What is UCC28742?
UCC28742 is the latest release in the UCC287xx Flyback family, more specifically an alternative to the secondary side regulated UCC28740.
While UCC28742 is similar to UCC28740, there are few significant key differences. Most notably, the UCC28742 is in a smaller SOT-23 package that does not have the HV pin 700V startup FET included in UCC28740’s larger SOIC package. While the elimination of this pin increases standby power consumption, this may not be a concern for designs that do not need to meet the ≤10mW standard provided by UCC28740. In addition, UCC28742 introduces a new over current protection: accurate constant current limit with 120ms delayed shutdown.
Despite these differences, both devices are Second-Side regulated (SSR) flyback controllers that operate in discontinuous conduction mode (DCM) with valley switching. Both devices use a similar AM/FM control law, where the frequency and duty cycle are modulated to regulate the output. Both have EMI frequency dithering, sophisticated protection for line brown-out, output over voltage, over current and short circuit protection, etc. These features result in highly efficient controllers with reduced generated EMI and robust fault conditions without the addition of external components.
Why should you choose UCC28742?
High Efficiency - UCC28742 uses advanced control algorithms to achieve high efficiency and performance over the entire operating range.
Simple Implementation - UCC28742 is simple to use, with integrated features that reduce potential required external components.
Excellent Transient Response and Output Regulation - Direct opto-coupler feedback enables fast transient response with tight output regulation.
Cost Effective - The latest of the UCC287xx Flyback family, UCC28742 provides a practical alternative to UCC28740. This device cuts back on unnecessary additional features and demonstrates high performance at the price point you need.
