Datasheet MAX4473 (Maxim)

19-1448; Rev 4; 11/08
Low-Cost, Low-Voltage, PA Power Control Amplifier for GSM Applications MAX4473 General Description Features
The MAX4473 PA power control IC is intended for ♦
Optimized for GSM Timing Requirements
closed-loop bias control of GSM power amplifiers. The device facilitates accurate control of the current deliv- ♦
2.7V to 6.5V Single-Supply Operation
ered to the power amplifier (PA) through a control volt- ♦
1.2mA Supply Current
age. The error amplifier senses the voltage drop across an external current-sense resistor placed between the ♦
≤ 1µA Supply Current in Shutdown Mode
supply and the PA. The output of the error amplifier adjusts the PA gain until the current is proportional to ♦
Guaranteed 1.5µs Enable/Disable Times
the power control voltage applied to the MAX4473. This ♦
Active Output Pull-Down in Shutdown Mode
unique topology is useful in time-division-multiple- access (TDMA) systems, such as GSM, where accurate ♦
Rail-to-Rail Error Amplifier Output
transmit burst shaping and power control is required. ♦
Rail-to-Rail Power Control Input
User-selectable current sensing and gain setting resis- tors maximize flexibility. ♦
Output Drive Capability—500Ω and 300pF Loads
The MAX4473 operates from a single 2.7V to 6.5V sup- ♦
1V to VCC Current Sense Input Common-Mode
ply and typically draws 1.2mA of supply current. The
Voltage Range
error amplifier has a common-mode range that extends ♦ from 1V to V
No Phase-Reversal for Common-Mode Voltage
CC. The power control input and error amplifier outputs swing rail-to-rail. A low-power shut-
from 0 to VCC
down mode reduces supply current to less than 1µA ♦
External Current Sensing and Gain Setting
and activates an on-board active pull-down at the error
Resistors Maximize Flexibility
amplifier output. Fast enable/disable times of 0.9µs reduce average power consumption without compro- ♦
Available in a Space-Saving 8-Pin µMAX
mising dynamic performance. The MAX4473 is avail- able in a space-saving 8-pin µMAX® package.
Ordering Information Applications PART TEMP RANGE PIN-PACKAGE
GSM Cellular Phones MAX4473EUA -40°C to +85°C 8 µMAX Cordless Phones MAX4473ESA -40°C to +85°C 8 SO Precision Current Control
Pin Configuration appears at end of data sheet.
High-Frequency Servo Loops µMAX is a registered trademark of Maxim Integrated Products, Inc.
Typical Operating Circuit
VCC 0.1μF RSENSE RG1 RG2 8 1 2 4 PC VCC SR1 SR2 OUT 7 I A1 A3 CCPA BUFFER 3R GC V-TO-I ERROR CONVERTER IN VCC AMPLIFIER PA A2 Q1 R 3 SHDN MAX4473 GND SR3 RFIN 5 6 VPC
·
RG1 ICCPA = RG3 4
·
RG3
·
RSENSE
________________________________________________________________ Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.