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 25kHz by a microcontroller for LED dimming. With no need for additional external components, this CCR is fully integrated into an SOT26 (SC74R) minimizing PCB area and component count.
Features:
• 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 (BCR421U)
• 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
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
