NSI45025AT1G Constant Current Regulator & LED Driver 45 V, 25 mA + 10%, 460 mW Package The linear constant current regulator (CCR) is a simple, economical and robust device designed to provide a cost−effective solution for regulating current in LEDs (similar to Constant Current Diode, CCD). The CCR is based on Self-Biased Transistor (SBT) technology and regulates current over a wide voltage range. It is designed with a negative temperature coefficient to protect LEDs from thermal runaway at extreme voltages and currents. The CCR turns on immediately and is at 25% of regulation with only 0.5 V Vak. It requires no external components allowing it to be designed as a high or low−side regulator. The high anode-cathode voltage rating withstands surges common in Automotive, Industrial and Commercial Signage applications. The CCR comes in thermally robust packages and is UL94−V0 certified. http://onsemi.com Ireg(SS) = 25 mA @ Vak = 7.5 V Anode 2 Features • • • • • • • • • Robust Power Package: 460 mW Wide Operating Voltage Range Immediate Turn-On Voltage Surge Suppressing − Protecting LEDs UL94−V0 Certified SBT (Self−Biased Transistor) Technology Negative Temperature Coefficient NSV Prefix for Automotive and Other Applications Requiring Unique Site and Control Change Requirements; AEC−Q101 Qualified and PPAP Capable These Devices are Pb−Free, Halogen Free/BFR Free and are RoHS Compliant Cathode 1 2 1 SOD−123 CASE 425 STYLE 1 MARKING DIAGRAM Applications 1 • Automobile: Chevron Side Mirror Markers, Cluster, Display & • • • • Instrument Backlighting, CHMSL, Map Light AC Lighting Panels, Display Signage, Decorative Lighting, Channel Lettering Switch Contact Wetting Application Note AND8391/D − Power Dissipation Considerations Application Note AND8349/D − Automotive CHMSL MAXIMUM RATINGS (TA = 25°C unless otherwise noted) Rating Anode−Cathode Voltage Reverse Voltage Operating and Storage Junction Temperature Range ESD Rating: Human Body Model Machine Model Symbol Value Unit Vak Max 45 V VR 500 mV TJ, Tstg −55 to +150 °C ESD Class 1C Class B AF M G AF M G G 2 = Device Code = Date Code = Pb−Free Package (Note: Microdot may be in either location) ORDERING INFORMATION Shipping† Device Package NSI45025AT1G SOD−123 (Pb−Free) 3000/Tape & Reel NSV45025AT1G SOD−123 (Pb−Free) 3000/Tape & Reel †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. Stresses exceeding those listed in the Maximum Ratings table may damage the device. If any of these limits are exceeded, device functionality should not be assumed, damage may occur and reliability may be affected. © Semiconductor Components Industries, LLC, 2014 October, 2014 − Rev. 5 1 Publication Order Number: NSI45025A/D NSI45025AT1G ELECTRICAL CHARACTERISTICS (TA = 25°C unless otherwise noted) Characteristic Steady State Current @ Vak = 7.5 V (Note 1) Voltage Overhead (Note 2) 1. 2. 3. 4. Symbol Min Typ Max Unit Ireg(SS) 22.5 25 27.5 mA Voverhead 1.8 26.1 29.4 V Pulse Current @ Vak = 7.5 V (Note 3) Ireg(P) Capacitance @ Vak = 7.5 V (Note 4) C 2.5 32.75 mA pF Capacitance @ Vak = 0 V (Note 4) C 5.7 pF Ireg(SS) steady state is the voltage (Vak) applied for a time duration ≥ 10 sec, using FR−4 @ 300 mm2 1 oz. Copper traces, in still air. Voverhead = Vin − VLEDs. Voverhead is typical value for 80% Ireg(SS). Ireg(P) non−repetitive pulse test. Pulse width t ≤ 300 msec. f = 1 MHz, 0.02 V RMS. Figure 1. CCR Voltage−Current Characteristic http://onsemi.com 2 NSI45025AT1G THERMAL CHARACTERISTICS Characteristic Symbol Max Unit PD 208 1.66 mW mW/°C Thermal Resistance, Junction−to−Ambient (Note 5) RθJA 600 °C/W Thermal Reference, Lead−to−Ambient (Note 5) RψLA 404 °C/W Thermal Reference, Junction−to−Cathode Lead (Note 5) RψJL 196 °C/W PD 227 1.8 mW mW/°C Thermal Resistance, Junction−to−Ambient (Note 6) RθJA 550 °C/W Thermal Reference, Lead−to−Ambient (Note 6) RψLA 390 °C/W Thermal Reference, Junction−to−Cathode Lead (Note 6) RψJL 160 °C/W PD 347 2.8 mW mW/°C Thermal Resistance, Junction−to−Ambient (Note 7) RθJA 360 °C/W Thermal Reference, Lead−to−Ambient (Note 7) RψLA 200 °C/W Thermal Reference, Junction−to−Cathode Lead (Note 7) RψJL 160 °C/W PD 368 2.9 mW mW/°C Thermal Resistance, Junction−to−Ambient (Note 8) RθJA 340 °C/W Thermal Reference, Lead−to−Ambient (Note 8) RψLA 208 °C/W Thermal Reference, Junction−to−Cathode Lead (Note 8) RψJL 132 °C/W PD 436 3.5 mW mW/°C Thermal Resistance, Junction−to−Ambient (Note 9) RθJA 287 °C/W Thermal Reference, Lead−to−Ambient (Note 9) RψLA 139 °C/W Thermal Reference, Junction−to−Cathode Lead (Note 9) RψJL 148 °C/W PD 463 3.7 mW mW/°C Total Device Dissipation (Note 5) TA = 25°C Derate above 25°C Total Device Dissipation (Note 6) TA = 25°C Derate above 25°C Total Device Dissipation (Note 7) TA = 25°C Derate above 25°C Total Device Dissipation (Note 8) TA = 25°C Derate above 25°C Total Device Dissipation (Note 9) TA = 25°C Derate above 25°C Total Device Dissipation (Note 10) TA = 25°C Derate above 25°C RθJA 270 °C/W Thermal Reference, Lead−to−Ambient (Note 10) RψLA 150 °C/W Thermal Reference, Junction−to−Cathode Lead (Note 10) RψJL 120 °C/W TJ, Tstg −55 to +150 °C Thermal Resistance, Junction−to−Ambient (Note 10) Junction and Storage Temperature Range mm2, mm2, mm2, mm2, mm2, mm2, 5. FR−4 @ 100 1 oz. copper traces, still air. 2 oz. copper traces, still air. 6. FR−4 @ 100 1 oz. copper traces, still air. 7. FR−4 @ 300 2 oz. copper traces, still air. 8. FR−4 @ 300 1 oz. copper traces, still air. 9. FR−4 @ 500 2 oz. copper traces, still air. 10. FR−4 @ 500 NOTE: Lead measurements are made by non−contact methods such as IR with treated surface to increase emissivity to 0.9. Lead temperature measurement by attaching a T/C may yield values as high as 30% higher °C/W values based upon empirical measurements and method of attachment. http://onsemi.com 3 NSI45025AT1G TYPICAL PERFORMANCE CURVES 31 35 30 TA = −40°C 25 TA = 25°C Ireg(P), PULSE CURRENT (mA) Ireg(SS), STEADY STATE CURRENT (mA) Minimum FR−4 @ 300 mm2, 1 oz Copper Trace, Still Air [ −0.061 mA/°C typ @ Vak = 7.5 V TA = 85°C 20 [ −0.055 mA/°C typ @ Vak = 7.5 V 15 10 5 0 1 3 2 4 5 7 6 8 9 TA = 25°C 29 28 27 26 Non−Repetitive Pulse Test DC Test Steady State, Still Air 0 30 25 3.0 10 4.0 Ireg, CURRENT REGULATION (mA) Vak @ 7.5 V TA = 25°C 26 25 24 23 8.0 9.0 10 Vak @ 7.5 V TA = 25°C 29 28 27 26 25 24 27 28 29 31 30 32 0 33 5 10 15 20 25 30 Ireg(P), PULSE CURRENT (mA) TIME (s) Figure 4. Steady State Current vs. Pulse Current Testing Figure 5. Current Regulation vs. Time 800 POWER DISSIPATION (mW) Ireg(SS), STEADY STATE CURRENT (mA) 7.0 30 28 22 26 6.0 Figure 3. Pulse Current (Ireg(P)) vs. Anode−Cathode Voltage (Vak) Figure 2. Steady State Current (Ireg(SS)) vs. Anode−Cathode Voltage (Vak) 27 5.0 Vak, ANODE−CATHODE VOLTAGE (V) Vak, ANODE−CATHODE VOLTAGE (V) 700 500 mm2/2 oz 600 500 mm2/1 oz 500 400 300 mm2/1 300 mm2/2 oz oz 300 200 100 mm2/2 oz 100 mm2/1 oz 100 −40 −20 0 40 20 60 80 TA, AMBIENT TEMPERATURE (°C) Figure 6. Power Dissipation vs. Ambient Temperature @ TJ = 1505C http://onsemi.com 4 35 NSI45025AT1G APPLICATIONS INFORMATION The CCR is a self biased transistor designed to regulate the current through itself and any devices in series with it. The device has a slight negative temperature coefficient, as shown in Figure 2 – Tri Temp. (i.e. if the temperature increases the current will decrease). This negative temperature coefficient will protect the LEDS by reducing the current as temperature rises. The CCR turns on immediately and is typically at 20% of regulation with only 0.5 V across it. The device is capable of handling voltage for short durations of up to 45 V so long as the die temperature does not exceed 150°C. The determination will depend on the thermal pad it is mounted on, the ambient temperature, the pulse duration, pulse shape and repetition. Single LED String The CCR can be placed in series with LEDs as a High Side or a Low Side Driver. The number of the LEDs can vary from one to an unlimited number. The designer needs to calculate the maximum voltage across the CCR by taking the maximum input voltage less the voltage across the LED string (Figures 7 and 8). Figure 8. Higher Current LED Strings Two or more fixed current CCRs can be connected in parallel. The current through them is additive (Figure 9). Figure 7. Figure 9. http://onsemi.com 5 NSI45025AT1G Other Currents LEDs on and off for a portion of a single cycle. This on/off cycle is called the Duty cycle (D) and is expressed by the amount of time the LEDs are on (Ton) divided by the total time of an on/off cycle (Ts) (Figure 12). The adjustable CCR can be placed in parallel with any other CCR to obtain a desired current. The adjustable CCR provides the ability to adjust the current as LED efficiency increases to obtain the same light output (Figure 10). Figure 12. The current through the LEDs is constant during the period they are turned on resulting in the light being consistent with no shift in chromaticity (color). The brightness is in proportion to the percentage of time that the LEDs are turned on. Figure 13 is a typical response of Luminance vs Duty Cycle. 