The LM3242 is a DC-DC converter optimized for powering multi-mode 3G/4G RF power amplifiers (PAs) from a single Lithium-Ion cell. The LM3242 steps down an input voltage from 2.7V to 5.5V to a dynamically adjustable output voltage of 0.4V to 3.6V. The output voltage is set through a VCON analog input that adjusts the output voltage to ensure efficient operation at all power levels of the RF PA.
The LM3242 offers five modes of operation. In PWM mode the device operates at a fixed frequency of 6MHz (typ.) which minimizes RF interference when driving medium-to-heavy loads. At light load, the device enters into ECO mode automatically and operates with reduced switching frequency. In ECO mode, the quiescent current is reduced and extends the battery life. Shutdown mode turns the device off and reduces battery consumption to 0.1 µA (typ.). In low-battery condition Bypass mode reduces the voltage dropout to less than 50 mV (typ.). The part also features a Sleep mode.