Motore di ricerca datesheet componenti elettronici
  Italian  ▼
ALLDATASHEETIT.COM

X  

AD8253 Scheda tecnica(PDF) 11 Page - Analog Devices

Il numero della parte AD8253
Spiegazioni elettronici  Wide Supply Range, Rail-to-Rail Output Instrumentation Amplifier
Download  20 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Produttore elettronici  AD [Analog Devices]
Homepage  http://www.analog.com
Logo AD - Analog Devices

AD8253 Scheda tecnica(HTML) 11 Page - Analog Devices

Back Button AD8253 Datasheet HTML 7Page - Analog Devices AD8253 Datasheet HTML 8Page - Analog Devices AD8253 Datasheet HTML 9Page - Analog Devices AD8253 Datasheet HTML 10Page - Analog Devices AD8253 Datasheet HTML 11Page - Analog Devices AD8253 Datasheet HTML 12Page - Analog Devices AD8253 Datasheet HTML 13Page - Analog Devices AD8253 Datasheet HTML 14Page - Analog Devices AD8253 Datasheet HTML 15Page - Analog Devices Next Button
Zoom Inzoom in Zoom Outzoom out
 11 / 20 page
background image
Preliminary Technical Data
AD8426
Rev. PrD | Page 11 of 20
THEORY OF OPERATION
A3
R2
24.7kΩ
R1
24.7kΩ
A1
A2
Q2
Q1
–IN
+IN
+VS
–VS
R3
50kΩ
R4
50kΩ
R5
50kΩ
RB
RB
+VS
–VS
VOUT
REF
NODE 1
NODE 2
RG
VBIAS
+VS
–VS
+VS
–VS
NODE 4
NODE 3
R6
50kΩ
DIFFERENCE
AMPLIFIER STAGE
GAIN STAGE
ESD AND
OVERVOLTAGE
PROTECTION
ESD AND
OVERVOLTAGE
PROTECTION
–VS
Figure 7. Simplified Schematic
ARCHITECTURE
The AD8426 is based on the classic three op amp topology. This
topology has two stages: a gain stage (preamplifier) to provide
differential amplification, followed by a difference amplifier to
remove the common-mode voltage. Figure 7 shows a simplified
schematic of one of the instrumentation amplifiers in the AD8426.
The first stage works as follows: to maintain a constant voltage
across the bias resistor, RB, A1 must keep Node 3 at a constant
diode drop above the positive input voltage. Similarly, A2 keeps
Node 4 at a constant diode drop above the negative input voltage.
Therefore, a replica of the differential input voltage is placed
across the gain setting resistor, RG. The current that flows across
this resistance must also flow through the R1 and R2 resistors,
creating a gained differential signal between the A2 and A1 out-
puts. Note that, in addition to a gained differential signal, the
original common-mode signal, shifted a diode drop up, is also
still present.
The second stage is a difference amplifier, composed of A3 and
four 50 kΩ resistors. The purpose of this stage is to remove the
common-mode signal from the amplified differential signal.
The transfer function of the AD8426 is
VOUT = G × (VIN+ − VIN−) + VREF
where:
G
R
G
49.4
1 
GAIN SELECTION
Placing a resistor across the RG terminals sets the gain of the
AD8426, which can be calculated by referring to Table 7 or by
using the following gain equation:
1
49.4
G
R
G
Table 7. Gains Achieved Using 1% Resistors
1% Standard Table Value of RG
Calculated Gain
49.9 kΩ
1.990
12.4 kΩ
4.984
5.49 kΩ
9.998
2.61 kΩ
19.93
1.00 kΩ
50.40
499 Ω
100.0
249 Ω
199.4
100 Ω
495.0
49.9 Ω
991.0
The AD8426 defaults to G = 1 when no gain resistor is used.
The tolerance and gain drift of the RG resistor should be added
to the AD8426 specifications to determine the total gain accu-
racy of the system. When the gain resistor is not used, gain
error and gain drift are minimal.
REFERENCE TERMINAL
The output voltage of the AD8426 is developed with respect to
the potential on the reference terminal. This is useful when the
output signal needs to be offset to a precise midsupply level. For
example, a voltage source can be tied to the REF pin to level-
shift the output so that the AD8426 can drive a single-supply
ADC. The REF pin is protected with ESD diodes and should
not exceed either +VS or −VS by more than 0.3 V.
For the best performance, source impedance to the REF
terminal should be kept below 2 Ω. As shown in Figure 8,
the reference terminal, REF, is at one end of a 50 kΩ resistor.
Additional impedance at the REF terminal adds to this 50 kΩ
resistor and results in amplification of the signal connected to
the positive input. The amplification from the additional RREF
can be computed by 2 × (50 kΩ + RREF)/100 kΩ + RREF.


