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High-Frequency, Current-Mode PWM Controller with Accurate Programmable Oscillator

1.25MHz, Universal-Input, Current-Mode PWM Controller with Precision-Programmable Switching Frequency and Start/Stop Voltage

Product Details

Key Features

Simplified Block Diagram

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Key Features

  • Current-Mode Control with 47µA (typ) Startup Current
  • Resistor-Programmable ±4.5% Accurate Switching Frequency:
    • 25kHz to 1.25MHz (MAX5068A/B)
    • 12.5kHz to 625kHz (MAX5068C/D/E/F)
  • Rectified 85VAC to 265VAC or 36VDC to 72VDC Input (MAX5068A/C/D)
  • Input Directly Driven from 10.8V to 24V (MAX5068B/E/F)
  • Frequency Synchronization Input (MAX5068A/B/C/E)
  • Programmable Dead Time and Slope Compensation
  • Programmable Startup Voltage (UVLO)
  • Programmable UVLO Hysteresis (MAX5068A/B/D/F)
  • Integrating Fault Protection (Hiccup)
  • -40°C to +125°C Automotive Temperature Range
  • 16-Pin Thermally Enhanced TSSOP-EP Package

Applications/Uses

  • Industrial Power Conversion
  • Isolated Telecom Power Supplies
  • Networking System Power Supplies
  • Server Power Supplies
  • Universal-Input AC Power Supplies

Description

The MAX5068 is a high-frequency, current-mode, pulse-width modulation (PWM) controller that integrates all the building blocks necessary for implementing AC-DC or DC-DC fixed-frequency power supplies. Isolated or nonisolated power supplies are easily constructed using either primary- or secondary-side regulation. Current-mode control with leading-edge blanking simplifies control-loop design, and a programmable internal slope-compensation circuit stabilizes the current loop when operating at duty cycles above 50%. The MAX5068A/B limit the maximum duty cycle to 50% for use in single-ended forward converters. The MAX5068C/D/E/F allow duty cycles up to 75%. The MAX5068 features an accurate externally programmable oscillator that simplifies system design.

An input undervoltage lockout (UVLO) programs the input-supply startup voltage and ensures proper operation during brownout conditions.

A single external resistor programs the output switching frequency from 12.5kHz to 1.25MHz. The MAX5068A/B/C/E provide a SYNC input for synchronization to an external clock. The maximum FET-driver duty cycle is 50% for the MAX5068A/B and 75% for the MAX5068C/D/E/F. Programmable hiccup current limit provides additional protection under severe faults.

The MAX5068 is specified over the -40°C to +125°C automotive temperature range and is available in a 16-pin thermally enhanced TSSOP-EP package. Refer to the MAX5069 data sheet for dual FET-driver applications.

Warning: The MAX5068 is designed to work with high voltages. Exercise caution.

Simplified Block Diagram

MAX5068: Typical Operating Circuit MAX5068: Typical Operating Circuit Zoom icon

Technical Docs

Support & Training

Search our knowledge base for answers to your technical questions.

Filtered Search

Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .

Sampling:
Selecting the Sample button above will redirect to the third-party ADI Sample Site. The part selected will carry over to your cart on this site once logged in. Please create a new account there if you have never used the site before. Contact SampleSupport@analog.com with any questions regarding this Sample Site.