Monolithic 1Amp DC:DC Step-down Regulator

The EL7551 is an integrated, synchronous step-down regulator with output voltage adjustable from 1.0V to 3.8V. It is capable of delivering 1A continuous current at up to 95% efficiency. The EL7551 operates at a constant frequency pulse width modulation (PWM) mode, making external synchronization possible. Patented on-chip resistorless current sensing enables current mode control, which provides cycle-by-cycle current limiting, over-current protection, and excellent step load response. The EL7551 is available in a fused-lead 16-pin QSOP package. With proper external components, the whole converter fits into a less than 0.4 in2 area. The minimal external components and small size make this EL7551 ideal for desktop and portable applications.

Features
• Integrated synchronous MOSFETs and current mode controller
• 1A continuous output current
• Up to 95% efficiency
• 4.5V to 5.5V input voltage
• Adjustable output from 1V to 3.8V
• Cycle-by-cycle current limit
• Precision reference
• ±0.5% load and line regulation
• Adjustable switching frequency to 1.2MHz
• Oscillator synchronization possible
• Internal soft start
• Over temperature protection
• Under voltage lockout
• 16-pin QSOP package
• Pb-free plus anneal available (RoHS compliant)

Applications
• DSP, CPU Core and IO Supplies
• Logic/Bus Supplies
• Portable Equipment
• DC:DC Converter Modules
• GTL + Bus Power Supply