BCR420UW6Q / BCR421UW6Q LINEAR LED CONSTANT CURRENT REGULATOR IN SOT26 Description Features These Linear LED drivers are designed to meet the stringent requirements of automotive applications. The BCR420U and BCR421U monolithically integrate transistors, diodes and resistors to function as a Constant Current Regulator (CCR) for linear LED driving. The device regulates with a preset 10mA nominal that can be adjusted with an external resistor up to 350mA. It is designed for driving LEDs in strings and will reduce current at increasing temperatures to self-protect. Operating as a series linear CCR for LED string current control, it can be used in multiple applications, as long as the maximum supply voltage to the device is < 40V. With the low-side control, the BCR421U has an Enable (EN) pin which can be pulse-width modulated (PWM) up to 25 kHz by a microcontroller for LED dimming. LED Constant Current Regulator using NPN Emitter-Follower with Emitter Resistor to Current Limit IOUT – 10mA ± 10% Constant Current (Preset) IOUT up to 350mA Adjustable with an External Resistor VOUT – 40V Supply Voltage PD up to 1W in SOT26 (SC74R) Low-Side Control Enabling PWM Input < 25kHz (BCR421U) Negative Temperature Coefficient (NTC) Reduces IOUT with Increasing Temperature Parallel Devices to Increase Regulated Current Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2) Halogen and Antimony Free. “Green” Device (Note 3) Qualified to AEC-Q101 Standards for High Reliability PPAP Capable (Note 4) With no need for additional external components, this CCR is fully integrated into an SOT26 minimizing PCB area and component count. Applications Mechanical Data Constant Current Regulation (CCR) in: Automotive Interior Lighting Mood and Decorative Lighting SOT26 (SC74R ) EN Case: SOT26 (SC74R) Case Material: Molded Plastic. ―Green‖ Molding Compound. UL Flammability Rating 94V-0 Moisture Sensitivity: Level 1 per J-STD-020 Terminals: Finish - Matte Tin Plated Leads. Solderable per MIL-STD-202, Method 208 Weight: 0.018 grams (Approximate) OUT BCR420U BCR421U REXT (Optional) EN Pin Name Pin Function REXT OUT OUT OUT EN OUT GND REXT Regulated Output Current Enable for Biasing Transistor External Resistor for Adjusting Output Current Power Ground GND GND Top View Internal Device Schematic Top View Pin-Out Ordering Information (Note 5) Product BCR420UW6Q-7 BCR421UW6Q-7 Notes: Compliance Automotive Automotive Marking 420 421 Reel Size (inches) 7 7 Tape Width (mm) 8 8 Quantity per Reel 3,000 3,000 1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant. 2. See http://www.diodes.com/quality/lead_free.html for more information about Diodes Incorporated’s definitions of Halogen- and Antimony-free, "Green" and Lead-free. 3. Halogen- and Antimony-free "Green‖ products are defined as those which contain <900ppm bromine, <900ppm chlorine (<1500ppm total Br + Cl) and <1000ppm antimony compounds. 4. Automotive products are AEC-Q101 qualified and are PPAP capable. Refer to http://www.diodes.com/product_compliance_definitions.html. 5. For packaging details, go to our website at http://www.diodes.com/products/packages.html. BCR420UW6Q / BCR421UW6Q Document number: DS38302 Rev. 2 - 2 1 of 13 www.diodes.com May 2016 © Diodes Incorporated BCR420UW6Q / BCR421UW6Q Marking Information SOT26 (SC74R) xxx = Part Marking (See Ordering Information) YM = Date Code Marking Y = Year (ex: D = 2016) M = Month (ex: 9 = September) xxx Date Code Key Year Code Month Code 2016 D Jan 1 2017 E Feb 2 Mar 3 2018 F Apr 4 May 5 2019 G Jun 6 2020 H Jul 7 2021 I 2022 J Aug Sep Oct Nov Dec 8 9 O N D Absolute Maximum