MAX13020 Datasheet, PDF (9/15 Pages) Maxim Integrated Products – ±60V Fault-Protected LIN Transceivers

±60V Fault-Protected LIN Transceivers
Pin Description
PIN
NAME
FUNCTION
1
RXD
Data Receive Output, Open Drain. RXD is logic-low when the LIN bus is dominant. RXD is active low after
a wake-up event from sleep mode.
2
NSLP Sleep Input. Drive NSLP logic-high or logic-low to control the operating mode. (See Table 1 and Figures 1, 2)
3
NWAKE
Local Wake-Up Input. Present a falling edge on NWAKE to generate a local wake-up event. Connect
NWAKE to BAT with a 5kΩ resistor if local wake-up is not required.
4
TXD
Data Transmit Input, CMOS Compatible. Drive TXD logic-low to force the LIN bus to a dominant state in
normal/low slope mode.
5
GND Ground
6
LIN
LIN Bus I/O. LIN is terminated with an internal 30kΩ resistor in normal slope, low slope, and standby
modes.
7
BAT
Battery Voltage Input. Bypass BAT to ground with a 0.1µF ceramic capacitor as close to the device as
possible.
8
INH Inhibit Output. INH is active high in standby and normal/low slope modes. (See Table 1)
Detailed Description
The MAX13020/MAX13021 ±60V fault-protected low-
power local interconnect network (LIN) transceivers are
ideal for use in automotive network applications where
high reliability is required. The devices provide the
interface between the LIN master/slave protocol con-
troller and the physical bus described in the LIN 2.0
specification package and SAE J2602 specification.
The devices are intended for in-vehicle subnetworks
with a single master and multiple slaves.
The extended fault-protected voltage range of ±60V on
the LIN bus line allows for use in +12V, +24V, and
+42V automotive applications. The devices allow com-
munication up to 20kbaud, and include slew-rate limit-
ed transmitters for enhanced electromagnetic
emissions (EME) performance. The devices feature a
low-power 4µA sleep mode and provide wake-up
source detection.
The MAX13020 is a pin-to-pin replacement and is func-
tionally compatible with the Philips TJA1020. The
MAX13021 includes enhanced bus dominant clamping
fault-management for reduced quiescent current during
LIN bus shorts to GND.
Operating Modes
The MAX13020/MAX13021 provide two different trans-
mitting modes, an intermediate standby mode and a
low-power sleep mode. Normal slope mode allows full-
speed communication at 20kbaud with a slew-limited
transmitter to reduce EME. Low slope mode permits
communication up to 10.4kbaud, and provides addi-
STANDBY MODE
t_{(NSLP = 1 AFTER 0 TO 1)}
> t_GOTONORM
TXD = 1
NORMAL SLOPE MODE
t_(NSLP
>
= 1 AFTER 0 TO
t_GOTONORM
TXD = 0
1)
(t_NWAKE
=
0
AFTER 1
OR
TO
0)
>
t_(NSLP
>
t_NWAKE
= 1 AFTER 0 TO
t_GOTONORM
TXD = 1
t_(NSLP
1)
=0
AFTER
1
TO
0)
t_{(LIN = 0 AFTER 1 TO 0)} >t_BUS
> t_GOTOSLEEP
LOW SLOPE MODE
t_{(NSLP = 0 AFTER 1 TO 0)}
> t_GOTOSLEEP
t_{(NSLP = 1 AFTER 0 TO 1)}
> t_GOTONORM
TXD = 0
SLEEP MODE
INITIAL
POWER-ON STATE
Figure 1. MAX13020 Operating Modes
tional slew-rate limiting to further reduce EME. The
transmitting operating mode is selected by the logic
state of NSLP and TXD (Table 1). To enter normal slope
mode or low slope mode, drive TXD logic-high or logic-
low, then drive NSLP logic-high for longer than
t_GOTONORM. The MAX13021 features two additional
operating modes to reduce current consumption during
LIN bus shorts to GND.
On initial power-up, the device enters sleep mode.
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