Reference Circuit 4156

Reference Design for an 802.11b/g RF Front-End Module Using the MAX2830



Figure 1. The reference design board shows the MAX2830 in an 802.11b/g RF front-end module.

Important Design Features

  • Cascaded Receive Noise Figure of 6dB
  • Low Phase Noise of -95dBc/Hz at 10kHz Offset
  • Rx EVM < 9% at -74.5dBm with an 802.11g 54Mbps OFDM Signal
  • 95dB Receive Gain Control Range (32dB RF and 63dB BB VGA)
  • Tx EVM < 5.6% at 15dBm Output Power with an 802.11g 54Mbps OFDM Signal
  • 25dB Transmit Gain Control Range
  • Supports Full-Range 802.11b/g Data Rates
  • Small 11mm x 16mm Size
  • Low BOM Cost


Figure 2. Block diagram for the 802.11 b/g RF module.

Click here for an overview of the wireless components used in a typical radio transceiver.
Click here for an overview of the wireless components used in a typical radio transceiver.


Figure 1. The reference design board shows the MAX2830 in an 802.11b/g RF front-end module.

Important Design Features

  • Cascaded Receive Noise Figure of 6dB
  • Low Phase Noise of -95dBc/Hz at 10kHz Offset
  • Rx EVM < 9% at -74.5dBm with an 802.11g 54Mbps OFDM Signal
  • 95dB Receive Gain Control Range (32dB RF and 63dB BB VGA)
  • Tx EVM < 5.6% at 15dBm Output Power with an 802.11g 54Mbps OFDM Signal
  • 25dB Transmit Gain Control Range
  • Supports Full-Range 802.11b/g Data Rates
  • Small 11mm x 16mm Size
  • Low BOM Cost


Figure 2. Block diagram for the 802.11 b/g RF module.

Lab Measurements

DC Performance
VBATT = +3.3V, VCC = +2.85V, TA = +25°C

Parameter Test Condition Meas. Unit
Shutdown Supply Current   10 µA
Standby Supply Current PLL, VCO, LO Generator ON 28 mA
Receive Supply Current   65 mA
Transmit Supply Current POUT = 15dBm 289 mA


Receive Summary
VBATT = +3.3V, VCC = +2.85V, fRF = 2437MHz, RF input = 802.11a, 64QAM, 54MBps at antenna, VOUT = 112mVRMS at RXI and RXQ baseband outputs, RXHP = 0, TA = +25°C

Parameter Test Condition Meas. Unit
Frequency Range   2.4 to 2.5 GHz
Receive EVM Max Gain, VGA adjusted for VOUT = 112mVRMS, PIN = -65dBm 3.9 %
Mid Gain, VGA adjusted for VOUT = 112mVRMS, PIN = -45dBm 2.5
Min Gain, VGA adjusted for VOUT = 112mVRMS, PIN = -10dBm 2.7
Sensitivity Receive EVM = 9% Antenna 1 -73 dBm
Antenna 2 -74.5


Transmit Summary
VBATT = +3.3V, VCC = +2.85V, fRF = 2437MHz, baseband inputs = 110mVRMS, 802.11a, 64QAM, 54MBps, Tx output measured at Antenna 1, RXHP = 0, TA = +25°C

Parameter Test Condition Meas. Unit
Maximum Transmit Output Tx VGA adjusted for EVM = 5.6%, Tx VGA = -4dB 15 dBm
ACPR Tx VGA set for EVM < 5.6%, channel BW = 20MHz fOFFSET = 20MHz 36 dBc
fOFFSET = 40MHz 55
fOFFSET = 60MHz 60


Figure 3. Phase noise plot of the reference design.
Figure 3. Phase noise plot of the reference design.

Detailed Description

The MAX2830 is a single-chip, single-band, Dual Mode™ direct-convert transceiver designed for a 2.4GHz 802.11b/g (OFDM and CCK) WLAN application. The device integrates all the circuitry required to implement the complete RF transceiver function: PA, T/R switch, antenna diversity switch, LNA, 50Ω matching components, sigma-delta fractional synthesizer, crystal oscillator, and unique I/Q amplitude and phase-error calibration circuits. The device also eliminates the need for external SAW filters by implementing on-chip monolithic filters for both receiver and transmitter. The baseband Tx and Rx filters are optimized to meet the 802.11g IEEE standard. With an additional RF filter and several passive components, one can form a complete 802.11b/g WLAN RF front-end solution that delivers high performance within a small form factor and low price.

Application Note Links

Application note 3630, "Power Supply and Ground Design for a WiFi Transceiver

Dual Mode is a trademark of Maxim Integrated Products, Inc.
IEEE is a registered service mark of the Institute of Electrical and Electronics Engineers, Inc.


 
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MAX2830
2.4GHz to 2.5GHz 802.11g/b RF Transceiver with PA and Rx/Tx/Diversity Switch

  • 2.4GHz to 2.5GHz ISM Band Operation
  • IEEE 802.11g/b Compatible (54Mbps OFDM and 11Mbps CCK)
  • Complete RF Transceiver, PA, Rx/Tx and Antenna Diversity Switch, and Crystal Oscillator