1 Features
1• < 30-mW No-Load Power for 5-Star Rating
• Primary-Side Regulation (PSR) Eliminates Opto-
Coupler
• ±5% Voltage and Current Regulation
• 130-kHz Maximum Switching Frequency Enables
High-Power Density Charger Designs
• Quasi-Resonant Valley-Switching Operation for
Highest Overall Efficiency
• Patent-Pending Frequency-Jitter Scheme to Ease
EMI Compliance
• Wide VDD Range Allows Small Bias Capacitor
• Clamped Gate-Drive Output for MOSFET
• Protection Functions: Overvoltage, Low-Line, and
Overcurrent
• Programmable Cable Compensation (UCC28700
Only)
• NTC Resistor Interface (UCC28701, UCC28702
and UCC28703 Only) With Fixed Cable
Compensation Options
• SOT-23 Package

2 Applications
• USB-Compliant Adapters and Chargers for
Consumer Electronics (Cell Phones, Tablets and
Cameras)
• AC and DC Power Supplies

3 Description
The UCC28700 family of flyback power supply
controllers provides Constant-Voltage (CV) and Constant-Current (CC) output regulation without the
use of an optical coupler. The devices process
information from the primary power switch and an
auxiliary flyback winding for precise control of output
voltage and current. Low start-up current, dynamically
controlled operating states and a tailored modulation
profile support very low standby power without
sacrificing start-up time or output transient response.
Control algorithms in the UCC28700 family allow
operating efficiencies to meet or exceed applicable
standards. The output drive interfaces to a MOSFET
power switch. Discontinuous Conduction Mode
(DCM) with valley switching reduces switching losses.
Modulation of switching frequency and primary current peak amplitude (FM and AM) keeps the
conversion efficiency high across the entire load and
line ranges.
The controllers have a maximum switching frequency
of 130 kHz and always maintain control of the peak-
primary current in the transformer. Protection features
help keep primary and secondary component
stresses in check. The UCC28700 allows the level of
cable compensation to be programmed. The UCC28701, UCC28702, and UCC28703 devices
allow remote temperature sensing using a Negative
Temperature Coefficient (NTC) resistor while
providing fixed cable-compensation levels.