max5893egk-d Maxim Integrated Products, Inc., max5893egk-d Datasheet - Page 27

• Manufacturer Part Number: max5893egk-d
• Description: Max5893 12-bit, 500msps Interpolating And Modulating Dual Dac With Cmos Inputs
• Manufacturer: Maxim Integrated Products, Inc.

amplitudes. It is recommended to connect the trans-
former center tap to ground.
If a transformer is not used, the outputs must have a
resistive termination to ground. Figure 17 shows the
MAX5893 output configured for differential DC-coupled
mode. The DC-coupled configuration can be used to
eliminate waveform distortion due to highpass filter
effects. Applications include communication systems
employing analog quadrature upconverters and requir-
ing a high-speed DAC for baseband I/Q synthesis.
If a single-ended DC-coupled unipolar output is desir-
able, OUTIP (OUTQP) should be selected as the out-
put, and connect OUTIN (OUTQN) to ground. Using the
MAX5893 output single-ended is not recommended
because it introduces additional noise and distortion.
The distortion performance of the DAC also depends
on the load impedance. The MAX5893 is optimized for
a 50Ω double termination. It can be used with a trans-
former output as shown in Figure 16 or just one 25Ω
resistor from each output to ground and one 50Ω resis-
tor between the outputs (Figure 17). Higher output ter-
mination resistors may be used, as long as each output
voltage does not exceed +1V with respect to GND, but
at the cost of degraded distortion performance and
increased output noise voltage.
The MAX5893 supports operation with the on-chip 1.2V
bandgap reference or an external reference voltage
source. REFIO serves as the input for an external, low-
impedance reference source, and as the output if the
DAC is operating with the internal reference.
12-Bit, 500Msps Interpolating and Modulating
______________________________________________________________________________________
Reference Input/Output
Dual DAC with CMOS Inputs
Figure 17. The DC-Coupled Differential Output Configuration
12
12
MAX5893
QDAC
IDAC
OUTQN
OUTQP
OUTIN
OUTIP
25Ω
50Ω
25Ω
25Ω
50Ω
25Ω
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