Evaluation Board User Guide
EVAL-AD7450A/EVAL-AD7451
Rev. A | Page 9 of 28
LINK CONFIGURATION OPTIONS
There are 12 link options that must be set for the required
operating setup before using the evaluation board. The
functions of these options are outlined in Table 2, which
shows the position in which all the links are set when the
evaluation board is packaged. Jumper and solder link (LKx)
options must be set correctly to select the appropriate operating
setup before using the evaluation board. The default link posi-
tions are shown in Table 3 and Table 4 and the functions of these
options are outlined in Table 2.
Table 2. Link Options
Link No.
Function
LK1
INPUT A destination selection. This selects which buffer INPUT A is connected to.
Position A: INPUT A is connected to single-ended to differential buffer.
Position B: INPUT A is connected to single-ended buffer (U10-A).
Position C: INPUT A is connected to bias up circuit (U7-A/U7-B).
LK2
INPUT A input impedance selection.
Insert: INPUT A input impedance is 51 Ω.
LK3
INPUT B destination selection. This selects which buffer INPUT B is connected to.
Position A: INPUT B is connected to LK5 Position B.
Position B: INPUT B is connected to single-ended buffer (U10-B).
LK4
Input signal selection.
Insert when input signal at INPUT A is bipolar.
Remove when input signal at INPUT A is unipolar.
LK5
This selects the source for the positive terminal of U5-B.
Position A: ½ V
REF
is supplied to U5-B.
Position B: INPUT B is supplied to U5-B.
Position C: 0 V is supplied to U5-B.
LK6
VIN+ source selection. Select which buffered signal is routed to
AD7450A
/
AD7451
Pin V
IN+
.
Position A: Signal is sourced from single-ended to differential buffer output (U5-A).
Position B: Signal is sourced from single-ended buffer (U10-A).
Position C: Signal is sourced from bias up circuit (U7-B).
LK7
VIN− source selection. Select which buffered signal is routed to
AD7450A
/
AD7451
Pin V
IN−
.
Position A: Signal is sourced from single-ended to differential buffer output (U5-B).
Position B: Signal is sourced from single-ended buffer (U10-B).
LK8
INPUT B input impedance selection.
Insert: INPUT B input impedance is 51 Ω.
LK9
V
REF
source selection.
Position A: V
REF
is sourced from U2 (
ADR431
an ultralow noise XFET® voltage reference).
Position B: V
REF
is sourced externally via SMB connector EXT_VREF.
LK101
1
Amplifier negative voltage supply selection.
Position A: Amplifier negative voltage supplied from on-board supply.
Position B: Amplifier negative voltage supplied from external source via J100 Terminal 1 labeled VSS.
LK102
1
Amplifier positive voltage selection.
Position A: Amplifier positive voltage supplied from on board supply.
Position B: Amplifier positive voltage supplied from external source via J100 Terminal 3 labeled VDD.
LK701
V
DD
supply for
AD7450A
/
AD7451
.
Position A: V
DD
supplied from on board supply (5 V).
Position B: V
DD
supplied from external source via J703 terminal labeled VCC.
1
Both LK101 and LK102 should always be in corresponding positions.
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