参数资料
| 型号： | AD7249BR |
| 厂商： | Analog Devices Inc |
| 文件页数： | 14/14页 |
| 文件大小： | 0K |
| 描述： | IC DAC 12BIT SRL W/REF 16-SOIC |
| 产品培训模块： | Data Converter Fundamentals DAC Architectures |
| 标准包装： | 1 |
| 系列： | DACPORT® |
| 设置时间： | 10µs |
| 位数： | 12 |
| 数据接口： | 串行 |
| 转换器数目： | 2 |
| 电压电源： | 双 ± |
| 功率耗散（最大）： | 300mW |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 16-SOIC（0.295"，7.50mm 宽） |
| 供应商设备封装： | 16-SOIC W |
| 包装： | 管件 |
| 输出数目和类型： | 2 电压，单极；2 电压，双极 |
| 采样率（每秒）： | 125k |
AD7249
–9–
Bipolar ( 5 V) Configuration
The bipolar configuration for the AD7249, which gives an out-
put range of –5 V to +5 V, is achieved by connecting ROFSA,
ROFSB to VREFIN. The AD7249 must be operated from dual
supplies to achieve this output voltage range. Either offset binary
or twos complement coding may be selected. Figure 10 shows
the connection diagram for bipolar operation. An AD586 pro-
vides the reference voltage for the DAC but this could be pro-
vided by the on-chip reference by connecting REFOUT to
REFIN.
12-BIT
DAC A
12-BIT
DAC B
AD7249*
2R
VDD
REFIN
ROFSA
VOUTA
–5V TO +5V
ROFSB
VOUTB
–5V TO +5V
BIN/COMP
DGND
AGND
VSS
*ADDITIONAL PINS OMITTED FOR CLARITY.
VDD
VOUT
+VIN
AD586
A1
A2
Figure 10. Bipolar Configuration with External Reference
Bipolar Operation (Twos Complement Data Format)
The AD7249 is configured for twos complement data format
by connecting
BIN/COMP (Pin 7) high. The analog output vs.
digital code is shown in Table II.
Table II. Twos Complement Bipolar Code Table
Input Data Word
MSB
LSB
Analog Output, VOUT
XXXY 0111 1111 1111
+REFIN
× (2047/2048)
XXXY 0000 0000 0001
+REFIN
× (1/2048)
XXXY 0000 0000 0000
0 V
XXXY 1111 1111 1111
–REFIN
× (1/2048)
XXXY 1000 0000 0001
–REFIN
× (2047/2048)
XXXY 1000 0000 0000
–REFIN
× (2048/2048) = –REFIN
X = Don’t Care.
Y = DAC Select Bit, 0 = DAC A, 1 = DAC B.
Note: 1 LSB = REFIN/2048.
Bipolar Operation (Offset Binary Data Format)
The AD7249 is configured for Offset Binary data format by
connecting
BIN/COMP (Pin 7) low. The analog output vs.
digital code may be obtained by inverting the MSB in Table II.
APPLYING THE AD7249
Good printed circuit board layout is as important as the overall
circuit design itself in achieving high speed converter perfor-
mance. The AD7249 works on an LSB size of 2.44 mV for the
unipolar 0 V to 10 V range and the bipolar
±5 V range, when
using the unipolar 0 V to 5 V range the LSB size is 1.22 mV.
Therefore the designer must be conscious of minimizing noise in
both the converter itself and in the surrounding circuitry.
Switching mode power supplies are not recommended as switch-
ing spikes can feedthrough to the on-chip amplifier. Other causes of
concern are ground loops and feedthrough from microproces-
sors. These are factors which influence any high performance
converter, and proper printed circuit board layout which mini-
mizes these effects is essential to obtain high performance.
LAYOUT HINTS
Ensure that the layout has the digital and analog tracks sepa-
rated as much as possible. Take care not to run any digital track
alongside an analog signal track. Establish a single point analog
ground separate from the logic system ground. Place this star
ground as close as possible to the AD7249. Connect all analog
grounds to this star point and also connect the AD7249 DGND
pin to this point. Do not connect any other digital grounds to
this analog ground point. Low impedance analog and digital
power supply common returns are essential for low noise opera-
tion of high performance converters. To accomplish this track
widths should be kept a wide as possible and also the use of
ground planes minimizes impedance paths and also guards the
analog circuitry from digital noise.
