Datasheet

f =
FILTER
ln(2) (n+1)´
2 2 Rp ´ C´ ´ ´
R=
t
ACQ
ln(2) 2(n+1) C´ ´ ´
BGND
CHB1+
CHB1-
CHB0+
CHB0-
CHA1+
CHA1-
CHA0+
CHA0-
REF
IN
REF
OUT
AGND
1
2
BGND
3
4
5
6
7
8
9
10
11
12
24
23
22
21
20
19
18
17
16
15
14
13
BV
DD
SDOA
SDOB
BUSY
CLOCK
CS
RD
CONVST
SDI
M0
M1
AV
DD
ADS7863
AGND
AGND
AGND
AGND
OPA2365
AGND
OPA2365
0.1 Fm
1 Fm
1 Fm
0.1 F(min)m
BV
DD
AV
DD
OPA2365
AV
DD
OPA2365
470nF
(min)
BV
DD
BGND
BGND
Controller
Device
ADS7863
SBAS383E –JUNE 2007–REVISED JANUARY 2011 www.ti.com
APPLICATION INFORMATION
(3)
The absolute minimum configuration of the ADS7863
is shown in Figure 41. In this case, the ADS7863 is
It is recommended to use a capacitor value of at least
used in dual-channel mode only, with the default
20pF.
settings of the device after power up.
Keep the acquisition time in mind; the resistor value
The input signal for the amplifiers must fulfill the
can be calculated as shown in Equation 4 for each of
common-mode voltage requirements of the ADS7863
the series resistors (with n = 12, being the resolution
in this configuration. The actual values of the
of the ADSS7863).
resistors and capacitors depend on the bandwidth
and performance requirements of the application.
(4)
Those values can be calculated using Equation 3,
with n = 12 being the resolution of the ADS7863.
Figure 41. Minimum ADS7863 Configuration
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