NUD4700 LED Shunt The NUD4700 is an electronic shunt which provides a current bypass in the case of a single LED going into open circuit. LEDs are by nature quite fragile when subjected to transients and surge conditions. There are also many cases where high reliability of the LED lighting must be maintained such as headlights, lighthouses, bridges, aircraft, runways and so forth. In these cases the low cost addition of the NUD4700 will provide full assurance that an entire string of LEDs will not extinguish should one LED fail. NUD4700 is also applicable to other loads where circuit continuity is required. This device is designed to be used with 1 W LEDs (nominally 350 mA @ 3 V). http://onsemi.com Anode Control Circuit Features • • • • • A Simple Two Terminal Device Automatically Resets Itself if the LED Heals Itself or is Replaced ON−State Voltage Typically 1 V OFF−State Current less than 250 mA This is a Pb−Free Device Cathode Typical Applications • • • • • Anode LEDs where Preventive Maintenance is Non Practical LED Headlights LEDs with High Reliability Requirements Crowbar Protection for Open Circuit Conditions Overvoltage Protection for Sensitive Circuits Cathode POWERMITE[ CASE 457 PLASTIC MARKING DIAGRAM Anode M MNHG Cathode M = Date Code MNH = Device Code G = Pb−Free Package PIN FUNCTION DESCRIPTION Pin Description Anode Positive Input Voltage to the Device Cathode Negative Input Voltage to the Device ORDERING INFORMATION Device Package Shipping† NUD4700SNT1G POWERMITE 3000/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 Specifications Brochure, BRD8011/D. © Semiconductor Components Industries, LLC, 2010 March, 2010 − Rev. 8 1 Publication Order Number: NUD4700/D NUD4700 MAXIMUM RATINGS (Maximum ratings are those, that, if exceeded, may cause damage to the device. Electrical Characteristics are not guaranteed over this range) Rating Symbol Value Unit VDM −0.3 to 10 V Peak Repetitive Off State Voltage (Anode to Cathode) Average On−State Current, (TA = 25°C), (Note 1) (Note 2) IT(AVG) Thermal Resistance, Junction−to−Air (Note 1) (Note 2) QJA Thermal Resistance, Junction−to−Lead A 1.3 0.376 °C/W 80 277 35 QJL °C/W Power Dissipation (TA = 25°C) (Note 1) (Note 2) PMAX W Operating Temperature Range TJ −40 to 150 °C Non−Operating Temperature Range TJ 150 °C Lead Temperature, Soldering (10 Sec) TL 260 °C 1.56 0.45 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. Mounted onto a 1“ x 1” square copper pad. Normally this device would be mounted on the same copper heat sink and adjacent to the LED. If the LED were to go open, then the NUD4700 shunt would now dissipate the power using the same copper heat sink. Since the NUD4700 has a voltage that is nominally 30% of the LED, then the power dissipation would be easily handled by the same heat sink as the LED. 2. Device mounted on minimum copper pad. ELECTRICAL CHARACTERISTICS (Unless otherwise noted: TA = 25°C) Characteristics Symbol Min Typ Max Unit Off−State Current (VAnode = 5 V) ILEAK − 100 250 mA Breakdown Voltage (IBR = 1 mA) V(BR) 5.5 − 7.5 V Holding Current (VAnode = 10 V, Iinitial = 100 mA) IH − 6.0 12 mA Latching Current (VAnode = 10 V) IL − 35 70 mA VT − − − 1.0 1.0 1.0 1.2 − − V dV/dt 250 − − V/ms On−State Voltage (IT = 0.350 A) (IT = 0.750 A) (IT = 1.0 A) DYNAMIC CHARACTERISTICS Critical