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19-1912; Rev 3; 11/03
KIT ATION EVALU ILABLE AVA
2.4GHz to 2.5GHz Linear Power Amplifier
General Description
The MAX2242 low-voltage linear power amplifier (PA) is designed for 2.4GHz ISM-band wireless LAN applications. It delivers +22.5dBm of linear output power with an adjacent-channel power ratio (ACPR) of <-33dBc 1st-side lobe and <-55dBc 2nd-side lobe, compliant with the IEEE 802.11b 11MB/s WLAN standard with at least 3dB margin. The PA is packaged in the tiny 3x4 chip-scale package (UCSPTM), measuring only 1.5mm x 2.0mm, ideal for radios built in small PC card and compact flash card form factors. The MAX2242 PA consists of a three-stage PA, power detector, and power management circuitry. The power detector provides over 20dB of dynamic range with 0.8dB accuracy at the highest output power level. An accurate automatic level control (ALC) function can be easily implemented using this detector circuit. The PA also features an external bias control pin. Through the use of an external DAC, the current can be throttled back at lower output power levels while maintaining sufficient ACPR performance. As a result, the highest possible efficiency is maintained at all power levels. The device operates over a single +2.7V to +3.6V power-supply range. An on-chip shutdown feature reduces operating current to 0.5A, eliminating the need for an external supply switch. o 2.4GHz to 2.5GHz Operating Range o +22.5dBm Linear Output Power (ACPR of <-33dBc 1st-Side Lobe and <-55dbc 2nd-Side Lobe) o 28.5dB Power Gain o On-Chip Power Detector o External Bias Control for Current Throttleback o +2.7V to +3.6V Single-Supply Operation o 0.5A Shutdown Mode o Tiny Chip-Scale Package (1.5mm 2.0mm)
Features
MAX2242
Ordering Information
PART MAX2242EBC-T TEMP RANGE -40C to +85C PINPACKAGE 3 4 UCSP TOP MARK AAE
Pin Configuration
RF_IN C4 GND B4 VCC1 A4
________________________Applications
IEEE 802.11b DSSS Radios Wireless LANs HomeRF 2.4GHz Cordless Phones 2.4GHz ISM Radios
GND C3 VCCB BIAS CIRCUIT A3
SHDN C2
PD_OUT B2 A2
VCC2
Actual Size
DET
1.5mm 2.0mm
C1 B1 RF_OUT 34 UCSP A1 GND
Typical Application Circuit appears at end of data sheet. UCSP is a trademark of Maxim Integrated Products, Inc.
BIAS
________________________________________________________________ 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 to 2.5GHz Linear Power Amplifier MAX2242
ABSOLUTE MAXIMUM RATINGS
VCC1, VCC2 to GND (no RF signal applied) ..........-0.3V to +5.5V RF Input Power ...............................................................+10dBm SHDN, BIAS, PD_OUT, RF_OUT ................-0.3V to (VCC + 0.3V) DC Input Current at RF_IN Port.............................-1mA to +1mA Maximum VSWR Without Damage ........................................10:1 Maximum VSWR for Stable Operation.....................................5:1 Continuous Power Dissipation (TA = +85C) 34 UCSP (derate 80mW/C above +85C) ..................1.6W Operating Temperature Range ...........................-40C to +85C Thermal Resistance .........................................................25C/W Junction Temperature ......................................................+150C Storage Temperature Range .............................-65C to +125C Lead Temperature (soldering, 10s) .................................+260C 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. CAUTION! ESD SENSITIVE DEVICE
