应用笔记 335

Maxim无线/射频功率放大器选择指南


摘要 : 本文概括了Maxim针对蜂窝、PCS、802.11a/b/g、无绳电话以及Bluetooth等应用提供的射频(RF)功率放大器(PA)。列出了工作电压、电源电流、输出功率、封装、功效等参数的对照表,并给出了Maxim PA IC的特点。另外,还提供了一个根据市场应用选择的参考表。

更多信息: Maxim的RF功率放大器(PA)即可应用于线性调制,如QAM和QPSK,也可用于非线性调制,如:FM、FSK等。针对TDMA市场设计的PA在性能上有所改进,如:自动斜率控制可减小频谱扩散,自动斜率控制有助于保持VCC的稳定、降低VCO牵引。自动热保护功能能够根据需要临时减小输出功率,提供一个坚固、耐用的PA。针对CDMA市场推出的PA能够在城市或远郊CDMA环境下、对于大多数便携终端要求的输出功率电平提供更低的电源电流,CDMA PA在大多数时间工作在较低的输出功率状态。

对于2.4GHz ISM应用,如:802.11b WLAN、Bluetooth、HomeRF及无绳电话,Maxim可提供低成本、超小尺寸(如UCSP封装)的功率放大器,这些PA具有模拟或数字的功率控制、闭环功率控制、动态偏置控制、集成检测器等,并具有较高的效率。

以下列出了采用硅双极型工艺设计的RF功率放大器关键特性:
  1. 低成本,这一点得益于它较高的管芯产量和简单的器件制作工艺(与超外差器件相比)
  2. 小尺寸,采用UCSP封装和较少的外部元件
  3. 无需负偏置电源,不同于大多数GaAs放大器
  4. 在全温范围和负载变化范围内提供稳定的器件特性
  5. 自动斜率控制
下表列出了我们的一些功率放大器及其性能,注意,有几款PA需要在指定的性能参数和中心频点进行重新调谐,与表中参数有差异。

