NUD4011 Low Current LED Driver This device is designed to replace discrete solutions for driving LEDs in AC/DC high voltage applications (up to 200 V). An external resistor allows the circuit designer to set the drive current for different LED arrays. This discrete integration technology eliminates individual components by combining them into a single package, which results in a significant reduction of both system cost and board space. The device is a small surface mount package (SO−8). http://onsemi.com PIN CONFIGURATION AND SCHEMATIC Features • • • • Supplies Constant LED Current for Varying Input Voltages External Resistor Allows Designer to Set Current – up to 70 mA Offered in Surface Mount Package Technology (SO−8) Pb−Free Package is Available Vin 1 8 Iout Boost 2 7 Iout Rext 3 6 Iout PWM 4 5 Iout Benefits • • • • Maintains a Constant Light Output During Battery Drain One Device can be used for Many Different LED Products Reduces Board Space and Component Count Simplifies Circuit and System Designs Current Set Point Typical Applications • Portables: For Battery Back−up Applications, also Simple Ni−CAD • • Battery Charging Industrial: General Lighting Applications and Small Appliances Automotive: Tail Lights, Directional Lights, Back−up Light, Dome Light PIN FUNCTION DESCRIPTION Pin Symbol 1 Vin 2 Boost This pin may be used to drive an external transistor as described in the App Note AND8198/D. 3 Rext An external resistor between Rext and Vin pins sets different current levels for different application needs 4 PWM For high voltage applications (higher than 48 V), pin 4 is connected to the LEDs array. For low voltage applications (lower than 48 V), pin 4 is connected to ground. 5, 6, 7, 8 Iout Description Positive input voltage to the device The LEDs are connected from these pins to ground MARKING DIAGRAM 8 SO−8 CASE 751 8 1 1 4011 AYWWG G A = Assembly Location Y = Year WW = Work Week G = Pb−Free Package (Note: Microdot may be in either location) ORDERING INFORMATION Device NUD4011DR2 NUD4011DR2G Package Shipping † SO−8 2500 / Tape & Reel SO−8 2500 / Tape & Reel (Pb−Free) †For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging Specification Brochure, BRD8011/D. © Semiconductor Components Industries, LLC, 2006 June, 2006 − Rev. 3 1 Publication Order Number: NUD4011/D NUD4011 MAXIMUM RATINGS (TA = 25°C unless otherwise noted) Rating Symbol Value Unit Input Voltage Vin 200 V Output Current (For Vdrop ≤ 16 V) (Note 1) Iout 70 mA Output Voltage Vout 198 V Human Body Model (HBM) ESD 500 V Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect device reliability. 1. Vdrop = Vin – 0.7 V − VLEDs. THERMAL CHARACTERISTICS Characteristic Symbol Value Unit Operating Ambient Temperature TA −40 to +125 °C Maximum Junction Temperature TJ 150 °C TSTG −55 to +150 °C PD 1.13 9.0 W mW/°C Thermal Resistance, Junction–to–Ambient (Note 2) RJA 110 °C/W Thermal Resistance, Junction–to–Lead (Note 2) RJL 77 °C/W Storage Temperature Total Power Dissipation (Note 2) Derating above 25°C (Figure 3) 2. Mounted on FR−4 board, 2 in sq pad, 1 oz coverage. ELECTRICAL CHARACTERISTICS (TA = 25°C unless otherwise noted) Symbol Min Typ Max Unit Output Current1 (Note 3) (Vin = 120 Vdc, Rext = 24 , VLEDs = 90 V) Characteristic Iout1 26.0 27.5 29.5 mA Output Current2 (Note 3) (Vin = 200 Vdc, Rext = 68 , VLEDs = 120 V) Iout2 11.5 14.0 15.5 mA Bias Current (Vin = 120 Vdc, Rext = Open, Rshunt = 80 k) IBias − 1.1 2.0 mA Voltage Overhead (Note 4) Vover 5.0 − − V 3. Device’s pin 4 connected to the LEDs array (as shown in Figure 5). 