Ratings (Voltage relative to GND, @TA = +25°C, unless otherwise specified.) Characteristic Symbol Value Unit VEN 40 18 V Output Current IOUT 500 mA Output Voltage VOUT 40 V VR 0.5 V Value Unit BCR420U BCR421U Enable Voltage Reverse Voltage Between all Terminals Thermal Characteristics (@TA = +25°C, unless otherwise specified.) Characteristic Symbol (Note 6) (Note 7) (Note 6) (Note 7) Power Dissipation Thermal Resistance, Junction to Ambient Thermal Resistance, Junction to Lead (Note 8) Recommended Operating Junction Temperature Range Maximum Operating Junction and Storage Temperature Range 1,190 912 105 137 PD RθJA mW °C/W RθJL 50 TJ -55 to +150 TJ , TSTG -65 to +150 °C ESD Ratings (Note 9) Characteristics Electrostatic Discharge – Human Body Model Electrostatic Discharge – Machine Model Notes: Symbols BCR420U BCR421U BCR420U BCR421U HBM MM Value Unit JEDEC Class 500 1,000 300 400 V V V V 1B 1C B C 6. For a device mounted with the OUT leads on 50mm x 50mm 1oz copper that is on a single-sided 1.6mm FR-4 PCB; device is measured under still air conditions while operating in steady-state. 7. Same as Note 5, except mounted on 25mm x 25mm 1oz copper. 8. RθJL = Thermal resistance from junction to solder-point (at the end of the OUT leads). 9. Refer to JEDEC specification JESD22-A114 and JESD22-A115. BCR420UW6Q / BCR421UW6Q Document number: DS38302 Rev. 2 - 2 2 of 13 www.diodes.com May 2016 © Diodes Incorporated BCR420UW6Q / BCR421UW6Q Electrical Characteristics (@TA = +25°C, unless otherwise specified.) Characteristic Collector-Emitter Breakdown Voltage Enable Current BCR420U BCR421U DC Current Gain Internal Resistor Bias Resistor Output Current Output Current at REXT = 5.1Ω BCR420U BCR421U BCR420U BCR421U BCR420U BCR421U Voltage Drop (VREXT) Minimum Output Voltage Output Current Change vs. Temperature BCR420U Output Current Change vs. Supply Voltage BCR420U BCR421U BCR421U BCR420UW6Q / BCR421UW6Q Document number: DS38302 Rev. 2 - 2 Symbol Min Typ Max Unit BVCEO 40 — — V — 1.2 — — 1.2 — hFE 200 350 500 — IC = 50mA; VCE = 1V RINT 85 95 105 Ω IRINT = 10mA RB — — 20 1.5 — — kΩ — — 9 10 11 mA VOUT = 1.4V; VEN = 24V 9 10 11 mA VOUT = 1.4V; VEN = 3.3V — 150 — mA VOUT > 2.0V; VEN = 24V mA VOUT > 2.0V; VEN = 3.3V IEN IOUT mA Test Condition IC = 1mA VEN = 24V VEN = 3.3V IOUT — 150 — VDROP 0.85 0.95 1.05 V IOUT = 10mA VOUT(MIN) — 1.4 — V IOUT > 18mA — -0.2 — — -0.2 — — 1 — — 1 — ΔIOUT/IOUT ΔIOUT/IOUT 3 of 13 www.diodes.com %/°C %/V VOUT > 2.0V; VEN = 24V VOUT > 2.0V; VEN = 3.3V VOUT > 2.0V; VEN = 24V VOUT > 2.0V; VEN = 3.3V May 2016 © Diodes Incorporated BCR420UW6Q / BCR421UW6Q 1.4 800 1.2 700 Rth(JA) ( C/W) 50mm * 50mm 1oz Cu 1.0 0.8 0.6 0.4 25mm * 25mm 1oz Cu 0.2 0.0 600 500 o Max Power Dissipation (W) Typical Thermal Characteristics BCR420/1U (@TA = +25°C, unless otherwise specified.) 400 300 200 100 0 0 50 100 100 150 1000 2 o Copper Area (mm ) Temperature ( C) Rth(JA) VS Cu Area Derating Curve 75 50 Maximum Power (W) o T amb=25 C 100 o Thermal Resistance ( C/W) 125 50mm * 50mm 1oz Cu D=0.5 Single Pulse D=0.2 D=0.05 25 D=0.1 0 100μ 1m 10m 100m 1 10 100 o Single Pulse 50mm * 50mm 1oz Cu 1 100μ 1k T amb=25 C 10 1m Pulse Width (s) 10m 100m 1 10 100 1k Pulse Width (s) Transient Thermal Impedance Pulse Power Dissipation 100 Maximum Power (W) o 125 o Thermal Resistance ( C/W) 150 T amb=25 C 25mm * 25mm 1oz Cu D=0.5 75 50 D=0.2 Single Pulse D=0.05 25 D=0.1 0 100μ 1m 10m 100m 1 10 100 1k 1 100μ 1m 10m 100m 1 10 100 1k Pulse Width (s) Transient Thermal Impedance Document number: DS38302 Rev. 2 - 2 T amb=25 C 25mm * 25mm 1oz Cu Pulse Width (s) BCR420UW6Q / BCR421UW6Q Single Pulse o 10 Pulse Power Dissipation 4 of 13 www.diodes.com May 2016 © Diodes Incorporated BCR420UW6Q / BCR421UW6Q Typical Electrical Characteristics BCR421U (Cont.) (@TA = +25°C, unless otherwise specified.) 