参数资料
型号: MAX195BCWE+T
厂商: Maxim Integrated Products
文件页数: 15/28页
文件大小: 0K
描述: IC ADC 16BIT 85KSPS 16-SOIC
产品培训模块: Lead (SnPb) Finish for COTS
Obsolescence Mitigation Program
标准包装: 1,000
位数: 16
采样率(每秒): 85k
数据接口: QSPI?,串行,SPI?
转换器数目: 2
功率耗散(最大): 80mW
电压电源: 模拟和数字,双 ±
工作温度: 0°C ~ 70°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: 带卷 (TR)
输入数目和类型: 1 个单端,单极;1 个单端,双极
MAX195
16-Bit, 85ksps ADC with 10A Shutdown
22
______________________________________________________________________________________
MAX195
10
F
VDDD
VDDA
VSSA
VSSD
AGND
DGND
5V
0.1
F
0.1
F
10
F
10
10
10
F
0.1
F
0.1
F
10
F
100
0.01
1
10
100
1000
10,000 100,000
0.1
MAX195-FIG23
CONVERSIONS PER SECOND
POWER
DISSIPATION
(mW)
1
10
20
s WAKE-UP DELAY
0.25LSB ERROR
3.2
s WAKE-UP DELAY
0.5LSB ERROR
50
s WAKE-UP DELAY
0.01LSB ERROR
the MAX195 finishes the old conversion, allows four
clock (CLK) cycles for input acquisition, then begins
the new conversion.
_____________Dynamic Performance
High-speed sampling capability, 85ksps throughput,
and wide dynamic range make the MAX195 ideal for
AC applications and signal processing. To support
these and other related applications, Fast Fourier
Transform (FFT) test techniques are used to guarantee
the ADC’s dynamic frequency response, distortion, and
noise at the rated throughput. Specifically, this involves
applying a low-distortion sine wave to the ADC input
and recording the digital conversion results for a
specified time. The data is then analyzed using an FFT
algorithm, which determines its spectral content.
Conversion errors are then seen as spectral elements
other than the fundamental input frequency.
Signal-to-Noise Ratio and
Effective Number of Bits
Signal-to-Noise Ratio (SNR) is the ratio between the
RMS amplitude of the fundamental input frequency to
the RMS amplitude of all other ADC output signals. The
output band is limited to frequencies above DC and
below one-half the ADC sample rate. This usually (but
not always) includes distortion as well as noise compo-
nents. For this reason, the ratio is sometimes referred to
as Signal-to-Noise + Distortion (SINAD).
The theoretical minimum ADC noise is caused by quan-
tization error and is a direct result of the ADC’s resolu-
tion: SNR = (6.02N + 1.76)dB, where N is the number
of bits of resolution. A perfect 16-bit ADC can, there-
fore, do no better than 98dB. An FFT plot of the output
shows the output level in various spectral bands. Figure
25 shows the result of sampling a pure 1kHz sinusoid at
85ksps with the MAX195.
By transposing the equation that converts resolution to
SNR, we can, from the measured SNR, determine the
effective resolution or the “effective number of bits” the
ADC provides: N = (SNR - 1.76) / 6.02. Substituting
SINAD for SNR in this formula results in a better mea-
sure of the ADC’s usefulness. Figure 26 shows the
effective number of bits as a function of the MAX195’s
input frequency calculated from the SINAD.
If your intended sample rate is much lower than the
MAX195’s maximum of 85ksps, you can improve your
noise performance by taking more samples than neces-
sary (oversampling) and averaging them in software.
Figure 27 is a histogram showing 16,384 samples for
the MAX195 without averaging, with an ideal “noiseless
conversion,” and with a running average of five sam-
ples. The standard deviation is 0.621LSB without aver-
aging and 0.382LSB with the running average. If fewer
data points are needed, normal averaging (e.g., five
data points averaged to produce one data point) can be
used instead of a running average, with similar results.
Figure 22. Supply Bypassing and Grounding
Figure 23. Power Dissipation vs. Conversions/sec When
Shutting the MAX195 Down Between Conversions
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MAX195BEPE 功能描述:模数转换器 - ADC RoHS:否 制造商:Texas Instruments 通道数量:2 结构:Sigma-Delta 转换速率:125 SPs to 8 KSPs 分辨率:24 bit 输入类型:Differential 信噪比:107 dB 接口类型:SPI 工作电源电压:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-32
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MAX195BEPE+T 制造商:Maxim Integrated Products 功能描述:16-BIT, 85KSPS ADC WITH 10?A SHUTDOWN - Tape and Reel
MAX195BEWE 功能描述:模数转换器 - ADC RoHS:否 制造商:Texas Instruments 通道数量:2 结构:Sigma-Delta 转换速率:125 SPs to 8 KSPs 分辨率:24 bit 输入类型:Differential 信噪比:107 dB 接口类型:SPI 工作电源电压:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-32
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