4. Vover = Vin – VLEDs. http://onsemi.com 2 NUD4011 TYPICAL PERFORMANCE CURVES (TA = 25°C unless otherwise noted) 1000 0.9 0.8 0.7 100 Rext, Vsense (V) 0.6 10 0.5 0.4 0.3 0.2 0.1 1 1 10 100 0.0 −40 −25 −10 5 20 35 50 65 80 95 110 125 140 155 TJ, JUNCTION TEMPERATURE (°C) 1000 IOUT (mA) Figure 1. Output Current (IOUT) vs. External Resistor (Rext) Figure 2. Vsense vs. Junction Temperature 1.2 PD, POWER DISSIPATION (W) OUTPUT CURRENT, NORMALIZED 1.200 1.000 0.800 0.600 0.400 0.200 0.000 25 35 45 55 65 75 85 95 105 115 125 1.0 0.8 0.6 0.4 0.2 0.0 −40 −25 −10 5 20 35 50 65 80 95 110 125 140 155 TJ, JUNCTION TEMPERATURE (°C) TA, AMBIENT TEMPERATURE (°C) Figure 3. Total Power Dissipation (PD) vs. Ambient Temperature (TA) Figure 4. Current Regulation vs. Junction Temperature http://onsemi.com 3 NUD4011 APPLICATION INFORMATION Design Guide for DC Applications NUD4011 Vin 1. Define LED’s current: a. ILED = 30 mA Boost 2. Calculate Resistor Value for Rext: a. Rext = Vsense (see Figure 2) / ILED b. Rext = 0.7(TJ = 25 °C) / 0.030 = 24 Rext PWM 3. Define Vin: a. Per example in Figure 5, Vin = 120 Vdc 4. Define VLED @ ILED per LED supplier’s data sheet: per example in Figure 5, a. VLED = 3.0 V (30 LEDs in series) b. VLEDs = 90 V 1 8 2 7 3 4 Current Set Point 6 5 120 V Iout Iout Iout Iout LED1 LED2 5. Calculate Vdrop across the NUD4001 device: a. Vdrop = Vin – Vsense – VLEDs b. Vdrop = 120 V – 0.7 V – 90 V c. Vdrop = 29.3 V LED30 6. Calculate Power Dissipation on the NUD4001 device’s driver: a. PD_driver = Vdrop * Iout b. PD_driver = 29.3 V 0.030 A c. PD_driver = 0.879 W Figure 5. 120 V Application (Series LED’s Array) 7. Establish Power Dissipation on the NUD4001 device’s control circuit per below formula: a. PD_control = (Vin – 1.4 – VLEDs)@ / 20,000 b. PD_control = 0.040 W 8. Calculate Total Power Dissipation on the device: a. PD_total = PD_driver + PD_control b. PD_total = 0.879 W + 0.040 W = 0.919 W 9. If PD_total > 1.13 W (or derated value per Figure 3), then select the most appropriate recourse and repeat steps 1−8: a. Reduce Vin b. Reconfigure LED array to reduce Vdrop c. Reduce Iout by increasing Rext d. Use external resistors or parallel device’s configuration 10. Calculate the junction temperature using the thermal information on Page 8 and refer to Figure 4 to check the output current drop due to the calculated junction temperature. If desired, compensate it by adjusting the value of Rext. http://onsemi.com 4 NUD4011 APPLICATION INFORMATION (continued) Design Guide for AC Applications Vin Full Bridge Rectifier 1 1. Define LED’s current: a. ILED = 30 mA 2. Define Vin: a. Per example in Figure 5, Vin = 120 Vac 2 3 1 Iout 8 Boost Iout 2 Rext 3. Define VLED @ ILED per LED supplier’s data sheet: a. Per example in Figure 6, VLED = 3.0 V (30 LEDs in series) VLEDs = 90 V 4 + − 120 Vac 60 Hz NUD4011 3 7 Current Set Point PWM 4 Iout 6 Iout 5 LED1 4. Calculate Resistor Value for Rext: The calculation of the Rext for AC applications is totally different than for DC. This is because current conduction only occurs during the time that the ac cycles’ amplitude is higher than VLEDs. Therefore Rext calculation is now dependent on the peak current value and the conduction time. a. Calculate for VLEDs = 90 V: Sin V = Vpeak Ǹ2) 90 V = (120 Sin LED2 LED30 Figure 6. 