NOISE
Keep the signal leads on the VOUTA and VOUTB signals and the
signal return leads to AGND as short as possible to minimize
noise coupling. In applications where this is not possible use a
shielded cable between the DAC outputs and their destination.
Reduce the ground circuit impedance as much as possible since
any potential difference in grounds between the DAC and its
destination device appears as an error voltage in series with the
DAC output.
Power Supply Decoupling
To achieve optimum performance when using the AD7249, the
VDD and VSS lines should be decoupled to AGND using 0.1
F
capacitors. In noisy environments it is recommended that 10
F
capacitors be connected in parallel with the 0.1
F capacitors.
REV. D
相关PDF资料 |
PDF描述 |
|---|---|
| AD7262BSTZ | IC ADC 2CH 12BIT PGA/COM 48LQFP |
| AD7264BCPZ | IC ADC 14BIT 2CH 1MSPS 48LFCSP |
| AD7265BSUZ-REEL7 | IC ADC 12BIT 3CHAN 1MSPS 32TQFP |
| AD7266BSUZ | IC ADC 12BIT 3CH 2MSPS 32-TQFP |
| AD7274BRM | IC ADC 12BIT 3MSPS HS LP 8MSOP |
相关代理商/技术参数 |
参数描述 |
|---|---|
| AD7249BR-REEL | 功能描述:IC DAC 12BIT SRL W/REF 16-SOIC RoHS:否 类别:集成电路 (IC) >> 数据采集 - 数模转换器 系列:DACPORT® 产品培训模块:Data Converter Fundamentals DAC Architectures 标准包装:750 系列:- 设置时间:7µs 位数:16 数据接口:并联 转换器数目:1 电压电源:双 ± 功率耗散（最大）:100mW 工作温度:0°C ~ 70°C 安装类型:表面贴装 封装/外壳:28-LCC（J 形引线） 供应商设备封装:28-PLCC（11.51x11.51） 包装:带卷 (TR) 输出数目和类型:1 电压，单极；1 电压，双极 采样率（每秒）:143k |
| AD7249BRZ | 功能描述:IC DAC 12BIT SRL W/REF 16SOIC RoHS:是 类别:集成电路 (IC) >> 数据采集 - 数模转换器 系列:DACPORT® 标准包装:1 系列:- 设置时间:4.5µs 位数:12 数据接口:串行，SPI? 转换器数目:1 电压电源:单电源 功率耗散（最大）:- 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:8-SOIC（0.154"，3.90mm 宽） 供应商设备封装:8-SOICN 包装:剪切带 (CT) 输出数目和类型:1 电压，单极；1 电压，双极 采样率（每秒）:* 其它名称:MCP4921T-E/SNCTMCP4921T-E/SNRCTMCP4921T-E/SNRCT-ND |
| AD7249BRZ-REEL | 功能描述:IC DAC 12BIT SRL W/REF 16SOIC RoHS:是 类别:集成电路 (IC) >> 数据采集 - 数模转换器 系列:DACPORT® 产品培训模块:Data Converter Fundamentals DAC Architectures 标准包装:750 系列:- 设置时间:7µs 位数:16 数据接口:并联 转换器数目:1 电压电源:双 ± 功率耗散（最大）:100mW 工作温度:0°C ~ 70°C 安装类型:表面贴装 封装/外壳:28-LCC（J 形引线） 供应商设备封装:28-PLCC（11.51x11.51） 包装:带卷 (TR) 输出数目和类型:1 电压，单极；1 电压，双极 采样率（每秒）:143k |
| AD7249SQ | 功能描述:数模转换器- DAC LC2MOS DUAL 12-BIT SERIAL IC RoHS:否 制造商:Analog Devices 转换器数量:4 DAC 输出端数量:4 转换速率: 分辨率:12 bit 接口类型:Serial (I2C) 稳定时间: 最大工作温度:+ 105 C 安装风格: 封装 / 箱体:TSSOP 封装:Reel |
| AD7249SQ/883B | 制造商:未知厂家 制造商全称:未知厂家 功能描述:12-Bit Digital-to-Analog Converter |
发布紧急采购，3分钟左右您将得到回复。