Datasheet

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NI
THS4031
NI
THS4031
(−)IN
W4
W2
W3
U5
U6
C31
R7
C3
C17
C4
C18
R8
C38
R15
R16
C28
R18
NI
NI
C41
C40
R12
C32
R9
C5
C19
C20
C6
R17
R11
R10
C39
NI
49.9 
−V
CC
0.1 F
4.7 F
0 
4.7 F
0.1 F
5 
−
+
(+)IN
68 pF
C0G
NI
0 
+V
IN
0 − 5 V
+V
CC
NI
49.9 
−V
CC
−
+
0.1 F
4.7 F
0 
4.7 F
0.1 F
5 0 
NI
−V
IN
0 − 5 V
+V
CC
REFOUT
(+2.5 V DC)
4.1 Reference
Analog Interface
Table 1. Analog Input Connector (continued)
Description Signal Name Connector.Pin# Signal Name Description
Pin tied to ground AGND J1.9 J1.10 N/A Reserved
Pin tied to ground AGND J1.11 J1.12 N/A Reserved
Reserved N/A J1.13 J1.14 N/A Reserved
Pin tied to ground AGND J1.15 J1.16 N/A Reserved
Pin tied to ground AGND J1.17 J1.18 N/A Reserved
Reserved N/A J1.19 J1.20 REF+ External reference input
The factory recommends that the analog input to any SAR-type converter be buffered and low-pass
filtered. The recommended circuit is shown in Figure 1 . This circuit was tested to ensure that the ac
specifications listed in the data sheet of the converter could be met, given a quality input signal.
Figure 1. ADS8323 Input Buffer Circuit
The ADS8323EVM can be configured to use its on-chip reference, or external reference voltage applied at
J1 pin 20 via W1. The EVM is shipped with the on-chip reference (REFout) shorted to REFin of the
converter.
SLAU087A – July 2002 – Revised December 2004 3ADS8323EVM