ADS7863_08 Datasheet, PDF (29/40 Pages) Texas Instruments – Dual, 2MSPS, 12-Bit, 2 + 2 or 3 + 3 Channel, Simultaneous Sampling ANALOG-TO-DIGITAL CONVERTER

ADS7863
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APPLICATION INFORMATION
The absolute minimum configuration of the ADS7863
is shown in Figure 41. In this case, the ADS7863 is
used in dual-channel mode only, with the default
settings of the device after power up.
The input signal for the amplifiers must fulfill the
common-mode voltage requirements of the ADS7863
in this configuration. The actual values of the
resistors and capacitors depend on the bandwidth
and performance requirements of the application.
Those values can be calculated using Equation 3,
with n = 12 being the resolution of the ADS7863.
SBAS383B – JUNE 2007 – REVISED MARCH 2008
f_FILTER =
ln(2) ´ (n + 1)
2´p´2´R´C
(3)
It is recommended to use a capacitor value of at least
20pF.
Keep the acquisition time in mind; the resistor value
can be calculated as shown in Equation 4 for each of
the series resistors (with n = 12, being the resolution
of the ADSS7863).
R
=
ln(2)
´
t_ACQ
(n + 1)
´
2
´
C
(4)
BV_DD
1mF
0.1mF
AV_DD
OPA2365
OPA2365
AGND
AV_DD
OPA2365
BGND
AGND
AGND
470nF
(min)
ADS7863
1 BGND
2 CHB1+
BV_DD 24
SDOA 23
3 CHB1-
4 CHB0+
SDOB 22
BUSY 21
5 CHB0-
6 CHA1+
CLOCK 20
CS 19
7 CHA1-
8 CHA0+
RD 18
CONVST 17
9 CHA0-
10 REF_IN
11 REF_OUT
12 AGND
SDI 16
M0 15
M1 14
AV_DD 13
0.1mF (min)
BGND
Controller
Device
BGND
BV_DD
1mF
OPA2365
AGND
AGND
Figure 41. Minimum ADS7863 Configuration
Copyright © 2007–2008, Texas Instruments Incorporated
Product Folder Link(s): ADS7863
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