Low Dropout Positive Linear Regulator

www.DataSheet4U.com ® SPX2810 1A Low Dropout Positive Linear Regulator FEATURES ■ Guaranteed 1A Output ■ Three Terminal Adjustable or Fixed 2.5V, 3.0V and 3.3V ■ Low Quiescent Current ■ Low Dropout Voltage of 1.1V at Full Load ■ 0.2% Line and 0.3% Load Regulation ■ Voltage Temperature Stability 0.25% ■ Overcurrent and Thermal Protection ■ Available Packages: SOT-223,TO-252, TO-220, and TO-263 APPLICATIONS ■ SCSI-II Active Terminator ■ Portable/Palm Top/Notebook Computers ■ Battery Chargers SPX2810 3 Pin TO-263 1 2 3 ADJ/GND VOUT VIN Now Available in Lead Free Packaging SPX2810 is 2% Accuracy SPX2810A is 1% Accuracy ■ ■ ■ ■ Disk Drives Portable Consumer Equipment Portable Instrumentation SMPS Post-Regulator DESCRIPTION The SPX2810 is a low power positive-voltage regulator designed to satisfy moderate power requirements with a cost effective, small footprint solution. This device is an excellent choice for use in battery-powered applications and portable computers. The SPX2810 has a very low quiescent current and a low dropout voltage of 1.1V at full load. As output current decreases, quiescent current flows into the load, increasing efficiency. SPX2810 is available in adjustable or fixed 2.5V, 3.0V and 3.3V output voltages. The SPX2810 is offered in several industry standard 3-pin surface mount packages: SOT-223, TO-252, TO-220 and TO-263. An output capacitor of 10µF or larger, provides unconditionally stability for most applications. TYPICAL APPLICATION CIRCUITS VIN 4.7µF + C1 IN SPX2810 ADJ I ADJ 50µA OUT C2 VREF R1 VOUT VOUT = V REF (1+R 2 /R1 ) +I ADJ R 2 R2 Date: 5/25/04 SPX2810 1A Low Dropout Linear Regulator © Copyright 2004 Sipex Corporation 1 ABSOLUTE MAXIMUM RATINGS Lead Temperature (soldering, 5 seconds) .................. 300°C Storage Temperature Range ...................... -65°C to +150°C Operating Junction Temperature Range ..... -40°C to +125°C Input Supply Voltage ..................................................... +10V ELECTRICAL CHARACTERISITCS VIN=VOUT + 1.5V, COUT = 10µF, at IOUT = 10mA, TA = 25°C, unless otherwise specified. Limits in Boldface applies over the full operating temperature range. SPX2810A PARAMETER 2.5V Version Output Voltage (Note 2) 3.0V Version Output Voltage (Note 2) 3.3V Version Output Voltage (Note 2) All Output Options Reference Voltage Min Load Current (Note 3) Line Regulation Load Regulation Dropout Voltage (Note 2) Current Limit Long Term Stability Thermal Regulation RMS Output Noise Thermal Resistance IOUT=10mA, VIN = VOUT +3V 10≤IOUT≤ 1A, 1.5V≤(VIN-VOUT)≤ 5.75V 1.5≤(VIN - VOUT)≤5.75V 2.75≤VIN≤ 7V, IOUT=TJ=25°C (Note 2) (VIN - VOUT)=3.0V, 10mA≤IOUT≤ 1A, TJ=25°C (Note 3) IOUT=1A (Note 3) IOUT=1A (Note 2) VIN=7V,1.4≤(VIN-VOUT)(Note 3) TA=25°C, 1000Hrs (Note2) 25°C, 20mS Pulse TA=25°C, 10Hz≤f≤10kHz TO-220 Junction to Tab TO-220 Junction to Ambient TO-220 Junction to Tab TO-220 Juinction to Ambient TO-220 Junction to Tab TO-220 Junction to Ambient SOT-223 Junction Tab TO-220 Junction to Ambient 0.01 0.003 3.0 60 3.0 60 6 126 15 156 1.2 1.238 1.225 1.250 5 0.005 0.05 1.1 1.05 2.0 0.03 0.02 1.0 0.01 0.003 3.0 60 3.0 60 6 126 15 156 1.263 1.281 10 0.2 0.3 1.2 1.15 0.005 0.05 1.1 1.2 1.0 0.02 1.225 1.212 1.250 1.275 1.288 10 0.2 0.2 1.2 V