RT9168/A 200mA/500mA Fixed Output Voltage LDO Regulator General Description Features The RT9168/A is a 200mA/500mA low dropout and micropower regulator suitable for portable applications. The output voltages range from 1.5V to 5.0V in 100mV increments and 2% accuracy. The RT9168/A is designed for use with very low ESR capacitors. The output remains stable even with a 1μF ceramic output capacitor. z Stable with Low-ESR Output Capacitor z Low Dropout Voltage (220mV at 200mA) μA Typical Low Operation Current −80μ Shutdown Function Low Temperature Coefficient Current and Thermal Limiting Custom Voltage Available SOT-23-5 and SOP-8 Packages RoHS Compliant and 100% Lead (Pb)-Free The RT9168/A uses an internal PMOS as the pass device, which does not cause extra GND current in heavy load and dropout conditions. The shutdown mode of nearly zero operation current makes the IC suitable for batterypowered devices. Other features include current limiting and over temperature protection. The SOT-23-5 and SOP-8 packages are also available for larger power dissipation and design flexibility. z z z z z z z Applications z z z z Ordering Information RT9168/A Package Type BR : SOT-23-5 S : SOP-8 SH : SOP-8, High Shutdown Cellular Telephones Laptop, Notebook, and Palmtop Computers Battery-powered Equipment Hand-held Equipment Marking Information For marking information, contact our sales representative directly or through a Richtek distributor located in your area. Pin Configurations Lead Plating System P : Pb Free G : Green (Halogen Free and Pb Free) (TOP VIEW) Output Voltage 15 : 1.5V 16 : 1.6V : : 49 : 4.9V 50 : 5.0V 500mA Output Current 200mA Output Current Note : Richtek products are : ` RoHS compliant and compatible with the current require- NC EN 5 4 2 3 VOUT GND VIN SOT-23-5 VOUT 8 VIN GND 2 7 GND GND 3 6 GND NC 4 5 EN/EN SOP-8 ments of IPC/JEDEC J-STD-020. ` Suitable for use in SnPb or Pb-free soldering processes. DS9168/A-18 April 2011 www.richtek.com 1 RT9168/A Typical Application Circuit RT9168/A VOUT + CIN 1uF VIN + VIN COUT 1uF GND VOUT NC EN/EN Functional Pin Description Pin Name Pin Function VIN Input Voltage GND Ground EN (EN) Chip Enable Active High (Low) NC No Connection VOUT Output Voltage Function Block Diagram Shutdown and Logic Control EN/EN VIN VREF + MOS Driver - Error Amplifier VOUT Current-Limit and Thermal Protection R1 R2 GND www.richtek.com 2 DS9168/A-18 April 2011 RT9168/A Absolute Maximum Ratings z z z z z z Input Voltage ---------------------------------------------------------------------------------------------------------- 8V Power Dissipation, PD @ TA = 25°C SOT-23-5 --------------------------------------------------------------------------------------------------------------- 0.4W SOP-8 ------------------------------------------------------------------------------------------------------------------ 0.625W Package Thermal Resistance (Note1) SOT-23-5, θJA --------------------------------------------------------------------------------------------------------- 250°C/W SOP-8, θJA ------------------------------------------------------------------------------------------------------------ 160°C/W Operating Junction Temperature Range ------------------------------------------------------------------------- −40°C to 125°C Storage Temperature Range --------------------------------------------------------------------------------------- −65°C to 150°C Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------- 260°C Electrical Characteristics (VIN = 5.0V, CIN = 1μF, COUT = 1μF, TA = 25°C, unless otherwise specified) Parameter Symbol Min Typ Max 2.9 -- 7 IL = 50mA 2.7 -- 7 IL = 1mA -2 -- +2 % 200 -- -- mA 500 -- -- mA -- 300 -- mA -- 700 -- mA No Load -- 80 150 IOUT = 200mA -- 90 150 RT9168A IOUT = 500mA -- 90 150 RT9168/A IOUT = 1mA -- 1.1 5 mV IOUT = 50mA -- 55 100 mV IOUT = 200mA -- 220 300 mV IOUT = 500mA -- 600 750 mV -0.2 -- +0.2 %/V IOUT = 0mA to 200mA -- 0.01 0.04 IOUT = 0mA to 500mA -- 0.01 0.04 Input Voltage Range VIN Output Voltage Accuracy Maximum Output Current ΔVOUT Test Conditions RT9168 RT9168A IMAX RT9168 Current Limit RT9168A ILIM RT9168/A GND Pin Current RT9168 IG (2) Dropout Voltage RT9168/A (VOUT(Nominal)≥3.0V RT9168/A Version) RT9168A VDROP ΔVLINE Line Regulation RT9168/A Load Regulation RT9168A ΔVLOAD RLOAD = 1Ω VIN = (VOUT+0.15) to 7V, IOUT = 1mA Unit V μA %/mA EN, EN Input High Threshold VIH V IN = 3V to 5.5V 2.2 -- -- V EN, EN Input Low Threshold VIL V IN = 3V to 5.5V -- -- 0.4 V EN, EN Bias Current ISD -- -- 100 nA Shutdown Supply Current IGSD -- 0.01 1 μA Thermal Shutdown Temperature T SD -- 155 -- °C Ripple Rejection PSRR -- 58 -- dB DS9168/A-18 April 2011 V OUT = 0V F = 100Hz, CB P = 10nF, COUT = 10μF www.richtek.com 3 RT9168/A Note 1. θ JA 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 2. The dropout voltage is defined as