- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄17065 > AD9788-DPG2-EBZ (Analog Devices Inc)BOARD EVALUATION FOR AD9788 PDF資料下載
參數(shù)資料
| 型號： | AD9788-DPG2-EBZ |
| 廠商： | Analog Devices Inc |
| 文件頁數(shù)： | 46/64頁 |
| 文件大?。?/td> | 0K |
| 描述： | BOARD EVALUATION FOR AD9788 |
| 設(shè)計資源： | Powering the AD9788 Using ADP2105 for Increased Efficiency (CN0141) |
| 標(biāo)準(zhǔn)包裝： | 1 |
| 系列： | * |
| DAC 的數(shù)量： | 2 |
| 位數(shù)： | 16 |
| 采樣率（每秒）： | 800M |
| 數(shù)據(jù)接口： | 串行 |
| 設(shè)置時間： | 22ms |
| DAC 型： | 電流 |
| 工作溫度： | -40°C ~ 85°C |
| 已供物品： | * |
| 已用 IC / 零件： | AD9788 |
第1頁第2頁第3頁第4頁第5頁第6頁第7頁第8頁第9頁第10頁第11頁第12頁第13頁第14頁第15頁第16頁第17頁第18頁第19頁第20頁第21頁第22頁第23頁第24頁第25頁第26頁第27頁第28頁第29頁第30頁第31頁第32頁第33頁第34頁第35頁第36頁第37頁第38頁第39頁第40頁第41頁第42頁第43頁第44頁第45頁當(dāng)前第46頁第47頁第48頁第49頁第50頁第51頁第52頁第53頁第54頁第55頁第56頁第57頁第58頁第59頁第60頁第61頁第62頁第63頁第64頁
AD9785/AD9787/AD9788
Rev. A | Page 50 of 64
ANALOG OUTPUTS
Full-scale current on the I DAC and Q DAC can be set from
8.66 mA to 31.66 mA. Initially, the 1.2 V band gap reference is
used to set up a current in an external resistor connected to
I120 (Pin 75). A simplified block diagram of the reference
circuitry is shown in Figure 69.
I DAC
DAC FULL-SCALE
REFERENCE
CURRENT
SCALING
I DAC GAIN
Q DAC GAIN
Q DAC
AD9788
VREF
10k
5k
1.2V BAND GAP
REFERENCE
0.1F
I120
070
98
-03
0
Figure 69. Full-Scale Current Generation Circuitry
The recommended value for the external resistor is 10 kΩ,
which sets up an IREFERENCE in the resistor of 120 μA, which in
turn provides a DAC output full-scale current of 20 mA. Because
the gain error is a linear function of this resistor, a high precision
resistor improves gain matching to the internal matching
specification of the devices. Internal current mirrors provide
a current-gain scaling, where DAC gain is a 10-bit word in the
SPI port register (Register 0x05 and Register 0x07). The default
value for the DAC gain registers gives an IFS of approximately
20 mA, where IFS for either I DAC or Q DAC is equal to
32
1024
6
12
27
V
2
1
DAC gain
R
.
35
0
1000
DAC GAIN CODE
I FS
(m
A
)
30
25
20
15
10
5
200
400
600
800
07
09
8-
03
1
Figure 70. DAC Full-Scale Current vs. DAC Gain Code
DIGITAL AMPLITUDE SCALING
Gain scaling of the analog DAC output can be achieved by
changing the values in Register 0x05 and Register 0x07.
However, if this is done, the output common-mode voltage at
the analog output also decreases proportionally. This poses a
problem when the AD9785/AD9787/AD9788 are dc-coupled to
a quadrature modulator. Typical quadrature modulators have
tight restrictions on input common-mode variation.
The AD9785/AD9787/AD9788 use a digital gain scaling block
to get around this problem. Because the gain scaling is done in
the digital processing of the AD9785/AD9787/AD9788, there is
no effect on the output full-scale current. This digital gain
scaling is done in such a way that the midscale value of the
signal is unaffected; the swing of the signal around midscale is
the value that is adjusted with the register settings. Digital gain
scaling is done using the amplitude scale factor (ASF) register
(Register 0x0C).
