Diodes Incorporated ZXLD1366QEN8TC

Overview

ZXLD1366QEN8TC from Diodes Incorporated is an AEC-Q100 Grade 1 qualified automotive LED driver IC implementing a continuous-mode inductive step-down (buck) converter. It delivers up to 1A output current with ±0.8% accuracy, operates from 6V–60V input, uses high-side current sensing via external resistor RS, and supports on/off and analog/PWM brightness control via the ADJ pin. It is used in automotive position lights, rear fog lamps, and internal door lighting.

For engineers reviewing the ZXLD1366QEN8TC datasheet, ZXLD1366QEN8TC pinout, ZXLD1366QEN8TC application, or ZXLD1366QEN8TC equivalent, key selection criteria include its 60V max input rating, 1A continuous switch current capability, 0.2V current sense threshold, 1.25V internal reference voltage, and thermal resistance of 45°C/W in SO-8EP package - all critical for robust automotive LED power management design.

Technical Context

The ZXLD1366QEN8TC integrates a self-oscillating buck controller with internal NDMOS switch, high-side current sense amplifier, and comparator-based hysteresis control (±15% around VADJ). Its switching frequency varies with VIN and LED string count (260kHz typical at 24V/3LEDs), and it employs a low-pass filtered ADJ pin to modulate the 200mV nominal VSENSE threshold.

Operation relies on continuous conduction mode (CCM) with coil L1 and external sense resistor RS defining average output current as IOUT = 0.2V / RS. Shutdown occurs when ADJ voltage falls ≤0.2V, reducing quiescent current to 65µA while maintaining reference bias; soft-start is programmable via capacitor from ADJ to GND.

Key Specifications

Pinout & Package

Package: SO-8EP (exposed pad), RoHS-compliant, thermally enhanced, θJA = 45°C/W. Exposed pad must be soldered to PCB ground plane for thermal performance but not used as primary GND current return path.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LED driver applications.

Compared with ZXLD1366QEN8TC, AL8862Q delivers higher accuracy and frequency scalability for future-proof designs, while LM3409QMYX/NOPB trades integration for thermal and current headroom - making ZXLD1366QEN8TC optimal for cost-sensitive, space-constrained 1A automotive lighting where AEC-Q100 Grade 1 compliance is mandatory.

Availability

ZXLD1366QEN8TC is available at Aetrix Electronics and suitable for automotive position lights, rear fog lamps, and internal door lighting requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for ZXLD1366QEN8TC 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 semiconductor company specializing in discrete, analog, and mixed-signal solutions for automotive, industrial, and consumer markets, with manufacturing certified to IATF 16949.

The ZXLD1366Q belongs to Diodes' automotive LED driver product line, engineered specifically for reliable, high-accuracy constant-current regulation in exterior and interior vehicle lighting systems under harsh environmental conditions.

FAQ

What is the minimum external current sense resistor (RS) value for ZXLD1366QEN8TC?

The minimum RS is 0.2Ω when the ADJ pin is floating (VADJ = 1.25V), ensuring the average output current does not exceed 1A and the internal switch remains within safe operating limits. Using RS < 0.2Ω risks exceeding the 1.25A absolute maximum LX current rating and may cause thermal shutdown or reliability degradation.

How does the ADJ pin function for PWM dimming?

The ADJ pin accepts direct PWM signals (frequency <300Hz recommended) to modulate LED current with up to 1000:1 resolution. The internal low-pass filter converts PWM duty cycle into an effective DC voltage that adjusts the 200mV VSENSE threshold proportionally - no external RC filtering or op-amp circuitry is required.

Can ZXLD1366QEN8TC drive multiple parallel LED strings?

No - the ZXLD1366QEN8TC is designed exclusively for series-connected LED strings. Driving parallel strings would cause current imbalance due to forward voltage mismatches, violating its single-point current regulation architecture and risking overcurrent in lower-Vf strings.

What thermal design guidance applies to the SO-8EP package?

For full 1A operation at +125°C ambient, the exposed pad must be soldered to ≥2cm² of 2oz copper connected to a solid ground plane. Thermal vias (≥6×0.3mm) should connect the pad to inner/secondary ground layers. Without this, power dissipation is limited to ~1.2W before exceeding 150°C junction temperature.