The AL8891Q uses a Constant-on-Time (COT) control scheme, enabling straightforward loop compensation and cycle-by-cycle current limiting. It does not require external compensation capacitors, ensuring a fast transient response. The switching frequency is adjustable from 200kHz to 2.5MHz, allowing for improved efficiency or the use of smaller inductors and compact form factors. The device employs spectrum frequency modulation to enhance EMI performance, helping it meet the most stringent CISPR 25 Class 5 standards.
The AL8891Q features two independent pins for PWM and analog dimming, increasing functionality. The PWM dimming range is 0.1kHz to 2kHz for high-resolution dimming, while analog dimming operates between 0.15V and 2V. A built-in soft-start function gently ramps up inductor and switch currents, minimizing potential overvoltage and overcurrent at the output.
The AL8891Q includes fault reporting and comprehensive protections, such as auto-restart thermal shutdown, input undervoltage lockout (UVLO), cycle-by-cycle current limiting, and open/short LED protection, enhancing system durability.
The AL8891Q is offered in a thermally-enhanced TSSOP-16EP package and operates over a -40°C to +125°C temperature range. A standard version, the AL8891, is also available for industrial and commercial product applications.