欢迎访问ic37.com |
会员登录 免费注册
发布采购

AD7714ARS-5 参数 Datasheet PDF下载

AD7714ARS-5图片预览
型号: AD7714ARS-5
PDF下载: 下载PDF文件 查看货源
内容描述: 3 V / 5 V , CMOS , 500微安信号调理ADC [3 V/5 V, CMOS, 500 uA Signal Conditioning ADC]
分类和应用: 转换器光电二极管
文件页数/大小: 40 页 / 308 K
品牌: ADI [ ADI ]
 浏览型号AD7714ARS-5的Datasheet PDF文件第8页浏览型号AD7714ARS-5的Datasheet PDF文件第9页浏览型号AD7714ARS-5的Datasheet PDF文件第10页浏览型号AD7714ARS-5的Datasheet PDF文件第11页浏览型号AD7714ARS-5的Datasheet PDF文件第13页浏览型号AD7714ARS-5的Datasheet PDF文件第14页浏览型号AD7714ARS-5的Datasheet PDF文件第15页浏览型号AD7714ARS-5的Datasheet PDF文件第16页  
AD7714  
AD7714-3 OUTPUT NOISE  
Table IIa shows the output rms noise and effective resolution for some typical notch and –3 dB frequencies for the AD7714-3 with  
fCLK IN = 2.4576 MHz while Table IIb gives the information for fCLK IN = 1 MHz. The numbers given are for the bipolar input  
ranges with a VREF of +1.25 V and BUFFER = 0. These numbers are typical and are generated at an analog input voltage of 0 V.  
The numbers in brackets in each table are for the effective resolution of the part (rounded to the nearest 0.5 LSB). The effective  
resolution of the device is defined as the ratio of the output rms noise to the input full scale (i.e., 2 × VREF/GAIN). It should be  
noted that it is not calculated using peak-to-peak output noise numbers. Peak-to-peak noise numbers can be up to 6.6 times the rms  
numbers while effective resolution numbers based on peak-to-peak noise can be 2.5 bits below the effective resolution based on rms  
noise as quoted in the tables.  
The output noise from the part comes from two sources. The first is the electrical noise in the semiconductor devices used in the  
implementation of the modulator (device noise). Secondly, when the analog input signal is converted into the digital domain, quan-  
tization noise is added. The device noise is at a low level and is largely independent of frequency. The quantization noise starts at  
an even lower level but rises rapidly with increasing frequency to become the dominant noise source. Consequently, lower filter  
notch settings (below 100 Hz approximately for fCLK IN = 2.4576 MHz and below 40 Hz approximately for fCLK IN = 1 MHz) tend to  
be device noise dominated while higher notch settings are dominated by quantization noise. Changing the filter notch and cutoff  
frequency in the quantization noise dominated region results in a more dramatic improvement in noise performance than it does in  
the device-noise dominated region as shown in Table II. Furthermore, quantization noise is added after the PGA, so effective reso-  
lution is largely independent of gain for the higher filter notch frequencies. Meanwhile, device noise is added in the PGA and, there-  
fore, effective resolution suffers a little at high gains for lower notch frequencies. Additionally, in the device-noise dominated region,  
the output noise (in µV) is largely independent of reference voltage while in the quantization-noise dominated region, the noise is  
proportional to the value of the reference. It is possible to do post-filtering on the device to improve the output data ratefor a given  
–3 dB frequency and also to further reduce the output noise.  
At the lower filter notch settings (below 60 Hz for fCLK IN = 2.4576 MHz and below 25 Hz for fCLK IN = 1 MHz), the no missing  
codes performance of the device is at the 24-bit level. At the higher settings, more codes will be missed until at 1 kHz notch setting  
for fCLK IN = 2.4576 MHz (400 Hz for fCLK IN = 1 MHz), no missing codes performance is only guaranteed to the 12-bit level.  
