LM3203

Features:

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 Overload Protection
Thermal Overload Protection


Application

Cellular Phones
Hand-Held Radios
RF PC Cards
Battery Powered RF Devices


Specifications

If Military/Aerospace specified devices are required,please contact the National Semiconductor Sales Office/Distributors for availability and specifications.
V_DD,PV_IN to SGND                            −0.2V to +6.0V
PGND to SGND                                 −0.2V to +0.2V
EN, FB, BYP, V_CON                              (SGND −0.2V)
                                                        to (VDD +0.2V)
                                                             w/6.0V max
SW, BYPOUT                                       (PGND −0.2V)
                                                        to (PV_IN +0.2V)
                                                             w/6.0V max
PV_IN to V_DD                                      −0.2V to +0.2V
Continuous Power Dissipation
(Note 3)                                        Internally Limited
Junction Temperature (T_J-MAX)                     +150˚C
Storage Temperature Range          −65˚C to +150˚C
Maximum Lead Temperature
    (Soldering, 10 sec)                                   +260˚C


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.