VIN -VOUT, which is measured when VOUT is VOUT(NORMAL) − 100mV. www.richtek.com 4 DS9168/A-18 April 2011 RT9168/A Typical Operating Characteristics GND Current vs. Temperature 120 3.32 105 3.31 90 GND Current (uA)1 Output Voltage (V) Output Voltage vs. Temperature 3.33 3.30 3.29 3.28 3.27 75 60 45 30 15 3.26 VOUT = 3.3V VOUT = 3.3V 0 3.25 -50 -25 0 25 50 75 100 125 -50 150 -25 0 Temperature (° C) 50 75 125 150 Current Limit vs. Temperature Dropout Voltage vs. Output Current 480 420 250 200 25°C 150 -40°C 100 Current Limit (mA) 85°C 360 300 240 180 120 50 RT9168 VOUT = 3.3V 60 VOUT = 3.3V 0 0 0 25 50 75 100 125 150 175 -50 200 -25 0 25 50 75 100 125 150 Temperature (° C) Output Current (mA) PSRR Current Limit vs. Temperature 900 70 800 60 700 50 PSRR (dB) Current Limit (mA) 100 Temperature (° C) 300 Dropout Voltage (mV) 25 600 500 400 40 30 20 300 RT9168A VOUT = 3.3V 200 0 100 -50 -25 0 25 50 75 100 Temperature (° C) DS9168/A-18 April 2011 125 150 VOUT = 3.3V, ILOAD = 1mA COUT = 4.7V 10 10 10 100 100 1K 1000 10K 10000 100K 100000 1M 1000000 Frequency (kHz) www.richtek.com 5 RT9168/A Load Transient Response CIN = 10uF COUT = 1uF 40 Load Transient Response 60 VIN = 4V VOUT = 3.0V Output Voltage Deviation (mV) Output Voltage Deviation (mV) 60 20 0 ≈ ≈ 50 1 -50 20 0 ≈ ≈ 50 1 -50 Time (50us/Div) Time (50us/Div) Line Transient Response VOUT = 3.0V COUT = 1uF 100 Line Transient Response 150 Loading = 1mA Output Voltage Deviation (mV) Output Voltage Deviation (mV) 150 50 0 100 VOUT = 3.0V COUT = 1uF 50 0 ≈ ≈ 5 4 ≈ ≈ 5 4 Time (1ms/Div) Time (1ms/Div) Line Transient Response VOUT = 3.0V 100 COUT = 4.7uF Line Transient Response Loading = 1mA 50 0 60 Output Voltage Deviation (mV) 150 Output Voltage Deviation (mV) Loading = 50mA -50 Input Voltage Deviation(V) Input Voltage Deviation(V) -50 -50 40 VOUT = 3.0V COUT = 4.7uF Loading = 50mA 20 0 -20 ≈ ≈ 5 4 Time (500us/Div) www.richtek.com 6 Input Voltage Deviation(V) Input Voltage Deviation(V) VIN = 4V VOUT = 3.0V -20 Load Current (mA) Load Current (mA) -20 CIN = 10uF COUT = 4.7uF 40 ≈ ≈ 5 4 Time (500us/Div) DS9168/A-18 April 2011 RT9168/A Application Information Region of Stable Cout ESR v.s Load Current Capacitor Selection and Regulator Stability 100 Like any low-dropout regulator, the external capacitors used with the RT9168/A must be carefully selected for regulator stability and performance. The output capacitor must meet both requirements for minimum amount of capacitance and ESR in all LDO applications. The RT9168/A is designed specifically to work with low ESR ceramic output capacitor in spacesaving and performance consideration. Using a ceramic capacitor whose value is at least 1μF with ESR is > 5mΩ on the RT9168/A output ensures stability. The RT9168/A still works well with output capacitor of other types due to the wide stable ESR range. Figure 1 shows the curves of allowable ESR range as a function of load current for various output voltages and capacitor values. Output capacitor of larger capacitance can reduce noise and improve load-transient response, stability, and PSRR. The output capacitor should be located not more than 0.5" from the VOUT pin of the RT9168/A and returned to a clean analog ground. Note that some ceramic dielectrics exhibit large capacitance and ESR variation with temperature. It may be necessary to use 2.2μF or more to ensure stability at temperatures below -10°C in this case. Also, tantalum capacitors, 2.2μF or more may be needed to maintain capacitance and ESR in the stable region for strict application environment. DS9168/A-18 April 2011 10 Cout ESR ( Ω )1 Using a capacitor whose value is > 1μF on the RT9168/A input and the amount of capacitance can be increased without limit. The input capacitor must be located not more than 0.5" from the input pin of the IC and returned to a clean analog ground. Any good quality ceramic or tantalum can be used for this capacitor. The capacitor with larger value and lower ESR (equivalent series resistance) provides better PSRR and linetransient response. Unstable Region COUT = 4.7uF Stable Region COUT = 1uF 1 0.1 Unstable Region 0.01 0.001 0 40 80 120 160 200 Load Current (mA) Figure 1 Tantalum capacitors maybe suffer failure due to surge current when it is connected to a low-impedance source of power (like a battery or very large capacitor). If a tantalum capacitor is used at the input, it must be guaranteed to have a surge current rating sufficient for the application by the manufacture. Load-Transient Considerations The RT9168/A load-transient response graphs (see Typical Operating Characteristics) show two components of the output response: a DC shift from the output impedance due to the load current change, and the transient response. The DC shift is quite small due to the excellent load regulation of the IC. Typical output voltage transient spike for a step