 |
Motor de Búsqueda de Datasheet de Componentes Electrónicos |
|
|
Motor de Búsqueda de Datasheet de Componentes Electrónicos |
|
AD8221BRZ-R7 Datasheet(PDF) 17 Page - Analog Devices |
|
|
|||||||||||||||||||||||||||||
AD8221BRZ-R7 Datasheet(HTML) 17 Page - Analog Devices |
|
|
17 / 24 page  AD8221 Rev. C | Page 17 of 24 THEORY OF OPERATION C1 C2 +VS +VS +IN –IN –VS –VS 10k Ω 10k Ω 10k Ω 400 Ω 400 Ω 10k Ω REF OUTPUT IB COMPENSATION IB COMPENSATION +VS –VS +VS –VS +VS VB I I R1 24.7k Ω 24.7k Ω RG Q1 R2 Q2 –VS +VS –VS A2 A1 A3 Figure 43. Simplified Schematic The AD8221 is a monolithic instrumentation amplifier based on the classic 3-op amp topology. Input transistors Q1 and Q2 are biased at a fixed current so that any differential input signal forces the output voltages of A1 and A2 to change accordingly. A signal applied to the input creates a current through RG, R1, and R2, such that the outputs of A1 and A2 deliver the correct voltage. Topologically, Q1, A1, R1 and Q2, A2, R2 can be viewed as precision current feedback amplifiers. The amplified differential and common-mode signals are applied to a difference amplifier that rejects the common-mode voltage but amplifies the differential voltage. The difference amplifier employs innovations that result in low output offset voltage as well as low output offset voltage drift. Laser-trimmed resistors allow for a highly accurate in-amp with gain error typically less than 20 ppm and CMRR that exceeds 90 dB (G = 1). Using superbeta input transistors and an IB compensation scheme, the AD8221 offers extremely high input impedance, low IB, low IB drift, low IOS, low input bias current noise, and extremely low voltage noise of 8 nV/√Hz. The transfer function of the AD8221 is G R G kΩ 4 . 49 1+ = Users can easily and accurately set the gain using a single standard resistor. Because the input amplifiers employ a current feedback architecture, the gain-bandwidth product of the AD8221 increases with gain, resulting in a system that does not suffer from the expected bandwidth loss of voltage feedback architectures at higher gains. To maintain precision even at low input levels, special attention was given to the design and layout of the AD8221, resulting in an in-amp whose performance satisfies the most demanding applications. A unique pinout enables the AD8221 to meet a CMRR specification of 80 dB at 10 kHz (G = 1) and 110 dB at 1 kHz (G = 1000). The balanced pinout, shown in Figure 44, reduces the parasitics that had, in the past, adversely affected CMRR performance. In addition, the new pinout simplifies board layout because associated traces are grouped together. For example, the gain setting resistor pins are adjacent to the inputs, and the reference pin is next to the output. 8 7 6 5 1 2 3 4 –IN RG RG +VS VOUT REF –VS +IN TOP VIEW AD8221 Figure 44. Pinout Diagram |
|
|
Enlace URL |
| ¿ALLDATASHEET es útil para Ud.? [ DONATE ] |
Todo acerca de Alldatasheet | Publicidad | Contáctenos | Política de Privacidad | Enlace a la hoja de datos | Intercambio de Enlaces | Lista de Fabricantes 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 |
Mexican ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
