参数资料
| 型号： | AD7400AYNSZ |
| 厂商： | Analog Devices Inc |
| 文件页数： | 5/20页 |
| 文件大小： | 0K |
| 描述： | IC MODULATOR SIGMADELTA 8-SMD |
| 产品变化通告： | AD7400AYNSZ Discontinuation 23/Mar/2012 |
| 标准包装： | 50 |
| 类型： | 调制器 |
| 分辨率（位）： | 16 b |
| 采样率（每秒）： | 10M |
| 数据接口： | 串行 |
| 电压电源： | 单电源 |
| 电源电压： | 4.5 V ~ 5.5 V |
| 工作温度： | -40°C ~ 125°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 8-SMD，鸥翼型 |
| 供应商设备封装： | 8-DIP 鸥翼型 |
| 包装： | 管件 |
| 产品目录页面： | 798 (CN2011-ZH PDF) |
Data Sheet
AD7400A
Rev. D | Page 13 of 20
THEORY OF OPERATION
CIRCUIT INFORMATION
The AD7400A isolated Σ-Δ modulator converts an analog input
signal into a high speed (10 MHz typical), single-bit data stream;
the time average of the single-bit data from the modulator is
directly proportional to the input signal. Figure 21 shows a
typical application circuit where the AD7400A is used to provide
isolation between the analog input, a current sensing resistor,
and the digital output, which is then processed by a digital filter
to provide an N-bit word.
ANALOG INPUT
The differential analog input of the AD7400A is implemented
with a switched capacitor circuit. This circuit implements a
second-order modulator stage that digitizes the input signal
into a 1-bit output stream. The sample clock (MCLKOUT)
provides the clock signal for the conversion process as well as
the output data-framing clock. This clock source is internal on
the AD7400A. The analog input signal is continuously sampled
by the modulator and compared to an internal voltage reference. A
digital stream that accurately represents the analog input over
time appears at the output of the converter (see Figure 19).
MODULATOR OUTPUT
+FS ANALOG INPUT
–FS ANALOG INPUT
ANALOG INPUT
07077-
019
Figure 19. Analog Input vs. Modulator Output
A differential signal of 0 V ideally results in a stream of 1s and
0s at the MDAT output pin. This output is high 50% of the time
and low 50% of the time. A differential input of 200 mV produces
a stream of 1s and 0s that are high 81.25% of the time (for a
+250 mV input, the output stream is high 89.06% of the time).
A differential input of 200 mV produces a stream of 1s and 0s
that are high 18.75% of the time (for a 250 mV input, the output
stream is high 10.94% of the time).
A differential input of 320 mV ideally results in a stream of all
1s. This is the absolute full-scale range of the AD7400A, while
250 mV is the specified full-scale range, as shown in Table 9.
Table 9. Analog Input Range
Analog Input
Voltage Input
Full-Scale Range
+640 mV
Positive Full Scale
+320 mV
Positive Typical Input Range
+250 mV
Positive Specified Input Range
+200 mV
Zero
0 mV
Negative Specified Input Range
200 mV
Negative Typical Input Range
250 mV
Negative Full Scale
320 mV
To reconstruct the original information, this output needs
to be digitally filtered and decimated. A Sinc3 filter is recom-
mended because this is one order higher than that of the
AD7400A modulator. If a 256 decimation rate is used, the
resulting 16-bit word rate is 39 kHz, assuming a 10 MHz
internal clock frequency. Figure 20 shows the transfer function
of the AD7400A relative to the 16-bit output.
65535
53248
SPECIFIED RANGE
ANALOG INPUT
ADC
CO
DE
12288
–320mV
–200mV
+200mV
+320mV
0
07077-
020
Figure 20. Filtered and Decimated 16-Bit Transfer Characteristic
Σ-Δ
MOD/
ENCODER
INPUT
CURRENT
NONISOLATED
5V/3V
ISOLATED
5V
VDD1
RSHUNT
VIN+
VIN–
GND1
VDD
GND
VDD2
MDAT
SINC3 FILTER*
AD7400A
MCLKOUT
SDAT
CS
SCLK
MCLK
GND2
DECODER
+
ENCODER
07077-
018
* THIS FILTER IS IMPLEMENTED
WITH AN FPGA OR DSP.
Figure 21. Typical Application Circuit
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相关代理商/技术参数 |
参数描述 |
|---|---|
| AD7400AYNSZREEL | 制造商:AD 制造商全称:Analog Devices 功能描述:Isolated Sigma-Delta Modulator |
| AD7400AYNSZREEL7 | 制造商:AD 制造商全称:Analog Devices 功能描述:Isolated Sigma-Delta Modulator |
| AD7400AYRWZ | 功能描述:IC MODULATOR SIGMA-DELTA 16SOIC RoHS:是 类别:集成电路 (IC) >> 数据采集 - ADCs/DAC - 专用型 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:50 系列:- 类型:数据采集系统（DAS） 分辨率（位）:16 b 采样率（每秒）:21.94k 数据接口:MICROWIRE?，QSPI?，串行，SPI? 电压电源:模拟和数字 电源电压:1.8 V ~ 3.6 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:40-WFQFN 裸露焊盘 供应商设备封装:40-TQFN-EP（6x6） 包装:托盘 |
| AD7400AYRWZ1 | 制造商:AD 制造商全称:Analog Devices 功能描述:Isolated Sigma-Delta Modulator |
| AD7400AYRWZREEL | 制造商:AD 制造商全称:Analog Devices 功能描述:Isolated Sigma-Delta Modulator |
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