The MC34067/MC33067 are high performance zero voltage switch resonant mode controllers designed for off-line and dc-to-dc converter applications that utilize frequency modulated constant off-time or constant deadtime control. These integrated circuits feature a variable frequency oscillator, a precise retriggerable one-shot timer, temperature compensated reference, high gain wide bandwidth error amplifier, steering flip-flop, and dual high current totem pole outputs ideally suited for driving power MOSFETs.
Also included are protective features consisting of a high speed fault comparator and latch, programmable soft-start circuitry, inputundervoltage lockout with selectable thresholds, and reference undervoltage lockout.
These devices are available in dual-in-line and surface mount packages.

• Zero Voltage Switch Resonant Mode Operation
• Variable Frequency Oscillator with a Control Range Exceeding 1000:1
• Precision One-Shot Timer for Controlled Off-Time
• Internally Trimmed Bandgap Reference
• 4.0 MHz Error Amplifier
• Dual High Current Totem Pole Outputs
• Selectable Undervoltage Lockout Thresholds with Hysteresis
• Enable Input
• Programmable Soft-Start Circuitry
• Low Startup Current for Off-Line Operation
• Pb-Free Packages are Available*