參數(shù)資料
型號: SP8544BN
英文描述: Two and Four Channel 12-Bit Multiplexed Sampling ADCs
中文描述: 雙和四通道12位多路采樣ADC
文件頁數(shù): 8/16頁
文件大?。?/td> 219K
代理商: SP8544BN
SP8542/8544DS/01 SP8542/8544 Two and Four Channel 12-Bit Multiplexed Sampling ADC's
Copyright 2000 Sipex Corporation
8
there is no connection made between VDA and
the system power supply. This is because
the analog supply pin (VDA) is connected
internally to the digital supply pin (VDD) through
a ten ohm resistor.
This connection when combined with a parallel
combination of 6.8
μ
F tantalum and 0.1
μ
F
ceramic capacitor between VDA and analog
ground, will provide some immunity to noise
which resides on the system supply. To
maintain maximum system accuracy, the
supply connected to the VDD pin should be well
isolated from digital supplies and wide load
variations.
To limit effects of digital switching elsewherein
a system, it often makes sense to run a seperate
+5Vsupply conductor from the supply requlator
to any analog components requiring +5V
including the
SP8542
and
SP8544
. Noise on the
power supply lines can degrade the converters
performance, especially corrupting are noise
and spikes from a switching power supply.
The ground pins (AGND and VSS) on the
SP8542
and
SP8544
are separated internally
and should be connected to each other under the
converter. The use of separate Analog & Digital
ground planes is usually the best technique for
preserving dynamic performance and reducing
noise coupling into sensitive converter circuits.
Where any compromise must be made the
common return of the analog input signal should
be referenced to the AGND pin of the converter.
This prevents any voltage drops that might
occur in the power supply common returns from
appearing in series with the input signal.
Coupling between analog and digital lines should
be minimized by careful layout. For instance, if
analog and digital lines must cross they should
do so at right angles. Parallel analog and digital
lines should be separated from each other by a
trace connected to common.
If external gain and offset potentiometers are
used, the potentiometers and related resistors
should be located as close to the
SP8542
and
SP8544
as possible.
Minimizing "Glitches"
Coupling of external transients into an analog to
digital converter can cause errors which are
difficult to debug. In addition to the above
discussions on layout considerations, bypassing
and grounding, there are several other useful
steps that can be taken to get the best analog
performance from a system using the
SP8542
or
SP8544
converter. These potential system
problem sources are particularly important to
consider when developing a new system, and
looking for causes of errors in breadboards.
First, care should be taken to avoid transients
during critical times in the sampling and
conversion process. Since the
SP8542
and
SP0544
have internal sample/hold function the
signal that puts the device into hold state (CS)
going low is critical, as it would be on any
sample/hold amplfier. The CS falling edge
should have 5 to 10 ns transition time, low jitter,
and have a minimal ringing, especially during
the first 35 ns after it falls.
相關(guān)PDF資料
PDF描述
SP8544BS Two and Four Channel 12-Bit Multiplexed Sampling ADCs
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SP8544AS Two and Four Channel 12-Bit Multiplexed Sampling ADCs
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SP8542BN Two and Four Channel 12-Bit Multiplexed Sampling ADCs
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
SP8544BS 制造商:SIPEX 制造商全稱:Sipex Corporation 功能描述:Two and Four Channel 12-Bit Multiplexed Sampling ADCs
SP8544JN 制造商:SIPEX 制造商全稱:Sipex Corporation 功能描述:Two and Four Channel 12-Bit Multiplexed Sampling ADCs
SP8544JS 制造商:SIPEX 制造商全稱:Sipex Corporation 功能描述:Two and Four Channel 12-Bit Multiplexed Sampling ADCs
SP8544KN 制造商:SIPEX 制造商全稱:Sipex Corporation 功能描述:Two and Four Channel 12-Bit Multiplexed Sampling ADCs
SP8544KS 制造商:SIPEX 制造商全稱:Sipex Corporation 功能描述:Two and Four Channel 12-Bit Multiplexed Sampling ADCs