Evaluation Board User Guide UG-210
Rev. A | Page 3 of 12
EVALUATION BOARD CONFIGURATIONS
3.3 V EVALUATION BOARD
The EVAL-ADM2482EEB3Z and EVAL-ADM2487EEB3Z are
shipped in a 3.3 V full-duplex configuration without any bus
biasing resistors inserted by default. The jumper settings are
shown in Table 1. The transformer fitted as U3 for the 3.3 V
version of the evaluation board is the DA2303-AL with a turns
ratio of 1:1.5. The DA2303-AL allows enough headroom for the
ADP3330 LDO to output a regulated 3.3 V output.
5 V EVALUATION BOARD
The EVAL-ADM2482EEB5Z and EVAL-ADM2487EEB5Z are
shipped in a 5 V full-duplex configuration without any bus
biasing resistors inserted by default. The jumper settings are
shown in Table 1. The transformer fitted as U3 for the 5 V
version of the evaluation board is the GA3157-AL with a turns
ratio of 1:1. The GA3157-AL is required to give a 5 V input to
the ADP3330 LDO, which regulates an output of 3.3 V.
FULL DUPLEX, BUS BIASING AND TERMINATION
RESISTORS ON RECEIVER INPUT
Bus biasing resistors can be fitted on the receiver input by
inserting resistors R3 and R4. Jumpers LK11 and LK13 must be
inserted for the bus biasing resistors to be active. All jumper
combinations are shown in Table 1.
A termination resistor can be fitted on the receiver input by
inserting RT. The value of the termination resistor should be
equal to the characteristic impedance of the cable used. To
activate the termination resistor, Jumper LK12 must be inserted.
FULL DUPLEX, BUS BIASING AND TERMINATION
RESISTORS ON RECEIVER AND TRANSMITTER
Bus biasing resistors can be fitted on the transmitter output as
well as on the receiver input. Resistors R3, R4, R2, and R11 and
Jumpers LK11, LK13, LK7, and LK9 must be inserted for this
configuration.
A termination resistor can also be fitted on the transmitter
output by inserting RT1. The value of the termination resistor
should be equal to the characteristic impedance of the cable
used. To activate the termination resistor, Jumper LK10 must be
inserted.
HALF DUPLEX WITH BUS BIASING AND
TERMINATION
To configure the evaluation board as half duplex, Receiver Input
Pin A must be connected to Transmitter Output Pin Y and
Receiver Input Pin B must be connected to Transmitter Output
Pin Z. This is accomplished by inserting Jumper LK15 and
Jumper LK16.
In this configuration if biasing resistors are inserted, only the
resistors on the receiver input, or on the transmitter output
should be selected. This is achieved by either inserting resistors
R3 and R4 and jumpers LK11 and LK13 (leaving LK7 and LK9
open), or by inserting resistors R2 and R11 and jumpers LK7
and LK9 (leaving LK11 and LK13 open).
Similarly only the termination resistor on the receiver input or
on the transmitter output should be selected (e.g. LK12
inserted, LK10 open).
POWERING UP THE BUS SIDE
The bus side can be powered using either the regulator built
into the board or by using an external power source. Jumper
LK1 allows the user to select between these two methods. By
inserting Jumper LK1 into Position A, the board can be pow-
ered using an external power source. Inserting Jumper LK1 into
Position B selects the built-in regulator to supply the bus side.
