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19-2520; Rev 3; 6/03
2.4GHz SiGe Linear Power Amplifier
General Description
The MAX2247 low-voltage, three-stage linear power amplifier (PA) is optimized for 802.11b/g wireless LAN (WLAN) applications in the 2.4GHz ISM band. The device is integrated with an adjustable bias control, power detector, and shutdown mode. The MAX2247 features 29dB of power gain and delivers up to +24dBm of linear output power at 24% efficiency from a single +3.3V supply. It achieves less than -32dBc firstside lobe suppression and less than -55dBc secondside lobe suppression under 802.11b modulation. In addition, the device can be matched for optimum efficiency and performance at output power levels from +10dBm to +24dBm. Its high +28dBm saturated output power also allows the device to meet the requirements of 802.11g OFDM modulation. The MAX2247 features an external bias-control pin that allows the supply current of the device to be dynamically throttled back at lower output power levels, thus improving efficiency while maintaining sufficient sidelobe suppression. Proprietary internal bias circuitry maintains stable device performance over temperature and voltage-supply variations. An additional power-saving feature is a logic-level shutdown pin that reduces supply current to 0.5A and eliminates the need for an external supply switch. The integrated shutdown function also allows guaranteed device ramp-on and rampoff times. The MAX2247 integrates a power detector with 20dB dynamic range and 0.8dB accuracy at the highest output power level. The detector provides a buffered DC voltage proportional to the output power of the device, saving cost and space by eliminating a coupler and op amp usually required to implement a power detector function. The device is packaged in the tiny 3 4 chip-scale package (UCSPTM), measuring only 1.5mm 2mm, making it the ideal solution for radios built in small form factors. o 2.4GHz to 2.5GHz Operating Range o Up to +24dBm Linear Output Power (ACPR of Less than -32dBc First-Side Lobe and Less than -55dBc Second-Side Lobe) o 24% PAE at +24dBm Linear Output Power, 3.3V 24% PAE at +21dBm Linear Output Power, 3.0V o 29dB Power Gain o On-Chip Power Detector with Buffered Output o Internal 50 Input Matching o External Bias Control for Current Throttleback o Integrated Bias Circuitry o +2.7V to +4.2V Single-Supply Operation o 0.5A Shutdown Mode o Tiny Chip-Scale Package (1.5mm 2mm)
Features
MAX2247
Ordering Information
PART TEMP RANGE PINPACKAGE TOP MARK
AAW MAX2247EBC-T -40C to +85C 3 x 4 UCSP* *Requires special solder temperature profile in the Absolute Maximum Ratings Sections.
Typical Operating Circuit appears at end of data sheet.
Pin Configuration
TOP VIEW
A1 BIAS
A2 VCC2
A3 GND2
A4 VCC1
Applications
IEEE 802.11b DSSS WLAN IEEE 802.11g OFDM WLAN HomeRFTM 2.4GHz Cordless Phones 2.4GHz ISM Radios
UCSP is a trademark of Maxim Integrated Products, Inc. HomeRF is a trademark of HomeRF Working Group.
