SNVS355D – MAY 2005 – REVISED APRIL 2013
LM3203 Step-Down DC-DC Converter with Bypass Mode for CDMA / WCDMA RF Power
Check for Samples: LM3203
•2 2MHz (Typ.) PWM Switching Frequency
• Operates from a Single Li-Ion Cell (2.7V to
• Adjustable Output Voltage (0.8V to 3.6V)
• 500mA Maximum Load Capability (PWM and
• PWM / Forced Bypass Mode
• Low RDSON Bypass FET: 85mΩ (Typ.)
• High Efficiency (96% typ. at 3.6VIN, 3.2VOUT at
• Fast Turn-On Time When Enabled (50µs typ.),
• 10-Pin DSBGA Package
• Current Overload Protection
• Thermal Overload Protection
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
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 DSBGA
package. A high switching frequency (2MHz) allows
use of tiny surface-mount components.
• Cellular Phones
• Hand-Held Radios
• RF PC Cards
• Battery Powered RF Devices
2.7V to 5.5V
0.267V to 1.20V
VDD PVIN BYPOUT
0.8V to 3.6V
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