Diodes Incorporated BCR420UFD-7

Overview

BCR420UFD-7 from Diodes Incorporated is a monolithic linear LED constant current regulator (CCR) in U-DFN2020-6 package, functioning as a low-side current sink with preset 10mA ±10% output and 40V maximum supply voltage. It integrates NPN emitter-follower, internal resistor (95Ω typ), and thermal foldback for self-protection, used in edge lighting strips and retail fridge lighting where compact size and stable current regulation are critical.

For engineers reviewing the BCR420UFD-7 datasheet, BCR420UFD-7 pinout, BCR420UFD-7 application, or BCR420UFD-7 equivalent, this device requires attention to its fixed-current operation (no EN pin), thermal derating on PCB copper area, negative temperature coefficient behavior (−0.2%/°C), and compatibility with LED strings up to 40V forward drop.

Technical Context

The BCR420UFD-7 operates as a series-connected linear current sink using an internal NPN transistor biased by an integrated 20kΩ resistor and 95Ω emitter resistor, delivering precise 10mA current without external components. Its collector-emitter breakdown voltage is 40V, and it exhibits −0.2%/°C current drift over −55°C to +150°C junction range.

Thermal performance depends on PCB copper area: R_θJA is 75°C/W on 50mm×50mm 1oz Cu, dropping to 100°C/W on 25mm×25mm Cu. Power dissipation is limited to 1.7W max at T_A = 25°C, with thermal shutdown initiated via inherent NTC behavior above ~85°C.

Key Specifications

Pinout & Package

Package: U-DFN2020-6 (2.0mm × 2.0mm × 0.6mm), molded green plastic, NiPdAu-plated terminals, moisture sensitivity level 1.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar linear LED constant current regulation applications.

Compared with BCR421UFD-7, the BCR420UFD-7 lacks PWM control but delivers identical current accuracy and thermal protection in a smaller footprint; versus AL5809-20E-7, it offers half the preset current and 0.6mm height advantage but requires careful thermal layout due to U-DFN2020-6's lower thermal mass.

Availability

BCR420UFD-7 is available at Aetrix Electronics and suitable for edge lighting strips, retail refrigeration lighting, and emergency exit signage requiring stable component supply, long-term lifecycle continuity, and RoHS 3-compliant sourcing.

Supply support for BCR420UFD-7 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, specializing in high-reliability power management, signal integrity, and LED driver solutions for industrial and consumer markets.

The BCR420UFD-7 belongs to Diodes' linear LED constant current regulator product line, designed specifically for cost-sensitive, space-constrained lighting applications where simplicity, thermal robustness, and zero-component operation are prioritized over programmability.

FAQ

Does BCR420UFD-7 support PWM dimming?

No, BCR420UFD-7 does not include an Enable (EN) pin and therefore cannot accept PWM signals for brightness control. Dimming must be implemented externally via supply voltage modulation or LED string switching. For PWM capability, use BCR421UFD-7, which features a dedicated EN pin rated for up to 25kHz operation.

What is the minimum LED string forward voltage compatible with BCR420UFD-7?

The minimum output voltage (V_OUT(MIN)) is 1.4V at I_OUT > 18mA. Below this, regulation degrades; thus, the LED string must present ≥1.4V forward drop at operating current. For 10mA operation, typical V_F of a single white LED (~2.8–3.3V) or two red LEDs (~3.0–3.6V) satisfies this requirement without risk of dropout.

Can multiple BCR420UFD-7 devices be paralleled safely?

Yes, the datasheet explicitly supports paralleling to increase total regulated current. Matching between units is ensured by tight ±10% I_OUT tolerance and shared thermal environment. Use identical PCB copper layout for each device and ensure common GND routing to avoid current imbalance caused by trace resistance differences.

How does ambient temperature affect BCR420UFD-7 power dissipation capability?

Maximum power dissipation decreases linearly with rising ambient temperature per the derating curve: PD = (150°C − T_A) / R_θJA. At 70°C ambient and R_θJA = 75°C/W, usable PD drops to 1.07W. Layouts must provide ≥50mm×50mm 1oz Cu for full 1.7W rating; smaller copper areas require stricter ambient limits.