C1 RF_ OUT C2 SHDN C3 VCCB C4 RF_IN B1 GND3 B3 B4 GND1 PD_ OUT
MAX2247
________________________________________________________________ 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.
2.4GHz SiGe Linear Power Amplifier MAX2247
ABSOLUTE MAXIMUM RATINGS
VCC1, VCC2, VCCB, RF_OUT to GND....................-0.3V to +4.5V SHDN, BIAS, PD_OUT ................................-0.3V to VCC_ + 0.3V RF Input Power (50 source)...........................................+5dBm RF_IN Input Current............................................................1mA Maximum VSWR Without Damage ........................................10:1 Maximum VSWR for Stable Operation, POUT < +25dBm........5:1 Continuous Power Dissipation (TA = +70C) 3 4 UCSP (derate 28.5mW/C above +70C) ..............1.3W Thermal Resistance .........................................................35C/W Operating Temperature Range ...........................-40C to +85C Junction Temperature ......................................................+150C Storage Temperature Range .............................-65C to +125C Bump Temperature (soldering) (Note 1) Infrared (15s) ...............................................................+220C Vapor Phase (60s) .......................................................+215C Continuous Operating Lifetime.....................10yrs x 0.92(TA - 60C) (For Operating Temperature, TA +60C)
Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
DC ELECTRICAL CHARACTERISTICS
(MAX2247 EV kit, VCC_ = +2.7V to +4.2V, SHDN = VCC, RF_IN and RF_OUT terminated to 50, TA = -40C to +85C. Typical values are at +3V and TA = +25C, unless otherwise noted.) (Note 2)
PARAMETER Supply Voltage Idle current = 250mA with VCC = 3.3V POUT = +24dBm, VCC_ = 3.3V POUT = +25dBm, VCC_ = 4.2V POUT = +23dBm, VCC_ = 3.0V CONDITIONS MIN 2.7 317 345 305 175 120 85 0.5 2 0.8 -1 -1 +5 +1 10 A V V A A mA TYP MAX 4.2 350 UNITS V
Supply Current (Notes 3, 4)
POUT = +21dBm with optimized output-matching circuit. Refer to the MAX2247 EV kit for details. POUT = +18dBm with optimized output-matching circuit. Refer to the MAX2247 EV kit for details. POUT = +15dBm with optimized output-matching circuit. Refer to the MAX2247 EV kit for details.
Shutdown Supply Current Digital Input Logic High Digital Input Logic Low Digital Input Current High Digital Input Current Low
SHDN = 0, no RF signal applied
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2.4GHz SiGe Linear Power Amplifier
AC ELECTRICAL CHARACTERISTICS
(MAX2247 EV kit, VCC_ = +3V, fRF = 2.45GHz, SHDN = VCC, 50 RF system impedance, TA = +25C, unless otherwise noted.) (Note 5)
PARAMETER RF Frequency Range (Notes 4, 6) VCC_ = 3V, POUT = +23dBm Power Gain (Notes 2, 4, 8) VCC_ = 3.3V, POUT = +24dBm VCC_ = 4.2V, POUT = +25dBm Gain Variation Over Supply Voltage (Note 4) Output Power Over Temperature (Notes 4, 8) Saturated Output Power Harmonic Output (2f, 3f, 4f) Input VSWR Output VSWR Power Ramp Turn-On Time (Note 7) Power Ramp Turn-Off Time (Note 9) RF Output Detector Response Time RF Output Detector Voltage (Note 10) POUT = +23dBm POUT = +15dBm POUT = +7dBm Over full PIN range Over full POUT range VCC = 3.0V to 3.6V ACPR: First-side lobe < -32dBc, second-side lobe < -55dBc PIN = +5dBm VCC_ = 3V VCC_ = 3.3V VCC_ = 4.2V 22 TA = +25C TA = -40C to +85C 26 25 29.5 30.5 0.5 23 24 25 27.8 -45 1.8:1 2:1 0.8 0.8 0.9 1 0.6 0.47 V 2.5:1 2.5:1 1.5 1.5 s s s dBm dBc dBm dB CONDITIONS MIN TYP 2.4 to 2.5 29.5 dB MAX UNITS GHz
MAX2247
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Note 1: This device is constructed using a unique set of packaging techniques that impose a limit on the thermal profile the device can be exposed to during board-level solder attach and rework. This limit permits the use of only the solder profiles recommended in the industry-standard specification, JEDEC 020A, paragraph 7.6, Table 3 for IR/VPR and convection reflow. Preheating is required. Hand or wave soldering is not recommended. Note 2: Characteristics are production tested at TA = +25C. DC specifications over temperature are guaranteed by design and characterization. Note 3: Idle current is controlled by external DAC for best efficiency over the entire output power range. Note 4: Parameter is measured with RF modulation based on IEEE 802.11b standard. Note 5: Minimum and maximum specifications are guaranteed by design and characterization. Note 6: Operation outside this range is possible but not guaranteed. Note 7: The total turn-on time required for PA output power to settle to within 0.5dB of the final value. Note 8: Specification is corrected for PC board loss of approximately 0.3dB, on the output of the MAX2247 EV kit. Note 9: Total turn-off time required for PA supply current to fall below 10A. Note 10: See the Typical Operating Characteristics for statistical variation.