Rate−of−Rise of Off State Voltage (Vpk = Rated V(BR), TJ = 125°C, Exponential Method) http://onsemi.com 2 NUD4700 TYPICAL PERFORMANCE CURVES (TA = 25°C unless otherwise noted) 6 35 IH, HOLDING CURRENT (mA) IL, LATCHING CURRENT (mA) 40 30 25 20 15 10 5 0 −50 −25 0 25 50 75 100 125 3 2 1 0 25 50 75 100 125 150 TA, AMBIENT TEMPERATURE (°C) TA, AMBIENT TEMPERATURE (°C) Figure 2. Holding Current vs Temperature IDSS, LEAKAGE CURRENT (mA) 450 90 80 70 60 50 0 1 2 3 4 400 350 300 250 200 150 100 50 0 −50 5 25 50 75 100 125 150 TA, AMBIENT TEMPERATURE (°C) Figure 4. Leakage Current vs Temperature 1.2 1.1 IT @ 1.0 mA 1 IT @ 350 mA 0.6 0.4 IT @ 750 mA 0.2 −50 0 VOLTS (V) 1.2 0.8 −25 Figure 3. Capacitance vs Voltage 1.4 0 −25 Figure 1. Latching Current vs Temperature VT, ON−STATE VOLTAGE (V) Cd, CAPACITANCE (pF) 4 0 −50 150 100 VT, ON−STATE VOLTAGE (V) 5 −25 0 25 50 75 100 125 150 1 0.9 0.8 0.7 0.6 0.5 0.25 175 0.35 0.45 0.55 0.65 0.75 0.85 0.95 TEMPERATURE (°C) IT, ON−STATE CURRNT (A) Figure 5. On−State Voltage vs. Temperature Figure 6. On−State Voltage vs. On−State Current (IT) at 255C http://onsemi.com 3 1.05 NUD4700 TYPICAL APPLICATION CIRCUIT Q1 AC/DC Converter NUD4001 R1 Current Source NUD4700 Control Circuit NUD4700 Control Circuit NUD4700 Control Circuit NUD4700 Control Circuit NUD4700 Control Circuit Figure 7. Typical Application Circuit http://onsemi.com 4 NUD4700 TYPICAL OPERATION WAVEFORMS Switching event LED being opened LED Current NUD4700 voltage Off state NUD4700 voltage ON−state NUD4700 switching waveforms (Powermite) Figure 8. NUD4700 Switching Waveforms Switching event LED being opened Current overshoot due to response time of current source LED Current NUD4700 voltage Off state NUD4700 voltage ON−state NUD4700 switching waveforms (zoom in) Figure 9. Zoom in of Figure 8 http://onsemi.com 5 NUD4700 PACKAGE DIMENSIONS POWERMITE CASE 457−04 ISSUE E F 0.08 (0.003) C −A− J T B M C S S S NOTES: 1. DIMENSIONING AND TOLERANCING PER ANSI Y14.5M, 1982. 2. CONTROLLING DIMENSION: MILLIMETER. 3. DIMENSION A DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.15 (0.006) PER SIDE. PIN 1 −B− DIM A B C D F H J K L R S K PIN 2 R L J MILLIMETERS INCHES MIN MAX MIN MAX 1.75 2.05 0.069 0.081 1.75 2.18 0.069 0.086 0.85 1.15 0.033 0.045 0.40 0.69 0.016 0.027 0.70 1.00 0.028 0.039 -0.05 +0.10 -0.002 +0.004 0.10 0.25 0.004 0.010 3.60 3.90 0.142 0.154 0.50 0.80 0.020 0.031 1.20 1.50 0.047 0.059 0.50 REF 0.019 REF D H −T− 0.08 (0.003) M T B S C S SOLDERING FOOTPRINT* 0.635 0.025 2.67 0.105 0.762 0.030 2.54 0.100 1.27 0.050 SCALE 10:1 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. POWERMITE is a registered trademark of and used under a license from Microsemi Corporation. The product described herein (NUD4700), may be covered by one or more U.S. patents. There may be other patents pending. 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. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does SCILLC assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages. “Typical” parameters which may be provided in SCILLC data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each customer application by customer’s technical experts. SCILLC does not convey any license under its patent rights nor the rights of others. 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