参数资料
| 型号： | AD9788BSVZRL |
| 厂商： | Analog Devices Inc |
| 文件页数： | 46/64页 |
| 文件大小： | 0K |
| 描述： | IC DAC 16BIT 800MSPS 100TQFP |
| 产品培训模块： | Data Converter Fundamentals DAC Architectures |
| 设计资源： | Powering the AD9788 Using ADP2105 for Increased Efficiency (CN0141) |
| 标准包装： | 1,000 |
| 系列： | TxDAC® |
| 位数： | 16 |
| 数据接口： | 串行 |
| 转换器数目： | 2 |
| 电压电源： | 模拟和数字 |
| 功率耗散（最大）： | 450mW |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 100-TQFP 裸露焊盘 |
| 供应商设备封装： | 100-TQFP-EP（14x14） |
| 包装： | 带卷 (TR) |
| 输出数目和类型： | 4 电流，单极；4 电流，双极 |
| 采样率（每秒）： | 800M |
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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.
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相关代理商/技术参数 |
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| AD9788-DPG2-EBZ | 功能描述:BOARD EVALUATION FOR AD9788 RoHS:是 类别:编程器，开发系统 >> 评估板 - 数模转换器 (DAC) 系列:* 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:1 系列:- DAC 的数量:4 位数:12 采样率（每秒）:- 数据接口:串行，SPI? 设置时间:3µs DAC 型:电流/电压 工作温度:-40°C ~ 85°C 已供物品:板 已用 IC / 零件:MAX5581 |
| 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:数模转换器- DAC 14 Bit 2.5 GSPS D-A Converter RoHS:否 制造商:Texas Instruments 转换器数量:1 DAC 输出端数量:1 转换速率:2 MSPs 分辨率:16 bit 接口类型:QSPI, SPI, Serial (3-Wire, Microwire) 稳定时间:1 us 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-14 封装: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 |
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