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2.4GHz SiGe Linear Power Amplifier MAX2247
Typical Operating Characteristics
(VCC_ = 3V, fRF = 2.45GHz, with MAX2247 EV kit optimized for POUT = +23dBm. TA = +25C, unless otherwise noted.)
OUTPUT POWER, SUPPLY CURRENT vs. SUPPLY VOLTAGE
30 28 26 POUT (dBm) 24 22 TA = -40C 20 18 16 2.7 ICC 3.0 3.3 3.6 3.9 250 4.2 350 300 POUT TA = +25C TA = +85C 450 400
MAX2247 toc01
OUTPUT POWER, SUPPLY CURRENT vs. SUPPLY VOLTAGE
550 28 500 SUPPLY CURRENT (mA) 26 24 POUT (dBm) 22 20 18 16 14 2.7 3.0 3.3 3.6 3.9 SUPPLY VOLTAGE (V) 300 ICC 250 4.2 TA = -40C 350 POUT TA = +25C TA = +85C
MAX2247 toc02
GAIN vs. SUPPLY VOLTAGE
34 500 SUPPLY CURRENT (mA) 450 400 33 32 GAIN (dB) 31 30 29 28 27 26 25 2.7 3.0 3.3 3.6 3.9 4.2 SUPPLY VOLTAGE (V) TA = +85C TA = +25C POUT = +23dBm TA = -40C
MAX2247 toc03
INPUT POWER ADJUSTED TO KEEP ADJ/ALT CPR = -30dBc/-50dBc
INPUT POWER ADJUSTED TO KEEP ADJ/ALT CPR = -32dBc/-55dBc
550
35
SUPPLY VOLTAGE (V)
SUPPLY CURRENT vs. SUPPLY VOLTAGE
MAX2247 toc04
ADJ CPR vs. SUPPLY VOLTAGE
MAX2247 toc05
ALT CPR vs. SUPPLY VOLTAGE
-48 -50 -52 ALT CPR (dBc) -54 -56 -58 -60 TA = +25C TA = +85C POUT = +23dBm
MAX2247 toc06
350 340 330 SUPPLY CURRENT (mA) 320 310 300 290 280 270 260 250
POUT = +23dBm TA = +85C
-24 -26 -28 ADJ CPR (dBc) -30 -32 -34 -36 -38 -40
POUT = +23dBm
-46
TA = +25C
TA = +25C
TA = +85C
TA = -40C
-62 TA = -40C 2.7 3.0 3.3 3.6 3.9 4.2 -64 -66 2.7 3.0
TA = -40C
2.7
3.0
3.3
3.6
3.9
4.2
3.3
3.6
3.9
4.2
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
OUTPUT POWER vs. INPUT POWER
MAX2247 toc07
SUPPLY CURRENT vs. OUTPUT POWER
BIAS CURRENT ADJUSTED TO KEEP ADJ/ALT CPR = -32dBc/-55dBc
MAX2247 toc08
ADJ/ALT CPR vs. OUTPUT POWER
-25 -30 ADJ/ALT CPR (dBc) -35 -40 -45 -50 -55 -60 -65 ALT CPR ADJ CPR
MAX2247 toc09
40 35 30 POUT (dBm) 25 20 15 10 5 0 -20 -15 -10 -5 0 5 PIN (dBm) VCC = +3.0V VCC = +3.3V VCC = +4.2V
300 250 SUPPLY CURRENT (mA) 200 150 100 50 0 10 12 14 16 18 20 22 POUT (dBm)
-20
-70 10 12 14 16 18 20 22 24 POUT (dBm)
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2.4GHz SiGe Linear Power Amplifier
Typical Operating Characteristics (continued)
(VCC_ = 3V, fRF = 2.45GHz, with MAX2247 EV kit optimized for POUT = +23dBm. TA = +25C, unless otherwise noted.)