DC ELECTRICAL CHARACTERISTICS
(VCC = +2.7V to +3.6V, fIN = 2.4GHz to 2.5GHz, V SHDN = VCC, RF_IN = RF_OUT = connected to 50 load, TA = -40C to +85C. Typical values are measured at VCC = +3.3V, fIN = 2.45GHz, TA = +25C, unless otherwise noted.) (Note 1)
PARAMETER Supply Voltage POUT = +22dBm, VCC = +3.3V, idle current = 280mA Supply Current (Notes 2, 3, 6) Shutdown Supply Current Logic Input Voltage High Logic Input Voltage Low Logic Input Current High Logic Input Current Low -1 -1 POUT = +13dBm, idle current = 55mA POUT = +5dBm, idle current = 25mA V SHDN = 0, no RF input 2.0 0.8 5 1 CONDITIONS MIN 2.7 300 90 50 0.5 10 A V V A A TYP MAX 3.6 335 mA UNITS V
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2.4GHz to 2.5GHz Linear Power Amplifier
AC ELECTRICAL CHARACTERISTICS
(MAX2242 Evaluation Kit, VCC = +3.3V, V SHDN = VCC, 50 source and load impedance, fIN = 2.45GHz, TA = +25C, unless otherwise noted.) (Note 6)
PARAMETER Frequency Range (Notes 3, 4) Power Gain (Notes 1, 3) Gain Variation Over Temperature (Note 3) Gain Variation Over VCC (10%) (Note 3) Output Power (Notes 3, 5, 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 7) RF Output Detector Response TIme Po = +22dBm (Note 9) RF Output Detector Voltage Po = +13dBm (Note 9) Po = +5dBm (Note 9) Over full PIN range Over full POUT range SHDN from low to high SHDN from high to low TA = +25C TA = -40C to +85C TA = -40C to +85C VCC = +3.0V to +3.6V ACPR, 1st-side lobe < -33dBc, 2nd-side lobe < -55dBc PIN = +5dBm CONDITIONS MIN 2.4 26.5 25.5 1.2 0.3 28.5 TYP MAX 2.5 UNITS GHz dB dB dB
MAX2242
21.5
22.5 26.5 -40 1.5:1 2.5:1 1 1 2.5 1.8 0.9 0.55 1.5 1.5 5
dBm dBm dBc
s s s
V
Note 1: Note 2: Note 3: Note 4: Note 5: Note 6: Note 7: Note 8: Note 9:
Specifications over TA = -40C to +85C are guaranteed by design. Production tests are performed at TA = +25C. Idle current is controlled by external DAC for best efficiency over the entire output power range. Parameter measured with RF modulation based on IEEE 802.11b standard. Power gain is guaranteed over this frequency range. Operation outside this range is possible, but is not guaranteed. Output two-tone third-order intercept point (OIP3) is production tested at TA = +25C. The OIP3 is tested with two signals at f1 = 2.450GHz and f2 = 2.451GHz with fixed PIN. Min/max limits are guaranteed by design and characterization. The total turn-on and turn-off times required for PA output power to settle to within 0.5dB of the final value. Excludes PC board loss of approximately 0.15dB. See Typical Operating Characteristics for statistical variation.
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2.4GHz to 2.5GHz Linear Power Amplifier MAX2242
Typical Operating Characteristics
(VCC = +3.3V, fIN = 2.45MHz, RF modulation = IEEE 802.11b, V SHDN = VCC, TA = +25C, unless otherwise noted.)
