RT9167/A Low-Noise, Fixed Output Voltage,300mA/500mA LDO Regulator General Description Features The RT9167/A is a 300mA/500mA low dropout and low noise micropower regulator suitable for portable applications. The output voltages range from 1.5V to 5.0V in 100mV increments and 2% accuracy. The RT9167/A is designed for use with very low ESR capacitors. The output remains stable even with 1μF ceramic output capacitor. z Stable with Low-ESR Output Capacitor z Low Dropout Voltage (350mV @ 300mA) μA Typical Low Operation Current −80μ Shutdown Function Low Noise Output 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 RT9167/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 battery-powered devices. Other features include a reference bypass pin to improve low noise performance, current limiting, and over temperature protection. z z z z z z z z Applications z z Ordering Information z z RT9167/A- Cellular Telephones Laptop, Notebook, and Palmtop Computers Battery-powered Equipment Hand-held Equipment Package Type Marking Information B : SOT-23-5 For marking information, contact our sales representative BR : SOT-23-5 (R-Type) S : SOP-8 directly or through a RichTek distributor located in your Operating Temperature Range area, otherwise visit our website for detail. P : Pb Free with Commercial Standard G : Green (Halogen Free with CommerPin Configurations cial Standard) Output Voltage 15 : 1.5V 16 : 1.6V : 49 : 4.9V 50 : 5.0V 2H : 2.85V 500mA Output Current 300mA Output Current (TOP VIEW) VIN 1 GND 2 EN 3 5 4 VOUT VOUT 1 GND 2 VIN 3 BP SOT-23-5 5 BP 4 EN SOT-23-5 (R-Type) Note : RichTek Pb-free and Green products are : `RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020. `Suitable for use in SnPb or Pb-free soldering processes. 8 GND VIN 2 7 VOUT 3 6 GND GND BP 4 5 GND EN `100%matte tin (Sn) plating. SOP-8 DS9167/A-26 March 2007 www.richtek.com 1 RT9167/A Functional Pin Description Pin Name Pin Function VIN Power Input Voltage GND Ground EN Chip Enable (Active High) BP Reference Noise Bypass VOUT Output Voltage Function Block Diagram Shutdown and Logic Control EN VIN VREF BP + MOS Driver - Error Amplifier Current-Limit and Thermal Protection VOUT R1 R2 GND Typical Application Circuit RT9167/A Chip Enable www.richtek.com 2 IN OUT GND EN BP V COUT OUT 1uF + CIN 1uF + VIN CBP 10nF DS9167/A-26 March 2007 RT9167/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 SOT-23-5, θJC ---------------------------------------------------------------------------------------------------------- 130°C/W SOP-8, θJA -------------------------------------------------------------------------------------------------------------- 160°C/W SOP-8, θJC -------------------------------------------------------------------------------------------------------------- 60°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 Input Voltage Range VIN Output Voltage Accuracy ΔVOUT Maximum Output Current RT9167 RT9167A RT9167 Current Limit RT9167A Quiescent Current (2) Dropout Voltage (VOUT(Normal) = 3.0V Version) Min Typ Max 2.9 -- 7 IL = 50mA 2.7 -- 7 IL = 1mA -2 -- +2 300 -- -- 500 -- -- 400 -- -- 500 700 -- IMAX ILIM RLOAD = 1Ω RT9167/A No Load -- 80 150 RT9167/A IG IOUT = 300mA -- 90 150 RT9167A IOUT = 500mA -- 90 150 RT9167/A IOUT = 1mA -- 1.1 5 IOUT = 50mA -- 55 100 IOUT = 300mA -- 350 450 IOUT = 500mA -- 600 750 VIN= (VOUT+0.15) to 7V, IOUT =1mA -- -- 6 IOUT = 0mA to 300mA -- -- 30 IOUT = 0mA to 500mA -- -- 35 RT9167/A RT9167/A VDROP RT9167A ΔVLINE Line Regulation Load Regulation Test Conditions RT9167/A RT9167A ΔVLOAD Units V % mA mA μA mV mV/V mV EN Input High Threshold VIH VIN= 3V to 5.5V 1.6 -- -- V EN Input Low Threshold VIL VIN = 3V to 5.5V -- -- 0.4 V EN Bias Current ISD -- -- 100 nA Shutdown Supply Current IGSD -- 0.01 1 μA Thermal Shutdown Temperature TSD -- 155 -- °C VOUT = 0V To be continued DS9167/A-26 March 2007 www.richtek.com 3 RT9167/A Parameter Symbol Test Conditions Min Typ Max Output Noise eNO CBP = 10nF, COUT = 10μF -- 350 -- Ripple Rejection PSRR F = 100Hz, CBP = 10nF, COUT = 10μF -- 58 -- Units nV Hz dB Note 1. 