The MC34166, MC33166 series are high performance fixed frequency power switching regulators that contain the primary functions required for dc–to–dc converters. This series was specifically designed to be incorporated in step–down and voltage–inverting configurations with a minimum number of external components and can also be used cost effectively in step–up applications.
These devices consist of an internal temperature compensated reference, fixed frequency oscillator with on–chip timing components, latching pulse width modulator for single pulse metering, high gain error amplifier, and a high current output switch.
Protective features consist of cycle–by–cycle current limiting, undervoltage lockout, and thermal shutdown. Also included is a low power standby mode that reduces power supply current to 36 µA.

• Output Switch Current in Excess of 3.0 A
• Fixed Frequency Oscillator (72 kHz) with On–Chip Timing
• Provides 5.05 V Output without External Resistor Divider
• Precision 2% Reference
• 0% to 95% Output Duty Cycle
• Cycle–by–Cycle Current Limiting
• Undervoltage Lockout with Hysteresis
• Internal Thermal Shutdown
• Operation from 7.5 V to 40 V
• Standby Mode Reduces Power Supply Current to 36 µA
• Economical 5–Lead TO–220 Package with Two Optional Leadforms
• Also Available in Surface Mount D2PAK Package
• Moisture Sensitivity Level (MSL) Equals 1