GAIN vs. SUPPLY VOLTAGE
MAX2242 toc01
ICC vs. SUPPLY VOLTAGE
320 PO = +22dBm 28 27 26 25 24 23 22 21 20 19 18 17 16 15
MAX2242 toc02
OUTPUT POWER vs. INPUT POWER
MAX2242 toc03
31 PO = +22dBm 30 TA = +25C TA = -40C
GAIN (dB)
ICC (mA)
29
280
TA = -40C TA = +25C TA = +85C
28 TA = +85C
260
27
240 IDLE CURRENT SET TO 280mA AT VCC = +3.3V, TA = +25C 220
26 2.7 3.0 3.3 3.6 SUPPLY VOLTAGE (V)
OUTPUT POWER (dBm)
300
2.7
3.0
3.3
3.6
-15 -13 -11 -9
-7 -5
-3 -1
1
3
5
SUPPLY VOLTAGE (V)
INPUT POWER (dBm)
ICC vs. OUTPUT POWER
MAX2242 toc04
ACPR vs. OUTPUT POWER
-24 -25 -26 -27 -28 -29 -30 -31 -32 -33 -34 -35 -36 -37 -38 -39 -40 16
MAX2242 toc05
ACPR vs. FREQUENCY
POUT = +22 dBm
MAX2242 toc06
330 300 270 240 210 ICC (mA) 180 150 120 90 60 30 0 0 2 4 6 TA = +85C TA = +25C IDLE CURRENT ADJUSTED TO KEEP ACPR/ALT = -33/-55dBc TA = -40C
-32
IDLE CURRENT = 280mA
-33 TA = -40C TA = +25C TA = +85C -35 17 18 19 20 21 22 23 24 25 2400 2425 2450 FREQUENCY (MHz) 2475 2500 OUTPUT POWER (dBm) ACPR (dBc) -34
8 10 12 14 16 18 20 22
OUTPUT POWER (dBm)
ACPR (dBc)
ICC vs. FREQUENCY
MAX2242 toc07
POWER DETECTOR VOLTAGE vs. OUTPUT POWER
MAX2242 toc08
OUTPUT POWER HISTOGRAM AT FIXED 1.6V POWER DETECTOR VOLTAGE
SIGMA = 0.14dBm BASED ON 100 PARTS
MAX2242 toc09
320 315 310 ICC (mA) 305 300 295 290 285 280 2400 2425 2450 FREQUENCY (MHz) 2475 TA = -40C PO = +22dBm TA = +25C
2 POWER DETECTOR VOLTAGE (V) 1.8 1.6 1.4 1.2 1 0.8 0.6 0.4 0 2
TA = +85C
OCCURENCES
VCC = +3.0V, TA = +25C VCC = +3.3V, TA = +85C VCC = +3.3V, TA = -40C VCC = +3.6V, TA = +25C VCC = +3.3V, TA = +25C
30 25 20 15 10 5 0
VCC = +2.7V, TA = +25C 4 6 8 10 12 14 16 18 20 22
2500
21.6
21.8
22
22.2
22.4
OUTPUT POWER (dBm)
OUTPUT POWER (dBm)
4
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p2.4GHz to 2.5GHz Linear Power Amplifier
Typical Operating Characteristics (continued)
(VCC = +3.3V, fIN = 2.45MHz, RF modulation = IEEE 802.11b, V SHDN = VCC, TA = +25C, unless otherwise noted.)
OUTPUT POWER HISTOGRAM AT FIXED 0.8V POWER DETECTOR VOLTAGE
MAX2242 toc10
MAX2242
OUTPUT POWER HISTOGRAM AT FIXED 0.5V POWER DETECTOR VOLTAGE
SIGMA = 0.75dBm BASED ON 100 PARTS
MAX2242 toc11
25
SIGMA = 0.25dBm BASED ON 100 PARTS
20
20 OCCURRENCES
15 OCCURRENCES 12.1 12.3 12.5 12.7 12.9 13.1 13.3 13.5 13.7 OUTPUT POWER (dBm)
15
10
10
5
5
0
0 2.2 2.8 3.4 4.0 4.6 5.2 5.8 6.4 7.0 OUTPUT POWER (dBm)
S11, S22, vs. FREQUENCY
MAX2242 toc12
MAX2242 S21 vs. FREQUENCY
PIN = -15dBm 29
MAX2242 toc13
30
-1 -3 S11, S22 (dB) -5 -7 -9 -11 -13 -15
PIN = -15dBm
S22 S21 (dB) S11 2400 2420 2440 2460 2480 2500
28
27
26
25 2400 2420 2440 2460 2480 2500 FREQUENCY (MHz) FREQUENCY (MHz)
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5
2.4GHz to 2.5GHz Linear Power Amplifier MAX2242
Pin Description
PIN A1 A2 A3 A4 B1 B2 B4 C1 C2 C3 C4 NAME GND VCC2 GND VCC1 RF_OUT PD_OUT GND BIAS SHDN VCCB RF_IN FUNCTION 3rd Stage Ground. Refer to Application Information section for detailed PC-board layout information. 2nd Stage Supply Voltage. Bypass to ground using configuration in the typical operating circuit. 3rd Stage Ground. Refer to Application Information section for detailed PC-board layout information. 1st Stage Supply Voltage. Bypass to ground using configuration in the typical operating circuit. RF Output. Requires external matching. Power Detector Output. This output is a DC voltage indicating the PA output power. Connect a 47k resistor to GND. 1st Stage and Bias Control Circuit Ground Bias Control. Connect one 8k resistor from BIAS to GND and one 8k resistor from BIAS to DAC block to set the idle current. 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 configuration in the typical operating circuit. RF Input. Requires external matching.
