19-2494; Rev 2; 8/03 KIT ATION EVALU E L B AVAILA 5GHz Linear Power Amplifiers The MAX2840/MAX2841 low-cost linear power amplifiers (PAs) operate in the 5GHz to 6GHz band. The PAs are designed for high gain and high linearity, which makes them ideal for use in IEEE 802.11a OFDM systems. The MAX2840 delivers +15dBm output power, and the MAX2841 delivers +18dBm output power. The devices integrate a power detector that provides over 15dB dynamic range and ±1.0dB accuracy. With the detector circuit built in, an automatic level control (ALC) function can be easily implemented. The PAs also feature an external bias control function. The idle current can be adjusted through an external DAC to improve efficiency at reduced output powers while maintaining sufficient ACPR and EVM performance. As a result, the highest possible efficiency is maintained at all power levels. The MAX2840/MAX2841 operate over a single +2.7V to +3.6V power-supply range. An on-chip shutdown feature reduces operating current to less than 10µA, eliminating the need for an external supply switch. The MAX2840/MAX2841 are packaged in a 2mm ✕ 1.5mm chip-scale package (UCSP™), which significantly minimizes parasitic effects and reduces the required board area. Features ♦ 5GHz to 6GHz Operating Frequency Range ♦ High Linear Output Power +15dBm at 5.25GHz (MAX2840) +18dBm at 5.25GHz (MAX2841) ♦ 22dB Power Gain ♦ On-Chip Detector With 15dB Dynamic Range and ±1.0dB Detector Accuracy ♦ Simple Input and Output Matching ♦ +2.7V to +3.6V Single Supply ♦ Shutdown Mode With Less than 10µA Current ♦ 2mm ✕ 1.5mm Chip-Scale Package Ordering Information PART TEMP RANGE PINPACKAGE TOP MARK MAX2840EBC-T -40°C to +85°C 3 ✕ 4 UCSP AAT MAX2841EBC-T -40°C to +85°C 3 ✕ 4 UCSP AAU Typical Operating Circuit appears at end of data sheet. Applications Pin Configuration IEEE 802.11a OFDM WLAN HiperLAN2 WLAN 5GHz Cordless Phones SHDN Functional Diagram SHDN A1 P_DET GND A2 BIAS BIAS CIRCUIT RF_IN B2 C1 MAX2840 MAX2841 GND C2 DETECTOR MAX2840 MAX2841 VCC BIAS BIAS CIRCUIT RF_IN VCC P_DET A3 C3 RF_OUT DET GND GND GND GND A4 B4 C4 GND RF_OUT GND UCSP is a trademark of Maxim Integrated Products, Inc. ________________________________________________________________ Maxim Integrated Products 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. 1 MAX2840/MAX2841 General Description MAX2840/MAX2841 5GHz Linear Power Amplifiers ABSOLUTE MAXIMUM RATINGS VCC to GND ...........................................................-0.3V to +4.2V SHDN, BIAS, P_DET, RF_OUT to GND ......-0.3V to (VCC + 0.3V) RF_IN to GND........................................................-0.3V to +0.9V Input Power ................................................................... +10dBm Max VSWR Without Damage .................................................10:1 Max VSWR for Stable Operation .............................................5:1 Continuous Operating Lifetime.....................10yrs ✕ 0.93(TA - 60°C) (for operating temperature 60°C < TA < 85°C) Continuous Power Dissipation (TA = +85°C) 3 ✕ 4 UCSP (derate 80mW/°C above +85°C) .................. 1.6W Operating Temperature Range ...........................-40°C to +85°C Thermal Resistance .........................................................25°C/W Junction Temperature ......................................................+150°C Storage Temperature Range .............................-65°C to +125°C Soldering Temperature (10s) ...........................................