參數(shù)資料
型號(hào): ADS7841P
英文描述: 12-Bit, 4-Channel Serial Output Sampling ANALOG-TO-DIGITAL CONVERTER
中文描述: 12位,4通道串行輸出采樣模擬到數(shù)字轉(zhuǎn)換器
文件頁(yè)數(shù): 14/14頁(yè)
文件大?。?/td> 277K
代理商: ADS7841P
14
ADS7841
LAYOUT
For optimum performance, care should be taken with the
physical layout of the ADS7841 circuitry. This is particu-
larly true if the reference voltage is low and/or the conver-
sion rate is high.
The basic SAR architecture is sensitive to glitches or sudden
changes on the power supply, reference, ground connec-
tions, and digital inputs that occur just prior to latching the
output of the analog comparator. Thus, during any single
conversion for an n-bit SAR converter, there are n “win-
dows” in which large external transient voltages can easily
affect the conversion result. Such glitches might originate
from switching power supplies, nearby digital logic, and
high power devices. The degree of error in the digital output
depends on the reference voltage, layout, and the exact
timing of the external event. The error can change if the
external event changes in time with respect to the DCLK
input.
With this in mind, power to the ADS7841 should be clean
and well bypassed. A 0.1
μ
F ceramic bypass capacitor should
be placed as close to the device as possible. In addition, a
1
μ
F to 10
μ
F capacitor and a 5
or 10
series resistor may
be used to lowpass filter a noisy supply.
The reference should be similarly bypassed with a 0.1
μ
F
capacitor. Again, a series resistor and large capacitor can be
used to lowpass filter the reference voltage. If the reference
voltage originates from an op amp, make sure that it can
drive the bypass capacitor without oscillation (the series
resistor can help in this case). The ADS7841 draws very
little current from the reference on average, but it does place
larger demands on the reference circuitry over short periods
of time (on each rising edge of DCLK during a conversion).
The ADS7841 architecture offers no inherent rejection of
noise or voltage variation in regards to the reference input.
This is of particular concern when the reference input is tied
to the power supply. Any noise and ripple from the supply
will appear directly in the digital results. While high fre-
quency noise can be filtered out as discussed in the previous
paragraph, voltage variation due to line frequency (50Hz or
60Hz) can be difficult to remove.
The GND pin should be connected to a clean ground point.
In many cases, this will be the “analog” ground. Avoid
connections which are too near the grounding point of a
microcontroller or digital signal processor. If needed, run a
ground trace directly from the converter to the power supply
entry point. The ideal layout will include an analog ground
plane dedicated to the converter and associated analog
circuitry.
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
ADS7841P 制造商:BURR-BROWN 功能描述:IC 12BIT ADC 7841 DIP16
ADS7841PB 功能描述:模數(shù)轉(zhuǎn)換器 - ADC 12-Bit 4-Ch Serial Output Sampling 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
ADS7841PB 制造商:Texas Instruments 功能描述:IC 12BIT ADC 7841 PDIP16
ADS7841PBG4 功能描述:模數(shù)轉(zhuǎn)換器 - ADC 12B 4-Ch Serial Output Sampling 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
ADS7841PG4 功能描述:模數(shù)轉(zhuǎn)換器 - ADC 12-Bit 4-Ch Serial Output Sampling 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