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10mA-150mA, Adjustable, DFN2020

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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.


  • Edge Lighting Strips
  • Emergency Lighting
  • Signage, Advertising, Decorative and Architectural Lighting
  • Retail Lighting in Fridges, Freezer Cases and Vending Machines


  • 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 1.7W in U-DFN2020-6 Package
  • 0.6mm Height for Low-profile Edge Lighting
  • Low-Side Control Enabling PWM Input < 25kHz (BCR421U)
  • Negative Temperature Coefficient (NTC) Reduces IOUT with Increasing Temperature
  • Parallel Devices to Increase Regulated Current

Product Specifications

Product Parameters

Qualified to AEC-Q10x No
Compliance (Only Automotive supports PPAP) Standard
Topology Linear LED Driver
Minimum Supply Voltage (V) 1.4 V
Maximum Supply Voltage (V) 40 V
Maximum VOUT (V) 40 V
Number of Channels 1
LED Current Sense Voltage (mV) 700 mV
Output Current (mA) 350 mA
Channel Max. Output Current (mA) 10 Preset mA
Accuracy (%) 10 %
Dimming PWM by external transistor
Temperature Range (°C) -55 to 150 °C

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Orderable Part Number Buy from Distributor / Contact Sales Request Samples


Authorized Distributor Quantity Inventory Date Countries/Regions Buy Online
RS Components 1700 9/18/2021 England Buy Now
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Authorized Distributor Quantity Inventory Date Countries/Regions Buy Online
Arrow Electronics 2870 9/19/2021 United States Buy Now
Mouser Electronics Inc. 2999 9/19/2021 South America, North America, Asia, Europe, Middle East Buy Now
Digi-Key Electronics 2120 9/18/2021 Europe, Asia, North America Buy Now
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Product Change Notices

PCN # Issue Date Implementation Date Subject
PCN-2495 2021-03-31 2021-07-01 Qualification of Additional Assembly & Test Sites and Additional Wafer Back Grinding and Back Metal Process
Source for Select Discrete Products