 |
数据搜索系统，热门电子元器件搜索 |
|
|
数据搜索系统，热门电子元器件搜索 |
|
TLA2022IRUGR 数据表(PDF) 10 Page - Texas Instruments |
|
|
||||||||||||||||||||||||||||||
TLA2022IRUGR 数据表(HTML) 10 Page - Texas Instruments |
|
|
10 / 33 page  t SAMPLE ON OFF S 1 S 2 OFF ON Equivalent Circuit fMOD = 250 kHz ZCM ZDIFF ZCM AINN AINP 0.7 V 0.7 V S1 S1 CA1 CB CA2 S2 S2 0.7 V 0.7 V AINN AINP 10 TLA2021, TLA2022, TLA2024 SBAS846 – NOVEMBER 2017 www.ti.com Product Folder Links: TLA2021 TLA2022 TLA2024 Submit Documentation Feedback Copyright © 2017, Texas Instruments Incorporated Feature Description (continued) 8.3.2 Analog Inputs The TLA202x use a switched-capacitor input stage where capacitors are continuously charged and then discharged to measure the voltage between AINP and AINN. The frequency at which the input signal is sampled is referred to as the sampling frequency or the modulator frequency (fMOD). The TLA202x have a 1-MHz internal oscillator that is further divided by a factor of 4 to generate fMOD at 250 kHz. The capacitors used in this input stage are small, and to external circuitry, the average loading appears resistive. Figure 9 shows this structure. The capacitor values set the resistance and switching rate. Figure 10 shows the timing for the switches in Figure 9. During the sampling phase, switches S1 are closed. This event charges CA1 to VAINP, CA2 to VAINN, and CB to (VAINP – VAINN). During the discharge phase, S1 is first opened and then S2 is closed. CA1 and CA2 then discharge to approximately 0.7 V and CB discharges to 0 V. This charging draws a very small transient current from the source driving the TLA202x analog inputs. The average value of this current can be used to calculate the effective impedance (Zeff), where Zeff = VIN / IAVERAGE. Figure 9. Simplified Analog Input Circuit Figure 10. S1 and S2 Switch Timing The common-mode input impedance is measured by applying a common-mode signal to the shorted AINP and AINN inputs and measuring the average current consumed by each pin. The common-mode input impedance changes depending on the full-scale range, but is approximately 6 M Ω for the default full-scale range. In Figure 9, the common-mode input impedance is ZCM. The differential input impedance is measured by applying a differential signal to the AINP and AINN inputs where one input is held at 0.7 V. The current that flows through the pin connected to 0.7 V is the differential current and scales with the full-scale range. In Figure 9, the differential input impedance is ZDIFF. Consider the typical value of the input impedance. Unless the input source has a low impedance, the TLA202x input impedance may affect the measurement accuracy. For sources with high-output impedance, buffering may be necessary. Active buffers introduce noise, offset, and gain errors. Consider all of these factors in high- accuracy applications. The clock oscillator frequency drifts slightly with temperature; therefore, the input impedances also drift. For most applications, this input impedance drift is negligible and can be ignored. |
类似零件编号 - TLA2022IRUGR |
|
类似说明 - TLA2022IRUGR |
|
|
链接网址 |
| 隐私政策 |
| ALLDATASHEETCN.COM |
| ALLDATASHEET是否为您带来帮助? [ DONATE ] |
关于 Alldatasheet | 广告服务 | 联系我们 | 隐私政策 | 链接交换 | 制造商名单 All Rights Reserved©Alldatasheet.com |
| Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
|
Family Site : ic2ic.com |
icmetro.com |
Chinese ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
