Linear Technology DC2222A Demo Manual page 9

Dc2222a Jumpers
Definitions
JP1: EEPROM is for factory use only. Leave this in the
default WP position.
JP2: Coupling selects AC or DC coupling of A
default setting is DC.
JP3: VCCIO sets the output levels at P1 to either 3.3V or
2.5V. Use 2.5V to interface to the DC890 which is the default
setting. Use 3.3V to interface to the DC590 or DC2026.
V
REF
–
IN
J4
RF , BNC
R53, 0
+
A
IN
0V – V
REF
+
V
C45
0.1µF
R86
499
5
+
3 V
+
C78
LT6202-S5
4.7µF
4
R87
–
–
499
V
2
–
V
J2
RF , BNC
R55, 0
–
A
IN
0V – V
REF
Figure 10. DC2222A Input Coupling
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa-
tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.
DEMO MANUAL DC2222A
JP4: CM sets the DC bias for A
are AC coupled. To enable AC coupling, R35 and R36 (R =
1k) shown in the schematic of Figure 10 must be installed.
Installing these resistors will degrade the THD of the input
. The
signal to the ADC. V
selected the input common mode voltage can be set by
driving terminal E5 (EXT_CM).
JP5: Coupling selects AC or DC coupling of A
default setting is DC.
COUPLING
JP5
3 1
AC DC
2
C18, 10µF
R54
C67
OPT
OPT
R88, 1
CM
1
C8 R18
1µF 249
C77
JP4
0.1µF
E5
EXT_CM
COUPLING
JP2
3 1
AC DC
2
C69, 10µF
C70 R56
OPT
OPT
+
and A
IN IN
/2 is the default setting. If EXT is
REF
R35
C68
OPT
15pF
C60
10µF
1
V
2
REF/2
3 EXT
C59
C74
10µF
1µF
R36
OPT
DC2222a F10
–
if the inputs
+
. The
IN
dc2222af
9