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參數資料
| 型號： | AD7994 |
| 廠商： | Analog Devices, Inc. |
| 英文描述： | 4-Channel, 12-/10-Bit ADCs with I2C Compatible Interface in 16-Lead TSSOP |
| 中文描述： | 4通道，12-/10-Bit ADC的16 - I2C兼容接口的無鉛TSSOP封裝 |
| 文件頁數： | 24/27頁 |
| 文件大小： | 277K |
| 代理商： | AD7994 |
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AD7994/AD7993
–24–
REV. PrF
PRELIMINARY TECHNICAL DATA
Placing the AD7994-1/AD7993-1 into High-speed Mode.
Hs-Mode communication commences after the master
addresses all devices connected to the bus with the Master
code, 00001XXX, to indicate that a High-Speed Mode
transfer is to begin. No device connected to the bus is
allowed to Acknowledge the High-Speed Master code,
therefore the code is followed by a not-Acknowledge, Fig-
Figure 15. Placing the part into Hs Mode
MODES OF OPERATION
When supplies are first applied to the AD7994/AD7993,
the ADC powers up in shutdown mode and will normally
remain in this shutdown state while not converting. There
are three different methods of initiating a conversion on
the AD7994/AD7993.
Mode 1 - Using CONVST Pin.
A conversion can be initiated on the AD7994/AD7993 by
pulsing the
CONVST
signal. The conversion clock for
the part is internally generated so no external clock is
required, except when reading from, or writing to the
serial port. On the rising edge of
CONVST
the AD7994/
AD7993 will begin to power up, see point A on Figure
16. The power up time from shutdown mode for the
AD7994/AD7993 is approximately 1 us, the
CONVST
signal must remain high for 1 μs for the part to power up
fully. Then
CONVST
can be brought low after this time.
The falling edge of the
CONVST
signal places the track
and hold into hold mode and a conversion is also initiated
at this point, see point B Figure 16. When the conversion
is complete, approximately 2 us later, the part will return
to shutdown (see point C Figure 16) and remain so until
the next rising edge of
CONVST
. The master can then
read address the ADC to obtain the conversion result. The
address point register must be pointing to the conversion
result register in order to read back the conversion result.
If the
CONVST
pulse does not remain high for more
than 1 μs, then the falling edge of
CONVST
will still
initiate a conversion but the result will be invalid as the
AD7994/AD7993 will not be fully powered up when the
conversion takes place. The
CONVST
pin should not be
pulsed when reading from or writing to the serial port.
The Cycle Timer Register and bits C4 - C1 in the Ad-
dress Pointer Register should contain all 0’s to operate the
AD7994/AD7993 in this mode. The
CONVST
pin
should be tied low for all other Modes of operation. To
select an Analog Input Channel for conversion in this
mode, the user must write to the Configuration Register
and select the corresponding channel for conversion. To
set up a sequence of channels to be converted on with each
CONVST
pulse, set the corresponding channel bits in
the Configuration register, see Table V.
ure 15. The master must then issue a repeated start fol-
lowed by the device Address with a R/
W
bit. The selected
device will then acknowledge its address.
All devices continue to operate in Hs-Mode until such a
time as the master issues a STOP condition. When the
STOP condition is issued the devices all return to F/S
Mode.
Figure 16. Mode 1 Operation
1
1
9
SCL
9
S
7-BIT ADDRESS
R
A
FIRST DATA BYTE (MSBs)
A
SECOND DATA BYTE (LSBs)
9
P
SDA
tCONVERT
tPOWER-UP
B
A
C
SDA
ACK. BY
AD7994/3
START BY
MASTER
HS-MODE MASTER CODE
SERIAL BUS ADDRESS BYTE
NACK.
1
9
1
9
0
1
A2
A1
A0
X
X
1
0
0
0
SCL
0
0
A3
X
Sr
FAST MODE
HIGH-SPEED MODE
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PDF描述 |
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| AD7993BRU-1 | 4-Channel, 12-/10-Bit ADCs with I2C Compatible Interface in 16-Lead TSSOP |
| AD7997 | 8-Channel, 10- and 12-Bit ADCs with I2CCompatible |
| AD7997BRU-0 | 8-Channel, 10- and 12-Bit ADCs with I2CCompatible |
| AD7997BRU-0REEL | 8-Channel, 10- and 12-Bit ADCs with I2CCompatible |
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相關代理商/技術參數 |
參數描述 |
|---|---|
| AD7994-0 | 制造商:AD 制造商全稱:Analog Devices 功能描述:4-Channel, 10- and 12-Bit ADCs with I2C Compatible Interface in 16-Lead TSSOP |
| AD7994-1 | 制造商:AD 制造商全稱:Analog Devices 功能描述:4-Channel, 10- and 12-Bit ADCs with I2C Compatible Interface in 16-Lead TSSOP |
| AD7994BRU-0 | 功能描述:IC ADC 12BIT 4CHAN I2C 16TSSOP RoHS:否 類別:集成電路 (IC) >> 數據采集 - 模數轉換器 系列:- 標準包裝:1,000 系列:- 位數:16 采樣率（每秒）:45k 數據接口:串行 轉換器數目:2 功率耗散（最大）:315mW 電壓電源:模擬和數字 工作溫度:0°C ~ 70°C 安裝類型:表面貼裝 封裝/外殼:28-SOIC（0.295"，7.50mm 寬） 供應商設備封裝:28-SOIC W 包裝:帶卷 (TR) 輸入數目和類型:2 個單端，單極 |
| AD7994BRU-0REEL | 功能描述:IC ADC 12BIT 4CHAN I2C 16TSSOP RoHS:否 類別:集成電路 (IC) >> 數據采集 - 模數轉換器 系列:- 標準包裝:1,000 系列:- 位數:16 采樣率（每秒）:45k 數據接口:串行 轉換器數目:2 功率耗散（最大）:315mW 電壓電源:模擬和數字 工作溫度:0°C ~ 70°C 安裝類型:表面貼裝 封裝/外殼:28-SOIC（0.295"，7.50mm 寬） 供應商設備封裝:28-SOIC W 包裝:帶卷 (TR) 輸入數目和類型:2 個單端，單極 |
| AD7994BRU-1 | 制造商:Analog Devices 功能描述:ADC Single SAR 188ksps 12-bit Serial 16-Pin TSSOP 制造商:Rochester Electronics LLC 功能描述: |
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