+260°C 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, GND = 0V, SHDN = VCC, VDAC = 1.6V (MAX2840), VDAC = 1.9V (MAX2841), TA = -40°C to +85°C. Typical values are measured at VCC = +3.3V, fRF = 5.25GHz, TA = +25°C, unless otherwise noted.) (Note 1) PARAMETER CONDITIONS MIN TYP MAX UNITS 3.6 V POUT = 15dBm, VCC = 3.3V, MAX2840 (Notes 2, 3) 155 190 POUT = 18dBm, VCC = 3.3V, MAX2841 (Notes 2, 3) 260 310 MAX2840 120 MAX2841 165 Supply Voltage Supply Current 2.7 No RF signal, RF input and output terminated with 50Ω SHDN = 0V, no RF signal 0.5 mA 10 µA Digital Input Voltage Low 0.8 V Digital Input Current High 5 µA Digital Input Voltage High 2 Digital Input Current Low V -1 µA AC ELECTRICAL CHARACTERISTICS (MAX2840/MAX2841 EV kits, VCC = +2.7V to +3.6V, GND = 0V, SHDN = VCC, VDAC = 1.6V (MAX2840), VDAC = 1.9V (MAX2841), TA = +25°C. Typical values are measured at VCC = +3.3V, fRF = 5.25GHz, unless otherwise noted.) (Note 3) PARAMETER RF Frequency Range Power Gain (Note 5) CONDITIONS 22.8 POUT = 18dBm (MAX2841) 22.5 TA = +85°C, VCC = 3.3V (Note 5) Output Power ACPR: -23dBc at 11MHz offset, -31dBc at 20MHz offset, -43dBc at 30MHz offset over 100kHz BW; OFDM, 64-QAM signal (Notes 6, 7) Harmonic Output (2f, 3f) 2 TYP 5.15 POUT = 15dBm (MAX2840) Power Gain Error Vector Magnitude (Note 7) MIN (Note 4) 19.5 MAX UNITS 5.35 GHz dB dB MAX2840 15 MAX2841 18 dBm POUT = 15dBm (MAX2840) 3.9 POUT = 18dBm (MAX2841) 3.5 POUT = 15dBm (MAX2840) POUT = 18dBm (MAX2841) -45 _______________________________________________________________________________________ %RMS dBc 5GHz Linear Power Amplifiers (MAX2840/MAX2841 EV kits, VCC = +2.7V to +3.6V, GND = 0V, SHDN = VCC, VDAC = 1.6V (MAX2840), VDAC = 1.9V (MAX2841), TA = +25°C. Typical values are measured at VCC = +3.3V, fRF = 5.25GHz, unless otherwise noted.) (Note 3) PARAMETER CONDITIONS MIN TYP Input VSWR 1.8:1 Output VSWR 1.9:1 Nonharmonic Spurious Output MAX UNITS -60 dBc Power Ramp Turn-On Time SHDN from low to high (Note 8) 1 1.5 µs Power Ramp Turn-Off Time SHDN from high to low (Note 8) 1 1.5 µs RF Output Detector Response Time External capacitor, C = 10pF 0.5 1.5 µs RF Output Detector Voltage Range Load >100kΩ (Note 7) POUT = 15dBm (MAX2840) 1.1 POUT = 18dBm (MAX2841) 1.2 POUT = 12dBm (MAX2840) 1 POUT = 15dBm (MAX2841) 1 POUT = 5dBm (MAX2840) 0.7 POUT = 5dBm (MAX2841) 0.7 RF Output Detector Accuracy When output detector voltage = 1.2V RF Output Detector Slope At maximum output power Note 1: Note 2: Note 3: Note 4: Note 5: Note 6: Note 7: Note 8: V ±1 dB 6 dB/V Specifications over temperature range are guaranteed by design. Production tests are performed at TA = +85°C. 5.25GHz 64-QAM modulated OFDM signal is applied at RF input port. Min and max values are guaranteed by design and characterization. Operation outside of this frequency range is possible but not guaranteed. Specifications are corrected for board losses on the EV kits (0.3dB at the input, 0.3dB at the output). RF input signal is following IEEE 802.11a standards. Specifications are corrected for board losses on the EV kits (0.3dB at the output). The total turn-on/settling time required for PA output power is within 0.5dB range of the final value. Typical Operating Characteristics (MAX2840/MAX2841 EV kits, VCC = +2.7V to +3.6V, GND = 0V, SHDN = VCC, VDAC = 1.6V (MAX2840), VDAC = 1.9V (MAX2841), TA = +25°C. Typical values are measured at VCC = +3.3V, fRF = 5.25GHz, unless otherwise noted.) (Note 2) MAX2840 SUPPLY CURRENT vs. SUPPLY VOLTAGE 160 140 120 0.30 MAX2840/41 toc02 SUPPLY CURRENT (mA) PIN = -8.9dBm 0.25 SHUTDOWN CURRENT (µA) MAX2840/41 toc01 180 MAX2840 SHUTDOWN CURRENT vs. SUPPLY VOLTAGE TA = +85°C 0.20 0.15 TA = +25°C 0.10 0.05 TA = -40°C 0 100 2.7 3.0 3.3 SUPPLY VOLTAGE (V) 3.6 2.7 3.0 3.3 3.6 SUPPLY