BCR420UFD / BCR421UFD

BCR420UFD / BCR421UFD

Document number: DS38588 Rev. 3 - 2

1 of 13

www.diodes.com

January 2018

© Diodes Incorporated

Pin Name

Pin Function

OUT

Regulated Output Current

EN

Enable for Biasing

Transistor

Rext

External Resistor for

Adjusting Output Current

GND

Power Ground

N/C

Not connected internally

LINEAR LED CONSTANT CURRENT REGULATOR IN U-DFN2020-6

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. 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 25kHz by a micro-

controller for LED dimming.

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

integrated into a 2x2x0.6mm package (U-DFN2020-6) minimizing

PCB area, off-board height, and component count.



LED Constant Current Regulator Using NPN Emitter-Follower with

Emitter Resistor to Current Limit



– 10mA ±10% Constant Current (Preset)



(BCR421U)



– 40V Supply Voltage





0.6mm Height for Low-profile Edge Lighting



Low-Side Control Enabling PWM Input < 25kHz (BCR421U)



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)



Automotive-Compliant Parts are Available Under Separate

Datasheet (BCR420UFDQ/BCR421UFDQ)

Mechanical Data

Applications

Constant Current Regulation (CCR) in:



Edge Lighting Strips



Emergency Lighting



Signage, Advertising, Decorative and Architectural Lighting



Retail Lighting in Fridges, Freezer Cases and Vending Machines



Case: U-DFN2020-6



Case Material: Molded Plastic.

“Green” Molding Compound.

UL Flammability Rating 94V-0



Moisture Sensitivity: Level 1 per J-STD-020



Terminals: Finish - NiPdAu, Solderable per MIL-STD-202, Method



Weight: 0.018 grams (Approximate)

EN

OUT

U-DFN2020-6

Rext

(Optional)

N/C

OUT

GND

Rext

Bottom View

Internal Device

Schematic

GND

N/C

EN

Top View

Pin-Out

Part Number

Compliance

Marking

Reel Size (inches)

Tape Width (mm)

Quantity Per Reel

BCR420UFD-7

Standard

420

7

8

3,000

BCR421UFD-7

Standard

421

7

8

3,000

Notes:

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 <900ppm bromine, <900ppm chlorine (<1500ppm total Br + Cl) and

<1000ppm antimony compounds.

4. For packaging details, go to our website at https://www.diodes.com/design/support/packaging/diodes-packaging/.