AMP03
–6–
REV. F
ECM
+V
0.1F
0.1F
–V
V
SIGNAL
GROUND REFERENCE 1 GROUND REFERENCE 2
(GROUND REFERENCE 2)
V
OUT
= –V
SIGNAL
AMP03
Figure 1. AMP03 Serves to Reject Common-Mode Volt-
ages in Instrumentation Systems. Common-Mode Volt-
ages Occur Due to Ground Current Returns. V
SIGNAL
and
E
CM
Must Be within the Common-Mode Range of AMP03.
APPLICATIONS INFORMATION
The AMP03 represents a versatile analog building block. In
order to capitalize on the fast settling time, high slew rate, and
high CMR, proper decoupling and grounding techniques must
be employed. Figure 1 illustrates the use of 0.1 µF decoupling
capacitors and proper ground connections.
MAINTAINING COMMON-MODE REJECTION
In order to achieve the full common-mode rejection capability
of the AMP03, the source impedance must be carefully con-
trolled. Slight imbalances of the source resistance will result in
a degradation of dc CMR—even a 5 Ω imbalance will degrade
CMR by 20 dB. Also, the matching of the reactive source
impedance must be matched in order to preserve the CMRR
over frequency.
APPLICATION CIRCUITS
AMP03
R1
25k⍀
R2
25k⍀
R3
25k⍀
R4
25k⍀
+IN E
2
–IN E
1
E
0
= E
2
– E
1
Figure 2. Precision Difference Amplifier. Rejects
Common-Mode Signal = (E
1
+ E
2
)/2 by 100 dB
AMP03
E
1
E
0
= –E
1
Figure 3. Precision Unity-Gain Inverting Amplifier
AMP03
+15V
–10V OUT
0.1F
REF10
+10V OUT
Figure 4.
ⴞ
10 V Precision Voltage Reference
+15V
–5V OUT
0.1F
REF10
+5V OUT
AMP03
Figure 5.
ⴞ
5 V Precision Voltage Reference
AMP03
E
1
E
2
E
0
= E
1
+ E
2
Figure 6. Precision Summing Amplifier
AMP03
R2
R1
E
1
E
2
E
0
= (R2/R1+1)
E
1
= E
2
2
Figure 7. Precision Summing Amplifier with Gain
