EVAL-AD7912_15 Datasheet, PDF (4/16 Pages) Analog Devices – Evaluation Board for 1 MSPS, 2-Channel, 12-/10-Bit ADCs

EVAL-AD7912/AD7922
Link No.
LK10
LK11
LK12
LK13
LK14
LK15
LK16, LK17
LK18
Function
This link option is used to select the source of the +12 V supply.
• In Position A, the +12 V is supplied from the EVAL-CONTROL-BRD2 through the 96-way connector.
• In Position B, the +12 V is supplied from an external source through the power connector, J2.
This link option is used to select the source of the −12 V supply.
• In Position A, the −12 V is supplied from the EVAL-CONTROL-BRD2 through the 96-way connector.
• In Position B, the −12 V is supplied from an external source through the power connector, J2.
This link selects the source of the VDD supplied to the AD7912/AD7922.
• When this link is in Position A, the VDD is supplied from the EVAL-CONTROL-BRD2.
• When this link is in Position B, the VDD must be supplied from an external source via J3.
• When this link is in Position C, the VDD is supplied from one of the voltage references, the AD780 or the ADR435.
This link selects the source for the SCLK signal applied to the SCLK pin of the AD7912/AD7922.
• When this link is in Position A, SCLK is applied from an external source via the SCLK SMB socket.
• When this link is in Position B, the SCLK signal is an inverted signal from the EVAL-CONTROL-BRD2.
• When this link is in Position C, the SCLK is sourced directly from the EVAL-CONTROL-BRD2.
This link option controls the program pin of the AD780 voltage reference.
• When this link is inserted, the AD780 output voltage is set to +3 V.
• When this link is removed, the AD780 output voltage is set to +2.5 V.
This link option is used to select a 50 Ω termination on the analog input buffer circuit, the AIN socket.
• When this link is inserted, the 50 Ω termination is applied.
• When this link is removed, the 50 Ω termination is removed.
These link options are used to select a 50 Ω termination on the analog input buffer circuit, the VIN0 and VIN1 socket,
respectively.
• When this link is inserted, the 50 Ω termination is applied.
• When this link is removed, the 50 Ω termination is removed.
This link selects the source of the VCC + 5 V supply for the 7S04.
• When this link is in Position A, VCC power is supplied from the same power source supplying the AD7912/AD7922 VDD pin.
• When this link is in Position B, VCC power must be supplied from an external source via the J3 power connector.
Table 2. Initial Link Positions
Link No.
Position
Function
LK1
A
Input of the AD8022 (U5) is connected to VIN0 (Channel 0).
LK2
B
Input of the AD8022 (U5) is connected to AGND.
LK3, LK4
LK5
A
Removed
VDD is selected as the dc bias voltage for the bias-up circuit.
This is not relevant due to the position of LK12.
LK6
Removed
50 Ω termination resistor is not applied to the input of the bias-up circuit.
LK7
A
CS signal is generated by the EVAL-CONTROL-BRD2.
LK8
A
DOUT pin is connected to the EVAL-CONTROL-BRD2.
LK9
A
Data applied to DIN pin of the AD7912/AD7922 is generated by the EVAL-CONTROL-BRD2.
LK10
A
+12 V is supplied from the EVAL-CONTROL-BRD2 via J1.
LK11
A
−12 V is supplied from the EVAL-CONTROL-BRD2 via J1.
LK12
A
VDD for the AD7912/AD7922 is supplied from the EVAL-CONTROL-BRD2 via J1.
LK13
C
SCLK signal is sourced directly from the EVAL-CONTROL-BRD2.
LK14
Removed
AD780 is set to provide a 2.5 V reference.
LK15
Removed
50 Ω termination resistor is not applied to the input of the bias-up circuit.
LK16, LK17
Removed
50 Ω termination resistor is not applied to the VIN0 and VIN1 analog inputs.
LK18
Removed
This is not relevant due to the position of LK13 because 7S04 is not in use.
Rev. 0 | Page 4 of 16