MAX14882
5kV
Isolated CAN Transceiver
RMS
with Integrated Transformer Driver
Pin Description (continued)
REF
SUPPLY
PIN
NAME
FUNCTION
TYPE
CAN BUS-SIDE (B-SIDE)
9, 15
10
GNDB Bus-Side/B-Side Ground. GNDB is the ground reference for V
, V
, CANH, and CANL.
—
Ground
LDO DDB
LDO Power Input. Connect a minimum voltage of 4.68V to V
to power the bus-side of the
LDO
Power
Input
V
transceiver. Bypass V
to GNDB with both 0.1μF and 1μF capacitors as close as possible
GNDB
LDO
LDO
to the device. To disable the internal LDO, leave V
unconnected or connect to GNDB.
LDO
11, 14
12
I.C.
Internally Connected. Connect to GNDB.
GNDB
GNDB
Differential
CANL Low-Level CAN Differential Bus Line
CANH High-Level CAN Differential Bus Line
I/O
Differential
13
16
GNDB
GNDB
I/O
Bus-Side Power Input/LDO Power Output. Bypass V
1μF capacitors as close as possible to the device. V
to GNDB with both 0.1μF and
is the output of the internal LDO
DDB
DDB
V
Power
DDB
when power is applied to V
or connected to GNDB), V
. When the internal LDO is not used (V
is the positive supply input for the bus-side of the IC.
is unconnected
LDO
DDB
LDO
Fault Protection
Detailed Description
The MAX14882 features ±54V fault protection on the
CANH and CANL bus lines. When CANH or CANL is pulled
above +30V (typ) or below -30V (typ), the I/O is set to
high-impedance. This wide fault protection range simplifies
selecting external TVS components for surge protection.
The MAX14882 isolated controller area network (CAN)
transceiver provides 5000V (60s) of galvanic isolation
RMS
between the cable-side (B-side) of the transceiver and
the controller-side (A-side). This device allows up to
1Mbps communication across the isolation barrier when
a large potential exists between grounds on each side
of the barrier. CANH and CANL outputs are short-circuit
current-limited and are protected against excessive power
dissipation by thermal shutdown circuitry that places the
driver outputs in a high-impedance state.
Transmitter
The transmitter converts a single-ended input signal
(TXD) from the CAN controller to differential outputs
for the bus lines (CANH, CANL). The truth table for the
transmitter and receiver is given in Table 1.
Isolation
Transmitter Dominant Timeout
The MAX14882 features a transmitter-dominant timeout
Both data and power can be transmitted across the isolation
barrier. Data isolation is achieved using integrated capaci-
tive isolation that allows data transmission between the
controller-side and the cable-side of the transceiver.
(t ) that prevents erroneous CAN controllers from
DOM
clamping the bus to a dominant level by maintaining a
continuous low TXD signal. When TXD remains in the
To achieve power isolation, the MAX14882 features an
integrated transformer driver to drive an external center-
tapped transformer, allowing the transfer of operating
power from the controller-side, across the isolation
barrier, to the cable-side. Connect the primary side of
the external transformer to the MAX14882’s transformer
driver outputs (TD1 and TD2).
dominant state (low) for greater than t
is disabled, releasing the bus to a recessive state (Table 1).
, the transmitter
DOM
After a dominant timeout fault, normal transmitter function
is re-enabled on the rising edge of a TXD. The transmitter-
dominant timeout limits the minimum possible data rate to
7.86kbps for standard CAN protocol.
Maxim Integrated
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