UG-1715
Rev. 0 | Page 6 of 11
LDO Regulator
The EVAL-ADM2463EEBZ/EVAL-ADM2763EEBZ feature two
on-board
LDO regulators that allow flexible power
supply configurations during evaluation.
The V
DD1
regulator, U1, is powered from the VDD1 terminal on
Connector P5, and is configured using the LK8 jumper. This
jumper position selects the regulator output to the V
DD1
pin.
Options of 1.8 V, 2.5 V, 3.3 V, and 5 V are available. To bypass
the V
DD1
regulator, U1, and power the V
DD1
pin directly
from the VDD1 terminal, insert the LK8 jumper into Position E.
The V
DD2
regulator, U3, is powered from the VDD2 terminal on
Connector P6, and is configured using the LK9 jumper. This
jumper position selects the regulator output to the
DD2
pin. Options of 3.3 V and 5 V are available.
To bypass the V
DD2
regulator, U3, and power the V
DD2
pin
directly from the VDD2 terminal, insert the LK9 jumper into
Position C.
Table 2 and Table 3 lists the supported power supply
configurations and the associated jumper configurations.
FULL DUPLEX RS-485 TRANSCEIVERS
LOOPBACK TEST
A loopback test can be set up with the EVAL-ADM2463EEBZ/
EVAL-ADM2763EEBZ by closing the LK4 and LK5 jumpers.
The details of this test are shown in Table 1 and in Figure 2. A
signal generator is connected to the TxD pin, which allows
verification of the bus signals and the receiver output. Note that
during the test, the jumper position for LK1 is Position C, LK2 is
Position A, and LK3 is Position C. See Table 2 for the jumper
configurations for different power supply configurations. The
LK6 and LK7 jumpers can be inserted to terminate the
transmitter and receiver with 120 Ω resistors. Connect both
jumpers when the board is configured in parallel by the loopback
to ensure that the test is conducted with a standard RS-485 load
of 60 Ω (bus terminated at both ends by 120 Ω).
Table 2. Primary Side Input Supply Configurations
Jumper LK8
VDD1 Input Voltage Range
V
DD1
Supply
A
2.2 V to 20 V
Regulator provides 1.8 V
B
2.9 V to 20 V
Regulator provides 2.5 V
C
3.7 V to 20 V
Regulator provides 3.3 V
D
5.4 V to 20 V
Regulator provides 5 V
E
1.7 V to 5.5 V
Supplied directly from the VDD1 terminal on P5
Table 3. Secondary Side Input Supply Configurations
Jumper LK9
VDD2 Input Voltage Range
V
DD2
Supply
A
3.7 V to 20 V
Regulator provides 3.3 V
B
5.4 V to 20 V
Regulator provides 5 V
C
3 V to 5.5 V
Supplied directly from the VDD2 terminal on P6
OSCILLOSCOPE
22523-
004
GND2
A
RxD
RE
DE
TxD
B
Z
Y
GND2
RxD
L
K9
L
K4
A
B
Z
Y
P5
P3
EVAL-ADM2463EEBZ/
EVAL-ADM2763EEBZ
4V TO 20V
POWER
SUPPLY
SIGNAL
GENERATOR
L
K5
L
K6
P4
INVR
TxD
L
K1
L
K2
L
K3
P2
P1
L
K10
RE
DE
INVR
LK8
LK9
P6
4V TO 20V
POWER
SUPPLY
Figure 2. Full Duplex RS-485 Loopback Test