mA % % V A % %/Ω % °C/W °C/W °C/W °C/W °CW °C/W 0 ≤ IOUT = 1A, 4.8V ≤ VIN ≤ 10V 3.267 3.234 3.300 3.333 3.366 3.234 3.069 3.300 3.366 3.399 V 0 ≤ IOUT = 1A, 4.5V ≤ VIN ≤ 10V 2.970 2.940 3.000 3.030 3.060 2.940 2.790 3.000 3.060 3.090 V 0 ≤ IOUT = 1A, 4.0V ≤ VIN ≤ 10V 2.475 2.450 2.500 2.525 2.550 2.450 2.425 2.500 2.550 2.575 V CONDITIONS MIN TYP MAX MIN SPX2810 TYP MAX UNITS NOTES: Note 1: Output temperature coefficient is defined as the worst case voltage change divided by the total temperature range. Note 2: Dropout voltage is defined as the input to output differential at which the output voltage drops 100mV below its nominal value measured at 1V differential at very low values of programmed output voltage, the minimum input supply voltage of 2V ( 2.3V over temperature) must be taken into account. Note 3: Thermal regulation is defined as the change in output voltage at a time T after a change in power dissipation is applied excluding load or line regulation effect. Date: 5/25/04 SPX2810 1A Low Dropout Linear Regulator © Copyright 2004 Sipex Corporation 2 TYPICAL PERFORMANCE CHARACTERISTICS 3.320 3.315 3.310 3.305 3.300 3.295 3.290 3.285 3.280 10 100 Output Current (A) 1000 Line Regulation at 25°C Output Voltage (V) 3.330 Series 1 Series 2 Vout (V) 3.320 3.310 3.300 4.8 9.8 Vin (V) 14.8 Figure 1. Load Regulation for SPX2810M3-3.3; VIN=4.8V, COUT=2.2µF Figure 2. Line Regulation for SPX2810M3--3.3; VIN=4.8V, COUT=2.2µF Current Limit VS Temp Dropout Voltage (V) Current Limit (A) 1.3 1.2 1.1 1.0 0.9 100 200 300 400 500 600 700 800 900 1000 Output Current (mA) 2.00 1.50 1.00 0.50 0.00 -50 Series 1 Series 2 -25 0 25 50 75 100 125 Temp (°C) Figure 3. Dropout Voltage vs Output Current for SPX2810M3-3.3; VIN=4.89V, COUT=10µF Figure 4. Current Limit for SP1202M3-3.3; VIN=4.8V, CIN=COUT=1.0µF, IOUT pulsed from 10mA to Current Limit Output Devation (mV) 100 0 125°C 22µF -100 15 Indicating Current Limit Starts Output Current (A) 10 0.5 0 V = 4.0V V =3.3V Fixed 1 =10mA C =1µF Ten Cap C =2.2µF Ten Cap IN IN O IN OUT 0 0.1 0.2 0.3 0.4 0.5 0.6 Time (ms) 0.7 0.8 0.9 1.0 Figure 5. Current Limit for SPX2810M3-3.3, Output Voltage Deviation, (IOUT pulsed from 10mA to 1A). Date: 5/25/04 SPX2810 1A Low Dropout Linear Regulator © Copyright 2004 Sipex Corporation 3 APPLICATION INFORMATION Output Capacitor To ensure the stability of the SPX1202, an output capacitor of at least 10µF (tantalum or ceramic) or 50µF (aluminum) is required. The value may change based on the application requirements of the output load or temperature range. The value of ESR can vary based on the type of capacitor used in the applications. The recommended value for ESR is 0.5Ω or less. A larger value of output capacitance (up to 100µF) can improve the load transient response. SOLDERING METHODS The SPX2810 SOT-223 package is designed to be compatible with infrared reflow or vaporphase reflow soldering techniques. During soldering, the non-active or mildly active fluxes may be used. The SPX2810 die is attached to the heatsink lead which exits opposite the input, output, and ground pins. Hand soldering and wave soldering should be avoided since these methods can cause damage to the device with excessive thermal gradients on the package. The SOT-223 recommended soldering