BCR420UW6Q-7

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 BCR420UW6Q and BCR421UW6Q 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, the device can be used in multiple applications, as long as the maximum supply voltage to the device is < 40V. With the low-side control, the BCR421UW6Q 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   (BCR421UW6Q) VOUT – 40V Supply Voltage PD up to 1W in SOT26   Low-Side Control Enabling PWM Input < 25kHz (BCR421UW6Q) Negative Temperature Coefficient (NTC) Reduces IOUT with     With no need for additional external components, this CCR is fully integrated into the SOT26 package, minimizing PCB area and component count. 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) The BCR420UW6Q and BCR420UW6Q are suitable for automotive applications requiring specific change control; these parts are AEC-Q100 qualified, PPAP capable, and manufactured in IATF16949 certified facilities. https://www.diodes.com/quality/product-definitions/ Applications Mechanical Data Constant Current Regulation (CCR) in:     Automotive interior lighting Mood and decorative lighting    SOT26 EN Package: SOT26 Package 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 GND Power Ground GND Top View Internal Device Schematic Top View Pin-Out Ordering Information (Note 4) 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) & 2015/863/EU (RoHS 3) compliant. 2. See https://www.diodes.com/quality/lead-free/ 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 2.0V; VEN = 24V VOUT > 2.0V; VEN = 3.3V VOUT > 2.0V; VEN = 24V VOUT > 2.0V; VEN = 3.3V January 2022 © Diodes Incorporated BCR420UW6Q / BCR421UW6Q 1.4 800 1.2 700 50mm * 50mm 1oz Cu 1.0 Rth(JA) ( C/W) 0.8 o Max Power Dissipation (W) Typical Thermal Characteristics BCR420UW6Q/BCR421UW6Q (@TA = +25°C, unless otherwise specified.) 0.6 0.4 25mm * 25mm 1oz Cu 0.2 0.0 600 500 400 300 200 100 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 100μµ 1m 10m 100m 1 10 100 o Single Pulse 50mm * 50mm 1oz Cu 1 100μ µ 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 o Maximum Power (W) 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 100μµ 1m 10m 100m 1 10 100 1k 1 100μµ 1m 10m 100m 1 10 100 1k Pulse Width (s) Transient Thermal Impedance Document number: DS38302 Rev. 5 - 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 January 2022 © Diodes Incorporated BCR420UW6Q / BCR421UW6Q Typical Electrical Characteristics BCR421U (@ TA = +25°C, unless otherwise specified.) 0.20 0.20 VEN=3.3V REXT=6.2 REXT=8.2 VOUT=5.4V 0.15 REXT=10 IOUT (A) IOUT (A) 0.16 0.12 0.08 REXT= 30 REXT=15 VOUT=1.4V 0.10 0.05 0.04 VEN=3.3V REXT=open 0.000 1 2 3 4 5 6 7 8 9 10 11 12 0.00 1 10 100 REXT () VOUT (V) REXT () vs IOUT VOUT vs IOUT 0.18 o -40 C 0.06 0.16 o -40 C 0.05 IOUT (A) IOUT (A) 0.14 0.12 o 25 C 0.10 o 85 C VEN=3.3V 0.08 0.06 0.04 o 25 C o 85 C VEN=3.3V 0.03 REXT=20 REXT=6.2 0 2 4 6 8 10 0.02 0 12 VOUT (V) 2 4 6 VOUT (V) 8 10 12 VOUT vs IOUT VOUT vs IOUT 0.15 0.02 REXT=8.2 VOUT=2V REXT=6.2 REXT=10 o IOUT (A) IOUT (A) -40 C 0.01 o 85 C 0.00 0 2 4 6 REXT= 60 0.05 REXT= open REXT=open 