參數資料
| 型號： | AD9772AASTZ |
| 廠商： | Analog Devices Inc |
| 文件頁數： | 24/40頁 |
| 文件大?。?/td> | 0K |
| 描述： | IC DAC 14BIT 160MSPS 48-LQFP |
| 產品培訓模塊： | DAC Architectures |
| 標準包裝： | 1 |
| 系列： | TxDAC+® |
| 設置時間： | 11ns |
| 位數： | 14 |
| 數據接口： | 并聯 |
| 轉換器數目： | 1 |
| 電壓電源： | 模擬和數字 |
| 功率耗散（最大）： | 272mW |
| 工作溫度： | -40°C ~ 85°C |
| 安裝類型： | 表面貼裝 |
| 封裝/外殼： | 48-LQFP |
| 供應商設備封裝： | 48-LQFP（7x7） |
| 包裝： | 托盤 |
| 輸出數目和類型： | 2 電流，單極；2 電流，雙極 |
| 采樣率（每秒）： | 160M |
| 產品目錄頁面： | 785 (CN2011-ZH PDF) |
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AD9772A
Rev. C | Page 30 of 40
BASEBAND SINGLE-CARRIER APPLICATIONS
The AD9772A is also well suited for wideband single-carrier
applications, such as WCDMA and multilevel quadrature
amplitude modulation (QAM), whose modulation scheme
requires wide dynamic range from the reconstruction DAC to
achieve the out-of-band spectral mask as well as the in-band
CNR performance. Many of these applications strategically
place the carrier frequency at one quarter of the DAC’s input
data rate (that is, fDATA/4) to simplify the digital modulator
design. Because this constitutes the first fixed IF frequency, the
frequency tuning is accomplished at a later IF stage. To enhance
the modulation accuracy and reduce the shape factor of the
second IF SAW filter, many applications specify that the pass
band of the IF SAW filter be greater than the channel
bandwidth; however, the trade-off is that this requires that the
TxDAC meet the spectral mask requirements of the application
within the extended pass band of the second IF, which may
include two or more adjacent channels.
Figure 56 shows a spectral plot of the AD9772A reconstructing a
test vector similar to those encountered in WCDMA applications.
However, WCDMA applications prescribe a root raised cosine
filter with an alpha = 0.22, which limits the theoretical ACPR of
the TxDAC to about 70 dB, whereas the test vector represents
white noise that has been band-limited by a brick wall band-
pass filter with a pass band for which the maximum ACPR
performance is theoretically 83 dB and the peak-to-rms ratio
is 12.4 dB. As Figure 56 reveals, the AD9772A is capable of
approximately 78 dB ACPR performance when one accounts for
the additive noise/distortion contributed by the Rohde & Schwarz
FSEA30 spectrum analyzer.
–30
CENTER 16.25MHz
SPAN 6MHz
600kHz
A
M
P
L
IT
UD
E
(
d
Bm
)
–40
–50
–60
–70
–80
–90
–100
–110
–120
–130
C11
C0
Cu1
022
53
-0
56
Figure 56. AD9772A Achieves 78 dB ACPR Performance Reconstructing a
WCDMA-Like Test Vector with fDATA = 65.536 MSPS and PLLVDD = 0
DIRECT IF
As discussed in the Digital Modes of Operation section, the
AD9772A can be configured to transform digital data representing
baseband signals into IF signals appearing at odd multiples of
the input data rate (that is, N × fDATA, where N = 1, 3, and so on).
This is accomplished by configuring the MOD1 and MOD0 digital
inputs high. Note that the maximum DAC update rate of 400 MSPS
limits the data input rate in this mode to 100 MSPS when the
zero-stuffing operation is enabled (that is, when MOD1 is high).
Applications requiring higher IFs (that is, 140 MHz) using
higher data rates should disable the zero-stuffing operation. In
addition, to minimize the effects of the PLL clock multipliers
phase noise as shown in Figure 31, an external low jitter/phase
noise clock source equal to 4 × fDATA is recommended.
Figure 57 shows the actual output spectrum of the AD9772A
reconstructing a 16-QAM test vector with a symbol rate of
5 MSPS. The particular test vector was centered at fDATA/4 with
fDATA = 100 MSPS and fDAC = 400 MHz. For many applications,
the pair of images appearing around fDATA will be more attractive
because this pair has the flattest pass band and highest signal
power. Higher frequency images can also be used, but such
images will have reduced pass-band flatness, dynamic range,
and signal power, thus reducing the CNR and ACP performance.
Figure 58 shows a dual-tone SFDR amplitude sweep at the various
IF images with fDATA = 100 MSPS, fDAC = 400 MHz, and the two
tones centered around fDATA/4. Note that because an IF filter is
assumed to precede the AD9772A, the SFDR was measured
over a 25 MHz window around the images occurring at 75 MHz,
125 MHz, 275 MHz, and 325 MHz.
FREQUENCY (MHz)
0
AM
P
L
IT
UDE
(
d
Bm)
–30
–50
–70
–90
–100
–80
–60
–40
–20
100
200
300
400
02
25
3-
05
7
Figure 57. Spectral Plot of 16-QAM Signal in Direct IF Mode at
fDATA = 100 MSPS
AOUT (dBFS)
90
85
60
–14
S
F
DR
(
IN
25
M
H
zW
IND
O
W
)(
d
B
F
S
)
80
75
70
65
–12
–10
–8
–6
–2
–4
0
55
50
325MHz
275MHz
75MHz
125MHz
022
53
-05
8
Figure 58. Dual-Tone Windowed SFDR vs. AOUT @ fDATA = 100 MSPS
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相關代理商/技術參數 |
參數描述 |
|---|---|
| AD9772AASTZRL | 功能描述:IC DAC 14BIT 160MSPS 48LQFP RoHS:是 類別:集成電路 (IC) >> 數據采集 - 數模轉換器 系列:TxDAC+® 產品培訓模塊:Data Converter Fundamentals DAC Architectures 標準包裝:750 系列:- 設置時間:7µs 位數:16 數據接口:并聯 轉換器數目:1 電壓電源:雙 ± 功率耗散（最大）:100mW 工作溫度:0°C ~ 70°C 安裝類型:表面貼裝 封裝/外殼:28-LCC（J 形引線） 供應商設備封裝:28-PLCC（11.51x11.51） 包裝:帶卷 (TR) 輸出數目和類型:1 電壓，單極；1 電壓，雙極 采樣率（每秒）:143k |
| AD9772A-EB | 制造商:Analog Devices 功能描述:14 BIT DAC W/2X INTERPOLATION 制造商:Analog Devices 功能描述:DEV TOOLS, EVAL BD FOR AD9772A - Bulk |
| AD9772A-EBZ | 功能描述:BOARD EVAL FOR AD9772A RoHS:是 類別:編程器，開發(fā)系統(tǒng) >> 評估板 - 數模轉換器 (DAC) 系列:TxDAC+® 產品培訓模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標準包裝:1 系列:- DAC 的數量:4 位數:12 采樣率（每秒）:- 數據接口:串行，SPI? 設置時間:3µs DAC 型:電流/電壓 工作溫度:-40°C ~ 85°C 已供物品:板 已用 IC / 零件:MAX5581 |
| AD9772AST | 制造商:Rochester Electronics LLC 功能描述:14 BIT DAC W/2X INTERPOLA - Tape and Reel |
| AD9772EB | 制造商:AD 制造商全稱:Analog Devices 功能描述:14-Bit, 160 MSPS TxDAC+ with 2x Interpolation Filter |
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