General Description

The MAX8649/MAX8649A high-efficiency DC-to-DC step down switching regulators deliver up to 1.8A of output current. The device operates from a 2.5V to 5.5V input voltage range, making it future proof for next-generation battery technologies. The output voltage is I2C programmable from 0.75V to 1.38V. Remote sense ensures precise DC regulation at the load. Total output error is less than 2 over load, line, and temperature.

The ICs operate at a 3.25MHz fixed frequency. The high operating frequency minimizes the size of external components. The switching frequency of the converter can be synchronized to the master clock of the application. When synchronizing to an external clock, the ICs measure the frequency of the external clock to ensure that the clock is stable before changing the switching frequency to the external clock frequency.

An on-board DAC allows adjustment of the output voltage in 10mV steps. The output voltage can be programmed directly through the I2C interface, or by

preloading a set of on-board registers and using the two VID logic signals to select the appropriate register. Other features include internal soft-start control circuitry to reduce inrush current, output overvoltage, overcurrent, and overtemperature protection.

The ICs feature different I2C addresses so that devices may be used in a system. For a 2.5A version of this device, refer to the MAX8952 data sheet.

Features

♦ 1.8A Guaranteed Output Current

♦ I2C Programmable VOUT (750mV to 1.38V in 10mV Steps)

♦ Operates from 2.5V to 5.5V Input Supply

♦ On-Chip FET and Synchronous Rectifier

♦ Fixed 3.25MHz PWM Switching Frequency

♦ Synchronizes to 13MHz, 19.2MHz, or 26MHz

   System Clock when Available

♦ Small 1.0µH Inductor

♦ Initial Accuracy 0.5 at 1.25V Output

♦ 2 Output Accuracy Over Load, Line, and Temperature

♦ Power-Save Mode Increases Light Load Efficiency

♦ Overvoltage and Overcurrent Protection

♦ Thermal Shutdown Protection

♦ 400kHz I2C Interface

♦ < 1µA Shutdown Current

♦ 16-Bump, 2mm x 2mm WLP Package

Applications

   Cell Phones and Smartphones

   PDAs and MP3 Players