MAX2247
ADJ CPR vs. FREQUENCY
MAX2247 toc10
ALT CPR vs. FREQUENCY
MAX2247 toc11
SUPPLY CURRENT vs. FREQUENCY
POUT = +23dBm 310 SUPPLY CURRENT (mA) 300 290 280 270 260 TA = +25C TA = -40C TA = +85C
MAX2247 toc12
-27 -28 -29 -30 ADJ CPR (dBc) -31 -32 -33 -34 -35 -36 -37
POUT = +23dBm TA = +85C TA = +25C
-50
POUT = +23dBm
320
-52 ALT CPR (dBc) TA = +25C
-54
TA = +85C
-56 TA = -40C
TA = -40C
-58
-60 2400 2420 2440 2460 2480 2500 2400 2420 2440 2460 2480 2500 FREQUENCY (MHz) FREQUENCY (MHz)
2400
2420
2440
2460
2480
2500
FREQUENCY (MHz)
GAIN vs. FREQUENCY
MAX2247 toc13
INPUT/OUTPUT RETURN LOSS vs. FREQUENCY
MAX2247 toc14
POWER DETECTOR VOLTAGE vs. OUTPUT POWER
1.4 POWER DETECTOR VOLTAGE (V) 1.2 1.0 0.8 0.6 0.4 0.2 0 VCC = +4.2V, TA = -40C VCC = +2.7V, TA = +85C
MAX2247 toc15
40 POUT = +23dBm 36 TA = -40C GAIN (dB) 32
-10 -15 RETURN LOSS (dB) -20 -25 -30 -35 -40 INPUT RETURN LOSS OUTPUT RETURN LOSS
1.6
28 TA = +25C TA = +85C
24
20 2400 2420 2440 2460 2480 2500 FREQUENCY (MHz)
2400
2420
2440
2460
2480
2500
0
5
10
15
20
25
FREQUENCY (MHz)
POUT (dBm)
OUTPUT POWER HISTOGRAM AT FIXED 1V POWER DETECTOR VOLTAGE
MAX2247 toc16
OUTPUT POWER HISTOGRAM AT FIXED 0.6V POWER DETECTOR VOLTAGE
MAX2247 toc17
OUTPUT POWER HISTOGRAM AT FIXED 0.47V POWER DETECTOR VOLTAGE
SIGMA = 0.38dBm BASED ON 50 PARTS 20 OCCURRENCES
MAX2247 toc18
16 14 12 OCCURRENCES 10 8 6 4 2 0
SIGMA = 0.25dBm BASED ON 50 PARTS
20 SIGMA = 0.237dBm BASED ON 50 PARTS 15 OCCURRENCES
25
15
10
10
5 5 0 22.625 22.875 23.125 23.375 14.408 14.645 14.882 15.119 15.356 15.593 OUTPUT POWER (dBm) OUTPUT POWER (dBm) 0 6.05 6.43 6.81 7.19 7.57 7.95 OUTPUT POWER (dBm)
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2.4GHz SiGe Linear Power Amplifier MAX2247
Pin Description
BUMP A1 A2 A3 A4 B1 B3 B4 C1 C2 C3 C4 NAME BIAS VCC2 GND2 VCC1 GND3 PD_OUT GND1 RF_OUT SHDN VCCB RF_IN DESCRIPTION Bias Control. The overall current is set by the current sourced through the bias pin. See the Bias Circuitry section. Second-Stage DC Supply Voltage. Sets the bias and external matching for the second amplifier stage. Requires a small inductance. Bypass to ground using the configuration in the Typical Operating Circuit. Second-Stage Ground. See the Applications Information section for detailed layout information. First-Stage DC Supply Voltage. Sets the bias and external matching for the first amplifier stage. Requires a small inductance. Bypass to ground using the configuration in the Typical Operating Circuit. Third-Stage Ground. See the Applications Information section for detailed layout information. Power-Detector Output. This output is a DC voltage indicating the PA output power. First-Stage and Bias-Control Circuit Ground RF Output. Open-collector output. Requires a pullup inductor, which is part of the matching network. Shutdown Input. Drive logic low to place the device in shutdown mode. Drive logic high for normal operation. Bias Circuit DC Supply Voltage. Bypass to ground using the configuration in the Typical Operating Circuit. RF Input. Internally matched to 50. Requires an external DC-blocking cap.