Detailed Description
The MAX2242 is a linear PA intended for 2.4GHz ISMband wireless LAN applications. The PA is fully characterized in the 2.4GHz to 2.5GHz ISM band. The PA consists of two driver stages and an output stage. The MAX2242 also features an integrated power detector and power shutdown control mode.
the DAC voltage, as shown in the Typical Application Circuit. Resistor values R1 and R2 are determined as follows: VMAX = 1.0 + (1.0 R1) / R2; (ICC = 0, VDAC = VMAX) (1) IMAX = (1.0 1867) (R1 + R2) / (R1 R2); (ICC = IMAX = max value, VDAC = 0) IDAC = (VDAC - 1.0) / R1 IMID = (1.0 1867) / R2; (VDAC = 1.0V or floating) ICC = 1867 IBIAS where VMAX = is the maximum DAC voltage IMAX = is the maximum idle current IMID = is the idle current with VDAC = 1.0V or not connected VDAC = is the DAC voltage IDAC = is the DAC current If no DAC is used and a constant idle current is desired, use equation 4 to determine the resistor values for a given total bias current. Only R2 is required. (2) (3) (4) (5)
Dynamic Power Control
The MAX2242 is designed to provide optimum poweradded efficiency (PAE) in both high and low power applications. For a +3.3V supply at high output power level, the output power is typically +22.5dBm with an idle current of 280mA. At low output-power levels, the DC current can be reduced by an external DAC to increase PAE while still maintaining sufficient ACPR performance. This is achieved by using external resistors connected to the BIAS pin to set the bias currents of the driver and output stages. The resistors are typically 8k. Typically, a DAC voltage of 1.0V will give a 280mA bias current. Increasing the DAC voltage will decrease the idle current. Similarly, decreasing the DAC voltage will increase the idle current. The BIAS pin is maintained at a constant voltage of 1.0V, allowing the user to set the desired idle current using only two off-chip 1% resistors: a shunt resistor, R2, from BIAS to ground; and a series resistor, R1, to
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2.4GHz to 2.5GHz Linear Power Amplifier
For a DAC capable of both sourcing and sinking currents, the full voltage range of the DAC (typically from 0 to +3V) can be used. By substituting the desired values of VMAX and IMAX into equations 1 and 2, R1 and R2 can be easily calculated. For a DAC capable of sourcing current only, use equation 4 to determine the value of resistor R2 for the desired maximum current. Use equation 1 to determine the value of resistor R1 for the desired minimum current. For a DAC capable of sinking current only, set resistors R1 and R2 to 0 and connect the DAC directly to the BIAS pin. Use equation 5 to determine the DAC current required for a given ICC. The RFOUT port is an open-collector output that must be pulled to VCC through a 10nH RF choke for proper biasing. A shunt 33pF 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 load impedance seen at the RFOUT port of the MAX2242 on the EV kit is approximately 8 + j5. This should serve as a good starting point for your layout. However, optimum performance is layout dependent and some component optimization may be required. See the Typical Application Circuit for the lumped and discrete component values used on the MAX2242 EV kit to achieve this impedance.
