Overview
The UC2842AQ, UC2843AQ, UC2844AQ, UC2845AQ series are high-performance, current-mode PWM controllers designed for off-line and DC-to-DC power supplies, featuring a range of operating temperatures from -40°C to 125°C. These devices ensure low startup current (below 0.5 mA) and trimmed oscillator discharge currents for precise operations. Following an extended lineage of UC284x controllers, these units offer enhancements like automatic feed-forward compensation, pulse-by-pulse current limiting, under-voltage lockout with hysteresis, and a high-current totem-pole output, suitable for applications demanding high reliability and performance.
Distinguishing Features
Enhanced load response characteristics and double pulse suppression make these controllers reliable for critical power management tasks. Key attributes include an internally trimmed bandgap reference and the ability for 500 kHz operations with a low Ro error amplifier. The available part numbers in this family – UC2842A, UC2843A, UC2844A, and UC2845A – differ primarily in their under-voltage lockout thresholds and maximum duty cycles, offering flexibility for various design needs.
Packaging Options and Ordering Information
Detailed ordering information is available for the controllers, with different top-side temperature range and packaging options outlined. Packaging options include the 8-pin SOIC-D8 and the 14-pin SOIC-D Tube or Tape and Reel, providing designer-friendly choices for incorporation into systems. Additional resources such as package drawings, packing quantities, thermal data, and PCB design guidelines can be found on the manufacturer’s website.
Block Diagram Analysis
The included block diagram in the datasheet provides insight into the internal architecture of the controllers. Features like the under-voltage lockout (UVLO), internally generated reference voltage (VREF), an error amplifier, and a PWM latch make up the core of the control system, accompanied by an oscillator, power ground, and other logic blocks. These components work together to maintain stability and control within switched-mode power supplies. The diagram also points out that a toggle flip-flop is used exclusively in the UC2844A and UC2845A models, distinguishing them within the product family.
Disclaimer and Copyright Notice
The datasheet also contains a standard disclaimer regarding product availability, warranty information, and the applicability in critical systems, highlighting the importance of referring to the latest documentation for accurate and detailed information. It mentions that specifications conform to the terms of Texas Instruments’ standard warranty and that production processing does not necessarily include testing of all parameters.
References:
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