更多信息 - 无线主页 - 应用笔记和技术讲座 - 评估板软件 - 技术支持   Abstract: This reference design is a complete RF front-end solution designed to meet the WLAN IEEE® 802.11b/g standard. Using the MAX2830 RF transceiver, the design is capable of accommodating full range of 802.11g OFDM data rates (6, 9, 12, 18, 24, 36, 48, and 54Mbps) and 802.11b QPSK data rates (1, 2, 5.5, and 11Mbps). This solution offers high performance, small size, and low BOM cost. Figure 1. The WLAN reference design features the MAX2830 RF transceiver. Important Design Features High-Performance Rx NF < 6dB (typ); Tx Output 15dBm (typ) Small Size: 17mm x 24.7mm Platform Design for Multiple Form-Factors such as Card Bus and Compact Flash Figure 2. Block diagram of the WLAN reference design. Lab Measurements Power Consumption Summary Operating conditions: VCC = 2.85V; VBAT = 3.3V; fRF = 2.437GHz; RXTX and active-low SHDN set according to operating mode; active-low CS = high; SCLK = DIN = low; transmitter and receiver in maximum gain. There were no input signals at RF inputs. Baseband outputs are open. 100mVRMS differential, 54Mbps IEEE 802.11g OFDM signals were applied to I and Q baseband inputs of transmitter in transmit mode. Parameter Test Conditions Meas. Unit Supply Current Shutdown   µA Standby; PLL + VCO + LO generator 28 mA Rx active 58 mA Tx active (most linear mode) at 3.3V for PA VCC, POUT = 15.7dBm 295 mA Receive Summary Operating conditions: VCC = 2.85V; TA = +25°C; fRF = 2.437GHz; fBB = 4MHz; Rx VOUT = 112mVRMS; fREF = 40MHz; active-low SHDN = high; RXTX = low; active-low CS = high; SCLK = DIN = low. Parameter Test Condition Meas. Unit Frequency Range   2.4 to 2.5 GHz Total Voltage Gain   94 dB RF Gain Steps Relative max gain (B7:B6 = 11) B7:B6 = 10 -16 dB B7:B6 = 0X -33 BB Gain Range Ratio of max to min gain 61 dB DSB NF LNA input referred, based on 10kHz to 8.6MHz integrated noise at I/Q baseband output. 1. B7:B6 = 11, voltage gain = 90dB 6.0 dB 2. B7:B6 = 11, voltage gain = 62dB 6.4 3. B7:B6 = 11, voltage gain = 48dB 7.0 I/Q Phase Error near DC Max gain < ±1 deg IQ Gain Imbalance Max gain < 0.1 dB Rx Sensitivity EVM < 9% Measured at J1 -73.6 dBm Measured at J2 -72.6 EVM PIN = -65dBm 4.2 % PIN = -40dBm 2.2 PIN = -10dBm 3.0 Transmit Summary Operating conditions: VCC = 2.85V; VBAT = 3.3V; TA = +25°C; fRF = 2.437GHz; fREF = 40MHz; active-low SHDN = high; RXTX = high; active-low CS = high; SCLK = DIN = low; 100mVRMS, 54Mbps 802.11g OFDM signal applied to I and Q baseband inputs of transmitter. Parameter Test Condition Meas. Unit Frequency Range   2.4 to 2.5 GHz Transmit Power For EVM = 5.6%; meets the ACPR spec 15.7 dBm/16MHz Transmit EVM POUT = +15.7dBm 5.4%   Adjacent Channel Power Ratio (for 54Mbps OFDM Signal) At 11MHz offset over 100kHz RBW See Figure 3 dBc At 20MHz offset over 100kHz RBW At 30MHz offset over 100kHz RBW Operating Characteristics Figure 3. ACPR performance at Tx power = 15.7dBm, EVM < 5.6%. Figure 4. Rx I/Q constellation diagram at RF input = -40dBm, 54Mbps 64QAM, EVM = 2.2%. Figure 5. Rx I/Q constellation diagram at PIN = -65dBm, 54Mbps 64QAM. The EVM is only 4.2%, which is better than the 9% requirement for sensitivity. Detailed Description This reference design is suitable for the full range of 802.11g OFDM data rates (6, 9, 12, 18, 24, 36, 48, and 54Mbps) and 802.11b QPSK data rates (1, 2, 5.5, and 11Mbps) at corresponding sensitivity levels. Using the MAX2830 chipset eliminates the need for external SAW filters, a RF switch, and a PA. Only a RF filter, RF balun, and a small number of passive components are required to form a complete 11b/g WLAN RF front-end solution that delivers high performance in a small PCB form-factor. IEEE is a registered service mark of the Institute of Electrical and Electronics Engineers. 我们期待您的反馈！ 喜欢？不喜欢？有待改善？或为我们提供建议？请与我们联系 — 我们将根据您的意见或建议改善我们的工作。 网页评价或提供建议 自动更新 需要自动接收最新发布的应用笔记吗？请订阅EE-Mail™ (English only)。 更多信息   APP 4276: Sep 18, 2008 MAX2830 2.4GHz至2.5GHz 802.11g/b RF收发器，提供PA和Rx/Tx/模式开关 免费样品   下载，PDF格式 (136kB)  AN4276, AN 4276, APP4276, Appnote4276, Appnote 4276