参数资料
| 型号： | SX8724E082TDT |
| 厂商： | Semtech |
| 文件页数： | 30/53页 |
| 文件大小： | 0K |
| 描述： | IC DAS PRESS/TEMP SENS 16MLPQ |
| 标准包装： | 1 |
| 系列： | ZoomingADC™ |
| 类型： | 数据采集系统（DAS） |
| 输入类型： | 差分 |
| 输出类型： | 数字 |
| 接口： | I²C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 16-VQFN 裸露焊盘 |
| 供应商设备封装： | 16-MLPQ（4x4） |
| 包装： | 标准包装 |
| 产品目录页面： | 585 (CN2011-ZH PDF) |
| 其它名称： | SX8724E082TDTDKR |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页第15页第16页第17页第18页第19页第20页第21页第22页第23页第24页第25页第26页第27页第28页第29页当前第30页第31页第32页第33页第34页第35页第36页第37页第38页第39页第40页第41页第42页第43页第44页第45页第46页第47页第48页第49页第50页第51页第52页第53页
ADVANCED COMMUNICATIONS & SENSING
V1.23 2009 Semtech Corp.
www.semtech.com
36
SX8724
ZoomingADC for Pressure and Temperature Sensing
Switched Capacitor Principle
Basically, a switched capacitor is a way to emulate a resistor by using a capacitor. The capacitors are much
easier to realize on CMOS technologies and they show a very good matching precision.
Figure 19 - The Switched Capacitor Principle
A resistor is characterized by the current that flows through it (positive current leaves node V1):
R
V
I
2
1
=
(A)
Equation 22
One can verify that the mean current leaving node V1 with a capacitor switched at frequency f is:
(
) C
f
V
I
=
2
1
(A)
Equation 23
Therefore as a mean value, the switched capacitor
C
f
1
is equivalent to a resistor.
It is important to consider that this is only a mean value. If the current is not integrated (low impedance source),
the impedance is infinite during the whole time but the transition.
What does it mean for the ZoomingADC?
If the fs clock is reduced, the mean impedance is increased. By dividing the fs clock by a factor 10, the
impedance is increased by a factor 10.
One can reduce the capacitor that is switched by using an amplifier set to its minimal gain. In particular if PGA1
is used with gain 1, its mean impedance is 10x bigger than when it is used with gain 10.
Figure 20 - The Switched Capacitor Principle
One can increase the effective impedance by increasing the electrical bandwidth of the sensor node so that the
switching current is absorbed through the sensor before the switching period is over. Measuring the sensor
node will show short voltage spikes at the frequency fs, but these will not influence the measurement. Whereas
if the bandwidth of the node is lower, no spikes will arise, but a small offset can be generated by the integration
of the charges generated by the switched capacitors, this corresponds to the mean impedance effect.
Note:
One can increase the mean input impedance of the ZoomingADC by lowering the acquisition clock fs.
One can increase the mean input impedance of the ZoomingADC by decreasing the gain of the first enabled amplifier.
One can increase the effective input impedance of the ZoomingADC by having a source with a high electrical bandwidth (sensor electrical
bandwidth much higher than fs).
Sensor
C
ZoomingADC (model)
V
1
f
V
2
Sensor
impedence
Node
Capacitance
Current
integration
V
1
V
2
R
V
1
f
V
2
相关PDF资料 |
PDF描述 |
|---|---|
| SX8725CWLTDT | IC DAS ADC 16BIT I2C/SRL |
| SX8725E083TDT | IC DAS PRESS/TEMP SENS 12MLPD |
| SY10E445JC | IC CONV 4-BIT SER/PAR 28-PLCC |
| SY10E446JC TR | IC CONV 4-BIT SER/PAR 28-PLCC |
| SY54017ARMG TR | IC MULTIPLEXER DUAL 1X1 16MLF |
相关代理商/技术参数 |
参数描述 |
|---|---|
| SX8724E082TRT | 功能描述:IC DAS PRESSURE/TEMP SENS 16MLPQ RoHS:是 类别:集成电路 (IC) >> 接口 - 传感器和探测器接口 系列:ZoomingADC™ 其它有关文件:Automotive Product Guide 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:74 系列:- 类型:触控式传感器 输入类型:数字 输出类型:数字 接口:JTAG，串行 电流 - 电源:100µA 安装类型:表面贴装 封装/外壳:20-TSSOP（0.173"，4.40mm 宽） 供应商设备封装:20-TSSOP 包装:管件 |
| SX8724EVK | 制造商:Semtech Corporation 功能描述:Evaluation Board for SX8724E082TRT Data Acquisition System |
| SX8724S | 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:ZoomingADC for sensing data acquisition |
| SX8724SEVK | 制造商:Semtech Corporation 功能描述: 制造商:Semtech Corporation 功能描述:Evaluation Kit for SX8724S |
| SX8724SWLTDT | 制造商:Semtech Corporation 功能描述:3 INPUTS ZOOMING ADC WITH SPI |
发布紧急采购，3分钟左右您将得到回复。