Low Dropout Voltage Regulator

www.DataSheet4U.com ® SPX2941 1A Low Dropout Voltage Regulator, Adjustable Output, Fast Response Now Available in Lead Free Packaging APPLICATIONS ■ Powering VGA & Sound Card ■ LCD Monitors ■ USB Power Supply ■ Power PC Supplies ■ SMPS Post-Regulator ■ High Efficiency Linear Power Supplies ■ Battery Charger ■ Portable Instrumentation ■ Constant Current Regulators ■ Adjustable Power Supplies DESCRIPTION The SPX2941 is a 1A, accurate voltage regulator with a low drop out voltage of 280mV(typ.) at 1A. These regulators are specifically designed for low voltage applications that require a low dropout voltage and a fast transient response. They are fully fault protected against over-current, reverse battery, and positive and negative voltage transients. Other features include Enable, and Error Flag. The SPX2941 is offered in 5-pin TO-220 & TO-263 packages. For a 3A version, refer to the SPX29300 data sheet. TYPICAL APPLICATIONS CIRCUIT VIN 6.8µF + 4 EN 2 5 + ADJ R1 VOUT 10µF FEATURES ■ Adjustable Output Down To 1.25V ■ Low Quiescent Current ■ Guaranteed 1.5A Peak Output Current ■ Low Dropout Voltage of 280mV @ 1A ■ Extremely Tight Load and Line Regulation ■ Extremely Fast Transient Response ■ Reverse-battery Protection ■ Internal Thermal and Current Limit Protection ■ Zero Current Shutdown ■ Error Flag Output for Out of Regulation State ■ Standard TO-220 and TO-263 packages ■ Replacement for LM2941 and AS2941 SPX2941 5 Pin TO-263 1 2 3 4 5 ADJUST ENABLE GND SPX2941 3 1 GND R2 Figure 1. Adjustable Output Linear Regulator Date: 08/25/04 SPX2941 1A Low Dropout Voltage Regulator © Copyright 2004 Sipex Corporation 1 VOUT VIN ABSOLUTE MAXIMUM RATINGS Lead Temperature (soldering, 5 seconds) ................260°C Storage Temperature Range........................-65°C to +150°C Operating Junction Temperature Range......-40°C to +125°C Input Supply Voltage (NOTE 7) .... .....................................16V ELECTRICAL CHARACTERISTICS VIN=VOUT + 1V, IOUT=10mA, CIN=6.8µF, COUT=10µF, TA = 25°C, unless otherwis specified. The boldface applies over the junction temperature range. Adjustable versions are set at +5.0V. PARAMETER Reference Voltage Adjust Pin Bias Current Reference Voltage Temperature Coefficient Adjust Pin Bias Current Temperature Coefficient Line Regulation Load Regulation Dropout Voltage (Note1) (except 1.8V version) Ground Current (Note3) (NOTE 4) CONDITIONS Adjustable version only MIN. 1.228 1.215 TYP. 1.240 40 20 0.1 0.2 0.3 70 280 12 18 1.2 1.5 2.2 400 260 0.1 200 40 25 60 75 15 0.8 2.4 100 600 750 1 2 10 500 Junction to Case, at Tab Junction to Ambient Junction to Case, at Tab Junction to Ambient 3 60 3 60 °C/W °C/W µA 95 140 1 2 300 400 1.0 1.5 200 550 25 MAX 1.252 1.265 80 120 UNIT V V ppm/°C nA/°C % % mV mA mA A µVRMS IOUT=10mA, (VOUT+1V)≤VIN≤16V VIN=VOUT+1V, 10mA≤IOUT≤IFULL IOUT=100mA IOUT=1A IOUT=750mA, VIN=VOUT+1V IOUT=1A Ground Pin Current at VIN=0.1V less than specified VOUT, Dropout IOUT=10mA Current Limit VOUT=0V (Note2) Output Noise Voltage 10Hz to 100kHz, IOUT =100mA, CL=10µF CL=33µF ERROR COMPARATOR (FLAG OUTPUT) Output Leakage Current VOH=16V Output Low Voltage Upper Threshold Voltage Lower Threshold Voltage Hysteresis Input Logic Voltage