Datasheet Maxim MAX4473

19-1448; Rev 4; 11/08 Low-Cost, Low-Voltage, PA Power Control
Amplifier for GSM Applications
Features The MAX4473 PA power control IC is intended for
closed-loop bias control of GSM power amplifiers. The
device facilitates accurate control of the current delivered to the power amplifier (PA) through a control voltage. The error amplifier senses the voltage drop across
an external current-sense resistor placed between the
supply and the PA. The output of the error amplifier
adjusts the PA gain until the current is proportional to
the power control voltage applied to the MAX4473. This
unique topology is useful in time-division-multipleaccess (TDMA) systems, such as GSM, where accurate
transmit burst shaping and power control is required.
User-selectable current sensing and gain setting resistors maximize flexibility.
The MAX4473 operates from a single 2.7V to 6.5V supply and typically draws 1.2mA of supply current. The
error amplifier has a common-mode range that extends
from 1V to V CC . The power control input and error
amplifier outputs swing rail-to-rail. A low-power shutdown mode reduces supply current to less than 1µA
and activates an on-board active pull-down at the error
amplifier output. Fast enable/disable times of 0.9µs
reduce average power consumption without compromising dynamic performance. The MAX4473 is available in a space-saving 8-pin µMAX® package. ♦ Optimized for GSM Timing Requirements
♦ 2.7V to 6.5V Single-Supply Operation
♦ 1.2mA Supply Current
♦ ≤ 1µA Supply Current in Shutdown Mode
♦ Guaranteed 1.5µs Enable/Disable Times …