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. Pin 1 of SOP-8 and pin4 of SOT-23-5 packages are the case position for θJA measurement. Note 2. The dropout voltage is defined as VIN -VOUT, which is measured when VOUT is VOUT(NORMAL) − 100mV. www.richtek.com 4 DS9167/A-26 March 2007 RT9167/A Typical Operating Characteristics Quiescent Current vs. Temperature 120 3.32 105 Quiescent Current (uA)1 Output Voltage (V) Output Voltage vs. Temperature 3.33 3.31 3.30 3.29 3.28 3.27 90 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) 25 50 75 100 125 150 Temperature (° C) Dropout Voltage vs. Load Current Dropout Voltage vs. Load Current 600 250 Dropout Voltage (mV) Dropout Voltage (mV) 125°C 125°C 200 25°C 150 -40°C 100 50 500 25°C 400 300 -40°C 200 100 RT9167 RT9167A VOUT = 5.0V VOUT = 3.3V 0 0 0 0.05 0.1 0.15 0.2 0.25 0.3 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 Load Current (A) Load Current (A) Current Limit vs. Temperature 900 650 800 600 Current Limit (mA) Current Limit (mA) Current Limit vs. Temperature 700 550 500 450 400 RT9167 350 700 600 500 400 RT9167A 300 VOUT = 5.0V VOUT = 3.3V 200 300 -50 -25 0 25 50 75 Temperature (° C) DS9167/A-26 March 2007 100 125 -50 -25 0 25 50 75 100 125 Temperature (° C) www.richtek.com 5 RT9167/A Load Transient Response 20 VIN = 4V VOUT = 3.0V Output Voltage Deviation (mV) CIN = 10uF COUT = 1uF CBP = 10nF 40 Load Transient Response 60 0 -20 ≈ ≈ 50 1 Load Current (mA) Load Current (mA) Output Voltage Deviation (mV) 60 -50 CIN = 10uF COUT = 4.7uF CBP = 10nF 40 20 0 -20 ≈ ≈ 50 1 -50 Time (50us/Div) Time (50us/Div) Line Transient Response 50 Output Voltage Deviation (mV) Loading = 1mA VOUT = 3.0V COUT = 1uF CBP = 10nF 100 Line Transient Response 150 0 -50 ≈ ≈ 5 4 Input Voltage Deviation (V) Input Voltage Deviation (V) Output Voltage Deviation (mV) 150 100 50 VOUT = 3.0V COUT = 1uF CBP = 10nF -50 ≈ ≈ 5 4 Time (1ms/Div) Line Transient Response VOUT = 3.0V COUT = 4.7uF CBP = 10nF Line Transient Response 60 Output Voltage Deviation (mV) Loading = 1mA 50 0 -50 ≈ ≈ 5 4 Time (500us/Div) www.richtek.com 6 Input Voltage Deviation (V) Output Voltage Deviation (mV) Input Voltage Deviation (V) 100 Loading = 50mA 0 Time (1ms/Div) 150 VIN = 4V VOUT = 3.0V 40 20 VOUT = 3.0V COUT = 4.7uF CBP = 10nF Loading = 50mA 0 -20 ≈ ≈ 5 4 Time (500us/Div) DS9167/A-26 March 2007 RT9167/A PSRR 70 60 PSRR (dB) 50 40 30 20 10 0 VOUT = 3.3V, ILOAD = 1mA COUT = 4.7uF, CBP = 10nF 10 10 100 100 1K 1000 10K 10000 100K 100000 1M 1000000 Frequency (kHz) DS9167/A-26 March 2007 www.richtek.com 7 RT9167/A Application Information Capacitor Selection and Regulator Stability Like any low-dropout regulator, the external capacitors used with the RT9167/A must be carefully selected for regulator stability and performance. Using a capacitor whose value is > 1μF on the RT9167/A input and the amount of capacitance can be increased without limit. The input capacitor must be located a distance of 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 line-transient response. The output capacitor must meet both requirements for minimum amount of capacitance and ESR in all LDOs application. The RT9167/A is designed specifically to work with low ESR ceramic output capacitor in space-saving and performance consideration. Using a ceramic capacitor whose value is at least 1μF with ESR is > 5mΩ on the RT9167/A output ensures stability. The RT9167/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 loadtransient response, stability, and PSRR. The output capacitor should be located not more than 0.5" from the VOUT pin of the RT9167/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. 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. Use a 10nF bypass capacitor at BP for low output voltage noise. The capacitor, in conjunction with an internal 200kΩ resistor, which connects bypass pin and the band-gap reference, creates an 80Hz low-pass filter for noise reduction. Increasing the capacitance will slightly decrease the output noise, but increase the start-up time. The capacitor connected to the bypass pin for noise reduction must have very low leakage. This capacitor leakage current causes the output voltage to decline by a proportional amount to the current due to the voltage drop on the internal 200kΩ resistor. Figure 2 shows the power on response. Region of Stable COUT ESR vs. Load Current 100.00 100 COUT = 1uF Unstable Region C CBP 1nF BP==10nF Stable Region Voltage (0.5V/Div) Voltage (0.5V / DIV) COUT ESR (Ω) 10.00 10 1.001 0.1 0.10 Unstable Region 0.01 0.01 CBP 10nF BP==10nF 0.001 0.00 0 50 100 150 200 Load Current (mA) Figure 1 www.richtek.com 8 250 VV 3.0V OUT ==3.0V OUT 300 00 5.0 10.0 15.0 15.0 Time(ms) (ms) Time Figure 2 DS9167/A-26 March 2007 RT9167/A Load-Transient Considerations Input-Output (Dropout) Voltage The RT9167/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. 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 RT9167/ A uses a P-Channel MOSFET pass transistor, the dropout voltage is a function of drain-to-source on-resistance [RDS(ON)] multiplied by the load current. Shutdown Input Operation The RT9167/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). 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 pullup resistor to the RT9167/A input voltage or another logic supply. The high-level voltage may exceed the RT9167/A input voltage, but must remain within the absolute maximum ratings for the EN pin. Reverse Current Path The power transistor used in the RT9167/A has an inherent diode connected between the regulator input and output (see Figure 3). 