Datasheet

ManualsBrandsDiodes Incorporated ManualsDriversLED Driver IC SOT-26

BCR420UW6 / BCR421UW6

Document number: DS37667 Rev. 3 - 2

1 of 13

www.diodes.com

November 2015

BCR420UW6 / BCR421UW6

Linear LED Constant Current Regulator in SOT26

Description

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 10 kHz by a micro-

controller for LED dimming.

With no need for additional external components, this CCR is fully

integrated into an SOT26 minimizing PCB area and component count.

Applications

Constant Current Regulation (CCR) in:

 Automotive Interior Lighting

 Emergency Lighting

 Signage, Advertising, Decorative and Architectural Lighting

 Retail Lighting in Fridges, Freezer Cases and Vending Machines

Features

 LED Constant Current Regulator using NPN Emitter-Follower with

Emitter Resistor to Current Limit

 I

OUT

– 10mA ± 10% Constant Current (Preset)

 I

OUT

up to 350mA Adjustable with an External Resistor

 V

OUT

– 40V Supply Voltage

 P

up to 1W in SOT26 (SC-74)

 Low-Side Control Enabling PWM Input < 10kHz (BCR421U)

 Negative Temperature Coefficient (NTC) Reduces I

OUT

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

 An Automotive-Compliant Part is Available Under Separate

Datasheet (BCR421UW6Q)

Mechanical Data

 Case: SOT26 (SC-74)

 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)

Rext

(Optional)

GND

BCR420U

BCR421U

OUT

Ordering Information (Note 4)

Product

Compliance

Marking

Reel Size (inches)

Tape Width (mm)

Quantity per Reel

BCR420UW6-7

AEC-Q101

420

3,000

BCR421UW6-7

AEC-Q101

421

3,000

Notes: 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. For packaging details, go to our website at http://www.diodes.com/products/packages.html.

Pin Name

Pin Function

OUT

Regulated Output Current

Enable for Biasing

Transistor

EXT

External Resistor for

Adjusting Output Current

GND

Power Ground

Top View

Pin-Out

SOT26 (SC-74)

Top View

OUT

Rext

GND

OUT

Internal Device

Schematic

Summary of content (13 pages)

