Evaluation Board User Guide
UG-240
Rev. 0 | Page 3 of 8
EVALUATION BOARD CONFIGURATIONS
SETTING UP THE EVALUATION BOARD
The EVAL-ADM2486EBZ allows the isolated
RS-485 transceivers to be easily and quickly evaluated. The
evaluation board allows all of the input and output functions to
be exercised without the need for external components.
A termination resistor, RT, is fitted on the receiver inputs;
this can be changed or removed if necessary. The value of
the termination resistor should be equal to the characteristic
impedance of the cable used. The 220 Ω resistor fitted is for
standard PROFIBUS® operation. Remove RT if the board is
connected to a bus that is already terminated at both ends.
The logic side is suitable for 5 V or 3 V operation on VDD1. There
is a 0.1 μF decoupling capacitor, C1, fitted between VDD1 and
GND1. The bus side is suitable for 5 V operation on VDD2.
There is a 0.1 μF decoupling capacitor, C2, fitted between VDD2
and GND2.
Bus biasing resistors, R1 and R2, are fitted on the receiver inputs
with 390 Ω resistors for a standard PROFIBUS biasing network. If
additional EVAL-ADM2486EBZ boards are connected together,
remove these resistors from all but one board.
Refer to
RS-485/RS-422 Circuit
Implementation Guide
, for an explanation of bus termination
and fail-safe biasing.
www.BDTIC.com/ADI
