参数资料
型号: AD7731BRZ-REEL
厂商: Analog Devices Inc
文件页数: 19/44页
文件大小: 0K
描述: IC ADC 24BIT SIGMA-DELTA 24-SOIC
标准包装: 1,000
位数: 24
采样率(每秒): 6.4k
数据接口: DSP,串行,SPI?
转换器数目: 1
功率耗散(最大): 125mW
电压电源: 模拟和数字
工作温度: -40°C ~ 85°C
安装类型: 表面贴装
封装/外壳: 24-SOIC(0.295",7.50mm 宽)
供应商设备封装: 24-SOIC W
包装: 带卷 (TR)
输入数目和类型: 3 个差分,单极;3 个差分,双极;5 个伪差分,单极;5 个伪差分,双极
配用: EVAL-AD7731EBZ-ND - BOARD EVALUATION FOR AD7731
AD7731
–26–
REV. 0
Chop Mode (SKIP = 0, CHP = 1)
With CHOP mode enabled and SKIP mode disabled, the sec-
ond stage filter is presented with alternating first stage filter
outputs and processes data accordingly. It has two primary
functions. One is to set the overall frequency response and the
second is to eliminate the modulated offset effect which appears
on the output of the first stage filter. Time to first output is
22
× 1/Output Rate in this mode. Table XVIII summarizes the
settling time and subsequent throughput rate for the various
different modes.
Figure 9 shows the full frequency response of the AD7731 when
the second stage filter is set for normal FIR operation. This
response is for chop mode enabled with the decimal equivalent
of the word in the SF bits set to 512 and a master clock fre-
quency of 4.9152 MHz. The response will scale proportionately
with master clock frequency. The response is shown from dc to
100 Hz. The rejection at 50 Hz
± 1 Hz and 60 Hz ± 1 Hz is
better than 88 dB.
The –3 dB frequency for the frequency response of the AD7731
with the second stage filter set for normal FIR operation and
chop mode enabled is determined by the following relationship:
f
3 dB = 0. 0395 × f MOD ×
1
3
× SF
CHP
= 1
()
In this case, f3dB = 7.9 Hz and the stop-band, where the attenua-
tion is greater than 64.5 dB, is determined by:
f
STOP = 0.14 × f MOD ×
1
3
× SF
CHP
= 1
()
In this case, fSTOP = 28 Hz.
FREQUENCY – Hz
0
–60
–100
090
GAIN
dB
10
20
30
40
50
60
70
80
–10
–50
–70
–90
–30
–40
–80
–20
–120
–110
100
Figure 9. Detailed Full Frequency Response of AD7731
(SKIP = 0, CHP = 1, SF = 512)
Figure 10 shows the frequency response for the same set of
conditions as for Figure 9 but in this case the response in shown
out to 600 Hz. This response shows that the attenuation of
input frequencies close to 200 Hz and 400 Hz is significantly
less than at other input frequencies. These “peaks” in the fre-
quency response are a by-product of the chopping of the input.
The plot of Figure 10 is the amplitude for different input fre-
quencies. Note that because the output rate is 200 Hz for the
conditions under which Figure 10 is plotted, if something ex-
isted in the input frequency domain at 200 Hz, it would be
aliased and appear in the output frequency domain at dc.
Because of this effect, care should be taken in choosing an out-
put rate which is close to the line frequency in the application.
For example, if the line frequency is 50 Hz, an output update
rate of 50 Hz should not be chosen as it will significantly reduce
the AD7731’s line frequency rejection (the 50 Hz will appear as
a dc component with only 6 dB attenuation). However, choos-
ing 60 Hz as the output rate (SF = 1707) will give better than
90 dB attenuation of the aliased line frequency. In a similar
fashion, if the line frequency is 60 Hz, it is recommended that
the user choose an output update rate of 50 Hz (SF = 2048).
FREQUENCY – Hz
0
–60
–100
0
450
GAIN
dB
50
100 150 200 250 300 350 400
–10
–50
–70
–90
–30
–40
–80
–20
–120
–110
500 550
600
Figure 10. Expanded Full Frequency Response of AD7731
(SKIP = 0, CHP = 1, SF = 512)
Similarly, multiples of the line frequency should be avoided as
the output rate because harmonics of the line frequency will not
be fully attenuated. The programmability of the AD7731’s
output rate should allow the user to readily choose an output
rate which overcomes this issue. An alternative is to use the part
in nonchop mode.
REV. A
相关PDF资料
PDF描述
SP3076EEN-L/TR IC TXRX RS485/RS422 ESD 14NSOIC
AD7667ACPZRL IC ADC 16BIT UNIPOLAR 48LFCSP
SP3075EEN-L/TR IC TXRX RS485/RS422 ESD 8NSOIC
AD7667ASTZRL IC ADC 16BIT UNIPOLAR 48LQFP
SP3074EEN-L/TR IC TXRX RS485/RS422 ESD 8NSOIC
相关代理商/技术参数
参数描述
AD7731BRZ-REEL7 功能描述:IC ADC 24BIT SIGMA-DELTA 24-SOIC RoHS:是 类别:集成电路 (IC) >> 数据采集 - 模数转换器 系列:- 标准包装:1,000 系列:- 位数:12 采样率(每秒):300k 数据接口:并联 转换器数目:1 功率耗散(最大):75mW 电压电源:单电源 工作温度:0°C ~ 70°C 安装类型:表面贴装 封装/外壳:24-SOIC(0.295",7.50mm 宽) 供应商设备封装:24-SOIC 包装:带卷 (TR) 输入数目和类型:1 个单端,单极;1 个单端,双极
AD7731EB 制造商:AD 制造商全称:Analog Devices 功能描述:Low Noise High Throughput 24-Bit Sigma-Delta ADC(411.99 k)
AD7732 制造商:AD 制造商全称:Analog Devices 功能描述:2-Channel, +-10 V Input Range, High Throughput, 24-Bit SIGMA- ADC
AD7732BRU 功能描述:IC ADC 24BIT 2-CH 28-TSSOP RoHS:否 类别:集成电路 (IC) >> 数据采集 - 模数转换器 系列:- 标准包装:1,000 系列:- 位数:12 采样率(每秒):300k 数据接口:并联 转换器数目:1 功率耗散(最大):75mW 电压电源:单电源 工作温度:0°C ~ 70°C 安装类型:表面贴装 封装/外壳:24-SOIC(0.295",7.50mm 宽) 供应商设备封装:24-SOIC 包装:带卷 (TR) 输入数目和类型:1 个单端,单极;1 个单端,双极
AD7732BRU-REEL 制造商:Analog Devices 功能描述:ADC Single Delta-Sigma 15.437ksps 24-bit Serial 28-Pin TSSOP T/R 制造商:Analog Devices 功能描述:ADC SGL DELTA-SIGMA 15.437KSPS 24BIT SERL 28TSSOP - Tape and Reel