Codice articolo simile - AD8253

Produttore elettroniciIl numero della parteScheda tecnicaSpiegazioni elettronici
logo
Analog Devices
AD8253 AD-AD8253 Datasheet
217Kb / 10P
   10 MHz, 20 V/關s, G = 1, 10, 100, 1000 i CMOS짰 Programmable Gain Instrumentation Amplifier
Rev. prA
AD8253 AD-AD8253 Datasheet
584Kb / 24P
   10 MHz, 20 V/關s, G = 1, 10, 100, 1000 iCMOS Programmable Gain Instrumentation Amplifier
REV. 0
AD8253 AD-AD8253 Datasheet
529Kb / 28P
   Wide Supply Range, Micropower,
REV. 0
AD8253 AD-AD8253 Datasheet
805Kb / 28P
   Wide Supply Range, Rail-to-Rail
REV. 0
AD8253 AD-AD8253 Datasheet
3Mb / 34P
   36V Fully-Differential Programmable-Gain Instrumentation Amplifier with 25pA Input Bias Current
More results

Descrizione simile - AD8253

Produttore elettroniciIl numero della parteScheda tecnicaSpiegazioni elettronici
logo
Analog Devices
AD8226 AD-AD8226_16 Datasheet
707Kb / 29P
   Wide Supply Range, Rail-to-Rail Output Instrumentation Amplifier
AD8426 AD-AD8426_16 Datasheet
625Kb / 29P
   Wide Supply Range, Rail-to-Rail Output Instrumentation Amplifier
AD8226ARMZ AD-AD8226ARMZ Datasheet
685Kb / 28P
   Wide Supply Range, Rail-to-Rail Output Instrumentation Amplifier
REV. A
AD8227 AD-AD8227_16 Datasheet
539Kb / 25P
   Wide Supply Range, Rail-to-Rail Output Instrumentation Amplifier
AD8226 AD-AD8226 Datasheet
547Kb / 16P
   Wide Supply Range, Rail-to-Rail Output Instrumentation Amplifier
Rev. PrA
logo
Texas Instruments
INA827 TI1-INA827_13 Datasheet
1Mb / 30P
[Old version datasheet]   Wide Supply Range, Rail-to-Rail Output Instrumentation Amplifier
logo
Analog Devices
AD8227 AD-AD8227 Datasheet
657Kb / 24P
   Wide Supply Range, Rail-to-Rail Output Instrumentation Amplifier
REV. 0
AD8420 AD-AD8420 Datasheet
256Kb / 10P
   Wide Supply Range, Rail-to-Rail Output Instrumentation Amplifier
Rev. PrD
AD8420 AD-AD8420_16 Datasheet
553Kb / 27P
   Wide Supply Range, Micropower, Rail-to-Rail Instrumentation Amplifier
logo
Texas Instruments
INA827 TI1-INA827 Datasheet
875Kb / 29P
[Old version datasheet]   Wide Supply Range, Rail-to-Rail Output Instrumentation Amplifier with a Minimum Gain of 5
More results


Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20


Scheda tecnica Scarica

Go To PDF Page


Link URL




Privacy Policy
ALLDATASHEETIT.COM
Lei ha avuto il aiuto da alldatasheet?  [ DONATE ] 

Di alldatasheet   |   Richest di pubblicita   |   contatti   |   Privacy Policy   |   scambio Link   |   Ricerca produttore
All Rights Reserved©Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  |   English : Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp
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