120 Vac Application (Series LED’s array) = 32.027° b. Calculate conduction time for = 32.027°. For a sinuousoidal waveform Vpeak happens at = 90°. This translates to 4.165 ms in time for a 60 Hz frequency, therefore 32.027° is 1.48 ms and finally: Conduction time = (4.165 ms – 1.48 ms) 2 = 5.37 ms c. Calculate the Ipeak needed for I(avg) = 30 mA Since a full bridge rectifier is being used (per Figure 6), the frequency of the voltage signal applied to the NUD4011 device is now 120 Hz. To simplify the calculation, it is assumed that the 120 Hz waveform is square shaped so that the following formula can be used: I(avg) = Ipeak duty cycle; If 8.33 ms is 100% duty cycle, then 5.37 ms is 64.46%, then: Ipeak = I(avg) / duty cycle Ipeak = 30 mA / 0.645 = 46 mA d. Calculate Rext Rext = 0.7 V / Ipeak Rext = 15.21 6. Calculate Power Dissipation on the NUD4011 device’s driver: a. PD_driver = Vdrop * I(avg) b. PD_driver = 29.3 V 0.030 A c. PD_driver = 0.879 W 7. Establish Power Dissipation on the NUD4011device’s control circuit per below formula: a. PD_control = (Vin – 1.4 – VLEDs)@ / 20,000 b. PD_control = 0.040 W 8. Calculate Total Power Dissipation on the device: a. PD_total = PD_driver + PD_control b. PD_total = 0.879 W + 0.040 W = 0.919 W 9. If PD_total > 1.13 W (or derated value per Figure 3), then select the most appropriate recourse and repeat steps 1−8: a. Reduce Vin b. Reconfigure LED array to reduce Vdrop c. Reduce Iout by increasing Rext d. Use external resistors or parallel device’s configuration 5. Calculate Vdrop across the NUD4011 device: a. Vdrop = Vin – Vsense – VLEDs b. Vdrop = 120 V – 0.7 V – 90 V c. Vdrop = 29.3 V 10. Calculate the junction temperature using the thermal information on Page 8 and refer to Figure 4 to check the output current drop due to the calculated junction temperature. If desired, compensate it by adjusting the value of Rext. http://onsemi.com 5 NUD4011 TYPICAL APPLICATION CIRCUITS NUD4011 Switch Vin 35 , 1/4 W Boost Rext PWM + − 1 8 2 7 Current Set Point 3 6 4 5 Iout Iout Iout Iout 120 Vdc LED1 LED2 LED30 Figure 7. 120 Vdc Application Circuit for a Series Array of 30 LEDs (3.0 V, 20 mA) NUD4011 Vin Full Bridge Rectifier Switch + 2 VARISTOR 200 V − 1 30 , 1/4 W 3 Boost Rext PWM 4 1 8 2 7 3 4 Current Set Point 6 5 Iout Iout Iout Iout 120 Vac 60 Hz LED1 LED2 LED30 Figure 8. 120 Vac Application Circuit for a Series Array of 30 LEDs (3.0 V, 20 mA) http://onsemi.com 6 NUD4011 TYPICAL APPLICATION CIRCUITS (continued) Switch 35 , 1/4 W NUD4011 Vin Boost Rext PWM 120 Vdc 8 2 7 Current Set Point 3 6 4 + − 1 5 Rshunt 80 k, 1/4 W 1.0 k + − Iout Iout Iout Iout LED1 Q1 200 V LED2 PWM / ENABLE LED30 Figure 9. 120 Vdc Application with PWM / Enable Function, 30 LEDs in Series (3.0 V, 20 mA) NUD4011 Vin Full Bridge Rectifier Switch + 2 VARISTOR 200 V − 120 Vac 60 Hz 1 35 , 1/4 W 3 4 Boost Rext 200 V Electrolytic Cap PWM 1 8 2 7 3 4 Rshunt 80 k, 1/4 W 1.0 k + PWM / ENABLE − Q1 200 V Current Set Point 6 5 Iout Iout Iout Iout LED1 LED2 LED30 Figure 10. 