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 Figure4). 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. < 100mA to prevent damage to the part. VIN VOUT Internal P-Channel Pass Transistor The RT9167/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 RT9167/A does not suffer from these problems and consume only 80μA of quiescent current whether in dropout, light-load, or heavyload applications. DS9167/A-26 March 2007 Figure 3 VIN VOUT Figure 4 www.richtek.com 9 RT9167/A The maximum power dissipation of RT9167/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 RT9167/A die junction and the surrounding environment, θJA is the thermal resistance from the junction to the surrounding environment. The GND pin of the RT9167/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. Current Limit and Thermal Protection T9167 includes a current limit which monitors and controls the pass transistor's gate voltage limiting the output current to 350mA Typ. (700mA Typ. for RT9167A). Thermaloverload protection limits total power dissipation in the RT9167/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 RT9167/A in the event of fault conditions. Do not exceed the absolute maximum junctiontemperature 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. Thermal Considerations Thermal protection limits power dissipation in RT9167/A. When the operation junction temperature exceeds 165°C, the OTP circuit starts the thermal shutdown function and turns the pass element off. The pass element turn on again after the junction temperature cools by 30°C. For continuous operation, do not exceed absolute maximum operation junction temperature 125°C. The power dissipation definition in device is: PD = (VIN − VOUT) x IOUT + VIN x IQ www.richtek.com 10 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 125°C, TA is the ambient temperature and the θJA is the junction to ambient thermal resistance. For recommended operating conditions specification of RT9167/A, where T J(MAX) is the maximum junction temperature of the die (125°C) and TA is the operated ambient temperature. The junction to ambient thermal resistance θJA is layout dependent. For SOT-23-5 package, 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 : PD(MAX) = (125°C − 25°C) / 250 = 0.4W for SOT-23-5 package PD(MAX) = (125°C - 25°C) / 160 = 0.625W for SOP-8 package The maximum power dissipation depends on operating ambient temperature for fixed T J(MAX) and thermal resistance θJA. For RT9167/A packages, the Figure 5 of derating curves allows the designer to see the effect of rising ambient temperature on the maximum power allowed. Maximum Power Dissipation (mW)1 Operating Region and Power Dissipation 700 SOP-8 600 500 SOT-23-5 400 300 200 100 0 0 20 40 60 80 100 120 140 Ambient Temperature Figure 5. Derating Curves for RT9167/A Packages DS9167/A-26 March 2007 RT9167/A The value of junction to case thermal resistance θJC is popular for users. This thermal parameter is convenient for users to estimate the internal junction operated temperature of packages while IC operating. It’ s independent of PCB layout, the surroundings airflow effects and temperature difference between junction to ambient. The operated junction temperature can be calculated by following formula : TJ = TC + PD x θJC Where TC is the package case temperature measured by thermal sensor, PD is the power dissipation defined by user’ s function and the θJC is the junction to case thermal resistance provided by IC manufacturer. Therefore it’ s easy to estimate the junction temperature by any condition. For example, how to calculate the junction temperature of RT9167A-28CB SOT-23-5 package? If we use input voltage VIN = 3.3V at an output current IO = 500mA and the case temperature (pin 4 of SOT-23-5 package) TC = 70°C measured by thermal couple while operating, then our power dissipation is as follows: PD = (3.3V − 2.8V) x 500mA + 3.3V x 90μA ≅ 250mW And the junction temperature TJ could be calculated as following : TJ = TC + PD x θJC TJ = 70°C + 0.25W x 130°C/W = 70°C + 32.5°C = 102.5°C < TJ(MAX) =125°C For this operation application, TJ is lower than absolute maximum operation junction temperature 125°C and it’s safe to use. DS9167/A-26 March 2007 www.richtek.com 11 RT9167/A Outline Dimension H D L B C b A A1 e Symbol Dimensions In Millimeters Dimensions In Inches 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 12 DS9167/A-26 March 2007 RT9167/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 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] DS9167/A-26 March 2007 www.richtek.com 13