Auxiliary DAC Operation
Two auxiliary DACs are provided on the AD9785/AD9787/
AD9788. The full-scale output current on these DACs is derived
from the 1.2 V band gap reference and external resistor. The
gain scale from the reference amplifier current, IREFERENCE, to the
auxiliary DAC reference current is 16.67 with the auxiliary DAC
gain set to full scale (10-bit values, Register 0x06, Bits [9:0] and
Register 0x08, Bits [9:0]). This gives a full-scale current of approx-
imately 2 mA for Auxiliary DAC 1 and Auxiliary DAC 2.
The auxiliary DAC outputs are not differential. Only one side of
the auxiliary DAC (P or N) is active at one time. The inactive side
goes into a high impedance state (100 kΩ). In addition, the P or N
output can act as a current source or a current sink. Control of
the P and N sides for both auxiliary DACs is via Register 0x06 and
Register 0x08, Bits [15:14]. When sourcing current, the output
compliance voltage is 0 V to 1.6 V. When sinking current, the
output compliance voltage is 0.8 V to 1.6 V.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| SLPX223M025E7P3 | CAP ALUM 22000UF 25V 20% SNAP |
| EMA10DTKS | CONN EDGECARD 20POS DIP .125 SLD |
| EVAL-AD5392EBZ | BOARD EVAL FOR AD5392 |
| 380LX682M025H022 | CAP ALUM 6800UF 25V 20% SNAP |
| DC941A | BOARD DELTA SIGMA ADC LTC2482 |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| AD9788-EBZ | 制造商:Analog Devices 功能描述:Evaluation Board For AD9788 制造商:Analog Devices 功能描述:DUAL 16B, D-A CONVERTER - Bulk 制造商:Analog Devices 功能描述:Digital to Analog Eval. Board |
| AD9788MOD-EBZ | 制造商:Analog Devices 功能描述:DUAL 12-/14-/16-BIT 800 MSPS DAC WITH LOW POWER 32-BIT COMPLEX NCO 制造商:Analog Devices 功能描述:DUAL 16B, D-A CONVERTER - Bulk |
| AD9789BBC | 功能描述:數(shù)模轉(zhuǎn)換器- DAC 14 Bit 2.5 GSPS D-A Converter RoHS:否 制造商:Texas Instruments 轉(zhuǎn)換器數(shù)量:1 DAC 輸出端數(shù)量:1 轉(zhuǎn)換速率:2 MSPs 分辨率:16 bit 接口類型:QSPI, SPI, Serial (3-Wire, Microwire) 穩(wěn)定時間:1 us 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOIC-14 封裝:Tube |
| AD9789BBCRL | 制造商:Analog Devices 功能描述:QAM Encoder/Interpolator/Upconverter 164-Pin CSP-BGA T/R 制造商:Analog Devices 功能描述:QAM ENCODER/INTERPOLATOR/UPCNVRTR 164CSPBGA - Tape and Reel 制造商:Analog Devices 功能描述:IC DAC 14BIT 2.4GSPS 4CH 164BGA 制造商:Analog Devices Inc. 功能描述:Digital to Analog Converters - DAC 14 Bit 2.5 GSPS D-A Converter 制造商:Analog Devices Inc. 功能描述:Digital to Analog Converters - DAC 14B 2400MSPS RF w/ 4CH Signal Process 制造商:Analog Devices 功能描述:CONVERTER - DAC |
| AD9789BBCZ | 功能描述:數(shù)模轉(zhuǎn)換器- DAC 14 Bit 2.5 GSPS D-A Converter RoHS:否 制造商:Texas Instruments 轉(zhuǎn)換器數(shù)量:1 DAC 輸出端數(shù)量:1 轉(zhuǎn)換速率:2 MSPs 分辨率:16 bit 接口類型:QSPI, SPI, Serial (3-Wire, Microwire) 穩(wěn)定時間:1 us 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOIC-14 封裝:Tube |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。