AD9789 Analog Devices, AD9789 Datasheet - Page 41

• Manufacturer Part Number: AD9789
• Description: 14-Bit, 2400 MSPS RF DAC with 4-Channel Signal Processing
• Manufacturer: Analog Devices

Specifications of AD9789

• Resolution (bits): 14bit
• Dac Update Rate: 2.4GSPS
• Dac Settling Time: 13ns
• Max Pos Supply (v): +3.47V
• Single-supply: No
• Dac Type: Current Out
• Dac Input Format: LVDS,Par

If the SRRC filter is used, at least four of the 2× interpolation
filters must be enabled. The reason for this is that the SRRC
filter requires a minimum of 12 clock cycles at the f
per sample to function properly.
Half-Band Interpolation Filters
The AD9789 can provide from 1× to 32× interpolation through
the datapath using five bypassable half-band interpolation filters.
The half-band interpolation filters are controlled via Register
0x06[4:0]. The preferred order in terms of power savings for
bypassing these filters is to bypass Filter 0 first, then Filter 1,
and so on. The frequency response of the low-pass filters is
shown in Figure 79 through Figure 82. All of the filters have a
pass band of 0.8 × f
of each filter. The pass band is flat to within 0.01 dB for all
filters. The stop-band attenuation exceeds 85 dB in Filter 0,
Filter 1, and Filter 2, and 75 dB in Filter 3 and Filter 4.
–3.01dB
Figure 78. Conceptual Block Diagram of 2× Half-Band Interpolation Filters
0dB
–100
–10
–20
–30
–40
–50
–60
–70
–80
–90
10
0
–2.0
Figure 79. 2× Half-Band Interpolation Filter 0 Response
(1 –α)
–1.5
<0.4dB
Figure 77. SRRC Filter Characteristics
f
N
INPUT
–1.0
2
, where f
FREQUENCY ×
<0.4dB
f
N
–0.5
INPUT
<–43dB
0
f
INPUT
REGISTER 0x06[4:0]
is the data rate at the input
0.5
(Hz)
BYPASS
0
1
(1 +α)
FREQUENCY
1.0
f
N
1.5
DAC
/16 rate
2.0
Rev. A | Page 41 of 76
Figure 82. 2× Half-Band Interpolation Filter 3 and Filter 4 Response
–100
–100
–100
–10
–20
–30
–40
–50
–60
–70
–80
–90
–10
–20
–30
–40
–50
–60
–70
–80
–90
–10
–20
–30
–40
–50
–60
–70
–80
–90
10
10
10
–2.0
–2.0
0
0
0
Figure 80. 2× Half-Band Interpolation Filter 1 Response
Figure 81. 2× Half-Band Interpolation Filter 2 Response
–1.875
–1.5
–1.5
–1.250
–1.0
–1.0
FREQUENCY ×
FREQUENCY ×
–0.625
FREQUENCY ×
–0.5
–0.5
0
0
0
f
f
f
INPUT
INPUT
INPUT
0.5
0.5
0.625
(Hz)
(Hz)
(Hz)
1.0
1.0
1.250
1.5
1.5
AD9789
1.875
2.0
2.0