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参数资料
| 型号： | TLV1570IDW |
| 厂商： | TEXAS INSTRUMENTS INC |
| 元件分类： | ADC |
| 英文描述： | 8-CH 10-BIT SUCCESSIVE APPROXIMATION ADC, SERIAL ACCESS, PDSO20 |
| 封装： | GREEN, SOIC-20 |
| 文件页数： | 23/32页 |
| 文件大小： | 634K |
| 代理商： | TLV1570IDW |
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TLV1570
2.7 V TO 5.5 V 8-CHANNEL 10-BIT 1.25-MSPS
SERIAL ANALOG-TO-DIGITAL CONVERTER
SLAS169B – DECEMBER 1997– REVISED OCTOBER 2000
3
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
detailed description
analog-to-digital converter
The TLV1570 ADC uses the SAR architecture described in this section. The CMOS threshold detector in the
successive-approximation conversion system determines the value of each bit by examining the charge on a
series of binary-weighted capacitors (see Figure 1). In the first phase of the conversion process, the analog input
is sampled by closing the SC switch and all ST switches simultaneously. This action charges all of the capacitors
to the input voltage.
SC
Threshold
Detector
Node 512
REF –
REF+
ST
512
VI
To Output
Latches
REF –
ST
REF+
REF –
ST
REF+
REF –
ST
REF+
REF –
ST
REF+
ST
REF+
REF –
ST
REF+
REF –
ST
1
2
4
8
128
256
REF –
NOTE: REF– is tied to AGND
Figure 1. Simplified Model of the Successive-Approximation System
In the next phase of the conversion process, all ST and SC switches are opened and the threshold detector
begins identifying bits by identifying the charge (voltage) on each capacitor relative to the reference (REF–)
voltage (REF– is tied to AGND). In the switching sequence, ten capacitors are examined separately until all ten
bits are identified and then the charge-convert sequence is repeated. In the first step of the conversion phase,
the threshold detector looks at the first capacitor (weight = 512). Node 512 of this capacitor is switched to the
REF+ voltage, and the equivalent nodes of all the other capacitors on the ladder are switched to REF–. If the
voltage at the summing node is greater than the trip point of the threshold detector (approximately one-half VCC),
a bit 0 is placed in the output register and the 512-weight capacitor is switched to REF–. If the voltage at the
summing node is less than the trip point of the threshold detector, a bit 1 is placed in the register and the
512-weight capacitor remains connected to REF+ through the remainder of the successive-approximation
process. The process is repeated for the 256-weight capacitor, the 128-weight capacitor, and so forth down the
line until all bits are counted.
With each step of the successive-approximation process, the initial charge is redistributed among the
capacitors. The conversion process relies on charge redistribution to count and weigh the bits from MSB to LSB.
In the case of the TLV1570, REF– is tied to ground and REF+ is connected to the REF input.
The TLV1570 can be programmed to use the on-chip internal reference (DI6=1). The user can select between
two values of internal reference, 2.3 V or 3.8 V, using the control bit DI5.
During internal reference mode, the reference voltage is not output on the REF pin. Therefore it cannot be
decoupled to analog ground (AGND), which acts as the negative reference for the ADC, using an external
capacitor. Hence this mode requires the ground noise to be very low. The REF pin can be left open in this mode.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| TLV1570IDWG4 | 功能描述:模数转换器 - ADC 10-Bit 1.25 MSPS 8-Ch DSP 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 |
| TLV1570IDWR | 制造商:Texas Instruments 功能描述: |
| TLV1570IPW | 功能描述:模数转换器 - ADC 10bit 1.25MSPS Ser 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 |
| TLV1570IPWG4 | 功能描述:模数转换器 - ADC 10-Bit 1.25 MSPS 8-Ch DSP 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 |
| TLV1570IPWR | 功能描述:模数转换器 - ADC 10-Bit 1.25 MSPS 8-Ch DSP 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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