max5858a Maxim Integrated Products, Inc., max5858a Datasheet - Page 17

• Manufacturer Part Number: max5858a
• Description: Max5858a Dual, 10-bit, 300msps, Dac With 4x/2x/1x Interpolation Filters And Pll
• Manufacturer: Maxim Integrated Products, Inc.

This example demonstrates that 4x interpolation with
digital filtering yields significant benefits in reducing sys-
tem complexity, improving dynamic performance and
lowering cost. Data can be written to the MAX5858A at
much lower speeds while achieving image attenuation
greater than 60dB and image separation beyond three
octaves. The main benefit is in analog reconstruction fil-
Figure 3. MAX5858A in 4x Interpolation Mode
Dual, 10-Bit, 300Msps, DAC with 4x/2x/1x
SOLUTION 1
SOLUTION 2
SOLUTION 3
______________________________________________________________________________________
20MHz ±10MHz
BW = ±10MHz
BW = ±10MHz
20MHz
20MHz
f
f
f
OUT
OUT
OUT
Interpolation Filters and PLL
FREQUENCY AXIS NOT TO SCALE
FREQUENCY AXIS NOT TO SCALE
FREQUENCY AXIS NOT TO SCALE
f
DAC
IMAGE
48MHz
- f
SIMPLE ANALOG FILTER
OUT
ANALOG FILTER
LOWER ORDER
ATTENUATION >60dB
71.6MHz
DIGITAL FILTER
78MHz
ter design. Reducing the filter order eases gain/phase
matching while lowering filter cost and saving board
space. Because the data rate is lowered to 71.6MHz,
the setup and hold times are manageable and the clock
signal source is simplified, which results in improved
system reliability and lower cost.
f
f
DATA
DAC
f
DAC
108MHz
f
IMAGE
DAC
210MHz
IMAGE
NEW FIRST IMAGE SEPARATION > 3 OCTAVES
+ f
- f
OUT
OUT
IMAGE SEPARATION = 180MHz
IMAGE SEPARATION = 18MHz
HIGH ORDER ANALOG FILTER
HIGH-SPEED CLK = 240MHz
240MHz
LESS THAN ONE OCTAVE
f
f
DAC
DAC
256MHz
IMAGE
- f
OUT
f
DAC
270MHz
IMAGE
286MHz
+ f
f
DAC
OUT
f
DAC
316MHz
IMAGE
+ f
OUT
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