表1. 选择指南:型号列表
Part VCC
(V)
ICC
(mA)
Frequency
(MHz)
POUT
(dBm)
Class Package PAE
(full)
PAE
(derated)
Features
MAX2235 2.7 to 5.5 20 idle
610 full
800 to 1000 +30.3 C 20-Pin
TSSOP-EP
47% 22%
+24dBm
Analog Gain Control, Auto Power Ramp, Shutdown
MAX2430 3.0 to 5.5 52 800 to 1000 +21.4 AB 16-Pin
SO/QSOP
24% NA Power Control, Shutdown, Drives MAX2601/02
MAX2601 2.7 to 5.5 450 DC to 1000 +30.0 AB/C 8-Pin
PSOPII
54% 18%
+20dBm
Power Transistor
MAX2602 2.7 to 5.5 450 DC to 1000 +30.0 AB/C 8-Pin
PSOPII
54% 18%
+20dBm
Power Transistor with On-Chip Bias Diode, Power Ramp, Shutdown
MAX2264 2.7 to 5.0 34 idle,
58 avg,
95 full
824 to 849 +28.0 AB 16-Pin
TSSOP-EP
32% 12%
+16dBm
IS-98 CDMA U.S., Internal Switch,
Smallest, Most Economical Solution
MAX2265 2.7 to 5.0 83 full 824 to 849 +28.0 AB 16-Pin
TSSOP-EP
37% 7%
+16dBm
IS-98 CDMA U.S., TDMA PAE = 40% at +30dBm
MAX2266 2.7 to 5.0 34 idle,
52 avg,
100 full
824 to 849 +28.0 AB 16-Pin
TSSOP-EP
32% 17%
+16dBm
IS-98 CDMA U.S., Off-Chip Switch, Lowest Current
MAX2267 2.7 to 4.5 34 idle,
56 avg,
95 full
887 to 925 +27.0 AB 16-Pin
TSSOP-EP
28% 12%
+17dBm
IS-98 CDMA Japan, Internal Switch,
Smallest, Most Economical Solution
MAX2268 2.7 to 4.5 90 idle 887 to 925 +27.0 AB 16-Pin
TSSOP-EP
34% 7%
+13.6dBm
IS-98 CDMA Japan, PDC PAE = 41% at +29dBm
MAX2269 2.7 to 4.5 34 idle,
50 avg,
100 full
887 to 925 +27.0 AB 16-Pin
TSSOP-EP
29% 17%
+17dBm
IS-98 CDMA Japan, Off-Chip Switch, Lowest Current
MAX2240 2.7 to 5.0 65 idle
105 full
2400 to 2500 +20 AB UCSP
3x3
30% NA Bluetooth PA with Digital Power Control, Shutdown
MAX2242 2.7 to 3.6 280 idle
300 full
2400 to 2500 +22.5 AB UCSP
3x4
17%
Pin=
-7dBm
315mA
6.7%
+13dBm
+22.5dBm Output Power at -33dBc ACPR for 802.11b
28.5dB Power Gain
External Bias Control for Current Throttleback
On-Chip Power Detector
Output Power Tunable from +10dBm to +22dBm
MAX2244 3.0 to 3.6 65 idle
172 full
2400 to 2500 +22 AB UCSP
3x3
34.2% NA Integrated Input Match
Internal Bandwidth-Limited Power Ramping
Power Control Range: 0.5V to 2.0V
Supply Current = 170mA at +22dBm
MAX2245 3.0 to 3.6 65 idle
179 full
2400 to 2500 +22 AB UCSP
3x3
29.2% NA Integrated Input Match
Internal Bandwidth-Limited Power Ramping
Power Control Range: 0.9V to 2.0V
Supply Current = 170mA at +22dBm
MAX2246 3.0 to 3.6 42 idle
118 full
2400 to 2500 +20 AB UCSP
3x3
27.8% NA Integrated Input Match
Internal Bandwidth-Limited Power Ramping
Power Control Range: 0.5V to 2.0V
MAX2247 2.7 to 3.6 293 idle
390 full
2400 to 2500 +25 AB UCSP
3x4
24.5% 21%
+22.5dBm
High Linear Output Power: +25dBm with < -33dBc ACPR
(1st side lobe) and < -55dBc ACPR (2nd side lobe) (802.11b)
+17dBm and 3%EVM (802.11g)
25% Efficiency with Linear Output Power
29dB Power Gain
On-Chip Power Detector
External Bias Control for Current Throttleback
On-Chip Input Matching
0.5µA Shutdown Mode
MAX2251 2.8 to 4.5 205 idle
1029 full
824 to 849

+32.4
AMPS

+30
TDMA
AB UCSP
3x4


51%
AMPS

41%
TDMA
38%
+30dBm
AMPS
Gain: 28dB
Integrated Power Detector
Low-Power Shutdown Mode
PAE: 41% at +30dBm for TDMA
PAE: 51% at +32.4dBm for AMPS
MAX2840 2.7 to 3.6 120 idle
155 full
5150 to 5350 +15 A 12-UCSP-
1.52x2.02
6% NA High Linear Output Power
+15dBm at 5.25 GHz
(802.11a), 22dB Power
gain, On-chip Power
detector, Simple
input/output matching,
<10uA Shutdown current
MAX2841 2.7 to 3.6 165 idle
260 full
5150 to 5350 +18 A 12-UCSP-
1.52x2.02
7% NA High Linear Output Power
+18dBm at 5.25 GHz
(802.11a), 22dB Power
gain, On-chip Power
detector, Simple
input/output matching,
<10uA Shutdown current