VOLTAGE (V) _______________________________________________________________________________________ 3 MAX2840/MAX2841 AC ELECTRICAL CHARACTERISTICS (continued) Typical Operating Characteristics (continued) (MAX2840/MAX2841 EV kits, VCC = +2.7V to +3.6V, GND = 0V, SHDN = VCC, VDAC = 1.6V (MAX2840), VDAC = 1.9V (MAX2841), TA = +25°C. Typical values are measured at VCC = +3.3V, fRF = 5.25GHz, unless otherwise noted.) (Note 2) PAE (%) 12 160 140 10 3.0V 8 6 4 120 100 8 12 16 0 4 8 16 12 OUTPUT POWER (dBm) OUTPUT POWER (dBm) MAX2840 INPUT AND OUTPUT RETURN LOSS vs. FREQUENCY MAX2840 GAIN vs. FREQUENCY -8 S11 -12 25 GAIN (dB) -4 PIN = -8.9dBm 8 12 16 OUTPUT POWER (dBm) MAX2840 ACPR SPECTRUM PO = +15dBm 20 S22 15 -16 10 5300 5150 5350 5200 5250 5300 FREQUENCY (MHz) FREQUENCY (MHz) MAX2840 EVM vs. OUTPUT POWER MAX2840 EVM vs. FREQUENCY 6 MAX2840/41 toc09 6 PIN = -8.9dBm PIN = -8.9dBm 5 EVM (%) 5 4 VCC = 3.0V 5350 MAX2841 SUPPLY CURRENT vs. SUPPLY VOLTAGE VCC = 3.0V 4 VCC = 3.3V VCC = 3.3V 3 13 14 15 OUTPUT POWER (dBm) 16 PIN = -4.8dBm 260 240 200 2 12 280 220 3 2 SPAN: 100MHz CENTER: 5.25GHz MAX2840/41 toc011 5250 SUPPLY CURRENT (mA) 5200 MAX2840/41 toc10 -20 5150 4 4 0 20 MAX2840/41 toc07 30 MAX2840/41 toc06 0 INPUT AND OUTPUT RETURN LOSS (dB) 20 0.8 OUTPUT POWER, 10dB/div 4 0.9 0.6 0 0 1.0 0.7 3.6V 2 1.1 MAX2840/41 toc08 180 MAX2840/41 toc05 2.7V 14 1.2 POWER DETECTOR OUTPUT (V) 16 MAX2840/41 toc04 200 SUPPLY CURRENT (mA) 18 MAX2840/41 toc03 220 MAX2840 POWER DETECTOR OUTPUT vs. OUTPUT POWER MAX2840 POWER-ADDED EFFICIENCY (PAE) vs. OUTPUT POWER MAX2840 SUPPLY CURRENT vs. OUTPUT POWER EVM (%) MAX2840/MAX2841 5GHz Linear Power Amplifiers 5150 5200 5250 FREQUENCY (MHz) 5300 5350 2.7 3.0 3.3 SUPPLY VOLTAGE (V) _______________________________________________________________________________________ 3.6 5GHz Linear Power Amplifiers 0.15 TA = +25°C 0.10 0.05 TA = -40°C 3.0 3.3 MAX2840/41 toc13 TA = +25°C 250 200 3.6 10 3.0V 8 6 3.6V 4 TA = -40°C 2 0 4 0 8 12 16 20 24 5 0 10 15 20 SUPPLY VOLTAGE (V) OUTPUT POWER (dBm) OUTPUT POWER (dBm) MAX2841 POWER DETECTOR OUTPUT vs. OUTPUT POWER MAX2841 INPUT AND OUTPUT RETURN LOSS vs. FREQUENCY MAX2841 GAIN vs. FREQUENCY 1.4 1.2 TA = +25°C 1.0 TA = -40°C 0.8 0.6 5 10 15 20 -8 S22 -12 MAX2841 ACPR SPECTRUM 10 5200 5250 5300 5200 5250 5300 FREQUENCY (MHz) FREQUENCY (MHz) MAX2841 EVM vs. OUTPUT POWER MAX2841 EVM vs. FREQUENCY PIN = -4.8dBm 4 5350 6 PIN = -4.8dBm 5 EVM (%) 5 EVM (%) 5150 5350 6 MAX2840/41 toc18 OUTPUT POWER, 10dB/div 20 15 -16 OUTPUT POWER (dBm) POUT = +18dBm 25 S11 -20 5150 25 MAX2840/41 toc17 -4 MAX2840/41 toc20 TA = +85°C PIN = -4.8dBm GAIN (dB) 1.6 25 30 MAX2840/41 toc16 1.8 0 INPUT AND OUTPUT RETURN LOSS (dB) MAX2840/41 toc15 2.0 0 2.7V 12 100 2.7 POWER DETECTOR OUTPUT (V) 14 300 150 0 16 PAE (%) TA = +85°C 0.20 TA = +85°C 350 18 MAX2840/41 toc19 SHUTDOWN CURRENT (µA) 0.25 400 SUPPLY CURRENT (mA) MAX2840/41 toc12 0.30 MAX2841 POWER-ADDED EFFICIENCY (PAE) vs. OUTPUT POWER MAX2841 SUPPLY CURRENT vs. OUTPUT POWER MAX2840/41 toc14 MAX2841 SHUTDOWN CURRENT vs. SUPPLY VOLTAGE VCC = 3.0V 4 VCC = 3.0V VCC = 3.3V 3 3 VCC = 3.3V 2 2 CENTER: 5.25GHz SPAN: 100MHz 13 14 15 16 17 OUTPUT POWER (dBm) 18 19 5150 5200 5250 5300 5350 FREQUENCY (MHz) _______________________________________________________________________________________ 5 MAX2840/MAX2841 Typical Operating Characteristics (continued) (MAX2840/MAX2841 EV kits, VCC = +2.7V to +3.6V, GND = 0V, SHDN = VCC, VDAC = 1.6V (MAX2840), VDAC = 1.9V (MAX2841), TA = +25°C. Typical values are measured at VCC = +3.3V, fRF = 5.25GHz, unless otherwise noted.) (Note 2) MAX2840/MAX2841 5GHz Linear