method are as follows: vapor phase reflow and infrared reflow with the component preheated to within 65°C of the soldering temperature range. THERMAL CHARACTERISTICS The thermal resistance of SPX2810 depends on type of package and PC board layout as shown in Table 1. The SPX2810 features the internal thermal limiting to protect the device during overload conditions. Special care needs to be taken during continuous load conditions such that the maximum junction temperature does not exceed 125°C. Thermal protection is activated at >144°C and deactiviated at <137°C. Taking the FR-4 printed circuit board and 1/16 thick with 1 ounce copper foil as an experiment, the PCB material is effective at transmitting heat with the tab attached to the pad area and a ground plane layer on the backside of the substrate. Refer to table 1 for the results of the experiment. 50 X 50mm 35 X 17mm 16 X 10mm Figure 7. Substrate Layout for SOT-223 for thermal experiment. The thermal interaction from other components in the application can effect the thermal resistance of the SPX2810. The actual thermal resistance can be determined with experimentation. SPX2810 power dissipation is calculated as follows: PD = (VIN - VOUT)(IOUT) Maximum Junction Temperature range: TJ = TAMBIENT (max) + PD* (Junction to ambient Thermal Resistance) Although the SPX2810 offers some limiting circuitry for overload conditions, it is still necessary to insure that maximum junction tepmerature is not exceeded. Heat will flow through the lowest resistance path, in this case the junction to case. Therfore proper mounting of the regulator to the board is critical. The case of the device is electrically connected to the output. If the case must be electrically isolated, a thermal nonconductive spacer should be used between the case and the board. It thermal resistance must be taken into account. For example: VIN =10V, VOUT =5V. IOUT =1.5A and TA =50°C/W ThetaJC=3°C/W, thetaSinkCase= 6°C/W thetaSink=0.5°C/W Power dissipation is calculated as PD= (VIN-VOUT)* IOUT=7.5W Junction Temperature will be TJ=TA + PD*(thetaCase-Hs +thetaHs + thetaJc) or TJ = 50 + 7.5(0.5+6+3) = 121.25°C © Copyright 2004 Sipex Corporation Date: 5/25/04 SPX2810 1A Low Dropout Linear Regulator 4 Ripple Rejection Ripple rejection can be improved by adding a capacitor between the ADJ pin and ground as shown in Figure 6. When ADJ pin bypassing is used, the value of the output capacitor required increases to its maximum. If the ADJ pin is not bypassed, the value of the output capacitor can be lowered to 10(F for an electrolytic aluminum capacitor or 2.2µF for a solid tantalum capacitor (Fig 10). However the value of the ADJ-bypass capacitor should be chosen with respectto the following equation: C = 1 / ( 6.28 * FR * R1 ) Where C = value of the capacitor in Farads (select an equal or larger standard value), FR= ripple frequency in Hz, R1= value of resistor R1 in Ohms PC BOARD AREA mm2 TOPSIDE COPPER AREA mm2 If an ADJ-bypass capacitor is used, the amplitude of the output ripple will be independent of the output voltage. If an ADJbypass capacitor is not used, the output ripple will be proportional to the ratio of the output voltage to the reference voltage: M = VOUT / VREF Where M = multiplier for the ripple se