6000 ILLUMINANCE (lx) 5000 4000 Figure 10. 3000 Dimming using PWM The dimming of an LED string can be easily achieved by placing a BJT in series with the CCR (Figure 11). 2000 Lux Linear 1000 0 0 10 20 30 40 50 60 70 DUTY CYCLE (%) 80 90 100 Figure 13. Luminous Emmitance vs. Duty Cycle Reducing EMI Designers creating circuits switching medium to high currents need to be concerned about Electromagnetic Interference (EMI). The LEDs and the CCR switch extremely fast, less than 100 nanoseconds. To help eliminate EMI, a capacitor can be added to the circuit across R2. (Figure 11) This will cause the slope on the rising and falling edge on the current through the circuit to be extended. The slope of the CCR on/off current can be controlled by the values of R1 and C1. The selected delay / slope will impact the frequency that is selected to operate the dimming circuit. The longer the delay, the lower the frequency will be. The delay time should not be less than a 10:1 ratio of the minimum on time. The frequency is also impacted by the resolution and dimming steps that are required. With a delay of 1.5 microseconds on the rise and the fall edges, the minimum on time would be 30 microseconds. If the design called for a resolution of 100 dimming steps, then a total duty cycle time (Ts) of 3 milliseconds or a frequency of 333 Hz will be required. Figure 11. The method of pulsing the current through the LEDs is known as Pulse Width Modulation (PWM) and has become the preferred method of changing the light level. LEDs being a silicon device, turn on and off rapidly in response to the current through them being turned on and off. The switching time is in the order of 100 nanoseconds, this equates to a maximum frequency of 10 Mhz, and applications will typically operate from a 100 Hz to 100 kHz. Below 100 Hz the human eye will detect a flicker from the light emitted from the LEDs. Between 500 Hz and 20 kHz the circuit may generate audible sound. Dimming is achieved by turning the http://onsemi.com 6 NSI45025AT1G Thermal Considerations P D(MAX) + As power in the CCR increases, it might become necessary to provide some thermal relief. The maximum power dissipation supported by the device is dependent upon board design and layout. Mounting pad configuration on the PCB, the board material, and the ambient temperature affect the rate of junction temperature rise for the part. When the device has good thermal conductivity through the PCB, the junction temperature will be relatively low with high power applications. The maximum dissipation the device can handle is given by: T J(MAX) * T A R qJA Referring to the thermal table on page 2 the appropriate RqJA for the circuit board can be selected. AC Applications The CCR is a DC device; however, it can be used with full wave rectified AC as shown in application notes AND8433/D and AND8492/D and design notes DN05013/D and DN06065/D. Figure 14 shows the basic circuit configuration. Figure 14. Basic AC Application http://onsemi.com 7 NSI45025AT1G PACKAGE DIMENSIONS SOD−123 CASE 425−04 ISSUE G D ÂÂÂÂ ÂÂÂÂ A NOTES: 1. DIMENSIONING AND TOLERANCING PER ANSI Y14.5M, 1982. 2. CONTROLLING DIMENSION: INCH. A1 1 HE DIM A A1 b c D E HE L q E 2 q MIN 0.037 0.000 0.020 --0.055 0.100 0.140 0.010 0° INCHES NOM 0.046 0.002 0.024 --0.063 0.106 0.145 ----- MAX 0.053 0.004 0.028 0.006 0.071 0.112 0.152 --10 ° STYLE 1: PIN 1. CATHODE 2. ANODE L b MILLIMETERS MIN NOM MAX 0.94 1.17 1.35 0.00 0.05 0.10 0.51 0.61 0.71 ----0.15 1.40 1.60 1.80 2.54 2.69 2.84 3.56 3.68 3.86 ----0.25 --10 ° 0° C SOLDERING FOOTPRINT* ÉÉ ÉÉ ÉÉ ÉÉ 0.91 0.036 2.36 0.093 4.19 0.165 ÉÉ ÉÉ ÉÉ ÉÉ SCALE 10:1 1.22 0.048 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. ON Semiconductor and the are registered trademarks of Semiconductor Components Industries, LLC (SCILLC) or its subsidiaries in the United States and/or other countries. SCILLC owns the rights to a number of patents, trademarks, copyrights, trade secrets, and other intellectual property. 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