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參數(shù)資料
| 型號： | ADS7806PB |
| 英文描述： | Low-Power 12-Bit Sampling CMOS ANALOG-to-DIGITAL CONVERTER |
| 中文描述： | 低功耗12位采樣CMOS模擬數(shù)字轉換器 |
| 文件頁數(shù)： | 18/18頁 |
| 文件大?。?/td> | 209K |
| 代理商： | ADS7806PB |
18
ADS7806
SPI INTERFACE
The SPI interface is generally only capable of 8-bit data
transfers. For some microcontrollers with SPI interfaces, it
might be possible to receive data in a similar manner as
shown for the QSPI interface in Figure 12. The
microcontroller will need to fetch the 8 most significant bits
before the contents are overwritten by the least significant
bits.
A modified version of the QSPI interface shown in Figure 13
might be possible. For most microcontrollers with SPI inter-
face, the automatic generation of the start-of-conversion
pulse will be impossible and will have to be done with
software. This will limit the interface to ‘DC’ applications
due to the insufficient jitter performance of the convert pulse
itself.
DSP56000 INTERFACING
The DSP56000 serial interface has an SPI compatibility
mode with some enhancements. Figure 14 shows an inter-
face between the ADS7806 and the DSP56000 which is very
similar to the QSPI interface seen in Figure 12. As men-
tioned in the QSPI section, the DSP56000 must be pro-
grammed to enable the interface when a LOW to HIGH
transition on SC1 is observed (BUSY going HIGH at the end
of conversion).
The DSP56000 can also provide the convert pulse by includ-
ing a monostable multi-vibrator as seen in Figure 15. The
receive and transmit sections of the interface are decoupled
(asynchronous mode) and the transmit section is set to
generate a word length frame sync every other transmit
frame (frame rate divider set to two). The prescale modulus
should be set to five.
The monostable multi-vibrator in this circuit will provide
varying pulse widths for the convert pulse. The pulse width
will be determined by the external R and C values used with
the multi-vibrator. The 74HCT123N data sheet shows that
the pulse width is (0.7)RC. Choosing a pulse width as close
to the minimum value specified in this data sheet will offer
the best performance. See the
Starting A Conversion
sec-
tion of this data sheet for details on the conversion pulse
width.
The maximum conversion rate for a 20.48MHz DSP56000
is 35.6kHz. If a slower oscillator can be tolerated on the
DSP56000, a conversion rate of 40kHz can be achieved by
using a 19.2MHz clock and a prescale modulus of four.
FIGURE 15. DSP56000 Interface to the ADS7806. Processor Initiates Conversions.
R
EXT1
C
EXT1
Q1
B1
CLR1
A1
R/C
DATACLK
SDATA
CS
EXT/INT
BYTE
ADS7806
74HCT123N
SC2
SC0
SRD
DSP56000
SYN = 0 (Asychronous)
GCK = 1 (Gated clock)
SCD2 = 1 (SC2 is an output)
SHFD = 0 (Shift MSB first)
WL1 = 0 WL0 = 1 (Word length = 16 bits)
R
+5V
C
+5V
R/C
BUSY
SDATA
DATACLK
CS
EXT/INT
BYTE
ADS7806
SC1
SRD
SCO
DSP56000
SYN = 0 (Asychronous)
GCK = 1 (Gated clock)
SCD1 = 0 (SC1 is an input)
SHFD = 0 (Shift MSB first)
WL1 = 0 WL0 = 1 (Word length = 12 bits)
Convert Pulse
FIGURE 14. DSP56000 Interface to the ADS7806.
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| ADS7806UB | Low-Power 12-Bit Sampling CMOS ANALOG-to-DIGITAL CONVERTER |
| ADS7815 | 16-Bit 250kHz Sampling CMOS ANALOG-to-DIGITAL CONVERTER |
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相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| ADS7806PBG4 | 功能描述:模數(shù)轉換器 - ADC Low-Power 12-Bit Sampling CMOS RoHS:否 制造商:Texas Instruments 通道數(shù)量:2 結構:Sigma-Delta 轉換速率: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 安裝風格:SMD/SMT 封裝 / 箱體:VQFN-32 |
| ADS7806PG4 | 功能描述:模數(shù)轉換器 - ADC Low-Power 12-Bit Sampling CMOS RoHS:否 制造商:Texas Instruments 通道數(shù)量:2 結構:Sigma-Delta 轉換速率: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 安裝風格:SMD/SMT 封裝 / 箱體:VQFN-32 |
| ADS7806U | 功能描述:模數(shù)轉換器 - ADC Low-Power 12-Bit Sampling CMOS RoHS:否 制造商:Texas Instruments 通道數(shù)量:2 結構:Sigma-Delta 轉換速率: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 安裝風格:SMD/SMT 封裝 / 箱體:VQFN-32 |
| ADS7806U | 制造商:Texas Instruments 功能描述:12BIT ADC LOW POWER SERIAL 7806 |
| ADS7806U/1K | 功能描述:模數(shù)轉換器 - ADC Low-Power 12-Bit Sampling CMOS RoHS:否 制造商:Texas Instruments 通道數(shù)量:2 結構:Sigma-Delta 轉換速率: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 安裝風格:SMD/SMT 封裝 / 箱體:VQFN-32 |
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