1 Features

• 2-MHz High-Frequency Oscillator With 1-MHz Operation Per Channel
• Matched Internal Slope Compensation Circuits
• Programmable Maximum Duty Cycle Clamp 60% to 90% Per Channel
• Peak Current Mode Control With Cycle-by-Cycle Current Limit
• Current Sense Discharge Transistor for Improved Noise Immunity
• Accurate Line Undervoltage and Overvoltage Sense With Programmable Hysteresis
• Opto-Coupler Interface
• 110-V Internal Start-Up JFET (UCC28221)
• Operates From 12-V Supply (UCC28220)
• Programmable Soft Start

2 Applications

• High Output Current (50-A to 100-A) Converters
• Maximum Power Density Designs
• High-Efficiency 48-V Input With Low Output Ripple Converters
• High-Power Offline, Telecom, and Datacom Power Supplies

3 Description

The UCC28220 and UCC28221 are a family of BiCMOS interleaved dual channel PWM controllers. Peak current mode control is used to ensure current sharing between the two channels. A precise maximum duty cycle clamp can be set to any value between 60% and 90% duty cycle per channel.

The UCC28220 has an UVLO turnon threshold of
10 V for use in 12-V supplies while UCC28221 has a turnon threshold of 13 V for systems needing wider UVLO hysteresis. Both have 8-V turnoff thresholds.

Additional features include a programmable internal slope compensation with a special circuit which is used to ensure exactly the same slope is added to each channel and a high-voltage 110-V internal JFET for easier start-up for the wider hysteresis UCC28221 version.

The UCC28220 is available in both 16-pin SOIC and low-profile TSSOP packages. The UCC28221 also comes in 16-pin SOIC package and a slightly larger 20-pin TSSOP package to allow for high-voltage pin spacing to meet UL1950 creepage clearance safety requirements.

Device Information

1. For all available packages, see the orderable addendum at the end of the data sheet.

Typical Application

Pin 16 is a no connect (NC) on UCC28220 which does not include the JFET option.

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