8 10 12 0.00 0 1 2 3 VOUT (V) VEN (V) VOUT vs IOUT VEN vs IOUT BCR420UW6Q / BCR421UW6Q Document number: DS38302 Rev. 5 - 2 REXT=30 VEN=3.3V o 25 C 0.10 5 of 13 www.diodes.com 4 5 January 2022 © Diodes Incorporated BCR420UW6Q / BCR421UW6Q Typical Electrical Characteristics BCR421U (@ TA = +25°C, unless otherwise specified.) (continued) 0.015 3.0m o -40 C IOUT=0A o o 85 C REXT=open 2.0m IOUT (A) IEN (mA) 2.5m 1.5m 1.0m o 25 C o -40 C 25 C 0.010 o 85 C 0.005 VOUT=2V 500.0µ 500.0μ REXT=open 0.0 0 1 2 3 4 0.000 0 5 1 VEN (V) 2 3 4 5 VEN (V) VENvs IOUT VENvs IEN 0.06 0.20 o -40 C o -40 C 0.05 IOUT (A) IOUT (A) 0.15 0.04 o o 85 C 25 C 0.03 o 25 C o 0.10 85 C 0.02 0.01 0.00 VOUT=2V 0.05 VOUT=2V REXT=6.2 REXT= 20 0 1 2 3 4 5 0.00 0 VENvs IOUT BCR420UW6Q / BCR421UW6Q Document number: DS38302 Rev. 5 - 2 1 2 3 4 5 VEN (V) VEN (V) VEN vs IOUT 6 of 13 www.diodes.com January 2022 © Diodes Incorporated BCR420UW6Q / BCR421UW6Q Typical Electrical Characteristics BCR420UW6Q (@TA = +25°C, unless otherwise specified.) 0.20 0.20 REXT=6.2 0.16 REXT=8.2 VOUT = 5.4V 0.15 REXT=10 IOUT (A) IOUT (A) VEN=24V 0.12 0.08 REXT=15 REXT= 30 0.04 0.10 0.05 VEN=24V REXT=open 0.00 0 1 2 3 4 5 6 7 VOUT (V) 8 VOUT=1.4V 0.00 1 9 10 11 12 10 100 REXT () REXT ()vs IOUT VOUT vs IOUT 0.18 o -40 C 0.06 0.16 o -40 C IOUT (A) IOUT (A) 0.14 0.12 o 25 C 0.10 0.04 o 25 C 85 C VEN=24V VEN=24V 0.03 REXT=20 REXT=6.2 0 2 4 6 8 10 0.02 0 12 VOUT (V) 2 4 6 VOUT (V) 8 10 12 VOUT vs IOUT VOUT vs IOUT 0.15 0.02 VOUT=2V IOUT (A) IOUT (A) 0.01 o o 85 C 4 6 0.10 REXT=open 0.05 REXT=open 8 10 12 0.00 0 5 10 15 20 25 30 VEN (V) VOUT vs IOUT Document number: DS38302 Rev. 5 - 2 REXT=30 REXT=60 VOUT (V) BCR420UW6Q / BCR421UW6Q Rext=10 VEN=24V 25 C 2 REXT=8 REXT=20 o -40 C 0.00 0 o 85 C o 0.08 0.06 0.05 VEN vs IOUT 7 of 13 www.diodes.com January 2022 © Diodes Incorporated BCR420UW6Q / BCR421UW6Q Typical Electrical Characteristics BCR420UW6Q (@TA = +25°C, unless otherwise specified.) (continued) 0.015 3.0m o -40 C 2.5m IOUT=0A o IOUT (A) 1.5m 1.0m o 25 C 25 C 0.010 IEN (mA) 2.0m o 85 C REXT=open o 85 C 0.005 o -40 C VOUT=2V 500.0μ 500.0µ REXT=open 0.000 0.0 0 5 10 15 20 25 30 VEN (V) 35 0 40 5 10 VENvs IEN 15 VEN (V) 20 25 30 VENvs IOUT 0.06 0.20 o -40 C o -40 C 0.05 0.15 o 85 C o 25 C o 25 C IOUT (A) IOUT (A) 0.04 0.03 0.10 0.02 VOUT=2V 0.01 o 85 C VOUT=2V 0.05 REXT=6.2 REXT=20 0.00 0.00 0 5 10 15 20 VEN (V) 25 30 Document number: DS38302 Rev. 5 - 2 5 10 15 VEN (V) 20 25 30 VENvs IOUT VENvs IOUT BCR420UW6Q / BCR421UW6Q 0 8 of 13 www.diodes.com January 2022 © Diodes Incorporated BCR420UW6Q / BCR421UW6Q Application Information The BCR420UW6Q and BCR421UW6Q are 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 BCR420UW6Q/BCR421UW6Q 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 BCR420UW6Q/BCR421UW6Q’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 BCR420UW6Q/BCR421UW6Q 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. 