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參數(shù)資料
| 型號： | ADC12038CIWM |
| 廠商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分類： | ADC |
| 英文描述： | Self-Calibrating 12-Bit Plus Sign Serial I/O A/D Converters with MUX and Sample/Hold |
| 中文描述： | 8-CH 12-BIT SUCCESSIVE APPROXIMATION ADC, SERIAL ACCESS, PDSO28 |
| 封裝： | SOP-28 |
| 文件頁數(shù)： | 28/41頁 |
| 文件大?。?/td> | 1036K |
| 代理商： | ADC12038CIWM |
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Tables
(Continued)
TABLE 7. Status Register
Status Bit
Location
Status Bit
DB0
DB1
DB2
DB3
DB4
DB5
DB6
DB7
DB8
PU
PD
Cal
8 or 9
12 or 13
16 or 17
DO Output Format Status
“High”
indicates
a 16 or
17 bit
format
included.
When
“Low” the
sign bit is
not
included.
Sign
Justification
Test Mode
Device Status
“High”
indicates
a Power
Down
Sequence
is in
progress
Function
“High”
indicates
a Power
Up
Sequence
is in
progress
“High”
indicates
an
Auto-Cal
Sequence
is in
progress
“High”
indicates
an 8 or 9
bit format
“High”
indicates
a 12 or
13 bit
format
“High”
indicates
that the
sign bit is
When
“High” the
conversion
result will
be output
MSB first.
When
“Low” the
result will
be output
LSB first.
When
“High” the
device is in
test mode.
When
“Low” the
device is in
user mode.
Application Hints
1.0 DIGITAL INTERFACE
1.1 Interface Concepts
The example in Figure 7shows a typical sequence of events
after the power is applied to the ADC12030/2/4/8:
The first instruction input to the A/D via DI initiates Auto Cal.
The data output on DO at that time is meaningless and is
completely random. To determine whether the Auto Cal has
been completed, a read status instruction is issued to the
A/D. Again the data output at that time has no significance
since the Auto Cal procedure modifies the data in the output
shift register. To retrieve the status information, an additional
read status instruction is issued to the A/D. At this time the
status data is available on DO. If the Cal signal in the status
word, is low Auto Cal has been completed. Therefore, the
next instruction issued can start a conversion. The data out-
put at this time is again status information. To keep noise
from corrupting the A/D conversion, status can not be read
during a conversion. If CS is strobed and is brought low dur-
ing a conversion, that conversion is prematurely ended.
EOC can be used to determine the end of a conversion or
theA/D controller can keep track in software of when it would
be appropriate to comnmunicate to the A/D again. Once it
has been determined that the A/D has completed a conver-
sion, another instruction can be transmitted to the A/D. The
data from this conversion can be accessed when the next in-
struction is issued to the A/D.
Note, when CS is low continuously it is important to transmit
the exact number of SCLK cycles, as shown in the timing
diagrams. Not doing so will desynchronize the serial commu-
nication to the A/D. (See Section 1.3.)
1.2 Changing Configuration
The configuration of the ADC12030/2/4/8 on power up de-
faults to 12-bit plus sign resolution, 12- or 13-bit MSB First,
10 CCLK acquisition time, user mode, no Auto Cal, no Auto
Zero, and power up mode. Changing the aquisition time and
turning the sign bit on and off requires an 8-bit instruction to
be issued to the ADC. This instruction will not start a conver-
sion. The instructions that select a multiplexer address and
format the output data do start a conversion. Figure 8 de-
scribes an example of changing the configuration of the
ADC12030/2/4/8.
During I/O sequence 1, the instruction on DI configures the
ADC12030/2/4/8 to do a conversion with 12-bit +sign resolu-
tion. Notice that when the 6 CCLK Acquisition and Data Out
without Sign instructions are issued to the ADC, I/O se-
quences 2 and 3, a new conversion is not started. The data
output during these instructions is from conversion N which
was started during I/O sequence 1. The Configuration Modi-
fication timing diagram describes in detail the sequence of
events necessary for a Data Out without Sign, Data Out with
Sign, or 6/10/18/34 CCLK Acquisition time mode selection.
Table 5 describes the actual data necessary to be input to
the ADC to accomplish this configuration modification. The
next instruction, shown in Figure 8 issued to the A/D starts
conversion N+1 with 8 bits of resolution formatted MSB first.
Again the data output during this I/O cycle is the data from
conversion N.
The number of SCLKs applied to the A/D during any conver-
sion I/O sequence should vary in accord with the data out
word format chosen during the previous conversion I/O se-
quence. The various formats and resolutions available are
shown in Table 1 In Figure 8 since 8-bit without sign MSB
first format was chosen during I/O sequence 4, the number
of SCLKs required during I/O sequence 5 is 8. In the follow-
ing I/O sequence the format changes to 12-bit without sign
MSB first; therefore the number of SCLKs required during
I/O sequence 6 changes accordingly to 12.
DS011354-36
FIGURE 7. Typical Power Supply Power Up Sequence
www.national.com
28
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| ADC12038CIWM/NOPB | 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 |
| ADC12038CIWM/NOPB | 制造商:Texas Instruments 功能描述:A/D Converter (A-D) IC |
| ADC12038CIWMNOPB | 制造商:National Semiconductor 功能描述:ADC Single SAR 114ksps 12-bit+Sign Serial 28-Pin SOIC W Rail 制造商:National Semiconductor 功能描述:ADC Single SAR 114ksps 12-bit+Sign Serial 28-Pin SOIC Rail |
| ADC12038CIWMX | 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 |
| ADC12038CIWMX/NOPB | 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 |
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