MAX13020_12 Datasheet, PDF (10/16 Pages) Maxim Integrated Products – ±60V Fault-Protected LIN Transceivers

MAX13020/MAX13021
±60V Fault-Protected LIN Transceivers
t_{(NWAKE = 0 AFTER 1 TO 0)}
> t_NWAKE
t_{(NSLP = 0 AFTER 1 TO 0)}
> t_GOTOSLEEP
FAULT MODE
t_{(LIN = DOMINANT)}
> t_{LIN(DOM)(DET)}
NORMAL SLOPE MODE
DISABLE MODE
t_{(NSLP = 1 AFTER 0 TO 1)}
> t_GOTONORM
t_{(LIN = RECESSIVE)}
> t_{LIN(DOM)(REC)}
t_{(NSLP = 1 AFTER 0 TO 1)}
> t_GOTONORM
TXD = 1
t_{(NSLP = 1 AFTER 0 TO 1)}
> t_GOTONORM
t_{(LIN = DOMINANT)}
> t_{LIN(DOM)(DET)}
STANDBY MODE
TXD = 1
t_{(NSLP = 0 AFTER 1 TO 0)}
> t_GOTOSLEEP
t_{(NSLP = 1 AFTER 0 TO 1)}
> t_GOTONORM
TXD = 0
(t_NWAKE = 0 AFTER 1 TO 0) > t_NWAKE
OR
t_{(LIN = 0 AFTER 1 TO 0)} >t_BUS
LOW SLOPE MODE
t_{(NSLP = 0 AFTER 1 TO 0)}
> t_GOTOSLEEP
t_{(NSLP = 1 AFTER 0 TO 1)}
> t_GOTONORM
TXD = 0
t_{(LIN = RECESSIVE)}
> t_{LIN(DOM)(REC)}
SLEEP MODE
INITIAL
POWER-ON STATE
Figure 2. MAX13021 Operating Modes
Sleep Mode
Sleep mode is the lowest power operating mode and is
the default state after power is applied to BAT. In sleep
mode, the MAX13020/MAX13021 disable the LIN trans-
mitter and receiver to reduce power consumption. RXD
and INH are high impedance. The internal slave termi-
nation resistor between LIN and BAT is disabled, and
only a weak pullup from LIN to BAT is enabled. While in
sleep mode, the MAX13020/MAX13021 transition to
standby mode when a local or remote wake-up event is
detected. For applications with a continuously powered
microprocessor, drive NSLP logic-high for longer than
t_GOTONORM to force the MAX13020/MAX13021 directly
into normal slope mode if TXD is logic-high, and low
slope mode if TXD is logic-low. From normal slope or
low slope mode, drive NSLP logic-low for longer than
t_GOTOSLEEP to force the MAX13020/MAX13021 into
sleep mode.
Standby Mode
In standby mode, the LIN transmitter and receiver are
disabled, the internal slave termination resistor between
LIN and BAT is enabled, and the INH output is pulled
high. The MAX13020/MAX13021 transition to standby
mode from sleep mode when a wake-up event is
detected. From standby mode, drive TXD logic-high or
logic-low, then drive NSLP logic-high for longer than
t_GOTONORM to transition to normal slope or low slope
10
mode. In standby mode, RXD is driven logic-low to
transmit the wake-up interrupt flag to a microcontroller.
The wake-up source flag is presented on TXD as a
strong pulldown in the case of a local wake-up. In the
case of a remote wake-up, TXD is pulled low by the
internal 330kΩ resistor only. The wake-up interrupt and
wake-up source flag are cleared when the
MAX13020/MAX13021 transition to normal slope mode
or low slope mode.
Normal Slope Mode
In normal slope mode, the MAX13020/MAX13021 pro-
vide the physical layer interface to a LIN bus through
RXD and TXD. INH is pulled high and the internal slave
termination resistance from LIN to BAT is enabled. Data
presented on TXD is transmitted on the LIN bus with a
controlled slew rate to limit EME. Drive TXD logic-low to
assert a dominant state on LIN. The LIN bus state is
presented on the open-drain output RXD. A dominant
LIN state produces a logic-low on RXD. From standby
or sleep mode, drive TXD logic-high, then drive NSLP
logic-high for longer than t_GOTONORM to enter normal
slope mode. Drive NSLP logic-low for longer than
t_GOTOSLEEP to force the device into sleep mode from
normal slope mode.
Maxim Integrated