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.

Features
• 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
• Pb−Free Packages are Available