MAX13020 Datasheet, PDF (11/15 Pages) Maxim Integrated Products – ±60V Fault-Protected LIN Transceivers

±60V Fault-Protected LIN Transceivers
Low Slope Mode
Low slope mode is identical to normal slope mode, with
the exception of the LIN transmitter. In low slope mode,
the transmitter slew-rate is further limited for improved
EME performance. Maximum data rate is limited to
10.4kbaud due to the increased slew-rate limiting of the
LIN transmitter. From standby or sleep mode, drive
TXD logic-low, then drive NSLP logic-high for longer
than t_GOTONORM to enter low slope mode. Drive NSLP
logic-low for longer than t_GOTOSLEEP to force the
device into sleep mode from low slope mode.
LIN Bus Dominant Management
(MAX13021)
The MAX13021 provides two additional states to imple-
ment reduced current consumption during a LIN-to-
GND short condition. When the MAX13021 detects a
dominant-clamped fault on LIN, the device disables the
transmitter and enters a low-power fail-safe mode. The
receiver is disabled and a low-power comparator is
enabled to monitor the LIN bus. When a recessive state
is detected on LIN, the device exits fault mode and
returns to standby mode.
Fault Mode (MAX13021)
The device enters fault mode from normal slope or low
slope mode when a dominant state is detected on LIN
for longer than t_{LIN(DOM)(DET)}. In fault mode, the slave
termination resistor from LIN to BAT is disconnected,
and the LIN transmitter and receiver are disabled to
reduce power consumption. INH output remains pulled
high. A low-power comparator is enabled to monitor the
LIN bus. Fault mode is cleared, and the MAX13021
enters standby mode when a recessive state is detect-
ed on LIN for longer than t_{LIN(DOM)(REC)}.
Disable Mode (MAX13021)
The MAX13021 enters disable mode from fault mode
after NSLP is driven logic-low for longer than
t_GOTOSLEEP. The INH output is high impedance in dis-
able mode to reduce current consumption. The LIN
transmitter and receiver are disabled, and the slave ter-
mination resistor from LIN to BAT is disconnected. A
low-power comparator is enabled to monitor the LIN
bus. The MAX13021 enters fault mode when NSLP is
driven logic-high for longer than t_GOTONORM. The
device enters sleep mode if a recessive state is detect-
ed on LIN for longer than t_{LIN(DOM)(REC)}.
Local and Remote Wake-Up Events
The MAX13020/MAX13021 recognize local and remote
wake-up events from sleep mode. The MAX13021 also
recognizes local wake-up events from disable mode. A
local wake-up event is detected when NWAKE is held
at logic-low for longer than t_GOTONORM after a falling
edge. NWAKE is internally pulled up to BAT with a
Table 1. Operating Modes
MODE
SLEEP
STANDBY
NSLP
0
0
TXD
PULLDOWN
330kΩ
330kΩ or
strong
pulldown
RXD
High-Z
0
INH TRANSMITTER RECEIVER
COMMENTS
High-Z
1
Disabled
Disabled
Disabled
Disabled
No wake-up events detected
Wake-up detected from sleep
mode. TXD indicates wake-up
source. (Note 1)
NORMAL
1
330kΩ
SLOPE
LOW SLOPE 1
330kΩ
FAULT*
1
330kΩ
DISABLE*
0
330kΩ
*MAX13021 only.
High-Z = High impedance.
LIN
1
Normal slope
Enabled (Notes 2, 3, 4)
LIN
1
LIN
1
LIN
High-Z
Low slope
Disabled
Disabled
Enabled
Low power
Low power
(Notes 2, 3, 5)
—
—
Note 1: Standby mode is entered automatically after a local or remote wake-up event from sleep mode. INH and the 30kΩ termina-
tion resistor on LIN are enabled.
Note 2: The internal wake-up source flag on TXD is cleared upon entering normal slope or low slope mode.
Note 3: The internal wake-up interrupt flag on RXD is cleared upon entering normal slope or low slope mode.
Note 4: Drive NSLP high for longer than t_GOTONORM with TXD logic-high to enter normal slope mode.
Note 5: Drive NSLP high for longer than t_GOTONORM with TXD logic-low to enter low slope mode.
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