MAX2022ETX+ Maxim Integrated Products, MAX2022ETX+ Datasheet - Page 11

• Manufacturer Part Number: MAX2022ETX+
• Description: Modulator / Demodulator IC MOD 1500MHZ TO 2500MHZ
• Manufacturer: Maxim Integrated Products

Specifications of MAX2022ETX+

• Maximum Operating Temperature: + 85 C
• Maximum Power Dissipation: 1460 mW
• Minimum Operating Temperature: - 40 C
• Modulation Type: Quadrature
• Mounting Style: SMD/SMT
• Operating Supply Voltage: 4.75 V to 5.25 V
• Supply Current: 292 mA
• Package / Case: QFN-36
• Output Power: - 24 dBm
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

resistor to ground, and a 10mA nominal DC output cur-
rent results in a 0.5V common-mode DC level into the
modulator I/Q inputs. The nominal signal level provided
by the DACs will be in the -12dBm range for a single
CDMA or WCDMA carrier, reducing to -18dBm per car-
rier for a four-carrier application.
The I/Q input bandwidth is greater than 50MHz at
-0.1dB response. The direct connection of the DAC to
the MAX2022 insures the maximum signal fidelity, with
no performance-limiting baseband amplifiers required.
The DAC output can be passed through a lowpass filter
to remove the image frequencies from the DAC’s output
response. The MAX5895 dual interpolating DAC can be
operated at interpolation rates up to x8. This has the
benefit of moving the DAC image frequencies to a very
high, remote frequency, easing the design of the base-
band filters. The DAC’s output noise floor and interpola-
tion filter stopband attenuation are sufficiently good to
insure that the 3GPP noise floor requirement is met for
large frequency offsets, 60MHz for example, with no fil-
tering required on the RF output of the modulator.
Figure 1 illustrates the ease and efficiency of interfac-
ing the MAX2022 with a Maxim DAC, in this case the
MAX5895 dual 16-bit interpolating-modulating DAC.
The MAX5895 DAC has programmable gain and differ-
ential offset controls built in. These can be used to opti-
mize the LO leakage and sideband suppression of the
MAX2022 quadrature modulator.
The MAX2022 utilizes an internal passive mixer archi-
tecture. This enables a very low noise floor of
-173.2dBm/Hz for low-level signals, below about
Figure 2. Complete Transmitter Lineup for a Multicarrier WCDMA in the UMTS Band
1500MHz to 2500MHz Quadrature Modulator
High-Dynamic-Range, Direct Upconversion
______________________________________________________________________________________
Q
I
OFFSET ADJUST
I/Q GAIN AND
MAX5895
CLOCK
Q
RF Output
I
L-C FILTER
RF-MODULATOR
MAX2022
SYNTH
-20dBm output power level. For higher output level sig-
nals, the noise floor will be determined by the internal
LO noise level at approximately -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 voltages to the internal 50Ω termination. For simple
sinusoidal baseband signals, a level of 89mV
ential on the I 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 -27dBm RF output power.
The MAX2022 quadrature modulator makes an ideal
signal source for the generation of multiple WCDMA
carriers. The combination of high OIP3 and exception-
ally low output noise floor gives an unprecedented out-
put 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 requirements with no additional RF
filtering. This promotes an extremely simple and effi-
cient transmitter lineup. Figure 2 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 pro-
grammed to operate in x8 or x4 interpolation mode,
resulting in a 491.52Msps output sample rate. The
DAC will generate four carriers of WCDMA modulation
∑
+12dB
Generation of WCDMA Carriers
MAX2057
OUTPUT
TX
P-P
differ-
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