used for stable over full operating temperature range is 3.3µF. (see Application Information Section for further details) 1. VOUT 2. GND (TAB) 3. VIN Pin Description TOP VIEW 1 2 3 RT9166/ACX (Plastic SOT-89) 1 2 3 1. GND 2. VIN (TAB) 3. VOUT Pin Name RT9166/ACXL (Plastic SOT-89) TOP VIEW 1 2 3 RT9166/ACZ (Plastic TO-92) 1. GND 2. VIN (TAB) 3. VOUT Pin Function VIN Supply Input VOUT Regulator Output GND Common Ground TOP VIEW 1 2 3 1. VIN 2. GND 3. VOUT Function Block Diagram VOUT VIN Current Limiting Sensor Thermal Shutdown www.richtek.com 2 Error Amp _ + 1.2V Reference GND DS9166A-03 July 2003 RT9166/A Preliminary Absolute Maximum Ratings (Note 1) Supply Input Voltage Power Dissipation, PD @ TA = 25°C SOT-23 SOT-223 SOT-89 TO-92 Package Thermal Resistance SOT-23, θJA SOT-223, θJC SOT-223, θJA SOT-89, θJC SOT-89, θJA TO-92, θJA Lead Temperature (Soldering, 10 sec.) Junction Temperature Storage Temperature Range ESD Susceptibility (Note 2) HBM MM 6.5V 0.25W 2W 0.5W 0.6W 250°C/W 15°C/W 60°C/W 100°C/W 180°C/W 160°C/W 260°C 150°C −65°C to 150°C 2kV 200V Recommended Operating Conditions (Note 3) Supply Input Voltage Junction Temperature Range 2.8V to 5.5V −40°C to 125°C Electrical Characteristics (VIN = VOUT + 1V or VIN = 2.8V whichever is greater, CIN = 1µF, COUT = 1µF, TA = 25°C, unless otherwise specified) Parameter Symbol Output Voltage Accuracy RT9166 Current Limit RT9166A Quiescent Current (Note 6) Dropout Voltage (Note 4) RT9166 RT9166A Test Conditions Min Typ Max Units −1 -- +3 % 300 -- -- 500 -- -- ∆VOUT IOUT = 1mA ILIM RLOAD = 1Ω IQ IOUT = 0mA -- 220 300 IOUT = 300mA -- 230 -- IOUT = 500mA VIN = (VOUT + 0.3V) to 5.5V, IOUT = 1mA -- 430 -- -- 0.2 -- %/V VDROP mA µA mV Line Regulation ∆VLINE Load Regulation (Note 5) ∆VLOAD 1mA < IOUT < 300mA 1mA < IOUT < 500mA --- 15 25 35 50 mV Power Supply Rejection Rate PSRR f = 1kHz, COUT = 1µF -- −55 -- dB Thermal Shutdown Temperature TSD -- 170 -- °C Thermal Shutdown Hysteresis ∆TSD -- 40 -- °C DS9166A-03 July 2003 www.richtek.com 3 RT9166/A Preliminary Note 1. Stresses beyond those listed under “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 for extended periods may affect device reliability. Note 2. Devices are ESD sensitive. Handling precaution recommended. The human body model is a 100pF capacitor discharged through a 1.5KΩ resistor into each pin. Note 3. The device is not guaranteed to function outside its operating conditions. Note 4. Dropout voltage is defined as the input to output differential at which the output voltage drops 1% below its nominal value measured at 1V differential. Dropout voltage does not apply to some lower voltage versions since the dropout voltage limited by input voltage range limitations. Note 5. 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 300mA and 500mA respectively. 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. www.richtek.com 4 DS9166A-03 July 2003 RT9166/A Preliminary Typical Operating Characteristics Dropout Voltage vs. Output Current VIN = 5V CIN = 1µF COUT = 1µF 500 Power Supply Rejection Ratio 0 400 TJ = +25°C 300 TJ = -40°C 200 VIN = 5V CIN = 1µF COUT = 1µF -10 TJ = +125°C PSRR (dB) Dropout Voltage (mV) 600 -20 -30 100mA -40 1mA 100 -50 0 -60 0 100 200 300 400 500 10 10 100 100 Output Current (mA) Output Noise Signal (µV) Output Capacitor ESR (Ω) Unstable