MAX2829ETN+T Maxim Integrated Products, MAX2829ETN+T Datasheet - Page 29

• Manufacturer Part Number: MAX2829ETN+T
• Description: RF Transceiver Dual-Band 802.11a-b- -g Transceivers WLAN
• Manufacturer: Maxim Integrated Products

Specifications of MAX2829ETN+T

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Shutdown mode is achieved by driving SHDN low. In
shutdown mode, all circuit blocks are powered down,
except for the serial interface. While the device is in
shutdown, the values of the serial interface registers
are maintained and can be changed as long as V
(pin 25) is applied.
By driving RXENA and TXENA high while setting SHDN
low, all circuit blocks are powered down, as in shut-
down mode. However, in SPI reset mode, all registers
are returned to their default states. It is recommended
to reset the SPI and all registers at the start of power-up
to ensure that the registers are set to the correct values
(see Table 9).
To place the device in standby mode, set SHDN high
and RXENA and TXENA low. This mode is mainly used
to enable the frequency synthesizer block while the rest
of the device is powered down. In this mode, various
blocks in the system can be selectively turned on or off
according to the standby register table (Table 10).
To place the device in Rx mode, set RXENA high. All
receiver blocks are enabled in this mode.
To place the device in Tx mode, set TXENA high. All
transmitter blocks are enabled in this mode.
The MAX2828/MAX2829 feature Tx/Rx calibration
modes to detect I/Q imbalances and transmit LO leak-
age. In the Tx calibration mode, the LO leakage cali-
bration is done only for the LO leakage signal that is
present at the center frequency of the channel (i.e., in
the middle of the OFDM or QPSK spectrum). The LO
leakage calibration includes the effect of all DC offsets
in the entire baseband paths of the I/Q modulator, and
also includes direct leakage of the LO to the I/Q modu-
lator output.
The transmitter LO leakage and sideband-detector out-
put is taken at the receiver I- or Q-channel output dur-
ing this calibration phase.
______________________________________________________________________________________
Tx/Rx Calibration Mode
Transmit (Tx) Mode
Receive (Rx) Mode
Shutdown Mode
Standby Mode
Single-/Dual-Band 802.11a/b/g
SPI Reset
World-Band Transceiver ICs
CC
During Tx LO leakage and I/Q imbalance calibration, a
sine and cosine signal (f = f
band I/Q Tx pins from the baseband IC. At the LO leak-
age and sideband-detector output, the LO leakage
corresponds to the signal at f
suppression corresponds to the signal at 2 x f
The output power of these signals vary 2dB for 1dB of
variation in the LO leakage and unwanted sideband
levels. To calibrate the Tx path, first set the power-
detector gain to 8dB (Table 14). Adjust the DC offset of
the baseband inputs to minimize the signal at f
(LO leakage). Then, adjust the baseband input relative
magnitude and phase offsets to reduce the signal at 2
x f
LO leakage and sideband-detector gain settings to
decrease LO leakage and increase image suppression.
After calibrating the transmitter, receiver calibration can
be done. In Rx calibration mode, the calibrated Tx RF
signal is internally routed to the Rx downconverter
inputs. In this loopback calibration mode, the voltage
regulator must be able to source 350mA total since
both Tx and Rx are turned on simultaneously.
In the 5GHz mode, the RF frequency synthesizer cov-
ers a 4.9GHz to 5.9GHz range. To achieve this large
tuning range while maintaining excellent noise perfor-
mance, the 1GHz band is divided into sub-bands within
which the VCO is tuned. The selection of the appropri-
ate VCO sub-band is done automatically by a finite
state machine (FSM). The PLL settling time is approxi-
mately 300µs for a change of 1GHz in the channel fre-
quency. A faster PLL settling can be achieved by
overriding the FSM and manually programming the
VCO sub-band.
By enabling this band-selection mode, only 1 bit needs
to be programmed to start the frequency acquisition.
The FSM will automatically stop after it selects the cor-
rect VCO sub-band, and after the PLL has locked.
TONE
. If required, calibration can be done with higher
Automatic VCO Sub-Band Selection
RF Synthesizer Programming
TONE
TONE
) is input to the base-
and the sideband
in 5GHz Mode
TONE
TONE
29
.