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

All versions are Not Recommended for New Designs. See Ordering Information for recommended replacements.

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.

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