MAX2022ETX+TD Maxim Integrated, MAX2022ETX+TD Datasheet - Page 14

• Manufacturer Part Number: MAX2022ETX+TD
• Description: Modulator / Demodulator 1.5-2.5GHz Quadratr Modulator
• Manufacturer: Maxim Integrated

Specifications of MAX2022ETX+TD

• Rohs: yes

Figure 2. Complete Transmitter Lineup for a Multicarrier WCDMA in the UMTS Band
MAX2022
RF Output
The MAX2022 utilizes an internal passive mixer architec-
ture. This enables a very low noise floor of -173.2dBm/Hz
for low-level signals, below about -20dBm output power
level. For higher output level signals, the noise floor will
be determined by the internal LO noise level at approxi-
mately -162dBc/Hz.
The I/Q input power levels and the insertion loss of the
device will determine the RF output power level. The input
power is the function of the delivered input I and Q voltag-
es to the internal 50Ω termination. For simple sinusoidal
baseband signals, a level of 89mV
and the Q inputs results in an input power level of -17dBm
delivered to the I and Q internal 50Ω terminations. This
results in a -23.5dBm RF output power.
Generation of WCDMA Carriers
The MAX2022 quadrature modulator makes an ideal sig-
nal source for the generation of multiple WCDMA carriers.
The combination of high OIP3 and exceptionally low out-
put noise floor gives an unprecedented output dynamic
range. The output dynamic range allows the generation of
four WCDMA carriers in the UMTS band with a noise floor
sufficiently low to meet the 3GPP specification require-
ments with no additional RF filtering. This promotes an
extremely simple and efficient transmitter lineup.
www.maximintegrated.com
Q
I
OFFSET ADJUST
I/Q GAIN AND
MAX5895
CLOCK
P-P
differential on the I
Q
I
L-C FILTER
Figure 2
RF-MODULATOR
MAX2022
SYNTH
Downconversion 1500MHz to 3000MHz
illustrates a complete transmitter lineup for a multicarrier
WCDMA transmitter in the UMTS band.
The MAX5895 dual interpolating-modulating DAC is
operated as a baseband signal generator. For genera-
tion of four carriers of WCDMA modulation, and digital
predistortion, an input data rate of 61.44 or 122.88Mbps
can be used. The DAC can then be programmed to
operate in x8 or x4 interpolation mode, resulting in a
491.52Msps output sample rate. The DAC will gener-
ate four carriers of WCDMA modulation with an ACLR
typically greater than 77dB under these conditions. The
output power will be approximately -18dBm per carrier,
with a noise floor typically less than -144dBc/Hz.
The MAX5895 DAC has built-in gain and offset fine
adjustments. These are programmable by a 3-wire serial
logic interface. The gain adjustment can be used to adjust
the relative gains of the I and Q DAC outputs. This feature
can be used to improve the native sideband suppression
of the MAX2022 quadrature modulator. The gain adjust-
ment resolution of 0.01dB allows sideband nulling down
to approximately -60dB. The offset adjustment can simi-
larly be used to adjust the offset DC output of each I and
Q DAC. These offsets can then be used to improve the
native LO leakage of the MAX2022. The DAC resolution
of 4 LSBs will yield nulled LO leakage of typically less
than -50dBc relative to four-carrier output levels.
∑
Quadrature Modulator/Demodulator
+12dB
High-Dynamic-Range, Direct Up/
MAX2057
OUTPUT
TX
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