
MAX5856A
Dual 8-Bit, 300Msps DAC with 4x/2x/1x
Interpolation Filters and PLL
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15
FS ANALOG OUT
SPECIFIED OVER
ENTIRE SUPPLY RANGE
+2.7V TO +3.3V
CLOCK SOURCE
FDAC = 286.4MHz
SINGLE SUPPLY
+2.7V TO +3.3V
CHA
DAC
CHB
DAC
DIV-4
DIV-2
DIV-1
INTERPOLATING
FILTERS 4X/2X
INTERPOLATING
FILTERS 4X/2X
DATA LATCH
8-BIT BUS
DATA LATCH
8-BIT BUS
DIGITAL BASEBAND
OFDM PROCESSOR
QAM-MAPPER
INTERLEAVE
DATA LATCH
8
BOUT
AOUT
SINGLE 8-BIT BUS
SAVES I/O PINS
DATA CLOCK OUT
fDATA = 71.6MHz
MAX5856A
Figure 2. Typical Application Circuit
OPTION
SOLUTION
ADVANTAGE
DISADVANTAGE
1
No interpolation
2.6x oversample
fDAC = fDATA = 78MHz
Low data rate
Low clock rate
High-order filter
Filter gain/phase match
2
No interpolation
8x oversample
fDAC = fDATA = 240MHz
Push image to fIMAGE = 210MHz
Lower order filter
Filter gain/phase match
High clock rate
High data rate
3
4x interpolation
fDAC = 286.4MHz, fDATA = 71.6MHz
Passband attenuation = 0.1dB
Push image to 256MHz
Low data rate
Low-order filter
60dB image attenuate
Filter gain/phase match
None
Table 4. Benefits of Interpolation