50 dB GSM PA Controller AD8311 Its high sensitivity allows control at low signal levels, thus FEATURES reducing the amount of power that needs to be coupled to the Complete RF detector/controller function detector. For convenience, the signal is internally ac-coupled. >50 dB range at 0.9 GHz (48 dBm to +3 dBm re 50 ) This high-pass coupling, with a corner at approximately Accurate scaling from 0.1 GHz to 2.5 GHz 0.016 GHz, determines the lowest operating frequency. Thus, Temperature-stable linear-in-dB response the source can be dc-grounded. Log slope of 23 mV/dB, intercept at 60 dBm at 0.9 GHz True integration function in control loop The AD8311 provides a voltage output, VAPC, which has the Low power: 20 mW at 2.7 V voltage range and current drive to directly connect to the gain control pin of most handset power amplifiers. VAPC can swing from 300 mV above ground to within 200 mV below the supply APPLICATIONS voltage. Load currents of up to 6 mA can be supported. Single, dual, and triple band mobile handset (GSM, DCS, EDGE) The setpoint control input is applied to pin VSET and has an Transmitter power control operating range of 0.25 V to 1.4 V. The associated circuit determines the slope and intercept of the linear-in-dB measurement system these are nominally 23.6 mV/dB and GENERAL DESCRIPTION 59.7 dBm at 0.9 GHz. Further simplifying the application of The AD8311 is a complete low cost subsystem for the precise the AD8311, the input resistance of the setpoint interface is over control of RF power amplifiers operating in the frequency range 35 M, and the bias current is typically 0.26 A. 0.1 GHz to 2.5 GHz and over a typical dynamic range of 50 dB. It is intended for use in cellular handsets and other battery- The AD8311 is available in a 6-ball wafer-level chip scale operated wireless devices. The log amp technique provides a package (WLCSP), 1.0 mm 1.5 mm, and consumes 7.6 mA much wider measurement range and better accuracy than from a 2.7 V to 5.5 V supply. controllers using diode detectors. In particular, its temperature stability is excellent over a specified range of 40C to +85C. FUNCTIONAL BLOCK DIAGRAM LOW NOISE LOW NOISE VPOS BAND GAP GAIN BIAS REFERENCE VAPC 1.35 HI-Z DET DET DET DET DET LOW NOISE RAIL-TO-RAIL BUFFER RFIN FLTR 10dB 10dB 10dB 10dB VSET V I 23mV/dB OFFSET INTERCEPT 250mV TO COMPENSATION POSITIONING 1.4V = 50dB COMM Figure 1. Rev. A Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. rights of third parties that may result from its use. Specifications subject to change without notice. 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Trademarks and registered trademarks are the property of their respective owners. 05545-001AD8311 TABLE OF CONTENTS Specifications..................................................................................... 3 Mobile Handset Power Control Example ............................... 15 Absolute Maximum Ratings............................................................ 5 Power-On and Power-Off ......................................................... 16 ESD Caution.................................................................................. 5 Input Coupling Options ............................................................ 16 Pin Configuration and Function Descriptions............................. 6 Temperature Drift ...................................................................... 17 Typical Performance Characteristics ............................................. 7 Device Calibration and Error Calculation.............................. 17 Theory of Operation ...................................................................... 11 Selecting Calibration Points to Improve Accuracy over a Reduced Range ........................................................................... 18 Basic Theory................................................................................ 11 Device Handling......................................................................... 19 Controller-Mode Log Amps ..................................................... 12 Evaluation Board ............................................................................ 20 Control Loop Dynamics............................................................ 12 Outline Dimensions....................................................................... 22 Basic Connections ...................................................................... 14 Ordering Guide .......................................................................... 22 Range on VSET and RFIN......................................................... 14 Transient Response..................................................................... 15 REVISION HISTORY 1/11Rev. 0 to Rev. A Updated Outline Dimensions ....................................................... 22 Changes to Ordering Guide .......................................................... 22 6/05Revision 0: Initial Version Rev. A Page 2 of 24