The MCP1603 is a high efficient, fully integrated 500 mA synchronous buck regulator whose 2.7V to 5.5V input voltage range makes it ideally suited for applications powered from 1-cell Li-Ion or 2-cell/3-cell NiMH/NiCd batteries. At heavy loads, the MCP1603 operates in the 2.0 MHz fixed frequency PWM mode which provides a low noise, low output ripple, small-size solution. When the load is reduced to light levels, the MCP1603 automatically changes operation to a PFM mode to minimize quiescent current draw from the battery. No intervention is necessary for a smooth transition from one mode to another. These two modes of operation allow the MCP1603 to achieve the highest efficiency over the entire operating current range. The MCP1603 is available in space saving 5-Lead TSOT and 8-Lead 2X3 DFN packages.
The MCP1603 is a high‑efficiency, fully integrated 500 mA synchronous buck regulator that operates from a 2.7 V to 5.5 V input range. It switches at a fixed 2.0 MHz frequency under heavy load and automatically transitions to PFM mode at light load to minimize quiescent current.
The device is offered in 5‑lead TSOT and 8‑lead 2×3 DFN packages and includes built‑in protection features such as UVLO, over‑temperature, and over‑current protection. Detailed electrical characteristics, temperature specifications, and typical performance curves are provided for both adjustable (0.8 V–4.5 V) and fixed output versions (1.2 V, 1.5 V, 1.8 V, 2.5 V, 3.3 V).
| Input Voltage Range | 2.7 V to 5.5 V |
|---|---|
| Maximum Output Current | 500 mA |
| Typical Efficiency | >90 % |
| Quiescent Current (typical) | 45 µA |
| Shutdown Current (typical) | 0.1 µA |
| Adjustable Output Voltage Range | 0.8 V to 4.5 V |
| Fixed Output Voltage Options | 1.2 V, 1.5 V, 1.8 V, 2.5 V, 3.3 V |
| Switching Frequency | 2.0 MHz |
| Package Types | 5‑Lead TSOT, 8‑Lead 2×3 DFN |
| Operating Junction Temperature | -40 °C to +125 °C |
| Storage Temperature Range | -65 °C to +150 °C |
| Thermal Resistance (TSOT) | 256 °C/W |
| Thermal Resistance (DFN) | 84.5 °C/W |
The MCP1603 operates with an input voltage from 2.7 V to 5.5 V.
It can deliver up to 500 mA of output current.
The regulator includes UVLO, over‑temperature, and over‑current protection.
Typical quiescent current is 45 µA and shutdown current is 0.1 µA.