MS1509-12

The MS1509-X.X series regulators are monolithic ICs that provide all active functions required for a step-down switching regulator, capable of driving 3A loads with excellent line and load regulation. The series offers fixed output voltage versions of 3.3V, 5V, and 12V, as well as an adjustable output voltage version. These regulators require minimal external components, are easy to use, and incorporate internal frequency compensation and a fixed-frequency oscillator. The MS1509-X.X series operates at a switching frequency of 150 kHz, allowing the use of smaller filter components compared to lower-frequency switching regulators. Standard inductors optimized for the MS1509-X.X are available from multiple manufacturers, a feature that greatly simplifies switching power supply design. Additional features include: output voltage tolerance guaranteed at ±4% under specified input voltage and output load conditions, and oscillator frequency tolerance of ±15%. An external shutdown function is included, with a typical standby current of 50 μA. The output switch incorporates cycle-by-cycle current limiting and thermal shutdown for full protection under fault conditions. The MS1509-X.X is available in an SOP8 package.

Applications

• Simple, high-efficiency step-down regulator
• High-efficiency pre-regulator for linear regulators
• On-board switching regulator
• Positive-to-negative converter

Key features

• Fixed output voltage versions: 3.3V, 5V, 12V, plus adjustable output version
• High efficiency
• Wide input voltage range up to 37V
• Guaranteed 3A output current
• Only 4 external components required
• 150 kHz fixed-frequency internal oscillator
• TTL shutdown capability with low-power standby mode
• Compatible with standard off-the-shelf inductors
• Thermal shutdown and current limiting protection
• Adjustable version output voltage range: 1.23V to 37V, maximum deviation ±4% under line and load conditions