max5852etlt Maxim Integrated Products, Inc., max5852etlt Datasheet - Page 15

• Manufacturer Part Number: max5852etlt
• Description: Max5852 Dual, 8-bit, 165msps, Current-output Dac
• Manufacturer: Maxim Integrated Products, Inc.

The MAX5852 exhibits excellent dynamic performance
to synthesize a wide variety of modulation schemes,
including high-order QAM modulation with OFDM.
Figure 7 shows a typical application circuit with output
transformers performing the required differential-to-sin-
gle-ended signal conversion. In this configuration, the
MAX5852 operates in differential mode, which reduces
even-order harmonics, and increases the available out-
put power.
Figure 8 shows the MAX5852 output operating in differ-
ential, DC-coupled mode. This configuration can be
used in communications systems employing analog
quadrature upconverters and requiring a baseband
sampling, dual-channel, high-speed DAC for I/Q synthe-
sis. In these applications, information bandwidth can
Figure 7. Application with Output Transformer (Coilcraft
TTWB3010-1) Performing Differential-to-Single-Ended Conversion
8
8
DA0–DA7
DB0–DB7
Differential-to-Single-Ended Conversion
Differential DC-Coupled Configuration
AGND
AV
DD
DGND
DV
MAX5852
MAX5852
Dual, 8-Bit, 165Msps, Current-Output DAC
Applications Information
DD
1/2
1/2
CGND
______________________________________________________________________________________
CV
DD
OUTPA
OUTNA
OUTPB
OUTNB
50Ω
100Ω
50Ω
50Ω
100Ω
50Ω
SINGLE ENDED
SINGLE ENDED
V
V
OUTA
OUTB
,
,
extend from 10MHz down to several hundred kilohertz.
DC-coupling is desirable to eliminate long discharge
time constants that are problematic with large, expensive
coupling capacitors. Analog quadrature upconverters
have a DC common-mode input requirement of typically
0.7V to 1.0V. The MAX5852 differential I/Q outputs can
maintain the desired full-scale level at the required 0.7V
to 1.0V DC common-mode level when powered from a
single 2.85V (±5%) supply. The MAX5852 meets this
low-power requirement with minimal reduction in dynam-
ic range while eliminating the need for level-shifting
resistor networks.
Grounding and power-supply decoupling strongly influ-
ence the MAX5852 performance. Unwanted digital
crosstalk can couple through the input, reference,
power-supply, and ground connections, which can
affect dynamic specifications, like signal-to-noise ratio
Figure 8. Application with DC-Coupled Differential Outputs
8
8
DA0–DA7
DB0–DB7
AGND
AV
DD
DGND
DV
MAX5852
MAX5852
DD
Power Supplies, Bypassing,
1/2
1/2
CGND
CV
DD
Decoupling, and Layout
50Ω
50Ω
50Ω
50Ω
OUTPA
OUTNA
OUTPB
OUTNB
15