參數(shù)資料
型號(hào): MAX195BCWE
廠商: MAXIM INTEGRATED PRODUCTS INC
元件分類: ADC
英文描述: 16-Bit, 85ksps ADC with 10レA Shutdown
中文描述: 1-CH 16-BIT SUCCESSIVE APPROXIMATION ADC, SERIAL ACCESS, PDSO16
封裝: 0.300 INCH, PLASTIC, SOIC-16
文件頁(yè)數(shù): 22/28頁(yè)
文件大?。?/td> 311K
代理商: MAX195BCWE
M
16-Bit, 85ksps ADC with 10μA S hutdown
22
______________________________________________________________________________________
MAX195
10
μ
F
VDDD
VDDA
VSSA
VSSD
AGND
DGND
5V
5V
0.1
μ
F
0.1
μ
F
10
μ
F
10
10
10
μ
F
0.1
μ
F
0.1
μ
F
10
μ
F
100
0.01
1
10
CONVERSIONS PER SECOND
100
1000
10,000 100,000
0.1
M
P
1
10
20
μ
s WAKE-UP DELAY
0.25LSB ERROR
3.2
μ
s WAKE-UP DELAY
0.5LSB ERROR
50
μ
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 Performanc e
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.
S ignal-to-Noise Ratio and
Effec tive 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
相關(guān)PDF資料
PDF描述
MAX195BCPE 16-Bit, 85ksps ADC with 10レA Shutdown
MAX195AMDE 16-Bit, 85ksps ADC with 10レA Shutdown
MAX195BEPE 16-Bit, 85ksps ADC with 10レA Shutdown
MAX195BEWE 16-Bit, 85ksps ADC with 10レA Shutdown
MAX195BMDE 16-Bit, 85ksps ADC with 10レA Shutdown
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MAX195BCWE+ 功能描述:模數(shù)轉(zhuǎn)換器 - ADC 16-Bit 85ksps 5V Precision ADC RoHS:否 制造商:Texas Instruments 通道數(shù)量:2 結(jié)構(gòu):Sigma-Delta 轉(zhuǎn)換速率:125 SPs to 8 KSPs 分辨率:24 bit 輸入類型:Differential 信噪比:107 dB 接口類型:SPI 工作電源電壓:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-32
MAX195BCWE+T 功能描述:模數(shù)轉(zhuǎn)換器 - ADC 16-Bit 85ksps 5V Precision ADC RoHS:否 制造商:Texas Instruments 通道數(shù)量:2 結(jié)構(gòu):Sigma-Delta 轉(zhuǎn)換速率:125 SPs to 8 KSPs 分辨率:24 bit 輸入類型:Differential 信噪比:107 dB 接口類型:SPI 工作電源電壓:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-32
MAX195BCWE-T 功能描述:模數(shù)轉(zhuǎn)換器 - ADC RoHS:否 制造商:Texas Instruments 通道數(shù)量:2 結(jié)構(gòu):Sigma-Delta 轉(zhuǎn)換速率:125 SPs to 8 KSPs 分辨率:24 bit 輸入類型:Differential 信噪比:107 dB 接口類型:SPI 工作電源電壓:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-32
MAX195BEPE 功能描述:模數(shù)轉(zhuǎn)換器 - ADC RoHS:否 制造商:Texas Instruments 通道數(shù)量:2 結(jié)構(gòu):Sigma-Delta 轉(zhuǎn)換速率:125 SPs to 8 KSPs 分辨率:24 bit 輸入類型:Differential 信噪比:107 dB 接口類型:SPI 工作電源電壓:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-32
MAX195BEPE+ 功能描述:模數(shù)轉(zhuǎn)換器 - ADC 16-Bit 85ksps 5V Precision ADC RoHS:否 制造商:Texas Instruments 通道數(shù)量:2 結(jié)構(gòu):Sigma-Delta 轉(zhuǎn)換速率:125 SPs to 8 KSPs 分辨率:24 bit 輸入類型:Differential 信噪比:107 dB 接口類型:SPI 工作電源電壓:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-32