0.20 REXT=6 0.16 REXT=8 REXT=10 0.12 0.08 REXT=15 0.10 VOUT = 1.4V 0.05 REXT= 30 0.04 VOUT = 5.4V 0.15 IOUT (A) IOUT (A) VEN=3.3V VEN=3.3V REXT= open 0.00 0 1 2 3 4 5 6 7 8 0.00 9 10 11 12 1 10 VOUT (V) Rext () VOUT vs IOUT Rext () vs IOUT 0.16 0.06 VEN=3.3V o 0.14 o -40 C Rext=6 -40 C 0.05 0.12 IOUT (A) IOUT (A) 100 o 25 C o 85 C 0.10 0.08 o 0.04 25 C o 85 C VEN=3.3V 0.03 REXT= 20 0.06 0.02 0 2 4 6 8 10 12 0 2 VOUT (V) 8 10 12 VOUT vs IOUT 0.15 0.02 VOUT=2V VEN=3.3V IOUT (A) -40 C 0.01 o 2 0.10 Rext= 30 0.05 Rext= 60 Rext= open 85 C 4 6 8 10 12 0.00 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 VOUT (V) VEN (V) VOUT vs IOUT BCR420UW6Q / BCR421UW6Q Document number: DS38302 Rev. 2 - 2 REXT=10 o 25 C 0 REXT=6 REXT=8 REXT= open o IOUT (A) 6 VOUT (V) VOUT vs IOUT 0.00 4 VEN vs IOUT 5 of 13 www.diodes.com May 2016 © Diodes Incorporated BCR420UW6Q / BCR421UW6Q Typical Electrical Characteristics BCR421U (Cont.) (@TA = +25°C, unless otherwise specified.) 0.015 3.0m o -40 C 2.5m o 25 C 1.5m 0.010 IOUT = 0A IOUT (A) IEN (mA) 2.0m o 85 C REXT = open 1.0m o 25 C o -40 C o 85 C 0.005 VOUT=2V 500.0μ REXT= open 0.0 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 0.000 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 VEN (V) VEN (V) VENvs IEN VENvs IOUT 0.06 0.20 o -40 C o -40 C 0.05 0.15 o 25 C o 25 C IOUT (A) IOUT (A) 85 C 0.04 o 0.03 0.02 VOUT=2V 0.05 VOUT=2V 0.01 o 85 C 0.10 REXT=6 REXT= 20 0.00 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 0.00 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 VEN (V) VEN (V) VENvs IOUT VENvs IOUT BCR420UW6Q / BCR421UW6Q Document number: DS38302 Rev. 2 - 2 6 of 13 www.diodes.com May 2016 © Diodes Incorporated BCR420UW6Q / BCR421UW6Q Typical Electrical Characteristics BCR420U (Cont.) (@TA = +25°C, unless otherwise specified.) 0.20 VEN= 24V Rext=6 Ohms 0.16 Rext=8 IOUT (A) IOUT (A) 0.12 VOUT = 1.4V 0.10 REXT=15 0.08 VOUT = 5.4V 0.15 Rext=10 Rext= 30 0.05 0.04 VEN= 24V REXT= open 0.00 0 1 2 3 4 5 6 7 8 0.00 9 10 11 12 1 10 100 REXT () VOUT (V) VOUT vs IOUT REXT () vs IOUT 0.18 o -40 C 0.06 0.14 IOUT (A) IOUT (A) 0.16 o 25 C 0.12 o 85 C 0.10 VEN= 24V 0.08 0.05 o o -40 C 25 C o 85 C 0.04 VEN= 24V 0.03 REXT= 20 REXT=6 0.06 0.02 0 2 4 6 8 10 12 0 VOUT (V) 2 4 6 8 VOUT vs IOUT 12 VOUT vs IOUT 0.15 0.02 REXT=8 VOUT=2V REXT=10 o -40 C REXT= 30 IOUT (A) 0.10 IOUT (A) 10 VOUT (V) 0.01 o 25 C o 85 C REXT=20 REXT= 60 0.05 REXT= open VEN=24V REXT= open 0.00 0 2 4 6 8 10 12 0.00 0 VOUT (V) Document number: DS38302 Rev. 2 - 2 10 15 20 25 30 VEN (V) VOUT vs IOUT BCR420UW6Q / BCR421UW6Q 5 VEN vs IOUT 7 of 13 www.diodes.com May 2016 © Diodes Incorporated BCR420UW6Q / BCR421UW6Q Typical Electrical Characteristics BCR420U (Cont.) (@TA = +25°C, unless otherwise specified.) 0.015 3.0m IOUT= 0A 2.0m REXT= open o 25 C o 85 C IOUT (A) IEN (mA) o -40 C 2.5m 1.5m 1.0m o -40 C o 25 C 0.010 o 85 C 0.005 VOUT=2V 500.0μ 0.0 REXT= open 0.000 0 5 10 15 20 25 30 35 40 0 5 10 VEN (V) 15 20 25 30 VEN (V) VENvs IEN VENvs IOUT 0.06 0.20 o -40 C o -40 C 0.05 0.15 o 85 C 25 C o 25 C IOUT (A) IOUT (A) 0.04 o 0.03 0.10 0.02 0.01 o 85 C VOUT=2V 0.05 VOUT=2V REXT=6 REXT= 20 0.00 0.00 0 5 10 15 20 25 30 0 Document number: DS38302 Rev. 2 - 2 10 15 20 25 30 VENvs IOUT VENvs IOUT BCR420UW6Q / BCR421UW6Q 5 VEN (V) VEN (V) 8 of 13 www.diodes.com May 2016 © Diodes Incorporated BCR420UW6Q / BCR421UW6Q Application Information