Datasheet

EVAL-AD5420
Rev. 0 | Page 4 of 12
Table 4. Link Options
Link No. Description
LK1 Not applicable.
LK2 This link selects the state of the CLEAR pin (when the evaluation board is configured for external control).
Position A ties the CLEAR pin to 0 V.
Position B ties the CLEAR pin to DV
CC.
LK3 This link selects the state of the DV
CC
SELECT pin.
When inserted, the DV
CC
SELECT pin is tied to 0 V, disabling the internal supply; an external supply must be connected to the
DV
CC
pin via LK17.
When removed, the DV
CC
SELECT pin is unconnected, enabling the internal supply. Removing the requirement for an
external digital supply, LK17 can be removed.
LK4 Not applicable.
LK5 This link selects how the I
OUT
current loop return is connected to ground on the evaluation board.
Position A connects the I
OUT
current loop return directly to ground.
Position B connects the I
OUT
current loop return input to GND through a 51 Ω resistor. The high side of the resistor is
connected to the V
IN
1 input of the on-board ADC, allowing readback to the PC of the output current.
LK6 This link selects the 5 V power supply source for the digital circuitry.
Position A selects the USB port as the 5 V digital circuitry power supply source.
Position B selects J7 as the 5 V digital circuitry power supply source.
LK7 This link selects whether the AD5420 evaluation board is controlled by the PC via the USB port or by an external source via J8.
Position A selects the evaluation board to be controlled by the PC via the USB port.
Position B selects the evaluation board to be controlled by an external source via J8.
LK8 This link selects the digital supply voltage value for the AD5420 and the on-board ADC (U6):
Position A selects 5 V as the supply value.
Position B selects 3.3 V as the supply value.
LK9 This link selects the positive power supply source for U2 and U6.
Position A selects the AV
DD
input as the positive power supply source (use only if the power supply applied to AV
DD
is less
than 16.5 V).
Position B selects the V+ input as the positive power supply source (use if the power supply applied to AV
DD
input is greater
than 16.5 V). A power supply voltage of 10.8 V to 16.5 V can be applied to V+.
LK10 This link is used to enable/disable the external boost transistor.
When inserted, the external boost transistor is disabled.
When removed, the external boost transistor is enabled.
LK11 Not applicable.
LK12 Not applicable.
LK13 This link connects the I
OUT
connector directly to the GND connector.
When inserted, the I
OUT
connector is connected directly to the GND connector.
When removed, the I
OUT
connector is disconnected from the GND connector (an external load must be connected).
LK14 Not applicable.
LK15 This link selects the voltage reference source.
Position A selects the internal voltage reference of the AD5420 as the voltage reference source.
Position B selects an external source that can be applied at Connector J3.
Position C selects the on-board ADR435 as the voltage reference source.
LK16 Not applicable.
LK17 This link connects the DV
CC
pin of the AD5420 to the on-board digital power supply.
When inserted, the DV
CC
pin of the AD5420 is connected to the on-board digital power supply (LK3 must be inserted to
disable the AD5420 internal digital power supply)
When removed, the DV
CC
pin of the AD5420 is disconnected from the on-board digital power supply (LK3 should be
removed to enable the AD5420 internal digital power supply).
LK18
This link connects the AV
DD
pin of the AD5420 to the power supply applied at the AV
DD
input connector, J2 (LK18 must be
inserted for operation of the AD5420).