• 2.7-V to 5.5-V Input Voltage Operating From Single Li-Ion Cell
• 6-MHz (typical) PWM Switching Frequency
• 0.4-V to 3.6-V Adjustable Output Voltage
• 750-mA Maximum Load Capability (up to 1 A in Bypass)
• High Efficiency (95% typical at 3.9 VIN, 3.3 VOUT at 500 mA)
• Automatic ECO/PWM/BP Mode Change
• Current Overload Protection
• Thermal Overload Protection
• Soft-Start Function
• Small Chip Inductor in 0805 (2012) case size

• Battery-Powered 3G/4G RF PAs
• Battery-Powered RF Devices
• Hand-Held Radios
• RF PC Cards

The LM3242 is a DC-DC converter optimized for powering RF power amplifiers (PAs) from a single lithium-ion cell; however, it may be used in many other applications. It steps down an input voltage from 2.7 V to 5.5 V to an adjustable output voltage from 0.4 V to 3.6 V. Output voltage is set using a VCON analog input for controlling power levels and efficiency of the RF PA.

The LM3242 offers five modes of operation. In PWM mode the device operates at a fixed frequency of 6 MHz (typical) 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 (typical). In low-battery condition Bypass mode reduces the voltage dropout to less than 50 mV (typical). The part also features a Sleep mode.

The LM3242 is available in a 9-bump lead-free DSBGA package. A high switching frequency (6 MHz) allows use of only three tiny surface-mount components: one inductor and two ceramic capacitors.