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| 型号： | ADS1222IPWT |
| 厂商： | Texas Instruments |
| 文件页数： | 7/26页 |
| 文件大小： | 0K |
| 描述： | IC 24BIT ADC W/2CH MUX 14-TSSOP |
| 产品培训模块： | Data Converter Basics |
| 视频文件： | Nuts and Bolts of the Delta-Sigma Converter |
| 标准包装： | 1 |
| 位数： | 24 |
| 采样率（每秒）： | 240 |
| 数据接口： | 串行 |
| 转换器数目： | 1 |
| 功率耗散（最大）： | 2.25mW |
| 电压电源： | 模拟和数字 |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 14-TSSOP（0.173"，4.40mm 宽） |
| 供应商设备封装： | 14-TSSOP |
| 包装： | 标准包装 |
| 输入数目和类型： | 4 个单端，单极；2 个差分，双极 |
| 其它名称： | 296-17321-6 |
ADS1222
SBAS314B APRIL 2004 REVISED JANUARY 2009
www.ti.com
15
SELF-CALIBRATION
Self-calibration can be initiated at any time, although in
many applications the ADS1222 drift performance is so
good that the self-calibration performed automatically
at power-up is all that is needed. To initiate
self-calibration, apply at least two additional SCLKs
after retrieving 24 bits of data. Figure 27 shows the
timing pattern. The 25th SCLK will send DRDY/DOUT
high. The falling edge of the 26th SCLK will begin the
calibration cycle. Additional SCLK pulses may be sent
after the 26th SCLK; however, activity on SCLK should
be minimized during calibration for best results.
When the calibration is complete, DRDY/DOUT goes
low, indicating that new data is ready. There is no need
to alter the analog input signal applied to the ADS1222
during calibration; the input pins are disconnected
within the A/D converter and the appropriate signals are
applied
internally
and
automatically.
The
first
conversion after a calibration is fully settled and valid for
use. The time required for a calibration depends on two
independent signals: the falling edge of SCLK and an
internal clock derived from CLK. Variations in the
internal calibration values will change the time required
for calibration (t8) within the range given by the min/max
specs. t11 and t12 described in the next section are
affected likewise.
STANDBY MODE
Standby
mode
dramatically
reduces
power
consumption (typically < 1
W with CLK stopped) by
shutting down all of the active circuitry. To enter Standby
mode, simply hold SCLK high after DRDY/DOUT goes
low, as shown in Figure 28. Standby mode can be
initiated at any time during readback; it is not necessary
to retrieve all 24 bits of data beforehand. Note that
during standby mode, the buffer must be disabled to
prevent loading of the inputs.
When t11 has passed with SCLK held high, Standby mode
will activate. DRDY/DOUT stays high when Standby
mode begins. SCLK must remain high to stay in Standby
mode. To exit Standby mode (wakeup), set SCLK low.
The first data after exiting Standby mode is valid. It is not
necessary to stop CLK during Standby mode, but doing
so will further reduce the digital supply current.
Standby Mode With Self-Calibration
Self-calibration can be set to run immediately after
exiting Standby mode. This is useful when the
ADS1222 is put in Standby mode for long periods of
time and self-calibration is desired afterwards to
compensate
for
temperature
or
supply
voltage
changes.
To force a self-calibration with Standby mode, shift 25
bits out before taking SCLK high to enter Standby
mode. Self-calibration then begins after wakeup.
Figure 29 shows the appropriate timing. Note the extra
time needed after wakeup for calibration before data is
ready. The first data after Standby mode with
self-calibration is fully settled and can be used.
23
DRDY/DOUT
SCLK
1
24
t
8
25
26
23
22
21
0
Data Ready After Calibration
Calibration Begins
SYMBOL
DESCRIPTION
MIN
MAX
UNITS
t8(1)
First data ready after calibration
77.1
77.9
ms
(1) Values given for fCLK = 2MHz. For different fCLK frequencies, scale proportional to CLK period.
Figure 27. Self-Calibration Timing
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相关代理商/技术参数 |
参数描述 |
|---|---|
| ADS1222IPWT | 制造商:Texas Instruments 功能描述:IC 24-BIT ADC 2 CH DIFF I/P MULTI |
| ADS1222IPWTG4 | 功能描述:模数转换器 - ADC 24-Bit Conv w/2-Ch Diff Input Mltplxer RoHS:否 制造商:Texas Instruments 通道数量:2 结构:Sigma-Delta 转换速率:125 SPs to 8 KSPs 分辨率:24 bit 输入类型:Differential 信噪比:107 dB 接口类型:SPI 工作电源电压:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-32 |
| ADS1224 | 制造商:BB 制造商全称:BB 功能描述:24-Bit Analog-to-Digital Converter with 4-Channel Differential Input Multiplexer |
| ADS1224EVM | 功能描述:数据转换 IC 开发工具 ADS1224 Eval Mod RoHS:否 制造商:Texas Instruments 产品:Demonstration Kits 类型:ADC 工具用于评估:ADS130E08 接口类型:SPI 工作电源电压:- 6 V to + 6 V |
| ADS1224IPWR | 功能描述:模数转换器 - ADC 24-bit 240SPS RoHS:否 制造商:Texas Instruments 通道数量:2 结构:Sigma-Delta 转换速率:125 SPs to 8 KSPs 分辨率:24 bit 输入类型:Differential 信噪比:107 dB 接口类型:SPI 工作电源电压:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-32 |
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