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AD626
Low Cost, Single-Supply
Differential Amplifi er
FEATURES
Pin Selectable Gains of 10 and 100
Tr ue Single-Supply Operation
Single-Supply Range of +2.4 V to +10 V
Dual-Supply Range of ⴞ1.2 V to ⴞ6 V
Wide Output Voltage Range of 30 mV to 4.7 V
Optional Low-Pass Filtering
Excellent DC Performance
Low Input Offset Voltage: 500 V Max
Large Common-Mode Range: 0 V to +54 V
Low Power: 1.2 mW (V
S
= +5 V)
Good CMR of 90 dB Typ
AC Performance
Fast Settling Time: 24 s (0.01%)
Includes Input Protection
Series Resistive Inputs (R
IN
= 200 k⍀)
RFI Filters Included
Allows 50 V Continuous Overload
APPLICATIONS
Current Sensing
Interface for Pressure Transducers, Position Indicators,
Strain Gages, and Other Low Level Signal Sources
PROD UCT DE SCRIP TION
The AD626 is a low cost, true sin gle-sup ply dif fer en tial am pli fi er
de signed for am pli fy ing and low-pass fi ltering small dif fer en tial
voltages from sources having a large common-mode voltage.
The AD626 can operate from either a single supply of +2.4 V to
+10 V, or dual supplies of ±1.2 V to ±6 V. The input common-mode
range of this amplifi er is equal to 6 (+V
S
– 1 V) which pro vides a
+24 V CMR while operating from a +5 V sup ply. Fur ther more,
the AD626 features a CMR of 90 dB typ.
The amplifi er’s inputs are protected against continuous overload of
up to 50 V, and RFI fi lters are included in the attenuator network.
The output range is +0.03 V to +4.9 V using a +5 V sup ply. The
amplifi er provides a preset gain of 10, but gains be tween 10 and
100 can be easily con fi g ured with an external re sis tor. Fur ther -
more, a gain of 100 is available by connecting the G = 100 pin to
analog ground. The AD626 also offers low-pass fi lter capability by
connecting a ca pac i tor between the fi lter pin and analog ground.
The AD626A and AD626B operate over the industrial tem per a ture
range of –40°C to +85°C. The AD626 is available in two 8-lead
packages: a plastic mini-DIP and SOIC.
140
0
1M
60
20
1
40
0.1
120
80
100
100k10k 1k100 10
FREQUENCY – Hz
COMMON-MODE REJECTION – dB
G = 10, 100
V
S
= +5V
G = 100
V
S
= ⴞ5V
G = 10
V
S
= ⴞ5V
Figure 1. Common-Mode Rejection vs. Frequency
25
0
5
15
5
2
10
1
20
4
3
SUPPLY VOLTAGE – ⴞV
INPUT COMMON-MODE RANGE – V
ⴞV
CM
FOR SINGLE
AND DUAL SUPPLIES
ⴞV
CM
FOR DUAL
SUPPLIES ONLY
Figure 2. Input Common-Mode Range vs. Supply
CONNECTION DIAGRAM
8-Lead Plastic Mini-DIP (N)
and SOIC (R) Packages
1
2
3
4
8
7
6
5
AD626
1/6
200k⍀
–IN
ANALOG
GND
–V
S
FILTER
+IN
G = 100
OUT
+V
S
100k⍀
G
=
2
G = 30
200k⍀
REV. D
