MAX4473EUA-T

MAX4473EUA-T Features

♦ 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♦ Active Output Pull-Down in Shutdown Mode♦ Rail-to-Rail Error Amplifier Output♦ Rail-to-Rail Power Control Input♦ Output Drive Capability—500Ω and 300pF Loads♦ 1V to VCC Current Sense Input Common-ModeVoltage Range♦ No Phase-Reversal for Common-Mode Voltagefrom 0 to VCC♦ External Current Sensing and Gain SettingResistors Maximize Flexibility♦ Available in a Space-Saving 8-Pin µMAX

MAX4473EUA-T General Description

The MAX4473 PA power control IC is intended forclosed-loop bias control of GSM power amplifiers. Thedevice facilitates accurate control of the current deliv-ered to the power amplifier (PA) through a control volt-age. The error amplifier senses the voltage drop acrossan external current-sense resistor placed between thesupply and the PA. The output of the error amplifieradjusts the PA gain until the current is proportional tothe power control voltage applied to the MAX4473. Thisunique topology is useful in time-division-multiple-access (TDMA) systems, such as GSM, where accuratetransmit burst shaping and power control is required.User-selectable current sensing and gain setting resis-tors maximize flexibility.The MAX4473 operates from a single 2.7V to 6.5V sup-ply and typically draws 1.2mA of supply current. Theerror amplifier has a common-mode range that extendsfrom 1V to VCC. The power control input and erroramplifier outputs swing rail-to-rail. A low-power shut-down mode reduces supply current to less than 1µAand activates an on-board active pull-down at the erroramplifier output. Fast enable/disable times of 0.9µsreduce average power consumption without compro-mising dynamic performance. The MAX4473 is avail-able in a space-saving 8-pin µMAX® package.

MAX4473EUA-T Amplifier for GSM Applications

General DescriptionThe MAX4473 PA power control IC is intended forclosed-loop bias control of GSM power amplifiers. Thedevice facilitates accurate control of the current deliv-ered to the power amplifier (PA) through a control volt-age. The error amplifier senses the voltage drop acrossan external current-sense resistor placed between thesupply and the PA. The output of the error amplifieradjusts the PA gain until the current is proportional tothe power control voltage applied to the MAX4473. Thisunique topology is useful in time-division-multiple-access (TDMA) systems, such as GSM, where accuratetransmit burst shaping and power control is required.User-selectable current sensing and gain setting resis-tors maximize flexibility.The MAX4473 operates from a single 2.7V to 6.5V sup-ply and typically draws 1.2mA of supply current. Theerror amplifier has a common-mode range that extendsfrom 1V to VCC. The power control input and erroramplifier outputs swing rail-to-rail. A low-power shut-down mode reduces supply current to less than 1µAand activates an on-board active pull-down at the erroramplifier output. Fast enable/disable times of 0.9µsreduce average power consumption without compro-mising dynamic performance. The MAX4473 is avail-able in a space-saving 8-pin µMAX® package.ApplicationsGSM Cellular PhonesCordless PhonesPrecision Current ControlHigh-Frequency Servo Loops

MAX4473EUA-T Amplifier for GSM Applications