Diodes Incorporated BCR420UFDQ-7

Overview

BCR420UFDQ-7 from Diodes Incorporated is an AEC-Q101 qualified linear LED constant current regulator (CCR) in U-DFN2020-6 package, delivering 10mA ±10% preset output current with 40V maximum supply voltage, -55°C to +150°C junction temperature range, and integrated NPN emitter-follower architecture for automotive interior lighting applications.

For engineers reviewing the BCR420UFDQ-7 datasheet, BCR420UFDQ-7 pinout, BCR420UFDQ-7 application, or BCR420UFDQ-7 equivalent, this part supports low-side LED string regulation without external passive components, offers negative temperature coefficient current derating, and enables parallel configuration for higher current strings in space-constrained automotive lighting modules.

Technical Context

The BCR420UFDQ-7 operates as a monolithic series linear current sink using an internal 95Ω emitter resistor (R_INT) to set nominal 10mA output; it regulates by maintaining fixed V_REXT ≈ 0.95V across the parallel combination of R_INT and optional external R_EXT. No enable pin is present-unlike BCR421UFDQ-making it a fixed-function, always-on CCR.

Its thermal design relies on PCB copper area for heat dissipation: at 50mm × 50mm 1oz Cu, R_θJA = 75°C/W enables 1.7W max power dissipation; junction temperature must stay ≤150°C under worst-case V_OUT × I_OUT conditions, with self-protective current reduction above ambient due to NTC behavior (–0.2%/°C).

Key Specifications

Pinout & Package

U-DFN2020-6 package: 2.0 mm × 2.0 mm footprint, 0.6 mm height, 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 BCR421UFDQ-7, the BCR420UFDQ-7 eliminates enable logic overhead and reduces PCB routing complexity for always-on lighting; versus AL5809-10EVB, it delivers AEC-Q101 assurance and 40% smaller footprint at the cost of fixed 10mA base current.

Availability

BCR420UFDQ-7 is available at Aetrix Electronics and suitable for interior dome lighting, exterior side marker lights, and puddle light modules requiring stable component supply across automotive production lifecycles.

Supply support for BCR420UFDQ-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 solutions for automotive, industrial, and consumer markets.

The BCR420UFDQ-7 belongs to Diodes' automotive-grade linear LED driver product line, engineered specifically for space-constrained, thermally demanding interior/exterior lighting where simplicity, AEC-Q101 compliance, and minimal bill-of-materials are critical.

FAQ

What is the minimum supply voltage required for BCR420UFDQ-7 to regulate 10mA?

The device requires sufficient headroom across its OUT–GND path to maintain regulation. With typical V_REXT ≈ 0.95V and V_CE(sat) ≈ 0.45V, minimum supply voltage is ~1.4V above LED forward voltage. For a 10mA white LED (V_F ≈ 3.0V), minimum V_EN is ~4.4V. Below this, regulation degrades into saturation.

Can BCR420UFDQ-7 drive multiple LEDs in series?

Yes-it regulates current through any series-connected LED string as long as total V_LED remains below the 40V supply minus the device's dropout (~1.4V). For example, with 12 white LEDs (V_F ≈ 3.2V each), total V_LED ≈ 38.4V, leaving only 0.2V margin-insufficient. Max practical series count is 10 LEDs (32V), preserving ≥6V headroom for stable regulation.

How does the negative temperature coefficient affect long-term LED performance?

The –0.2%/°C current reduction lowers LED drive current as ambient rises, directly reducing junction temperature rise in the LED itself. This mitigates lumen depreciation and chromatic shift over time, extending useful life in hot environments like dashboard or lamp housings without requiring external thermal feedback loops.

Is R_EXT required for basic operation?

No-R_EXT is optional. The internal 95Ω resistor alone sets ~10mA output. Adding R_EXT in parallel lowers total emitter resistance, increasing current up to 350mA (with appropriate thermal design). Omitting R_EXT yields simplest, lowest-cost implementation for fixed 10mA applications.