change in the load current from 0mA to 50mA is tens mV, depending on the ESR of the output capacitor. Increasing the output capacitor's value and decreasing the ESR attenuates the overshoot. Shutdown Input Operation The RT9168/A is shutdown by pulling the EN input low, and turned on by driving the input high. If this feature is not to be used, the EN input should be tied to VIN to keep the regulator on at all times (the EN input must not be left floating). www.richtek.com 7 RT9168/A To ensure proper operation, the signal source used to drive the EN input must be able to swing above and below the specified turn-on/turn-off voltage thresholds which guarantee an ON or OFF state (see Electrical Characteristics). The ON/OFF signal may come from either CMOS output, or an open-collector output with pull-up resistor to the RT9168/A input voltage or another logic supply. The highlevel voltage may exceed the RT9168/A input voltage, but must remain within the absolute maximum ratings for the EN pin. 3). As shown, the Schottky diode is connected in parallel with the internal parasitic diode and prevents it from being turned on by limiting the voltage drop across it to about 0.3V. < 100 mA to prevent damage to the part. VIN VOUT Internal P-Channel Pass Transistor The RT9168/A features a typical 1.1Ω P-Channel MOSFET pass transistor. It provides several advantages over similar designs using PNP pass transistors, including longer battery life. The P-channel MOSFET requires no base drive, which reduces quiescent current considerably. PNPbased regulators waste considerable current in dropout when the pass transistor saturates. They also use high base-drive currents under large loads. The RT9168/A does not suffer from these problems and consume only 80μA of quiescent current whether in dropout, light-load, or heavyload applications. Input-Output (Dropout) Voltage A regulator's minimum input-output voltage differential (or dropout voltage) determines the lowest usable supply voltage. In battery-powered systems, this will determine the useful end-of-life battery voltage. Because the RT9168/A uses a P-channel MOSFET pass transistor, the dropout voltage is a function of drain-to-source onresistance [RDS(ON)] multiplied by the load current. Reverse Current Path The power transistor used in the RT9168/A has an inherent diode connected between the regulator input and output (see Figure 2). If the output is forced above the input by more than a diode-drop, this diode will become forward biased and current will flow from the VOUT terminal to VIN. This diode will also be turned on by abruptly stepping the input voltage to a value below the output voltage. To prevent regulator mis-operation, a Schottky diode should be used in any applications where input/output voltage conditions can cause the internal diode to be turned on (see Figure www.richtek.com 8 Figure 2 VIN VOUT Figure 3 Current Limit and Thermal Protection The RT9168 includes a current limit which monitors and controls the pass transistor's gate voltage limiting the output current to 300mA Typ. (700mA Typ. for RT9168A). Thermal-overload protection limits total power dissipation in the RT9168/A. When the junction temperature exceeds TJ = +155°C, the thermal sensor signals the shutdown logic turning off the pass transistor and allowing the IC to cool. The thermal sensor will turn the pass transistor on again after the IC's junction temperature cools by 10°C, resulting in a pulsed output during continuous thermaloverload conditions. Thermal-overloaded protection is designed to protect the RT9168/A in the event of fault conditions. Do not exceed the absolute maximum junction-temperature rating of TJ = +150°C for continuous operation. The output can be shorted to ground for an indefinite amount of time without damaging the part by cooperation of current limit and thermal protection. DS9168/A-18 April 2011 RT9168/A Operating Region and Power Dissipation The maximum power dissipation of RT9168/A depends on the thermal resistance of the case and circuit board, the temperature difference between the die junction and ambient air, and the rate of airflow. The power dissipation across the device is P = IOUT (VIN - VOUT). The maximum power dissipation is: PMAX = (TJ - TA) /θJA where TJ - TA is the temperature difference between the RT9168/A die junction and the surrounding environment, θJA is the thermal resistance from the junction to the surrounding environment. The GND pin of the RT9168/A 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. DS9168/A-18 April 2011 www.richtek.com 9 RT9168/A 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 www.richtek.com 10 DS9168/A-18 April 2011 RT9168/A 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 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. DS9168/A-18 April 2011 www.richtek.com 11