Power Amplifiers Pin Description PIN NAME DESCRIPTION A1 SHDN Shutdown Input. Drive logic low to place the PA in shutdown mode; drive logic high for normal operation. A2, A4, C2, C4 GND Ground. Requires a good connection to the circuit board ground plane with multiple vias for lowest possible inductance and lowest thermal resistance. A3 VCC DC Supply Voltage. Requires external RF bypass capacitor to ground. B2 RF_IN B4 RF_OUT Power Amplifier Input. Requires external DC-blocking capacitor. Power Amplifier Output. Requires external DC-blocking capacitor and pullup inductor. C1 BIAS Bias Control. Connect two external resistors and DAC block to adjust the bias current. C3 P_DET Power Detector Output. This output is a DC voltage indicating the PA output power. Detailed Description The MAX2840/MAX2841 linear power amplifiers (PAs) are intended for 5GHz to 6GHz band applications. The PAs are fully characterized in the 5.15GHz to 5.35GHz band. The PAs consist of two driver stages and an output stage. The ICs also feature an integrated power detector and power shutdown mode. Dynamic Power Control The MAX2840/MAX2841 are designed to provide optimum power-added efficiency (PAE) in both high- and low-power applications. For a +3.3V supply at high-output power level, the output power is typically +18dBm (MAX2841) with an idle current of 165mA, or +15dBm (MAX2840) with an idle current of 120mA. At low-output power levels, the DC current can be reduced by an external DAC to improve PAE while 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. See the Typical Application Circuit for resistor values. Typically, a DAC voltage of 1.9V gives a 260mA bias current for the MAX2841, a DAC voltage of 1.6V gives a 155mA bias current for the MAX2840. Increasing the DAC voltage decreases the idle current. Similarly, decreasing the DAC voltage increases the idle current. Users can 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 the DAC voltage, as shown in the Typical Application Circuit. Resistor values R1 and R2 are determined as follows: [Equation 1] VMAX = 1.2 ✕ (R1 + R2) / R2; (ICC = 0, VDAC = VMAX) 6 [Equation 2] IMAX = PART ✕ 1.2 / 2000 + (R1 ✕ R2) / (R1 + R2); (ICC = IMAX = max value, VDAC = 0) [Equation 3] IDAC = (VDAC - 0.82) / R1 [Equation 4] IMID = PART ✕ 1.2 / (2000 + R2); (VDAC = floating) [Equation 5] ICC = PART ✕ IBIAS where: VMAX IMAX IMID VDAC = maximum DAC voltage = maximum idle current = idle current with VDAC = floating = DAC voltage IDAC = DAC current PART = 1000 for MAX2840, 1600 for MAX2841 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. For a DAC capable of 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. _______________________________________________________________________________________ 5GHz Linear Power Amplifiers Shutdown Mode Apply logic low to SHDN (pin A1) to put the MAX2840/ MAX2841 in shutdown mode. In this mode, all gain stages are disabled and supply current drops to less than 10µA. Note that the shutdown current is lowest when VSHDN = 0. Power Detector The power detector generates a voltage proportional to the output power. It is fully temperature compensated and allows the user to set the bandwidth with an external capacitor. For maximum bandwidth, connect a 100kΩ resistor from P_DET to GND and do not use any external capacitors. Applications Information 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 via on pad (via diameter = 8 mils) placed under the device pin to reduce ground inductance and feedback between stages. Use the MAX2840/MAX2841 EV kit PC board layouts as a guide. Layout and Thermal Management Issues The MAX2840/MAX2841 EV kits serve as a layout guide. Use controlled-impedance lines on all high-frequency inputs and outputs. The GND pins also serve as heatsinks. 