Functional Diagram/Typical Operating Circuit
VCC 10nF C5 POWER-DETECTOR OUTPUT
SHUTDOWN CONTROL
TRANSMISSION LINE SHDN VCC2 PD_OUT VCC 10nF
DAC
BIAS
MAX2247
BIAS CIRCUIT DETECTOR
22pF
VCC 10nF
VCCB 3.9nH VCC1
VCC 10nF C4 RF_IN
RF_OUT INPUT MATCH C3 C33*
22pF RF OUTPUT
RF INPUT 22pF
GND1
GND2
GND3
*NOT REQUIRED FOR OUTPUT POWER LESS THAN +23dBm.
REFER TO THE MAX2247 EV KIT FOR LAYOUT AND DESIGN DETAILS.
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2.4GHz SiGe Linear Power Amplifier
Detailed Description
The MAX2247 linear power amplifier (PA) offers a wide variety of features incorporated into a tiny UCSP package. The device includes internal bias circuitry, an integrated power detector with buffered output, low-power shutdown mode, and internal input matching. The MAX2247 output power can be optimized for +15dBm to +24dBm by adjusting the output, first-stage, and secondstage matching network (see the Typical Operating Circuit) while exceeding 802.11b ACPR requirements. In addition, external bias control allows dynamic throttleback of the supply current to increase efficiency. The MAX2247's performance can be optimized for lower output power levels. Go to the Maxim website, www.maxim-ic.com, for MAX2247 application notes covering performance at +21dBm, +18dbm, and +15dBm. The overall current of the MAX2247 is set by the current sourced through the bias pin. The overall current is 540 times the bias current. An internal bandgap reference provides +1.2V to each bias stage (see Figure 1). An external resistor to ground can be placed at the bias pin to set the bias current (refer to the MAX2247 evaluation kit). An external current DAC can be connected directly to the bias pin to adjust the bias current of the MAX2247. Figure 2 shows the MAX2247 connected to the MAX2820 zero-IF transceiver, which includes a 4-bit DAC.
MAX2247
Shutdown Mode
The MAX2247 features a low-power shutdown mode to further reduce current consumption. The MAX2247 responds to logic-level signals at the SHDN pin. A logic-level high enables all circuitry, while a logic-level low places the device in low-power shutdown mode and reduces supply current to 0.5A (typ). Power-ramp turn-on and turn-off times are guaranteed to be less than 1.5s.
Bias Circuitry
To improve efficiency at lower output levels, a bias pin is offered to allow dynamic current control. An external current DAC or resistor network can be used to throttleback current at lower output powers while still maintaining ACPR requirements. By including an internal voltage regulator along with the bias circuitry, no external bias voltage is necessary. The internal voltage regulator maintains stable performance of the bias circuitry over temperature and supply variations.
Power Detector
This device includes a power detector that samples the peak voltage of the output and generates a voltage proportional to the output power. The detector is fully temperature compensated and allows the user to set the detector bandwidth with an external capacitor.
