UG-1000 EVAL-ADM3065EEBZ/EVAL-ADM3065EEB1Z User Guide
Rev. 0 | Page 4 of 10
HALF DUPLEX RS-485 TRANSCEIVERS POINT TO
POINT TEST
A point to point test can be set up with either two EVAL-
ADM3065EEBZ evaluation boards or two EVAL-ADM3065EEB1Z
evaluation boards. Figure 4 shows two half duplex evaluation
boards in this configuration. Note the positions of LK1 and LK2
on each evaluation board that enable the driver on one evaluation
board and the receiver on the other evaluation board. Remove
LK4 from the EVAL-ADM3065EEBZ or EVAL-ADM3065EEB1Z
evaluation board to ensure both ends of the bus have only a
120 Ω load. Differential signals on the bus are monitored with an
oscilloscope, as well as the DI pin and RO pin of the ADM3065E.
IEC 61000-4-2 ESD PROTECTION TO ±12 kV
(CONTACT) AND ±12 kV (AIR GAP)
The EVAL-ADM3065EEBZ and EVAL-ADM3065EEB1Z
evaluation boards are tested to achieve protection against
IEC 61000-4-2 ESD to ±12 kV (contact), ±12 kV (air gap) on
the RS-485 A and B bus pins.
IEC 61000-4-2 ESD describes testing using two coupling methods,
known as contact discharge and air-gap discharge. Contact
discharge implies a direct contact between the discharge gun
and the equipment under test (EUT).
During air discharge testing, the charged electrode of the
discharge gun is moved toward the EUT until a discharge
occurs as an arc across the air gap. The discharge gun does not
make direct contact with the EUT.
During testing, the EVAL-ADM3065EEBZ and EVAL-
ADM3065EEB1Z A and B pins are subjected to at least 10 positive
and 10 negative single discharges with a 1 sec interval between
each pulse. The highest specified IEC 61000-4-2 ESD test is
Level 4, which defines a contact discharge voltage of ±8 kV and
an air discharge voltage of ±15 kV.
Figure 3 shows the 8 kV contact discharge current waveform as
described in the ADM3065E data sheet. Some key IEC 61000-4-2
waveform parameters are rise times of less than 1 ns and pulse
widths of approximately 60 ns.
14670-003
Figure 3. IEC 61000-4-2 ESD Waveform (8 kV)
OSCILLOSCOPE
A
LK1
LK2
B
C
D
A
B
C
RO
RE
DE
DI
B
A
RO
RE
DE
DI
B
A
GND
J1
J3
VCC
A
LK1
LK2
B
C
D
A
B
C
SHIELD
RO
RE
DE
DI
B
A
GND
SHIELD
GND
RO
RE
DE
DI
LK3
LK4
LK3
LK4
B
A
GND
J1
J5
J5
J3
VCC
EVAL-ADM3065EEBZ
EVAL-ADM3065EEBZ
3.3V OR 5V
SUPPLY
3.3V OR 5V
SUPPLY
SIGNAL
GENERATOR
DI
DI
14670-004
Figure 4. Half Duplex RS-485 Two Board Point to Point Test