LOW (OFF) HIGH (ON) ENABLE Input Pin Current Device set for 5V, VIN=4.5, IOL=250µA Device set for 5V (Note 5) Device set for 5V (Note 5) Device set for 5V (Note 5) VIN<10V VEN=16V VEN=0.8V Regulator Output Current in Shutdown Thermal Resistance TO-220 TO-263 (NOTE 6) A mV mV mV mV V µA µA Date: 08/25/04 SPX2941 1A Low Dropout Voltage Regulator © Copyright 2004 Sipex Corporation 2 NOTE 1: Dropout voltage is defined as the input to output differential at which the output voltage drops to 99% of its nominal value. NOTE 2: VIN=VOUT(NOMINAL)+1V; for example, VIN=4.3V for a 3.3V regulator. Employ pulse-testing procedures to minimize temperature rise. NOTE 3: Ground pin current is the regulator quiescent current. The total current drawn from the source is the sum of the load and ground currents. NOTE 4: Thermal regulation is defined as the change in the output voltage at a time T after a change in power dissipation is applied, excluding load or line regulation effects. NOTE 5: Comparator threshold is expressed in terms of a voltage differential at the Adjust terminal below the nominal reference voltage measured 6V input. To express these thresholds in terms of output voltage change, multiply the error amplifier gain = VOUT/VREF = (R1 + R2)/R2. For example, at a programmable output voltage of 5V, the Error output is guaranteed to go low when the output drops by 95mVx 5V/ 1.240V = 38mV. Threshold remain constant as a percent of VOUT as VOUT is varied, with the dropout warning occurring at typically 5% below nominal, 7.7% guaranteed. NOTE 6: VEN ≤ 0.8V and VIN ≤ 16V, VOUT = 0. NOTE7: Maximum positive supply voltage of 20V must be of limited duration ( <100ms) and duty cycle (<1%). The maximum continuous supply voltage is 16V. NOTE 8: VREF ≤ VOUT ≤ (VIN-1), 2.5V ≤ VIN ≤ 16V, 10 mA ≤ IC ≤ IFL, TJ < TJMAX. BLOCK DIAGRAM IN O.V I LIMIT FLAG + 1.180V Reference 1.240V + ADJ EN Thermal Shutdown 28V R1* OUT R2* GND Figure 2. SP2941 Block Diagram Date: 08/25/04 SPX2941 1A Low Dropout Voltage Regulator © Copyright 2004 Sipex Corporation 3 TYPICAL PERFORMANCE CHARACTERISTICS 3.320 3.315 3.310 3.310 3.305 3.300 3.295 3.290 3.285 3.280 0.00 VOUT (V) 3.300 3.295 3.290 3.285 3.280 4 6 8 10 12 14 16 3.3V Device IL = 10mA CL = 10µF VOUT (V) 3.305 3.3V Device VIN = 4.3V CL = 10µF 0.25 0.50 0.75 1.00 1.25 1.50 VIN (V) IL (A) Figure 3. Line Regulation for 3.3V Device Figure 4. Load Regulation for 3.3V Device 80.0 70.0 300 280 60.0 IGnd (µA) IGnd (mA) 50.0 40.0 30.0 20.0 10.0 0.0 0.00 260 240 220 3.3V Device VIN = 4.3V CL = 10µF 0.25 0.50 0.75 1.00 1.25 1.50 200 180 4 6 8 10 12 3.3V Device IL = 10mA CL = 10µF 14 16 IL (A) VIN (V) Figure 5. Ground Current vs Load Current for 3.3V Device Figure 6. Ground Current vs Input Current 100 90 600 500 70 VDROPOUT (mV) 80 IGnd (mA) 400 300 200 100 0 0.00 60 50 40 30 20 10 0 0.00 0.25 0.50 0.75 1.00 3.3V Device VIN = 3.2V CL = 10µF 1.25 1.50 3.3V Device CL = 10µF 0.25 0.50 0.75 1.00 1.25 1.50 IL (A) IL (A) Figure 7. Ground Current vs Load Current in Dropout Figure 8. Dropout Voltage vs Load Current for 3.3V Device Date: 08/25/04 SPX2941 1A Low Dropout Voltage Regulator © Copyright 2004 Sipex Corporation 4 TYPICAL PERFORMANCE CHARACTERISTICS 280 270 260 250 3.320 3.310 3.300 3.290 