表2. 针对市场选择
Market Part Advantages Specs
Cellular CDMA (U.S.) MAX2265 Low-cost, Simple Layout, Few External Components,
High-peak Efficiency
Efficiency = 37% (ACPR = -45)
Efficiency = 35% (ACPR = -48)
MAX2264
MAX2266
Low-cost, World's Lowest Talk Current Talk Current=55mA
16dBm Efficiency =12/18% (2264/66)
Peak Efficiency =32%
MAX2251 Small Size Ultra-chip Scale Package
(2.06mm x 2.06mm),
Integrated Power Detector,
Low-power Shutdown Mode
Gain: 28dB
PAE: 41% at +30dBm for TDMA
PAE: 51% at +32.4dBm for AMPS
CDMA (Japan) MAX2268 Low-cost, Simple Layout, Few External Components,
High-peak Efficiency
Efficiency = 37% (ACPR = -45)
Efficiency = 35% (ACPR = -48)
MAX2267
MAX2269
Low-cost, World's Lowest Talk Current Talk Current=55mA
16dBm Efficiency =12/18% (2264/66 and ACPR=-45)
Peak Efficiency =33% (ACPR=-45)
Cellular TDM MAX2251 Small Size Ultra-chip Scale Package
(2.06mm x 2.06mm),
Integrated Power Detector,
Low-power Shutdown Mode
Gain: 28dB
PAE: 41% at +30dBm for TDMA
PDC MAX2265 Low-cost, Simple Layout, Few External Components,
High-peak Efficiency
Efficiency=40% (ACPR=-28)
POUT=30dBm
AMPs MAX2251 Small Size Ultra-chip Scale Package
(2.06mm x 2.06mm),
Integrated Power Detector,
Low-power Shutdown Mode
Efficiency=51%
POUT=32.4dBm
MAX2265 Low-cost, Simple Layout, Few External Components,
High-peak Efficiency
PAE: 48% at +31.5dBm Output Power for AMPS
WLL MAX2265 Low-cost, Simple Layout, Few External Components,
High-peak Efficiency
Efficiency=37% (ACPR=-45)
Efficiency=35% (ACPR=-48)
900MHz ISM MAX2235 Analog Gain Control, Auto Power Ramp, Shutdown PAE: 47% at +30.3dBm Output Power
MAX2251 Small Size Ultra-chip Scale Package
(2.06mm x 2.06mm),
Integrated Power Detector,
Low-power Shutdown Mode
Gain: 28dB
PAE: 41% at +30dBm for TDMA
PAE: 51% at +32.4dBm for AMPS
Bluetooth
HomeRF
2.4GHz DECT
MAX2240 Small Size Ultra-chip Scale Package
(1.56mm x 1.56mm),
2-bit Digital Power Control
+20dBm, Efficiency =30%
MAX2244 Closed-loop Analog Power Control,
Small Size Ultra-chip Scale Package
(1.56mm x 1.56mm)
+22dBm, Efficiency = 34.2%
Power control range 0.5V to 2V
MAX2245 Closed-loop Analog Power Control,
Small Size Ultra-chip Scale Package
(1.56mm x 1.56mm)
+22dBm, Efficiency = 29.2%
Power control range 0.9V to 2V
MAX2246 Closed-loop Analog Power Control,
Small Size Ultra-chip Scale Package
(1.56mm x 1.56mm)
+20dBm, Efficiency = 27.8%
Power control range 0.5V to 2V
Cellular TDMA/AMPS
Dual Mode
MAX2251 Small Size Ultra-chip Scale Package
(2.06mm x 2.06mm),
Integrated Power Detector,
Low-power Shutdown Mode
Gain: 28dB
PAE: 41% at +30dBm for TDMA
PAE: 51% at +32.4dBm for AMPS
802.11b WLAN MAX2242 Integrated Power Detector,
Dynamic Bias Control,
Output Power Tunable from +10dBm to +22dBm
+22.5dBm Output Power at -33dBc ACPR for 802.11B
28.5dB Power Gain
802.11b/g MAX2247 High linear output power, On-chip
power detector, External DAC
controllable Bias, On-chip input
matching
+25dBm Output Power for 802.11b,
+17dBm output power at 3.0% EVM
for 802.11g, 29dB Power Gain
802.11a MAX2840 High linear output power, On-chip
power detector, Simple Matching
External DAC controllable Bias
+15dBm Output Power at 3.9% EVN for
802.11a, 22dBm power gain
MAX2841 High linear output power, On-chip
power detector, Simple Matching
External DAC controllable Bias,
+18dBm Output Power at 3.5% EVN for
802.11a, 22dBm power gain

16-pin PQSOP Package Outline
16/20-pin TSSOP-EP Package Outline
16-pin SO/QSOP Package Outline
8-pin PSOPII Package Outline
9-pin UCSP Package Outline
12-pin UCSP Package Outline
25-pin UCSP Package Outline