Table IIa. AD7714-3 Output Noise/Resolution vs. Gain and First Notch for fCLK IN = 2.4576 MHz, BUFFER = 0  
Typical Output RMS Noise in V (Effective Resolution in Bits)  
Filter First  
Notch & O/P –3 dB  
Gain of  
1
Gain of  
2
Gain of  
4
Gain of  
8
Gain of  
16  
Gain of  
32  
Gain of  
64  
Gain of  
128  
Data Rate  
Frequency  
5 Hz  
1.31 Hz  
2.62 Hz  
6.55 Hz  
7.86 Hz  
13.1 Hz  
15.72 Hz  
26.2 Hz  
65.5 Hz  
131 Hz  
262 Hz  
1.07 (21)  
0.68 (21)  
0.29 (21)  
0.56 (20)  
0.24 (20) 0.22 (19.5) 0.22 (18.5) 0.22 (17.5) 0.22 (16.5)  
0.35 (19.5) 0.33 (19) 0.33 (18) 0.33 (17) 0.33 (16)  
10 Hz  
25 Hz  
30 Hz  
50 Hz  
60 Hz  
100 Hz  
250 Hz  
500 Hz  
1 kHz  
1.69 (20.5) 1.1  
3.03 (19.5) 1.7  
3.55 (19.5) 2.1  
4.72 (19)  
5.12 (19)  
9.68 (18)  
(20)  
(19.5) 0.89 (19.5) 0.55 (19) 0.49 (18.5) 0.46 (17.5) 0.46 (16.5) 0.45 (15.5)  
(19)  
(19)  
1.1 (19)  
1.5 (18.5) 0.84 (18.5) 0.7 (18)  
0.61 (18.5) 0.58 (18)  
0.57 (17) 0.55 (16) 0.55 (15)  
0.68 (17) 0.67 (16) 0.66 (15)  
2.3  
3.1  
5.6  
31  
(18.5) 1.6 (18)  
(18) 2.4 (18)  
(15.5) 15 (15.5) 5.8 (15.5) 3.7 (15.5) 2.4 (15) 1.8 (14.5) 1.8 (13.5)  
0.98 (18) 0.9 (17.5) 0.7 (17) 0.69 (16) 0.68 (15)  
1.3 (18) 1.1 (17)  
0.95 (16.5) 0.88 (15.5) 0.9 (14.5)  
44  
(16)  
304 (13)  
1410 (11)  
129 (13)  
715 (11)  
76 (13)  
350 (11)  
33 (13) 20 (13)  
11 (13) 6.3 (12.5) 3  
(12.5)  
177 (11) 101 (10.5) 51 (10.5) 31 (10.5) 12 (10.5)  
Table IIb. AD7714-3 Output Noise/Resolution vs. Gain and First Notch for fCLK IN = 1 MHz, BUFFER = 0  
Typical Output RMS Noise in V (Effective Resolution in Bits)  
Filter First  
Notch & O/P –3 dB  
Gain of  
1
Gain of  
2
Gain of  
4
Gain of  
8
Gain of  
16  
Gain of  
32  
Gain of  
64  
Gain of  
128  
Data Rate  
Frequency  
2 Hz  
4 Hz  
0.52 Hz  
1.05 Hz  
2.62 Hz  
6.55 Hz  
7.86 Hz  
13.1 Hz  
15.72 Hz  
26.2 Hz  
52.4 Hz  
104.8 Hz  
0.86 (21.5) 0.58 (21)  
1.26 (21)  
1.68 (20.5) 1.33 (20)  
3.82 (19.5) 2.0 (19.5) 1.2 (19)  
0.32 (21)  
0.21 (20.5) 0.2 (19.5) 0.2 (18.5) 0.2 (17.5) 0.2 (16.5)  
0.3 (18) 0.3 (17) 0.3 (16)  
0.5 (19) 0.49 (18.5) 0.49 (17.5) 0.48 (16.5) 0.47 (15.5)  
0.74 (20.5) 0.44 (20.5) 0.35 (20) 0.3 (19)  
10 Hz  
25 Hz  
30 Hz  
50 Hz  
60 Hz  
100 Hz  
200 Hz  
400 Hz  
0.73 (20)  
0.88 (18.5) 0.66 (18)  
0.93 (18.5) 0.82 (17.5) 0.69 (17) 0.68 (16) 0.66 (15)  
1.4 (18) 1.4 (17) 0.73 (16.5) 0.71 (15.5) 0.7 (15)  
0.57 (17) 0.55 (16) 0.55 (15)  
4.88 (19)  
11 (18)  
14.7 (17.5) 7.5  
61 (15.5) 30  
2.1  
4.8  
(19)  
(18)  
1.3 (19)  
2.4 (18)  
(17.5) 3.8 (17.5) 2.6 (17) 1.5 (16.5) 0.95 (16.5) 0.88 (15) 0.9 (14.5)  
(15.5) 12 (15.5) 6.1 (15.5) 2.9 (15.5) 2.4 (15) 1.8 (14.5) 1.8 (13.5)  
275 (13)  
1435 (11)  
130 (13)  
720 (11)  
65 (13)  
362 (11)  
33 (13) 17 (13)  
11 (13) 6.3 (12.5) 3  
(12.5)  
175 (11) 110 (10.5) 51 (10.5) 31 (10.5) 12 (10.5)  
–12–  
REV. C  
 复制成功!