5 - 2 9 of 13 www.diodes.com January 2022 © Diodes Incorporated BCR420UW6Q / BCR421UW6Q Application Information (continued) 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 shows 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-bandminimizing audible power-supply noise. Figure 3 Application Circuits for LED Driver with PWM Dimming Functionality using BCR421UW6Q Figure 4 Typical LED Current Response vs. PWM Duty Cycle for 25kHz PWM Frequency (Dimming Range 200:1) BCR420UW6Q / BCR421UW6Q Document number: DS38302 Rev. 5 - 2 10 of 13 www.diodes.com January 2022 © Diodes Incorporated BCR420UW6Q / BCR421UW6Q Application Information (continued) 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 6 Application Circuit for LED Driver with Assured Operation Regardless Of Polarity BCR420UW6Q / BCR421UW6Q Document number: DS38302 Rev. 5 - 2 Figure 7 shows an example configuration for 350mA operation using BCR421UW6Q. In such higher current configurations, adequate enable current is provided by increasing the enable voltage. Figure 7 Example for 350mA Operation using BCR421UW6Q 11 of 13 www.diodes.com January 2022 © Diodes Incorporated BCR420UW6Q / BCR421UW6Q Package Outline Dimensions Please see http://www.diodes.com/package-outlines.html for the latest version. SOT26 D E1 SOT26 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 C1 Y1 G C Y Dimensions Value (in mm) C 2.40 C1 0.95 G 1.60 X 0.55 Y 0.80 Y1 3.20 X BCR420UW6Q / BCR421UW6Q Document number: DS38302 Rev. 5 - 2 12 of 13 www.diodes.com January 2022 © Diodes Incorporated BCR420UW6Q / BCR421UW6Q IMPORTANT NOTICE 1. DIODES INCORPORATED AND ITS SUBSIDIARIES (“DIODES”) MAKE NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARDS TO ANY INFORMATION CONTAINED IN THIS DOCUMENT, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT OF THIRD PARTY INTELLECTUAL PROPERTY RIGHTS (AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION). 2. The Information contained herein is for informational purpose only and is provided only to illustrate the operation of Diodes products described herein and application examples. Diodes does not assume any liability arising out of the application or use of this document or any product described herein. This document is intended for skilled and technically trained engineering customers and users who design with Diodes products. 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Notwithstanding the foregoing, Diodes reserves the right to make modifications, enhancements, improvements, corrections or other changes without further notice to this document and any product described herein. This document is written in English but may be translated into multiple languages for reference. Only the English version of this document is the final and determinative format released by Diodes. 8. Any unauthorized copying, modification, distribution, transmission, display or other use of this document (or any portion hereof) is prohibited. Diodes assumes no responsibility for any losses incurred by the customers or users or any third parties arising from any such unauthorized use. Copyright © 2022 Diodes Incorporated www.diodes.com BCR420UW6Q / BCR421UW6Q Document number: DS38302 Rev. 5 - 2 13 of 13 www.diodes.com January 2022 © Diodes Incorporated