120 Vac Application with PWM / Enable Function, 30 LEDs in Series (3.0 V, 20 mA) http://onsemi.com 7 NUD4011 THERMAL INFORMATION NUD4011 Power Dissipation reduce the thermal resistance. Figure 11 shows how the thermal resistance changes for different copper areas. Another alternative would be to use a ceramic substrate or an aluminum core board such as Thermal Clad®. Using a board material such as Thermal Clad or an aluminum core board, the power dissipation can be even doubled using the same footprint. The power dissipation of the SO−8 is a function of the pad size. This can vary from the minimum pad size for soldering to a pad size given for maximum power dissipation. Power dissipation for a surface mount device is determined by TJ(max), the maximum rated junction temperature of the die, RJA, the thermal resistance from the device junction to ambient, and the operating temperature, TA. Using the values provided on the data sheet for the SO−8 package, PD can be calculated as follows: 180 160 T * TA PD + Jmax RJA 140 JA (°C/W) The values for the equation are found in the maximum ratings table on the data sheet. Substituting these values into the equation for an ambient temperature TA of 25°C, one can calculate the power dissipation of the device which in this case is 1.13 W. 120 100 80 PD + 150°C * 25°C + 1.13 W 110°C 60 The 110°C/W for the SO−8 package assumes the use of a FR−4 copper board with an area of 2 square inches with 2 oz coverage to achieve a power dissipation of 1.13 W. There are other alternatives to achieving higher dissipation from the SOIC package. One of them is to increase the copper area to 0 1 2 3 4 5 6 7 8 9 10 BOARD AREA (in2) Figure 11. qJA versus Board Area 250 1S −36.9 sq. mm −0.057 in sq. 1S −75.8 sq. mm −0.117 in sq. 200 R() (C°/W) 1S −150.0 sq. mm −0.233 in sq. 150 1S −321.5 sq. mm −0.498 in sq. 1S −681.0 sq. mm −1.056 in sq. 100 1S −1255.0 sq. mm −1.945 in sq. 50 0 0.000001 0.00001 0.0001 0.001 0.1 0.01 1 TIME (sec) Figure 12. Transient Thermal Response http://onsemi.com 8 10 100 1000 NUD4011 PACKAGE DIMENSIONS −X− SOIC−8 NB CASE 751−07 ISSUE AH A 8 NOTES: 1. DIMENSIONING AND TOLERANCING PER ANSI Y14.5M, 1982. 2. CONTROLLING DIMENSION: MILLIMETER. 3. DIMENSION A AND B DO NOT INCLUDE MOLD PROTRUSION. 4. MAXIMUM MOLD PROTRUSION 0.15 (0.006) PER SIDE. 5. DIMENSION D DOES NOT INCLUDE DAMBAR PROTRUSION. ALLOWABLE DAMBAR PROTRUSION SHALL BE 0.127 (0.005) TOTAL IN EXCESS OF THE D DIMENSION AT MAXIMUM MATERIAL CONDITION. 6. 751−01 THRU 751−06 ARE OBSOLETE. NEW STANDARD IS 751−07. 5 S B 1 0.25 (0.010) M Y M 4 −Y− K G C N DIM A B C D G H J K M N S X 45 _ SEATING PLANE −Z− H 0.10 (0.004) D 0.25 (0.010) M Z Y S X M J S MILLIMETERS MIN MAX 4.80 5.00 3.80 4.00 1.35 1.75 0.33 0.51 1.27 BSC 0.10 0.25 0.19 0.25 0.40 1.27 0_ 8 _ 0.25 0.50 5.80 6.20 INCHES MIN MAX 0.189 0.197 0.150 0.157 0.053 0.069 0.013 0.020 0.050 BSC 0.004 0.010 0.007 0.010 0.016 0.050 0 _ 8 _ 0.010 0.020 0.228 0.244 SOLDERING FOOTPRINT* 1.52 0.060 7.0 0.275 4.0 0.155 0.6 0.024 1.270 0.050 SCALE 6:1 mm Ǔ ǒinches *For additional information on our Pb−Free strategy and soldering details, please download the ON Semiconductor Soldering and Mounting Techniques Reference Manual, SOLDERRM/D. Thermal Clad is a registered trademark of the Bergquist Company. ON Semiconductor and are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes without further notice to any products herein. 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