max5883egmtd Maxim Integrated Products, Inc., max5883egmtd Datasheet - Page 12

• Manufacturer Part Number: max5883egmtd
• Description: Max5883 3.3v, 12-bit, 200msps High Dynamic Performance Dac With Cmos Inputs
• Manufacturer: Maxim Integrated Products, Inc.

A dominant specification is ACLR, a parameter which
reflects the ratio of the power in the desired carrier
band to the power in an adjacent carrier band. The
specification covers the first two adjacent bands, and is
measured on both sides of the desired carrier.
According to the transmit mask for CDMA and W-
CDMA architectures, the power ratio of the integrated
carrier channel energy to the integrated adjacent chan-
nel energy must be >45dB for the first adjacent carrier
slot (ACLR 1) and >50dB for the second adjacent carri-
er slot (ACLR 2). This specification applies to the output
of the entire transmitter signal chain. The requirement
for only the DAC block of the transmitter must be
tighter, with a typical margin of >15dB, requiring the
DAC’s ACLR 1 to be better than 60dB.
Adjacent channel leakage is caused by a single spread-
spectrum carrier, which generates intermodulation (IM)
3.3V, 12-Bit, 200Msps High Dynamic
Performance DAC with CMOS Inputs
Figure 6. Differential to Single-Ended Conversion Using a Wideband RF Transformer
Figure 7. MAX5883 Differential Output Configuration
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*Note that due to their own IM effects and noise limitations, spectrum analyzers introduce ACLR errors, which can falsify the measure-
ment. For a single-carrier ACLR measurement greater than 70dB, these measurement limitations are significant, becoming even more
restricting for multicarrier measurement. Before attempting an ACLR measurement, it is recommended consulting application notes pro-
vided by major spectrum analyzer manufacturers that provide useful tips on how to use their instruments for such tests.
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______________________________________________________________________________________
B0–B11
AGND
AV
DD
MAX5883
DV
DGND
DD
12
B0–B11
CLKGND
VCLK
AGND
AV
DD
IOUTN
IOUTP
MAX5883
DGND
DV
DD
50
100
50
CLKGND
VCLK
OUTP
OUTN
IOUTN
IOUTP
50
100
50
products between the frequency components located
within the carrier band. The energy at one end of the
carrier band generates IM products with the energy
from the opposite end of the carrier band. For single-
carrier W-CDMA modulation, these IMD products are
spread 3.84MHz over the adjacent sideband. Four con-
tiguous W-CDMA carriers spread their IM products over
a bandwidth of 20MHz on either side of the 20MHz total
carrier bandwidth. In this four-carrier scenario, only the
energy in the first adjacent 3.84MHz sideband is con-
sidered for ACLR 1. To measure ACLR, drive the con-
verter with a W-CDMA pattern. Make sure that the
signal is backed off by the peak-to-average ratio, such
that the DAC is not clipping the signal. ACLR can then
be measured with the ACLR measurement function built
into your spectrum analyzer.
Figure 8 shows the ACLR performance for a single
W-CDMA carrier (f
applied to the MAX5883 (including measurement system
limitations*).
Figure 9 illustrates the ACLR test results for the
MAX5883 with a four-carrier W-CDMA signal at an out-
put frequency of 30.72MHz and a sampling frequency
of 184.32MHz. Considerable care must be taken to
ensure accurate measurement of this parameter.
Grounding and power-supply decoupling can strongly
influence the performance of the MAX5883. Unwanted
digital crosstalk may couple through the input, refer-
ence, power supply, and ground connections, affecting
dynamic performance. Proper grounding and power-
Grounding, Bypassing, and Power-Supply
T1, 1:1
T2, 1:1
PERFORMS THE DIFFERENTIAL TO
WIDEBAND RF TRANSFORMER T2
SINGLE-ENDED CONVERSION.
CLK
V
OUT
, SINGLE ENDED
= 184.32MHz, f
Considerations
OUT
= 30.72MHz)