参数资料
| 型号： | AD676BD |
| 厂商： | Analog Devices Inc |
| 文件页数： | 3/16页 |
| 文件大小： | 0K |
| 描述： | IC ADC 16BIT SAMPLING 28-CDIP |
| 标准包装： | 1 |
| 位数： | 16 |
| 采样率（每秒）： | 100k |
| 数据接口： | 并联 |
| 转换器数目： | 2 |
| 功率耗散（最大）： | 480mW |
| 电压电源： | 模拟和数字，双 ± |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 通孔 |
| 封装/外壳： | 28-CDIP（0.605"，15.37mm） |
| 供应商设备封装： | 28-CDIP |
| 包装： | 管件 |
| 输入数目和类型： | 1 个单端，双极 |
| 配用： | AD676-EB-ND - BOARD EVAL SAMPLING ADC AD676 |
AD676
REV. A
–11–
Using AGND SENSE to remotely sense the ground potential of
the signal source can be useful if the signal has to be carried
some distance to the A/D converter. Since all IC ground cur-
rents have to return to the power supply and no ground leads
are free from resistance and inductance, there are always some
voltage differences from one ground point in a system to
another.
Over distance this voltage difference can easily amount to sev-
eral LSBs (in a 10 V input span, 16-bit system each LSB is
about 0.15 mV). This would directly corrupt the A/D input sig-
nal if the A/D measures its input with respect to power ground
(AGND) as shown in Figure 5a. To solve this problem the
AD676 offers an AGND SENSE pin. Figure 5b shows how the
AGND SENSE can be used to eliminate the problem in Figure
5a. Figure 5b also shows how the signal wires should be
shielded in a noisy environment to avoid capacitive coupling. If
inductive (magnetic) coupling is expected to be dominant such
as where motors are present, twisted-pair wires should be used
instead.
The digital ground pin is the reference point for all of the digital
signals that operate the AD676. This pin should be connected
to the digital common point in the system. As Figure 4 illus-
trated, the analog and digital grounds should be connected to-
gether at one point in the system, preferably at the AD676.
V
IN
AGND
SOURCE
V
S
GROUND LEAD
IGROUND > 0
TO POWER
SUPPLY GND
AD676
V
Figure 5a. Input to the A/D Is Corrupted by IR Drop in
Ground Leads: VIN = VS + V
V
IN
AGND
SENSE
AGND
SOURCE
VS
SHIELDED CABLE
GROUND LEAD
IGROUND > 0
TO POWER
SUPPLY GND
AD676
Figure 5b. AGND SENSE Eliminates the Problem in
Figure 5a.
VOLTAGE REFERENCE
The AD676 requires the use of an external voltage reference.
The input voltage range is determined by the value of the refer-
ence voltage; in general, a reference voltage of n volts allows an
input range of
±n volts. The AD676 is specified for both 10 V
and 5.0 V references. A 10 V reference will typically require
support circuitry operated from
±15 V supplies; a 5.0 V refer-
ence may be used with
±12 V supplies. Signal-to-noise perfor-
mance is increased proportionately with input signal range. In
the presence of a fixed amount of system noise, increasing the
LSB size (which results from increasing the reference voltage)
will increase the effective S/(N+D) performance. Figure 12
illustrates S/(N+D) as a function of reference voltage. In
contrast, INL will be optimal at lower reference voltage values
(such as 5 V) due to capacitor nonlinearity at higher voltage
values.
During a conversion, the switched capacitor array of the AD676
presents a dynamically changing current load at the voltage ref-
erence as the successive-approximation algorithm cycles through
various choices of capacitor weighting. (See the following sec-
tion “Analog Input” for a detailed discussion of the VREF input
characteristics.) The output impedance of the reference circuitry
must be low so that the output voltage will remain sufficiently
constant as the current drive changes. In some applications, this
may require that the output of the voltage reference be buffered
by an amplifier with low impedance at relatively high frequen-
cies. In choosing a voltage reference, consideration should be
made for selecting one with low noise. A capacitor connected
between REF IN and AGND will reduce the demands on the
reference by decreasing the magnitude of high frequency com-
ponents required to be sourced by the reference.
Figures 6 and 7 represent typical design approaches.
VIN
10
F
AGND
CN
1.0
F
+12V
AD586
AD676
13
16
6
2
4
8
VREF
+
Figure 6.
Figure 6 shows a voltage reference circuit featuring the 5 V out-
put AD586. The AD586 is a low cost reference which utilizes a
buried Zener architecture to provide low noise and drift. Over
the 0
°C to +70°C range, the AD586L grade exhibits less than
2.25 mV output change from its initial value at +25
°C. A noise-
reduction capacitor, CN, reduces the broadband noise of the
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相关代理商/技术参数 |
参数描述 |
|---|---|
| AD676-EB | 功能描述:BOARD EVAL SAMPLING ADC AD676 RoHS:否 类别:编程器，开发系统 >> 评估板 - 模数转换器 (ADC) 系列:- 产品培训模块:Obsolescence Mitigation Program 标准包装:1 系列:- ADC 的数量:1 位数:12 采样率（每秒）:94.4k 数据接口:USB 输入范围:±VREF/2 在以下条件下的电源（标准）:- 工作温度:-40°C ~ 85°C 已用 IC / 零件:MAX11645 已供物品:板，软件 |
| AD676JD | 功能描述:IC ADC 16BIT SAMPLING 28-CDIP RoHS:否 类别:集成电路 (IC) >> 数据采集 - 模数转换器 系列:- 标准包装:1 系列:- 位数:14 采样率（每秒）:83k 数据接口:串行，并联 转换器数目:1 功率耗散（最大）:95mW 电压电源:双 ± 工作温度:0°C ~ 70°C 安装类型:通孔 封装/外壳:28-DIP（0.600"，15.24mm） 供应商设备封装:28-PDIP 包装:管件 输入数目和类型:1 个单端，双极 |
| AD676JDZ | 功能描述:IC ADC 16BIT SAMPLING 28-CDIP RoHS:是 类别:集成电路 (IC) >> 数据采集 - 模数转换器 系列:- 标准包装:1 系列:- 位数:14 采样率（每秒）:83k 数据接口:串行，并联 转换器数目:1 功率耗散（最大）:95mW 电压电源:双 ± 工作温度:0°C ~ 70°C 安装类型:通孔 封装/外壳:28-DIP（0.600"，15.24mm） 供应商设备封装:28-PDIP 包装:管件 输入数目和类型:1 个单端，双极 |
| AD676JDZ# | 制造商:Analog Devices 功能描述: |
| AD676JN | 功能描述:IC ADC 16BIT 100KSPS 28-DIP RoHS:否 类别:集成电路 (IC) >> 数据采集 - 模数转换器 系列:- 标准包装:1 系列:- 位数:14 采样率（每秒）:83k 数据接口:串行，并联 转换器数目:1 功率耗散（最大）:95mW 电压电源:双 ± 工作温度:0°C ~ 70°C 安装类型:通孔 封装/外壳:28-DIP（0.600"，15.24mm） 供应商设备封装:28-PDIP 包装:管件 输入数目和类型:1 个单端，双极 |
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