LM3203

July 2005 www.DataSheet4U.com LM3203 Step-Down DC-DC Converter with Bypass Mode for CDMA / WCDMA RF Power Amplifiers LM3203 Step-Down DC-DC Converter with Bypass Mode for CDMA / WCDMA RF Power Amplifiers General Description The LM3203 is a DC-DC converter optimized for powering RF power amplifiers (PAs) from a single Lithium-Ion cell. However, they may be used in many other applications. It steps down an input voltage of 2.7V to 5.5V to an adjustable output voltage of 0.8V to 3.6V. The output voltage is set using a VCON analog input and external resistor dividers for optimizing efficiency of the RF PA at various power levels. The LM3203 offers 3 modes for mobile phones and similar RF PA applications. Fixed-frequency PWM mode minimizes RF interference. Bypass mode turns on an internal bypass switch to power the PA directly from the battery. Shutdown mode turns the device off and reduces battery consumption to 0.1µA (typ.). The LM3203 is available in a 10-pin lead free micro SMD package. A high switching frequency (2MHz) allows use of tiny surface-mount components. Features n n n n n n n n n n n 2MHz (typ.) PWM Switching Frequency Operates from a single Li-Ion cell (2.7V to 5.5V) Adjustable Output Voltage (0.8V to 3.6V) 500mA Maximum load capability (PWM and Bypass mode) PWM / Forced Bypass Mode Low RDSON Bypass FET: 85mΩ (typ.) High Efficiency (96% typ. at 3.6VIN, 3.2VOUT at 150mA) Fast Turn-on time when Enabled (50µs typ.), 3GPP Compliant 10-pin micro SMD Package Current O...