MAX2242
Shutdown Mode
Apply logic low to SHDN (pin C2) to place the MAX2242 into shutdown mode. In this mode, all gain stages are disabled and supply current typically drops to 0.5A. Note that the shutdown current is lowest when V SHDN = 0.
Ground Vias
Placement and type of ground vias are important to achieve optimum gain and output power and ACPR performance. Each ground pin requires its own throughhole via (via diameter = 10mils) placed as near to the device pin as possible to reduce ground inductance and feedback between stages. Use the MAX2242 EV kit PC board layout as a guide.
Power Detector
The power detector generates a voltage proportional to the output power by monitoring the output power using an internal coupler. It is fully temperature compensated and allows the user to set the bandwidth with an external capacitor. For maximum bandwidth, connect a 47k resistor from PD_OUT to GND and do not use any external capacitor.
Layout and Thermal Management Issues
The MAX2242 EV kit serves as a layout guide. Use controlled-impedance lines on all high-frequency inputs and outputs. The GND pins also serve as heat sinks. Connect all GND pins directly to the topside RF ground. On boards where the ground plane is not on the component side, connect all GND pins to the ground plane with plated multiple throughholes close to the package. PC board traces connecting the GND pins also serve as heat sinks. Make sure that the traces are sufficiently wide.
Applications Information
Interstage Matching and Bypassing
VCC1 and VCC2 provide bias to the first and second stage amplifiers, and are also part of the interstage matching networks required to optimize performance between the three amplifier stages. See the Typical Application Circuit for the lumped and discrete component values used on the MAX2242 EV kit for optimum interstage matching and RF bypassing. In addition to RF bypass capacitors on each bias line, a global bypass capacitor of 22F is necessary to filter any noise on the supply line. Route separate V CC bias paths from the global bypass capacitor (star topology) to avoid coupling between PA stages. Use the MAX2242 EV kit PC board layout as a guide.
UCSP Reliability
UCSP represents a unique packaging form factor that may not perform equally to a packaged product through traditional mechanical reliability tests. UCSP reliability is integrally linked to the user's assembly methods, circuit-board material, and usage environment. The user should closely review these areas when considering use of a UCSP. Performance through the 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. UCSPs are attached through direct solder contact to the user's PC board, foregoing the inherent stress relief of a packaged-product lead frame. Solder joint contact integrity must be considered. Testing done to characterize the
External Matching
The RFIN port requires a matching network. The RFIN port impedance is 16-j30 at 2.45GHz. See the Typical Application Circuit for recommended component values.
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7
2.4GHz to 2.5GHz Linear Power Amplifier MAX2242
Typical Application Circuit
VCC VCC
DAC
0.1F
DET OUT
47k
R1 8k
SHDN
VCC2
PD_OUT
0.1F
50
R2 8k
BIAS
33pF
VCC
VCCB
33pF
VCC1
BIAS CIRCUIT
DETECTOR
10nH
VCC
0.1F
100pF RF_OUT
RF_IN
6pF
1.8pF 2.2nH
GND GND GND
NOTE: REFER TO MAX2242 EV KIT DATA SHEET FOR DETAILED LAYOUT INFORMATION.
Chip Information
TRANSISTOR COUNT: 486
0.5
2.0
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.
Package Diagram
1.5 0.5 0.75 MAX
C4
B4
A4
C3
B3 NOT USED
A3
C2
B2
A2
C1
B1
A1
BOTTOM VIEW CHIP-SCALE PACKAGE (ALL DIMENSIONS IN mm)
SIDE VIEW
8
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2.4GHz to 2.5GHz Linear Power Amplifier
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.)
12L, UCSP 4x3.EPS
PACKAGE OUTLINE, 4x3 UCSP 21-0104 F
1 1
Note: MAX2242 does not use bump B3.
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.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 _____________________ 9 (c) 2003 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

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