- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄362802 > EVAL-AD7731EB (Analog Devices, Inc.) Low Noise, High Throughput 24-Bit Sigma-Delta ADC PDF資料下載
參數(shù)資料
| 型號： | EVAL-AD7731EB |
| 廠商： | Analog Devices, Inc. |
| 英文描述： | Low Noise, High Throughput 24-Bit Sigma-Delta ADC |
| 中文描述： | 低噪聲，高吞吐量的24位Σ-Δ模數(shù)轉換器 |
| 文件頁數(shù)： | 34/44頁 |
| 文件大?。?/td> | 411K |
| 代理商： | EVAL-AD7731EB |
第1頁第2頁第3頁第4頁第5頁第6頁第7頁第8頁第9頁第10頁第11頁第12頁第13頁第14頁第15頁第16頁第17頁第18頁第19頁第20頁第21頁第22頁第23頁第24頁第25頁第26頁第27頁第28頁第29頁第30頁第31頁第32頁第33頁當前第34頁第35頁第36頁第37頁第38頁第39頁第40頁第41頁第42頁第43頁第44頁
AD7731
–34–
REV. 0
SE RIAL INT E RFACE
T he AD7731’s programmable functions are controlled via a set
of on-chip registers. Access to these registers is via the part’s
serial interface. After power-on or RESET , the device expects a
write to its Communications Register. T he data written to this
register determines whether the next operation to the part is a
read or a write operation and also determines to which register
this read or write operation occurs. T herefore, write access to
one of the control registers on the part starts with a write opera-
tion to the Communications Register followed by a write to the
selected register. Reading from the part’s on-chip registers can
either take the form of a single read or continuous read. A single
read from a register consists of a write to the Communications
Register (with RW1 = 0 and RW0 = 1) followed by the read
from the specified register. T o perform continuous reads from a
register, write to the Communications Register (with RW1 = 1
and RW0 = 0) to place the part in continuous read mode. T he
specified register can then be read from continuously until a
write operation to the Communications Register (with RW1 = 1
and RW0 = 1) which takes the part out of continuous read
mode. When operating in continuous read mode, the part is
continuously monitoring its DIN line. T herefore, the DIN line
should be permanently low to allow the part to stay in continu-
ous read mode. Figure 5 and Figure 6, shown previously, indi-
cate the correct flow diagrams when reading and writing from
the AD7731’s registers.
T he AD7731’s serial interface consists of five signals,
CS
, SCLK ,
DIN, DOUT and
RDY
. T he DIN line is used for transferring
data into the on-chip registers while the DOUT line is used for
accessing data from the on-chip registers. SCLK is the serial
clock input for the device and all data transfers (either on DIN
or DOUT ) take place with respect to this SCLK signal.
Write Operation
T he transfer of data into the part is to an input shift register. On
completion of a write operation, data is transferred to the speci-
fied register. T his internal transfer will not take place until the
correct number of bits for the specified register have been
loaded to the input shift register. For example, the transfer of
data from the input shift register takes place after eight serial
clock cycles for a DAC Register write while the transfer of data
from the input shift register takes place after 24 serial clock
cycles when writing to the Filter Register. Figure 16 shows a
timing diagram for a write operation to the input shift register of
the AD7731. With the POL input at a logic high, the data is
latched into the input shift register on the rising edge of SCLK .
With the POL input at a logic low, the data is latched into the
input shift register on the falling edge of SCLK .
Figure 16 also shows the
CS
input being used to decode the
write operation to the AD7731. However, this
CS
input can be
used in a number of different ways. It is possible to operate the
part in three-wire mode where the
CS
input is permanently tied
low. In this case, the SCLK line should idle high between data
transfer when the POL input is high and should idle low be-
tween data transfers when the POL input is low. For POL = 1,
the first falling edge of SCLK clocks data from the microcontroller
onto the DIN line of the AD7731. It is then clocked into the
input shift register on the next rising edge of SCLK . For POL = 0,
the first clock edge which clocks data from the microcontroller
onto the DIN line of the AD7731 is a rising edge. It is then
clocked into the input shift register on the next falling edge of
SCLK .
