Motore di ricerca datesheet componenti elettronici
  Italian  ▼
ALLDATASHEETIT.COM

X  

AD624BD Scheda tecnica(PDF) 8 Page - Analog Devices

Il numero della parte AD624BD
Spiegazioni elettronici  Precision Instrumentation Amplifier
Download  17 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Produttore elettronici  AD [Analog Devices]
Homepage  http://www.analog.com
Logo AD - Analog Devices

AD624BD Scheda tecnica(HTML) 8 Page - Analog Devices

Back Button AD624BD Datasheet HTML 4Page - Analog Devices AD624BD Datasheet HTML 5Page - Analog Devices AD624BD Datasheet HTML 6Page - Analog Devices AD624BD Datasheet HTML 7Page - Analog Devices AD624BD Datasheet HTML 8Page - Analog Devices AD624BD Datasheet HTML 9Page - Analog Devices AD624BD Datasheet HTML 10Page - Analog Devices AD624BD Datasheet HTML 11Page - Analog Devices AD624BD Datasheet HTML 12Page - Analog Devices Next Button
Zoom Inzoom in Zoom Outzoom out
 8 / 17 page
background image
REV. C
AD624
–7–
AD624
+VS
VOUT
10k
1%
1k
10T
10k
1%
RG1
G = 100
G = 200
G = 500
RG2
–VS
200
0.1%
100k
1%
500
0.1%
1k
0.1%
INPUT
20V p-p
Figure 25. Settling Time Test Circuit
THEORY OF OPERATION
The AD624 is a monolithic instrumentation amplifier based on
a modification of the classic three-op-amp instrumentation
amplifier. Monolithic construction and laser-wafer-trimming
allow the tight matching and tracking of circuit components and
the high level of performance that this circuit architecture is ca-
pable of.
A preamp section (Q1–Q4) develops the programmed gain by
the use of feedback concepts. Feedback from the outputs of A1
and A2 forces the collector currents of Q1–Q4 to be constant
thereby impressing the input voltage across RG.
The gain is set by choosing the value of RG from the equation,
Gain =
40 k
RG
+ 1. The value of RG also sets the transconduct-
ance of the input preamp stage increasing it asymptotically to
the transconductance of the input transistors as RG is reduced
for larger gains. This has three important advantages. First, this
approach allows the circuit to achieve a very high open loop gain
of 3
× 108 at a programmed gain of 1000 thus reducing gain
related errors to a negligible 3 ppm. Second, the gain bandwidth
product which is determined by C3 or C4 and the input trans-
conductance, reaches 25 MHz. Third, the input voltage noise
reduces to a value determined by the collector current of the
input transistors for an RTI noise of 4 nV/
√Hz at G ≥ 500.
AD624
+VS
100
200
RG2
–VS
16.2k
+VS
1/2
AD712
9.09k
G1, 100, 200
1k
1 F
G500
100
1 F
1.62M
–VS
1 F
16.2k
1.82k
500
1/2
AD712
Figure 26. Noise Test Circuit
INPUT CONSIDERATIONS
Under input overload conditions the user will see RG + 100
and two diode drops (~1.2 V) between the plus and minus
inputs, in either direction. If safe overload current under all
conditions is assumed to be 10 mA, the maximum overload
voltage is ~
±2.5 V. While the AD624 can withstand this con-
tinuously, momentary overloads of
±10 V will not harm the
device. On the other hand the inputs should never exceed the
supply voltage.
The AD524 should be considered in applications that require
protection from severe input overload. If this is not possible,
external protection resistors can be put in series with the inputs
of the AD624 to augment the internal (50
Ω) protection resis-
tors. This will most seriously degrade the noise performance.
For this reason the value of these resistors should be chosen to
be as low as possible and still provide 10 mA of current limiting
under maximum continuous overload conditions. In selecting
the value of these resistors, the internal gain setting resistor and
the 1.2 volt drop need to be considered. For example, to pro-
tect the device from a continuous differential overload of 20 V
at a gain of 100, 1.9 k
Ω of resistance is required. The internal
gain resistor is 404
Ω; the internal protect resistor is 100 Ω.
There is a 1.2 V drop across D1 or D2 and the base-emitter
junction of either Q1 and Q3 or Q2 and Q4 as shown in Figure
27, 1400
Ω of external resistance would be required (700 Ω in
series with each input). The RTI noise in this case would be
4 KTRext
+(4 nV / Hz)2 = 6.2 nV / Hz
50
13
50 A
I1
50 A
C3
I2
50 A
R57
20k
R56
20k
500
SENSE
+IN
VO
REF
I4
50 A
200
100
4445
80.2
124
225.3
–IN
–VS
RG1 RG2
C4
VB
A2
R52
10k
R55
10k
A3
R53
10k
R54
10k
+VS
50
Q1, Q3
Q2,
Q4
A1
Figure 27. Simplified Circuit of Amplifier; Gain Is Defined
as (R56 + R57)/(RG) + 1. For a Gain of 1, RG Is an Open
Circuit.
INPUT OFFSET AND OUTPUT OFFSET
Voltage offset specifications are often considered a figure of
merit for instrumentation amplifiers. While initial offset may
be adjusted to zero, shifts in offset voltage due to temperature
variations will cause errors. Intelligent systems can often correct
for this factor with an autozero cycle, but there are many small-
signal high-gain applications that don’t have this capability.
Voltage offset and offset drift each have two components; input
and output. Input offset is that component of offset that is


Codice articolo simile - AD624BD

Produttore elettroniciIl numero della parteScheda tecnicaSpiegazioni elettronici
logo
Analog Devices
AD624BD AD-AD624BD Datasheet
691Kb / 15P
   Precision Instrumentation Amplifier
REV. C
More results

Descrizione simile - AD624BD

Produttore elettroniciIl numero della parteScheda tecnicaSpiegazioni elettronici
logo
Analog Devices
AD624 AD-AD624 Datasheet
691Kb / 15P
   Precision Instrumentation Amplifier
REV. C
logo
Burr-Brown (TI)
INA114AG BURR-BROWN-INA114AG Datasheet
430Kb / 13P
   Precision INSTRUMENTATION AMPLIFIER
logo
Analog Devices
AD624 AD-AD624_16 Datasheet
468Kb / 17P
   Precision Instrumentation Amplifier
logo
Texas Instruments
INA114 TI1-INA114 Datasheet
758Kb / 17P
[Old version datasheet]   Precision INSTRUMENTATION AMPLIFIER
logo
Burr-Brown (TI)
INA115 BURR-BROWN-INA115 Datasheet
211Kb / 11P
   Precision INSTRUMENTATION AMPLIFIER
logo
Analog Devices
AD620MIL AD-AD620MIL_15 Datasheet
1Mb / 4P
   PRECISION INSTRUMENTATION AMPLIFIER
REV. A
AD524SE AD-AD524SE Datasheet
614Kb / 28P
   Precision Instrumentation Amplifier
Rev. F
AD8221 AD-AD8221_15 Datasheet
512Kb / 24P
   Precision Instrumentation Amplifier
REV. C
AD524 AD-AD524_16 Datasheet
519Kb / 29P
   Precision Instrumentation Amplifier
AD8221 AD-AD8221_16 Datasheet
668Kb / 25P
   Precision Instrumentation Amplifier
More results


Html Pages

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


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