INTERNAL VOLTAGE REFERENCE
1ST-STAGE AMPLIFIER BIAS CURRENT
2ND-STAGE AMPLIFIER BIAS CURRENT
3RD-STAGE AMPLIFIER BIAS CURRENT
1.2V RF INPUT
1.2V
1.2V RF_OUT RF OUTPUT
MAX2247
BIAS CONNECTED TO EXTERNAL RESISTOR/DAC FOR SETTING THE BIAS CURRENT
Figure 1. Internal Bias Circuitry _______________________________________________________________________________________ 7
2.4GHz SiGe Linear Power Amplifier MAX2247
STANDARD BASEBAND/MAC IC TX POWER DETECTOR
MAX2820
RX BASEBAND I/Q ZERO-IF TRANSCEIVER
POWER DETECTOR
BIAS CIRCUIT
CURRENT DAC TX BASEBAND I/Q
MAX2247
BALUN
RF OUTPUT
PA DRIVER
SHUTDOWN CONTROL
Figure 2. The MAX2247 Connected to the Current DAC of the MAX2820 for Bias Control
Applications Information
The MAX2247 is a three-stage amplifier that requires special attention to board layout and grounding for optimum output power, gain, efficiency, and side-lobe suppression. For ease of implementation, the MAX2247 evaluation (EV) kit layout should be used as a model. Gerber files are available from Maxim upon request. Follow the recommendations below to optimize performance when adapting the layout to your board.
In addition to RF bypass capacitors on each bias line, a global bypass capacitor of 4.7F is necessary to filter any noise on the supply line. Route separate VCC bias paths from the global bypass capacitor (using a star topology) to avoid coupling between PA stages. Use the MAX2247 EV kit PC board layout as a guide.
Input Matching
The MAX2247 includes internal input matching to 50, so no external matching network is required. A DC-blocking capacitor is required at the input to the device.
Interstage Matching and Bypassing
VCC1 and VCC2 provide DC bias to the open-collector outputs of the first- and second-stage amplifiers and are also part of the interstage matching networks required to optimize performance among the three amplifier stages. The MAX2247 must have a small amount of inductance on the VCC lines in addition to the inductance already provided on-chip. See the Typical Application Circuit for the lumped and discrete component values used on the MAX2247 EV kit for optimum interstage matching and RF bypassing.
Output Matching
The RF_OUT port is an open-collector output that must be pulled to VCC through an RF choke for proper biasing (see the Typical Operating Circuit). A shunt 22pF capacitor to ground is required at the supply side of the inductor. In addition, a matching network is required for optimum gain, efficiency, ACPR, and output power. The EV kit should serve as a good starting point for your layout. However, optimum performance is layout dependent, and some component optimization may be required. It is important to leave room on your board for tuning/optimization.
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2.4GHz SiGe Linear Power Amplifier
Ground Vias
To achieve optimum gain, output power, thermal performance, and ACPR performance, ground vias should be properly placed throughout the layout. Each ground pin requires its own through-hole via (diameter = 10mils) placed as near as possible to the device pin. This reduces ground inductance, thermal resistance, and feedback between stages. Use the MAX2247 EV kit PC board layout as a guide. integrity must be considered because the package is attached through direct solder contact to the user's PC board. Testing done to characterize the UCSP reliability performance shows that it is capable of performing reliably through environmental stresses. Users should also be aware that as with any interconnect system there are electromigration-based current limits that, in this case, apply to the maximum allowable current in the bumps. Reliability is a function of this current, the duty cycle, lifetime, and bump temperature. See the Absolute Maximum Ratings section for any specific limitations listed under Continuous Operating Lifetime. Results of environmental stress tests and additional usage data and recommendations are detailed in the UCSP application note, which can be found on Maxim's website at www.maxim-ic.com/1st_pages/UCSP.htm.
MAX2247
UCSP Reliability
The tiny chip-scale package (UCSP) represents a unique package that greatly reduces board space compared to other packages. UCSP reliability is integrally linked to the user's assembly methods, circuit board material, and usage environment. Operating life test and moisture resistance remains uncompromised, as it is primarily determined by the wafer-fabrication process. Mechanical stress performance is a greater consideration for a UCSP. UCSP solder-joint contact
Chip Information
TRANSISTOR COUNT: 1425
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2.4GHz SiGe Linear Power Amplifier MAX2247
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.)
PACKAGE OUTLINE, 4x3 UCSP 21-0104 F
1 1
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
10 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 2003 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
12L, UCSP 4x3.EPS

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