Region 1 Stable Region 0.1 COUT = 1µF VIN = 5V CIN = 1µF 1M 1000000 ILOAD = 100mA COUT = 1µF 400 200 0 -200 -400 f = 10Hz to 100kHz 0.01 0 100 200 300 400 500 Time: 1mS/Div Output Current (mA) Current Limit vs. Input voltage Current Limit vs. Input voltage 900 900 850 850 Current Limit (mA) Current Limit (mA) 100k 100000 Output Noise COUT = 10µF 10 10k 10000 Frequency (Hz) Range of Stable ESR 100 1k 1000 800 VIN = 5V CIN = 1µF COUT = 1µF RL = 0.5Ω 750 RT9166-33CX 700 3 3.5 4 4.5 5 5.5 800 VIN = 5V CIN = 1µF COUT = 1µF RL = 0.5Ω 750 RT9166-33CVL 700 3 3.5 4 4.5 5 5.5 Input voltage (V) DS9166A-03 July 2003 www.richtek.com 5 RT9166/A Preliminary Current Limit vs. Temperature 900 850 850 Current Limit (mA) Current Limit (mA) Current Limit vs. Temperature 900 800 750 VIN = 5V CIN = 1µF COUT = 1µF RL = 0.5Ω 700 -50 -40 -25 RT9166-33CX 0 25 50 75 100 800 750 VIN = 5V CIN = 1µF COUT = 1µF RL = 0.5Ω 700 -40 -50 125 Temperature (°C) 240 240 (µA)1 Quiescent Current (uA) (µA) 1 Quiescent Current (uA) 260 220 200 180 140 -40 -50 -25 25 50 160 75 100 VIN = 5V CIN = 1µF COUT = 1µF 140 -40 -50 125 -25 RT9166-33CVL 0 3.35 Output Voltage (V) Output Voltage (V) 3.35 3.3 RT9166-33CX 0 25 50 75 Temperature (°C) www.richtek.com 6 25 50 75 100 125 Temperature Stability 3.4 -25 125 Temperature (°C) Temperature Stability 3.2 -40 -50 100 180 3.4 VIN = 5V CIN = 1µF COUT = 1µF 75 200 Temperature (°C) 3.25 50 220 RT9166-33CX 0 25 Quiescent Current vs. Temperature Quiescent Current vs. Temperature VIN = 5V CIN = 1µF COUT = 1µF 0 Temperature (°C) 260 160 -25 RT9166-33CVL 100 125 3.3 3.25 3.2 VIN = 5V CIN = 1µF COUT = 1µF -50 -40 -25 RT9166-33CVL 0 25 50 75 100 125 Temperature (°C) DS9166A-03 July 2003 RT9166/A Preliminary Load Transient Response Load Transient Response Load Current (mA) VIN = 5V ILOAD = 1 to 150mA 200 CIN = COUT = 1µF (Ceramic, X7R) Output Voltage Deviation (mV) 100 100 0 20 0 -20 0 Output Voltage Deviation (mV) Load Current (mA) VIN = 5V ILOAD = 1 to 150mA C 200 IN = COUT = 1µF (Ceramic, X7R) 20 0 -20 RT9166-33CX Time: 100µS/Div RT9166-33CVL Time: 100µS/Div Output Voltage Deviation (mV) Input Voltage Deviation (V) Line Transient Response 5 VIN = 4 to 5V CIN = 1µF COUT = 1µF 4 20 0 -20 Time: 1mS/Div DS9166A-03 July 2003 www.richtek.com 7 RT9166/A Preliminary Application Information Like any low-dropout regulator, the RT9166/A series requires input and output decoupling capacitors. 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 ≅1µF 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 ≅1µF over the entire operating temperature range. OUTPUT CAPACITOR The RT9166/A is designed specifically to work with very small ceramic output capacitors. The recommended minimum capacitance (temperature characteristics X7R or X5R) is 1µF to 4.7µF range with 10mΩ to 50mΩ range ceramic capacitor between 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. (When using the Y5V dielectric, the minimum value of the input/output capacitance that can be used for stable over full operating temperature range is 3.3µF.) 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: VDROUPOUT = VIN – VOUT = RDS(ON) × IOUT CURRENT LIMIT The RT9166/A monitors and controls the PMOS’ gate voltage, minimum limiting the output current to 300mA for RT9166 and 500mA for RT9166A. The output 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). DS9166A-03 July 2003 Preliminary Aluminum electrolytics also typically have large temperature variation of capacitance value. 