IGnd (µA) VOUT (V) 240 230 220 210 200 190 180 -40 -20 0 20 40 60 80 3.3V Device VIN = 4.3V IL = 10mA CL = 10µF 100 120 3.280 3.270 3.260 3.250 3.240 3.230 3.220 -40 -20 0 20 40 60 80 3.3V Device VIN = 4.3V IL = 10mA CL = 10µF 100 120 Temperature (°C) Temperature (°C) Figure 9. Ground Current vs Temperature at ILOAD=10mA Figure 10. Output Voltage vs Temperature at ILOAD=10mA 7.00 6.80 6.60 3.3V Device VIN = 4.3V IL = 500mA CL = 10µF 30 29 28 3.3V Device VIN = 3.2V IL = 750mA CL = 10µF IGnd (mA) 6.40 6.20 6.00 5.80 5.60 5.40 5.20 5.00 -40 -20 0 20 40 60 80 IGnd (mA) 27 26 25 24 23 22 21 20 -40 100 120 -20 0 20 40 60 80 100 120 Temperature (°C) Temperature (°C) Figure 11. Ground Current vs Temperature at ILOAD=500mA Figure 12. Ground Current vs Temperature in Dropout at ILOAD=750mA 52.0 50.0 100 95 IGnd (mA) IGnd (mA) 48.0 46.0 44.0 42.0 40.0 38.0 36.0 -40 -20 0 20 40 60 80 3.3V Device VIN = 4.3V IL = 1.5A CL = 10µF 100 120 90 85 80 75 70 -40 3.3V Device VIN = 3.2V IL = 1.5A CL = 10µF -20 0 20 40 60 80 100 120 Temperature (°C) Temperature (°C) Figure 13. Ground Current vs Temperature at ILOAD=1.5A Figure 14. Ground Current vs Temperature in Dropout at ILOAD=1.5A Date: 08/25/04 SPX2941 1A Low Dropout Voltage Regulator © Copyright 2004 Sipex Corporation 5 TYPICAL PERFORMANCE CHARACTERISTICS 350 330 310 500 480 VDROPOUT (mV) 290 270 250 230 210 190 170 150 -40 -20 0 20 40 60 80 100 120 3.3V Device IL = 750mA CL = 10µF VDROPOUT (mV) 460 440 420 400 380 360 340 320 -40 -20 0 20 40 60 80 100 120 3.3V Device IL = 1.5A CL = 10µF Temperature (°C) Temperature (°C) Figure 15. Dropout Voltage vs Temperature at ILOAD=750mA Figure 16. Dropout Voltage vs Temperature at ILOAD=1.5A 35 30 25 2.00 1.90 1.80 1.70 1.60 3.3V Device VIN = 3.2V IL = 750mA CL = 10µF IEN (µA) VTH (V) 120 20 15 10 5 0 -40 -20 0 20 40 60 80 3.3V Device VIN = 3.2V IL = 750mA CL = 10µF 100 1.50 1.40 1.30 1.20 1.10 1.00 -40 -20 0 20 40 60 80 100 120 Temperature (°C) Temperature (°C) Figure 17. Enable Current vs Temperature for 3.3V Devices Figure 18. Enable Threshold vs Temperature for 3.3V Devices Date: 08/25/04 SPX2941 1A Low Dropout Voltage Regulator © Copyright 2004 Sipex Corporation 6 APPLICATION INFORMATION The SPX2941 incorporates protection against over-current faults, reversed load insertion, over temperature operation, and positive and negative transient voltage. Thermal Considerations Although the SPX2941 offers limiting circuitry for overload conditions, it is still necessary to insure that the maximum junction temperature is not exceeded in the application. Heat will flow through the lowest resistance path, the junction-to-case path. In order to insure the best thermal flow of the component, proper mounting is required. Since the tab of the device is electrically connected to GND, the tab must be electrically isolated using a thermally conductive spacer, which itself contributes some small additional thermal resistance. Consult heatsink manufacturer for thermal resistance and design of heatsink. TO-220 Design Example: Assume that VIN = 10V, VOUT = 5V, IOUT = 1A, TA = 50°C, θHA= 1°C/W, θCH = 2°C/W, and θ JC = 3°C/W, where TA = ambient temperature, θHA = heatsink to ambient thermal resistance, θCH = case to heatsink thermal