In other microcontroller applications, which require a decoding
of the AD7731,
CS
can be generated from a port line. In this
case,
CS
would go low well in advance of the first falling edge of
SCLK (POL = 1) or the first rising edge of SCLK (POL = 0).
Clocking of each bit of data is as just described.
In DSP applications, the SCLK is generally a continuous clock.
In these applications, the
CS
input for the AD7731 is generated
from a frame synchronization signal from the DSP. For proces-
sors with the rising edge of SCLK as the active edge, the POL
input should be tied high. For processors with the falling edge of
SCLK as the active edge, the POL input should be tied low. In
these applications, the first edge after
CS
goes low is the active
edge. T he MSB of the data to be shifted into the AD7731 must
be set up prior to this first active edge.
DIN
SCLK
(POL = 1)
CS
MSB
t
12
t
15
LSB
t
16
t
14
t
11
t
13
SCLK
(POL = 0)
t
14
t
15
Figure 16. Write Cycle Timing Diagram
相關PDF資料 |
PDF描述 |
|---|---|
| EVAL-AD7751EB | Energy Metering IC With On-Chip Fault Detection |
| EVAL-AD7755EB | Energy Metering IC with Pulse Output |
| EVAL-AD7783EB | Read-Only, Pin Configured 24-Bit ADC with Excitation Current Sources |
| EVAL-AD7843CB | Touch Screen Digitizer |
| EVAL-AD7851CB | 14-Bit 333 kSPS Serial A/D Converter |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| EVAL-AD7731EBZ | 功能描述:BOARD EVALUATION FOR AD7731 RoHS:是 類別:編程器，開發(fā)系統(tǒng) >> 評估板 - 模數(shù)轉換器 (ADC) 系列:- 產(chǎn)品培訓模塊:Obsolescence Mitigation Program 標準包裝:1 系列:- ADC 的數(shù)量:1 位數(shù):12 采樣率（每秒）:94.4k 數(shù)據(jù)接口:USB 輸入范圍:±VREF/2 在以下條件下的電源（標準）:- 工作溫度:-40°C ~ 85°C 已用 IC / 零件:MAX11645 已供物品:板，軟件 |
| EVAL-AD7732EB | 制造商:Analog Devices 功能描述:2-CHANNEL, ??10 V INPUT RANGE, HIGH THROUGHPUT, 24-BIT ADC |
| EVAL-AD7732EBZ | 功能描述:BOARD EVAL FOR AD7732 RoHS:是 類別:編程器，開發(fā)系統(tǒng) >> 評估板 - 模數(shù)轉換器 (ADC) 系列:- 產(chǎn)品培訓模塊:Obsolescence Mitigation Program 標準包裝:1 系列:- ADC 的數(shù)量:1 位數(shù):12 采樣率（每秒）:94.4k 數(shù)據(jù)接口:USB 輸入范圍:±VREF/2 在以下條件下的電源（標準）:- 工作溫度:-40°C ~ 85°C 已用 IC / 零件:MAX11645 已供物品:板，軟件 |
| EVAL-AD7734EBZ | 功能描述:BOARD EVALUATION FOR AD7734 RoHS:是 類別:編程器，開發(fā)系統(tǒng) >> 評估板 - 模數(shù)轉換器 (ADC) 系列:- 產(chǎn)品培訓模塊:Obsolescence Mitigation Program 標準包裝:1 系列:- ADC 的數(shù)量:1 位數(shù):12 采樣率（每秒）:94.4k 數(shù)據(jù)接口:USB 輸入范圍:±VREF/2 在以下條件下的電源（標準）:- 工作溫度:-40°C ~ 85°C 已用 IC / 零件:MAX11645 已供物品:板，軟件 |
| EVAL-AD7738EB | 制造商:Analog Devices 功能描述:Evaluation Board For AD7738 ADC 制造商:Analog Devices 功能描述:EVALUATION BOARD I.C. - Bulk |
發(fā)布緊急采購，3分鐘左右您將得到回復。