The BCR420/1 is designed for driving low current LEDs with typical LED currents of 10mA to 350mA. They provide a cost-effective way for driving low current LEDs compared with more complex switching regulator solutions. Furthermore, they reduce the PCB board area of the solution as there is no need for external components like inductors, capacitors and switching diodes. Figure 1 shows a typical application circuit diagram for driving an LED or string of LEDs. The device comes with an internal resistor (RINT) of typically 95Ω, which in the absence of an external resistor, sets an LED current of 10mA (typical) from a VEN = 3.3V and VOUT = 1.4V for BCR421; or VEN = 24V and VOUT = 1.4V for BCR420. LED current can be increased to a desired value by choosing an appropriate external resistor, REXT. The REXT Vs IOUT graphs should be used to select the appropriate resistor. Choosing a low tolerance REXT will improve the overall accuracy of the current sense formed by the parallel connection of RINT and REXT. Figure 1 Typical Application Circuit for Linear Mode Current Sink LED Driver Two or more BCR420/1s can be connected in parallel to construct higher current LED strings as shown in Figure 2. Consideration of the expected linear mode power dissipation must be factored into the design, with respect to the BCR420/1’s thermal resistance. The maximum voltage across the device can be calculated by taking the maximum supply voltage and subtracting the voltage across the LED string. VOUT = VS – VLED PD = (VOUT × ILED) + (VEN × IEN) As the output current of BCR420/1 increases, it is necessary to provide appropriate thermal relief to the device. The power dissipation supported by the device is dependent upon the PCB board material, the copper area and the ambient temperature. The maximum dissipation the device can handle is given by: Figure 2 Application Circuit for Increasing LED Current PD = (TJ(MAX) - TA) / RθJA Refer to the thermal characteristic graphs on Page 4 for selecting the appropriate PCB copper area. BCR420UW6Q / BCR421UW6Q Document number: DS38302 Rev. 2 - 2 9 of 13 www.diodes.com May 2016 © Diodes Incorporated BCR420UW6Q / BCR421UW6Q Application Information (Cont.) PWM dimming can be achieved by driving the EN pin. Dimming is achieved by turning the LEDs ON and OFF for a portion of a single cycle. The PWM signal can be provided by a micro-controller or analog circuitry; typical circuit is shown in Figure 3. Figure 4 is a typical response of LED current vs PWM duty cycle on the EN pin. PWM up to 25kHz with duty cycle of 0.5% (dimming range 200:1). This is above the audio band minimizing audible power supply noise. Figure 3 Application Circuits for LED Driver with PWM Dimming Functionality Figure 4 Typical LED Current Response vs. PWM Duty Cycle for 25kHz PWM Frequency (Dimming Range 200:1) BCR420UW6Q / BCR421UW6Q Document number: DS38302 Rev. 2 - 2 10 of 13 www.diodes.com May 2016 © Diodes Incorporated BCR420UW6Q / BCR421UW6Q Application Information (Cont.) To remove the potential of incorrect connection of the power supply damaging the lamp’s LEDs, many systems use some form of reverse polarity protection. One solution for reverse input polarity protection is to simply use a diode with a low VF in line with the driver/LED combination. The low VF increases the available voltage to the LED stack and dissipates less power. A circuit example is presented in Figure 5 which protects the light engine although it will not function until the problem is diagnosed and corrected. An SDM10U45LP (0.1A/45V) is shown, providing exceptionally low VF for