전자부품 데이터시트 검색엔진
Selected language     Korean  ▼
부품명
         상세내용
Preview PDF Download HTML-1page HTML-10pages

AD620ANZ 데이터시트(Datasheet) 16 Page - Analog Devices

부품명 AD620ANZ
상세내용  Low Cost Low Power Instrumentation Amplifier
PDF  20 Pages
Scroll/Zoom Zoom In 100% Zoom Out
제조사  AD [Analog Devices]
홈페이지  http://www.analog.com
Logo 

 
 16 page
background image
AD620
Rev. G | Page 16 of 20
Precision V-I Converter
The AD620, along with another op amp and two resistors,
makes a precision current source (Figure 42). The op amp
buffers the reference terminal to maintain good CMR. The
output voltage, VX, of the AD620 appears across R1, which
converts it to a current. This current, less only the input bias
current of the op amp, then flows out to the load.
AD620
RG
–VS
VIN+
V
IN–
LOAD
R1
I
L
Vx
I =
L
R1
=
IN+
[(V
) – (V
)] G
IN–
R1
6
5
+ V –
X
4
2
1
8
3
7
+VS
AD705
Figure 42. Precision Voltage-to-Current Converter (Operates on 1.8 mA, ±3 V)
GAIN SELECTION
The AD620’s gain is resistor-programmed by RG, or more
precisely, by whatever impedance appears between Pins 1 and 8.
The AD620 is designed to offer accurate gains using 0.1% to 1%
resistors. Table 4 shows required values of RG for various gains.
Note that for G = 1, the RG pins are unconnected (RG = ∞). For
any arbitrary gain, RG can be calculated by using the formula:
1
4
.
49
=
G
k
R
G
To minimize gain error, avoid high parasitic resistance in series
with RG; to minimize gain drift, RG should have a low TC—less
than 10 ppm/°C—for the best performance.
Table 4. Required Values of Gain Resistors
1% Std Table
Value of RG(Ω)
Calculated
Gain
0.1% Std Table
Value of RG(Ω )
Calculated
Gain
49.9 k
1.990
49.3 k
2.002
12.4 k
4.984
12.4 k
4.984
5.49 k
9.998
5.49 k
9.998
2.61 k
19.93
2.61 k
19.93
1.00 k
50.40
1.01 k
49.91
499
100.0
499
100.0
249
199.4
249
199.4
100
495.0
98.8
501.0
49.9
991.0
49.3
1,003.0
INPUT AND OUTPUT OFFSET VOLTAGE
The low errors of the AD620 are attributed to two sources,
input and output errors. The output error is divided by G when
referred to the input. In practice, the input errors dominate at
high gains, and the output errors dominate at low gains. The
total VOS for a given gain is calculated as
Total Error RTI = input error + (output error/G)
Total Error RTO = (input error × G) + output error
REFERENCE TERMINAL
The reference terminal potential defines the zero output voltage
and is especially useful when the load does not share a precise
ground with the rest of the system. It provides a direct means of
injecting a precise offset to the output, with an allowable range
of 2 V within the supply voltages. Parasitic resistance should be
kept to a minimum for optimum CMR.
INPUT PROTECTION
The AD620 features 400 Ω of series thin film resistance at its
inputs and will safely withstand input overloads of up to ±15 V
or ±60 mA for several hours. This is true for all gains and power
on and off, which is particularly important since the signal
source and amplifier may be powered separately. For longer
time periods, the current should not exceed 6 mA
(IIN ≤ VIN/400 Ω). For input overloads beyond the supplies,
clamping the inputs to the supplies (using a low leakage diode
such as an FD333) will reduce the required resistance, yielding
lower noise.
RF INTERFERENCE
All instrumentation amplifiers rectify small out of band signals.
The disturbance may appear as a small dc voltage offset. High
frequency signals can be filtered with a low pass R-C network
placed at the input of the instrumentation amplifier. Figure 43
demonstrates such a configuration. The filter limits the input
signal according to the following relationship:
)
2
(
2
1
C
D
DIFF
C
C
R
FilterFreq
+
π
=
C
CM
RC
FilterFreq
π
=
2
1
where CD ≥10CC.
CD affects the difference signal. CC affects the common-mode
signal. Any mismatch in R × CC will degrade the AD620’s
CMRR. To avoid inadvertently reducing CMRR-bandwidth
performance, make sure that CC is at least one magnitude
smaller than CD. The effect of mismatched CCs is reduced with a
larger CD:CC ratio.




Html 페이지

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


데이터시트



관련 부품명

부품명상세내용Html View제조사
AD620_05Low Cost Low Power Instrumentation Amplifier 1 2 3 4 5 MoreAnalog Devices
LT1168_06Low Power Single Resistor Gain Programmable Precision Instrumentation Amplifier 1 2 3 4 5 MoreLinear Technology
2SD468LOW FREQUENCY POWER AMPLIFIER 1 2 3 Unisonic Technologies
SY88973BL3.3V 3.2Gbps CML Low Power Limiting Post Amplifier with TTL LOS 1 2 3 4 5 MoreMicrel Semiconductor
AS321LOW POWER SINGLE OPERATIONAL AMPLIFIER 1 2 3 4 5 MoreBCD Semiconductor Manufacturing Limited
FAN41131.2V 36MHz Low Power Rail-to-Rail Amplifier 1 2 3 4 5 MoreFairchild Semiconductor
RJK6014DPPSilicon N Channel MOS FET High Speed Power Switching 1 2 3 4 Renesas Technology Corp
LM2904WHLow power dual operational amplifier 1 2 3 4 5 MoreSTMicroelectronics
LM48410Low EMI Filterless 2.3W Stereo Class D Audio Power Amplifier with National 3D Enhancement Coming SoonNational Semiconductor (TI)
2SA1588_07Audio Frequency Low Power Amplifier Applications Driver Stage Amplifier Applications Switching Applications 1 2 3 Toshiba Semiconductor

링크 URL

ALLDATASHEET 가 귀하에 도움이 되셨나요?  [ DONATE ]  

Alldatasheet는?   |   광고문의    |   운영자에게 연락하기   |   개인정보취급방침   |   즐겨찾기   |   링크교환   |   제조사별 검색
All Rights Reserved© Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  , 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