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. DS9166A-03 July 2003 RT9166/A 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. 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. www.richtek.com 9 RT9166/A Preliminary THERMAL CONSIDERATIONS The RT9166/A series can deliver a current of up to 300/500mA 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. Power dissipation can be calculated based on the output current and the voltage drop across regulator. PD = (VIN – VOUT) IOUT + VIN IGND 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 TA is the maximum ambient temperature. The junction to ambient thermal resistance (θJA) for SOT-23 package at recommended minimum footprint is 250°C/W, 180°C/W for SOT-89 package, 60°C/W for SOT-223 package (θJA is layout dependent), and 160°C/W for TO-92 package. Visit our website in which “Recommended Footprints for Soldering Surface Mount Packages” for detail. 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: IN GND VOUT SOT-23 Board Layout PCB LAYOUT 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 VIN, 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”. www.richtek.com 10 DS9166A-03 July 2003 RT9166/A Preliminary Package Information H D L C B e A A1 b Symbol Dimensions In Millimeters Dimensions In Inches Min Max Min Max A 0.889 1.295 0.035 0.051 A1 -- 0.152 -- 0.006 B 1.397 1.803 0.055 0.071 b 0.356 0.508 0.014 0.020 C 2.591 2.997 0.102 0.118 D 2.692 3.099 0.106 0.122 e 1.803 2.007 0.071 0.079 H 0.102 0.254 0.004 0.010 L 0.356 0.610 0.014 0.024 SOT-23 Plastic Surface Mount DS9166A-03 July 2003 www.richtek.com 11 RT9166/A Preliminary D D1 A B C C1 e e H A b Symbol b1 b Dimensions In Millimeters Dimensions In Inches Min Max Min Max A 1.397 1.600 0.055 0.063 b 0.356 0.483 0.014 0.019 B 2.388 2.591 0.094 0.102 b1 0.406 0.533 0.016 0.021 C -- 4.242 -- 0.167 C1 0.787 1.194 0.031 0.047 D 4.394 4.597 0.173 0.181 D1 1.397 1.753 0.055 0.069 e 1.448 1.549 0.057 0.061 H 0.355 0.432 0.014 0.017 3-Lead SOT-89 Surface Mount www.richtek.com 12 DS9166A-03 July 2003 RT9166/A Preliminary D D1 H C B L e e A A1 b Symbol Dimensions In Millimeters Dimensions In Inches Min Max Min Max A -- 1.803 -- 0.071 b 0.610 0.787 0.024 0.031 B 3.302 3.708 0.130 0.146 C 6.706 7.290 0.264 0.287 D 6.299 6.706 0.248 0.264 D1 2.896 3.150 0.114 0.124 e 2.261 2.362 0.089 0.093 H 0.229 0.330 0.009 0.013 L 0.914 -- 0.036 -- 3-Lead SOT-223 Plastic Surface Mount DS9166A-03 July 2003 www.richtek.com 13 RT9166/A Preliminary A D E L b e C D1 A1 Symbol Dimensions In Millimeters Dimensions In Inches Min Max Min Max A 3.175 4.191 0.125 0.165 A1 1.143 1.372 0.045 0.054 b 0.406 0.533 0.016 0.021 C 0.406 0.533 0.016 0.021 D 4.445 5.207 0.175 0.205 D1 3.429 -- 0.135 -- E 4.318 5.334 0.170 0.210 e 1.143 1.397 0.045 0.055 L 12.700 -- 0.500 -- 3-Lead TO-92 Package www.richtek.com 14 DS9166A-03 July 2003 Preliminary DS9166A-03 July 2003 RT9166/A www.richtek.com 15 RT9166/A Preliminary RICHTEK TECHNOLOGY CORP. RICHTEK TECHNOLOGY CORP. Headquarter Taipei Office (Marketing) 5F, No. 20, Taiyuen Street, Chupei City 8F-1, 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 16 DS9166A-03 July 2003