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 through holes close to the package. PC board traces connecting the GND pins also serve as heatsinks. Make sure the traces are sufficiently wide. Supply Bypassing UCSP Reliability VCC provides bias to the first- and second-stage amplifiers. See the Typical Application Circuit for the lumped and discrete component values used on the MAX2840/MAX2841 EV kits for optimum RF bypassing. In addition to RF bypass capacitors on each bias line, a global bypass capacitor of 10µF is necessary to filter any noise on the supply line. Route separate VCC bias paths from the global bypass capacitor (star topology) to avoid coupling between PA stages. Use the MAX2840/MAX2841 EV kits PC board layout as a guide. The chip-scale package (UCSP) is a unique package that greatly reduces board space. 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 using a UCSP. This form factor might not perform equally to a packaged product through traditional mechanical reliability tests. Performance through operating life test and moisture resistance remains uncompromised, as it is primarily determined by the wafer- fabrication process. External Matching Mechanical stress performance is a greater consideration for a UCSP. UCSP solder-joint contact integrity must be considered because the package is attached through direct solder contact to the user’s PC board. Testing to characterize the UCSP reliability performance shows that it is capable of performing reliably through environmental stresses. 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, www.maxim-ic.com. Users should be aware that, as with any interconnect system, there are electromigration-based current limits, which 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 of the data sheet for any specific limitation, listed under “Continuous Operating Lifetime.” The RFIN port requires a matching network. The RFIN port impedance is 11 + j14Ω at 5.25GHz. See the Typical Application Circuit for recommended component values. The RFOUT port is an open-collector output that must be pulled to VCC through a 5.6nH RF choke for proper biasing. Two shunt capacitors to ground are 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 MAX2840/ MAX2841 on the EV kits is approximately 13 + j5Ω. This should serve as a good starting point for the 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 MAX2840/ MAX2841 EV kits to achieve this impedance. Chip Information TRANSISTOR COUNT: 1263 _______________________________________________________________________________________ 7 MAX2840/MAX2841 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. 5GHz Linear Power Amplifiers MAX2840/MAX2841 Typical Operating Circuit 10pF DAC SHDN P_DET R1 10kΩ 1000pF 10pF MAX2840 MAX2841 BIAS R2 5kΩ 100kΩ BIAS CIRCUIT DECTECTOR 1000pF 3pF VCC VCC 5.6nH 6.8pF T2* T1* 5pF RF_OUT RF_IN 1.2pF GND *T1 = 100 MILS, T2 = 70 MILS (MAX2840) T1 = 80 MILS, T2 = 60 MILS (MAX2841) **BOARD MATERIAL: FR4, DIELECTRIC THICKNESS: 6 MILS 8 C = 1pF (MAX2841) C = 0.6pF (MAX2840) GND GND GND _______________________________________________________________________________________ 5GHz Linear Power Amplifiers 12L, UCSP 4x3.EPS 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. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 _____________________ 9 © 2003 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products. MAX2840/MAX2841 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.)