 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
AD8221ARZ-R7 Datasheet(PDF) 20 Page - Analog Devices |
|
|
|||||||||||||||||||||||||||||
AD8221ARZ-R7 Datasheet(HTML) 20 Page - Analog Devices |
|
|
20 / 24 page  AD8221 Rev. C | Page 20 of 24 RF INTERFERENCE RF rectification is often a problem when amplifiers are used in applications where there are strong RF signals. The disturbance can appear as a small dc offset voltage. High frequency signals can be filtered with a low-pass RC network placed at the input of the instrumentation amplifier, as shown in Figure 49. The filter limits the input signal bandwidth according to the following relationship: ) 2 ( π 2 1 C D Diff C C R FilterFreq + = C CM RC FilterFreq π 2 1 = where CD ≥ 10CC. R R AD8221 +15V +IN –IN 0.1µF 10µF 10µF 0.1µF REF VOUT –15V R1 499 Ω CD CC CC 10nF 1nF 1nF 4.02k Ω 4.02k Ω Figure 49. RFI Suppression CD affects the difference signal, and CC affects the common- mode signal. Values of R and CC should be chosen to minimize RFI. Mismatch between the R × CC at the positive input and the R × CC at the negative input degrades the CMRR of the AD8221. By using a value of CD one magnitude larger than CC, the effect of the mismatch is reduced, and therefore, performance is improved. PRECISION STRAIN GAGE The low offset and high CMRR over frequency of the AD8221 make it an excellent candidate for bridge measurements. As shown in Figure 50, the bridge can be directly connected to the inputs of the amplifier. +5V +2.5V 10µF 0.1µF AD8221 +IN –IN R 350 Ω 350 Ω 350 Ω 350 Ω + – Figure 50. Precision Strain Gage CONDITIONING ±10 V SIGNALS FOR A +5 V DIFFERENTIAL INPUT ADC There is a need in many applications to condition ±10 V signals. However, many of today’s ADCs and digital ICs operate on much lower, single-supply voltages. Furthermore, new ADCs have differential inputs because they provide better common- mode rejection, noise immunity, and performance at low supply voltages. Interfacing a ±10 V, single-ended instrumentation amplifier to a +5 V, differential ADC can be a challenge. Interfacing the instrumentation amplifier to the ADC requires attenuation and a level shift. A solution is shown in Figure 51. +12V +IN –IN 0.1µF 10µF 0.1µF 10µF –12V R3 1k Ω +2.5V R4 1k Ω REF R5 499 Ω R2 10k Ω R1 10k Ω C1 470pF +12V 0.1µF 0.1µF –12V +12V +5V +5V 0.1µF 10nF 0.1µF –12V +12V 0.1µF 0.1µF –12V R6 27.4 Ω R7 27.4 Ω C2 220µF 10µF 0.1µF 22µF +5V 2.5V 220nF 10nF AD8221 AD8022 OP27 AD8022 AD7723 VIN(+) AVDD AGND DGND REF1 REF2 DVDD VIN(–) AD780 GND +VIN VOUT (½) (½) Figure 51. Interfacing to a Differential Input ADC |
|
|
Link URL |
| Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Datasheet Upload | Contact us | Privacy Policy | Link to Datasheet | Link Exchange | Manufacturer List 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 |
English ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
