AD8620BR-REEL Analog Devices Inc, AD8620BR-REEL Datasheet - Page 19
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AD8620BR-REEL
Manufacturer Part Number
AD8620BR-REEL
Description
IC,Operational Amplifier,DUAL,BIPOLAR/JFET,SOP,8PIN,PLASTIC
Manufacturer
Analog Devices Inc
Datasheet
1.AD8610ARMZ-REEL.pdf
(24 pages)
Specifications of AD8620BR-REEL
Rohs Status
RoHS non-compliant
Design Resources
Using AD7328 in Appls with Single-Ended Industrial-Level Signals (CN0047)
Amplifier Type
J-FET
Number Of Circuits
2
Slew Rate
60 V/µs
Gain Bandwidth Product
25MHz
Current - Input Bias
3pA
Voltage - Input Offset
45µV
Current - Supply
3mA
Current - Output / Channel
45mA
Voltage - Supply, Single/dual (±)
±5 V ~ 13 V
Operating Temperature
-40°C ~ 125°C
Mounting Type
Surface Mount
Package / Case
8-SOIC (3.9mm Width)
Output Type
-
-3db Bandwidth
-
Lead Free Status / RoHS Status
Input Offset Voltage Adjustment
Offset of AD8610 is very small and normally does not require
additional offset adjustment. However, the offset adjust pins can
be used as shown in Figure 66 to further reduce the dc offset. By
using resistors in the range of 50 kΩ, offset trim range is ±3.3 mV.
Programmable Gain Amplifier (PGA)
The combination of low noise, low input bias current, low input
offset voltage, and low temperature drift make the AD8610/
AD8620 a perfect solution for programmable gain amplifiers.
PGAs are often used immediately after sensors to increase the
dynamic range of the measurement circuit. Historically, the large
on resistance of switches (combined with the large I
of amplifiers) created a large dc offset in PGAs. Recent and
improved monolithic switches and amplifiers completely remove
these problems. A PGA discrete circuit is shown in Figure 67.
In Figure 67, when the 10 pA bias current of the AD8610 is
dropped across the (<5 Ω) R
negligible offset error.
When high precision resistors are used, as in the circuit of
Figure 67, the error introduced by the PGA is within the
½ LSB requirement for a 16-bit system.
Figure 66. Offset Voltage Nulling Circuit
2
3
V–
AD8610
4
V+
7
5
ON
R1
of the switch, it results in a
1
6
V
OUT
B
currents
Rev. F | Page 19 of 24
1. Room temperature error calculation due to R
2. Full temperature error calculation due to R
3. The temperature coefficient of switch and AD8610/AD8620
combined is essentially the same as the T
AD8610/AD8620.
ΔV
Total Offset = AD8610 (Offset) + ΔV
Total Offset = AD8610 (Offset_Trimmed) + ΔV
Total Offset = 5 μV + 10 pV ≈ 5 μV
ΔV
ΔV
ΔV
250 pA × 15 Ω = 3.75 nV
ΔV
OS
OS
OS
OS
A
A
/ΔT(total) = ΔV
/ΔT(total) = 0.5 μV/°C + 0.06 nV/°C ≈ 0.5 μV/°C
0
(@ 85°C) = I
1
= I
OS
/ΔT(I
74HC139
B
A
B
G
× R
V
Y
Y
Y
Y
IN
0
1
2
3
ON
B
5pF
16
× R
Figure 67. High Precision PGA
1
9
8
100Ω
= 2 pA × 5 Ω = 10 pV
B
12
ON
+5V
(@ 85°C) × R
V
IN1
IN2
IN3
IN4
)
L
OS
3
2
V
4
–5V
ADG452
SS
/ΔT(AD8610/AD8620) +
AD8610
–5V
+5V
+5V
V
7
4
DD
13
GND
5
1
5
S1
D1
S2
D2
S3
D3
S4
D4
ON
AD8610/AD8620
3
2
14
15
11
10
6
7
6
(@ 85°C) =
OS
C
10kΩ
1kΩ
10kΩ
100Ω
V
1kΩ
11Ω
ON
OS
ON
and I
of the
G = +1
G = +10
G = +100
G = +1000
V
and I
OUT
OS
B
B