Datasheet

AD628
Rev. G | Page 19 of 20
FILTER CAPACITOR VALUES
Connect a capacitor to Pin 4 (C
FILT
) to implement a low-pass
filter. The capacitor value is
C = 15.9/f
t
(µF)
where f
t
is the desired 3 dB filter frequency.
Table 7 shows several frequencies and their closest standard
capacitor values.
Table 7. Capacitor Values for Various Filter Frequencies
Frequency (Hz) Capacitor Value (μF)
10 1.5
50 0.33
60 0.27
100 0.15
400 0.039
1 k 0.015
5 k 0.0033
10 k 0.0015
KELVIN CONNECTION
In certain applications, it may be desirable to connect the
inverting input of an amplifier to a remote reference point.
This eliminates errors resulting in circuit losses in inter-
connecting wiring. The AD628 is particularly suited for this
type of connection. In
Figure 35, a 10 kΩ resistor added in the
feedback matches the source impedance of A2. This is
described in more detail in the
Gain Adjustment section.
+IN
–IN
A2
+V
S
–IN
+IN
V
REF
OUT
CIRCUIT
LOSS
LOAD
+IN
–IN
G = +0.1
A1
AD628
–V
S
10k
10k10k100k
100k
V
S
/2
C
FILT
R
G
10k
02992-033
Figure 35. Kelvin Connection