Datasheet
INH
Inhibit is an output that allows for the control of an exter-
nal voltage regulator. On a wake-up request or power-up
on BATT, the transceiver sets the output INH high. This
feature enables the external voltage regulator to be shut
down during sleep mode to reduce power consumption.
INH is floating while entering the sleep mode and stays
floating during the sleep mode. If INH is left floating, it
is not set to a high level again until the following events
occur:
● Power-on (V
BATT
switching on at cold start)
● Rising or falling edge on WAKE
● Dominant signal longer than 38μs during EN or STB at
low level
The signals on STB and EN are internally set to low level
when V
CC
is below a certain threshold voltage providing
fail-safe functionality.
After power-on (V
BATT
switched on) the signal on INH
becomes HIGH and an internal power-on flag is set. This
flag can be read in the power-on standby mode through
ERR (STB = 1, EN = 0) and is reset by entering the nor-
mal operating mode.
ERR
ERR is a wake-up and power-on indicator as well as an
error detector. Upon power-up, wake up, or when a bus
failure is detected, the output signal on ERR becomes
LOW. Upon error recovery, the output signal on ERR is
set HIGH.
STB
STB is the standby digital control signal into the logic
controller. This is an active-low input that is used with EN
to define the status of the transceiver in normal and low-
power modes.
EN
EN is the enable digital control signal into the logic con-
troller used in conjunction with STB to define the status of
the transceiver in normal and low-power modes.
WAKE
WAKE is an input to the logic controller within the device
to signal a wake-up condition. If WAKE receives a positive
or negative pulse for a period longer than t
WAKE
, wake
up occurs.
Figure 5. Block Diagram
FILTER
FILTER
THERMAL
SHUTDOWN
DRIVER
FAULT DETECTION
WAKE-UP
STANDBY
CONTROLLER
4ms
RECEIVER
IPD
GND
INH
WAKE
STB
EN
TXD
ERR
RXD
1
7
5
6
2
4
3
BATT
10
9
11
12
8
V
CC
RTL
CANH
CANL
RTH
MAX305_
MAX3054/MAX3055/
MAX3056
±80V Fault-Protected/Tolerant CAN Transceiver
www.maximintegrated.com
Maxim Integrated
│
12