PAGE 1
BCR420UW6 / BCR421UW6 Linear LED Constant Current Regulator in SOT26 Description Features 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.
PAGE 2
BCR420UW6 / BCR421UW6 Marking Information SOT26 (SC-74) xxx = Part Marking (See Ordering Information) YM = Date Code Marking Y = Year (ex: C = 2015) M = Month (ex: 9 = September) xxx Date Code Key Year Code Month Code 2015 C Jan 1 2016 D Feb 2 Mar 3 2017 E Apr 4 May 5 2018 F Jun 6 2019 G Jul 7 2020 H 2021 I Aug Sep Oct Nov Dec 8 9 O N D Absolute Maximum Ratings (Voltage relative to GND, @TA = +25°C, unless otherwise specified.
PAGE 3
BCR420UW6 / BCR421UW6 Electrical Characteristics (@TA = +25°C, unless otherwise specified.) Characteristic Collector-Emitter Breakdown Voltage Enable Current BCR420U BCR421U Symbol Min Typ Max Unit BVCEO 40 — — V — 1.2 — — 1.2 — 350 500 — IC = 50mA; VCE = 1V IRINT = 10mA IEN mA Test Condition IC = 1mA VEN = 24V VEN = 3.3V DC Current Gain hFE 200 Internal Resistor RINT 85 95 105 Ω RB — — 20 1.5 — — kΩ 9 10 11 mA VOUT = 1.4V; VEN = 24V 9 10 11 mA VOUT = 1.
PAGE 4
BCR420UW6 / BCR421UW6 1.4 800 1.2 700 Rth(JA) (°C/W) 600 50mm * 50mm 1oz Cu 1.0 500 0.8 400 0.6 300 0.4 25mm * 25mm 1oz Cu 200 0.2 0.0 100 0 0 50 100 100 150 Copper Area (mm ) Derating Curve Rth(JA) VS Cu Area 125 T amb=25°C 100 75 50 50mm * 50mm 1oz Cu D=0.5 Single Pulse D=0.2 D=0.05 25 D=0.
PAGE 5
BCR420UW6 / BCR421UW6 Typical Electrical Characteristics BCR421U (Continued) (@TA = +25°C, unless otherwise specified.) 0.20 Rext=6 Ohms 0.16 Rext=8 Ohms 0.12 0.10 0.08 Rext=15 Ohms VEN=3.3V Rext= open 0.00 0 1 2 3 4 5 6 7 8 VOUT = 1.4V 0.05 Rext= 30 Ohms 0.04 VOUT = 5.4V 0.15 Rext=10 Ohms IOUT (A) IOUT (A) VEN=3.3V 9 10 11 12 0.00 1 10 VOUT (V) 100 Rext (Ohms) Rext (Ohms)vs IOUT VOUT vs IOUT 0.16 0.06 VEN=3.3V -40°C 0.14 -40°C Rext=6 Ohms 0.05 IOUT (A) 0.
PAGE 6
BCR420UW6 / BCR421UW6 Typical Electrical Characteristics BCR421U (Cont.) (@TA = +25°C, unless otherwise specified.) 0.015 3.0m -40°C 2.5m IOUT = 0A 0.010 IOUT (A) IEN (mA) 25°C Rext= open 2.0m 85°C 1.5m 1.0m 25°C 85°C 0.005 -40°C 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 -40°C -40°C 0.05 0.15 85°C 0.04 IOUT (A) IOUT (A) 25°C 0.03 0.02 85°C 0.
PAGE 7
BCR420UW6 / BCR421UW6 Typical Electrical Characteristics BCR420U (Cont.) (@TA = +25°C, unless otherwise specified.) 0.20 VEN=3.3V Rext=6 Ohms 0.16 Rext=8 Ohms VOUT = 5.4V 0.15 0.12 IOUT (A) IOUT (A) Rext=10 Ohms VOUT = 1.4V 0.10 Rext=15 Ohms 0.08 Rext= 30 Ohms 0.05 0.04 VEN=3.3V Rext= open 0.00 0 1 2 3 4 5 6 7 8 9 10 11 12 0.00 1 10 VOUT (V) 100 Rext (Ohms) Rext (Ohms)vs IOUT VOUT vs IOUT 0.18 -40°C 0.06 0.16 0.14 0.05 0.12 85°C 25°C 85°C 0.04 0.10 VEN=3.3V 0.
PAGE 8
BCR420UW6 / BCR421UW6 Typical Electrical Characteristics BCR420U (Cont.) (@TA = +25°C, unless otherwise specified.) 0.015 -40°C 2.5m IOUT= 0A 2.0m Rext= open 25°C 85°C 0.010 IOUT (A) IEN (mA) 3.0m 1.5m 1.0m -40°C 25°C 85°C 0.005 VOUT=2V 500.0µ Rext= open 0.0 0 5 10 15 20 25 30 35 40 0.000 0 5 10 VEN (V) 15 20 25 30 VEN (V) VENvs IEN VENvs IOUT 0.06 0.20 -40°C -40°C 0.05 0.15 85°C 0.04 IOUT (A) IOUT (A) 0.03 0.02 0.10 85°C VOUT=2V 0.05 VOUT=2V 0.01 0.
PAGE 9
BCR420UW6 / BCR421UW6 Application Information The BCR420/1 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.
PAGE 10
BCR420UW6 / BCR421UW6 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 is a typical response of LED current vs. PWM duty cycle on the EN pin. Figure 3 Application Circuits for LED Driver with PWM Dimming Functionality Figure 4 Typical LED Current Response vs.
PAGE 11
BCR420UW6 / BCR421UW6 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.
PAGE 12
BCR420UW6 / BCR421UW6 Package Outline Dimensions Please see AP02002 at http://www.diodes.com/datasheets/ap02002.pdf 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 AP02001 at http://www.diodes.
PAGE 13
BCR420UW6 / BCR421UW6 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).