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) via 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 VCC. The power control input and error amplifier outputs swing Rail-to-Rail®. A low-power shutdown mode reduces supply current to less than µA 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.
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GSM Cellular PhonesCordless PhonesPrecision Current ControlHigh-Frequency Servo Loops
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Optimized for GSM Timing Requirements+2.7V to +6.5V Single-Supply Operation1.2mA Supply Current1µA Supply Current in Shutdown ModeGuaranteed 1.5µs Enable/Disable TimesActive Output Pull-Down in Shutdown ModeRail-to-Rail Error Amplifier OutputRail-to-Rail Power Control InputOutput Drive Capability-500 and 300pF Loads +1V to VCC Current Sense Input Common-Mode Voltage Range No Phase-Reversal for Common-Mode Voltage from 0 to VCC External Current Sensing and Gain Setting Resistors Maximize Flexibility Available in a Space-Saving 8-pin µMAX
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VCC to GND ........................................................................+7V
SR1, SR2, SR3, PC, SHDN,
OUT to GND ............................................-0.3V to (VCC + 0.3V)
SR1 to SR3..................................................................0 to VCC
OUT and SR3 Short-Circuit Duration
to VCC or GND .......................................................Continuous
Current into Any Pin.....................................................±50mA
Continuous Power Dissipation (TA = +70°C)
µMAX (derate 4.10mW/°C above +70°C) .................330mW
SO (derate 5.88mW/°C above +70°C)......................471mW
Operating Temperature Range ....................-40°C to +85°C
Junction Temperature.................................................+150°C
Storage Temperature Range. ....................-65°C to +150°C
Lead Temperature (soldering, 10sec) .......................+300°C
Post a Buying Lead
Required Field 