its package size of 1mm x 0.6mm. Other reverse voltage ratings are available from Diodes Incorporated’s website such as the SBR02U100LP (0.2A/100V) or SBR0220LP (0.2A/20V). While automotive applications commonly use this method for reverse battery protection, an alternative approach shown in Figure 6, provides reverse polarity protection and corrects the reversed polarity, allowing the light engine to function. The BAS40BRW incorporates four low VF Schottky diodes in a single package, reducing the power dissipated and maximizes the voltage across the LED stack. Figure 5 Application Circuit for LED Driver with Reverse Polarity Protection Figure 7 shows an example configuration for 350mA operation. In such higher current configurations adequate enable current is provided by increasing the enable voltage. Figure 6 Application Circuit for LED Driver with Assured Operation Regardless Of Polarity BCR420UW6Q / BCR421UW6Q Document number: DS38302 Rev. 2 - 2 Figure 7 Example for 350mA Operation 11 of 13 www.diodes.com May 2016 © Diodes Incorporated BCR420UW6Q / BCR421UW6Q Package Outline Dimensions Please see http://www.diodes.com/package-outlines.html for the latest version. SOT26 (SC74R) D E1 SOT26 (SC74R) Dim Min Max Typ A1 0.013 0.10 0.05 A2 1.00 1.30 1.10 A3 0.70 0.80 0.75 b 0.35 0.50 0.38 c 0.10 0.20 0.15 D 2.90 3.10 3.00 e 0.95 e1 1.90 E 2.70 3.00 2.80 E1 1.50 1.70 1.60 L 0.35 0.55 0.40 a 8° a1 7° All Dimensions in mm E b a1 e1 A2 A3 A1 Seating Plane e L c a Suggested Pad Layout Please see http://www.diodes.com/package-outlines.html for the latest version. SOT26 (SC74R) C1 Y1 G Dimensions Value (in mm) C 2.40 C1 0.95 G 1.60 X 0.55 Y 0.80 Y1 3.20 C Y X BCR420UW6Q / BCR421UW6Q Document number: DS38302 Rev. 2 - 2 12 of 13 www.diodes.com May 2016 © Diodes Incorporated BCR420UW6Q / BCR421UW6Q IMPORTANT NOTICE DIODES INCORPORATED MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARDS TO THIS DOCUMENT, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE (AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION). 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LIFE SUPPORT Diodes Incorporated products are specifically not authorized for use as critical components in life support devices or systems without the express written approval of the Chief Executive Officer of Diodes Incorporated. As used herein: A. Life support devices or systems are devices or systems which: 1. are intended to implant into the body, or 2. support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided in the labeling can be reasonably expected to result in significant injury to the user. B. A critical component is any component in a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or to affect its safety or effectiveness. Customers represent that they have all necessary expertise in the safety and regulatory ramifications of their life support devices or systems, and acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related requirements concerning their products and any use of Diodes Incorporated products in such safety-critical, life support devices or systems, notwithstanding any devices- or systems-related information or support that may be provided by Diodes Incorporated. Further, Customers must fully indemnify Diodes Incorporated and its representatives against any damages arising out of the use of Diodes Incorporated products in such safety-critical, life support devices or systems. Copyright © 2016, Diodes Incorporated www.diodes.com BCR420UW6Q / BCR421UW6Q Document number: DS38302 Rev. 2 - 2 13 of 13 www.diodes.com May 2016 © Diodes Incorporated