AMIS-42675
High Speed Low Power CAN
Transceiver for Long Wire
Networks
Description
The AMIS−42675 CAN transceiver is the interface between a
controller area network (CAN) protocol controller and the physical
bus. It may be used in both 12 V and 24 V systems. The transceiver
provides differential transmit capability to the bus and differential
receive capability to the CAN controller.
Due to the wide common−mode voltage range of the receiver inputs,
the AMIS−42675 is able to reach outstanding levels of
electro−magnetic susceptibility (EMS). Similarly, extremely low
electromagnetic emission (EME) is achieved by the excellent
matching of the output signals.
The AMIS−42675 is the industrial version of the AMIS−42665 and
primarily for applications where long network lengths are mandatory.
Examples are elevators, in−building networks, process control and
trains. To cope with the long bus delay the communication speed
needs to be low. AMIS−42675 allows low transmit data rates down 10
Kbit/s or lower.
The AMIS−42675 is the low power member of the CAN high−speed
transceiver family and offers the following additional features:
Features
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PIN ASSIGNMENT
TxD
GND
V
CC
RxD
1
2
3
4
8
7
6
5
STB
CANH
CANL
V
SPLIT
(Top View)
AMIS−
42675
PC20041204.3
•
•
•
•
•
•
•
•
•
•
Ideal Passive Behavior When Supply Voltage is Removed
Wake−up Over Bus
Extremely Low Current Standby Mode
Compatible With the ISO 11898 standard (ISO
11898−2, ISO 11898−5 and SAE J2284)
Wide Range of Bus Communication Speed (0 up to
1 Mbit/s)
Ideally Suited for 12 V and 24 V Industrial and
Automotive Applications
Allows Low Transmit Data Rate in Networks
Exceeding 1 km
Extremely Low Current Standby Mode with Wake−up
via the Bus
Low Electromagnetic Emission (EME):
Common−Mode Choke is No Longer Required
Differential Receiver with Wide Common−Mode
Range ($35 V) for High EMS
ORDERING INFORMATION
See detailed ordering and shipping information in the package
dimensions section on page 11 of this data sheet.
•
Voltage Source via V
SPLIT
Pin for Stabilizing the
•
•
•
•
•
•
•
•
Recessive Bus Level (Further EMC Improvement)
No Disturbance of the Bus Lines with an Unpowered
Node
Thermal Protection
Bus Pins Protected Against Transients
Power Down Mode in Which the Transmitter is
Disabled
Bus and V
SPLIT
Pins Short Circuit Proof to Supply
Voltage and Ground
Logic Level Inputs Compatible with 3.3 V Devices
At Least 110 Nodes can be Connected to the Same Bus
These are Pb−Free Devices*
*For additional information on our Pb−Free strategy and soldering details, please
download the ON Semiconductor Soldering and Mounting Techniques
Reference Manual, SOLDERRM/D.
©
Semiconductor Components Industries, LLC, 2008
December, 2008
−
Rev. 2
1
Publication Order Number:
AMIS−42675/D
AMIS−42675
Table 1. TECHNICAL CHARACTERISTICS
Symbol
V
CC
V
STB
V
TxD
V
RxD
V
CANH
V
CANL
V
SPLIT
V
O(dif)(bus_dom)
CM−range
V
CM−peak
C
load
t
pd(rec−dom)
t
pd(dom−rec)
V
CM−step
T
junc
Parameter
Power Supply Voltage
DC Voltage at Pin STB
DC Voltage at Pin TxD
DC Voltage at Pin RxD
DC Voltage at Pin CANH
DC Voltage at Pin CANL
DC Voltage at Pin V
SPLIT
Differential Bus Output Voltage in
Dominant State
Input Common−Mode Range for
Comparator
Common−Mode Peak
Load Capacitance on IC Outputs
Propagation Delay TxD to RxD
Propagation Delay TxD to RxD
Common−Mode Step
Junction Temperature
See Figure 4
See Figure 4
Note 1
70
100
−150
−40
0 < V
CC
< 5.25 V; No Time Limit
0 < V
CC
< 5.25 V; No Time Limit
0 < V
CC
< 5.25 V; No Time Limit
42.5
W
< R
LT
< 60
W
Guaranteed Differential Receiver Threshold
and Leakage Current
Note 1
Condition
Max
4.75
−0.3
−0.3
−0.3
−35
−35
−35
1.5
−35
−500
Max
5.25
V
CC
V
CC
V
CC
+35
+35
+35
3
+35
500
15
230
245
150
150
Unit
V
V
V
V
V
V
V
V
V
mV
pF
ns
ns
mV
°C
1. The parameters V
CM−peak
and V
CM−step
guarantee low EME.
V
CC
VCC
AMIS−42675
3
POR
7
TxD
1
VCC
CANH
V
SPLIT
CANL
Thermal
shutdown
VCC
V
SPLIT
5
STB
8
Mode &
wake−up
control
Driver
control
6
RxD
GND
4
Wake
−up
Filter
COMP
2
COMP
PC20071005.2
Figure 1. Block Diagram
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2
AMIS−42675
Table 2. PIN DESCRIPTION
Pin
1
2
3
4
5
6
7
8
Name
TxD
GND
V
CC
RxD
V
SPLIT
CANL
CANH
STB
Description
Transmit Data Input; Low Input
→
Dominant Driver; Internal Pullup Current
Ground
Supply Voltage
Receive Data Output; Dominant Transmitter
→
Low Output
Common−Mode Stabilization Output
Low−Level CAN Bus Line (Low in Dominant Mode)
High−Level CAN Bus Line (High in Dominant Mode)
Standby Mode Control Input
Table 3. ABSOLUTE MAXIMUM RATINGS
Symbol
V
CC
V
CANH
V
CANL
V
SPLIT
V
TxD
V
RxD
V
STB
V
tran(CANH)
V
tran(CANL)
V
tran(VSPLIT)
V
esd(
Latch−up
T
stg
T
A
T
J
Parameter
Supply Voltage
DC Voltage at Pin CANH
DC Voltage at Pin CANL
DC Voltage at Pin V
SPLIT
DC Voltage at Pin TxD
DC Voltage at Pin RxD
DC Voltage at Pin STB
Transient Voltage at Pin CANH
Transient Voltage at Pin CANL
Transient Voltage at Pin V
SPLIT
Electrostatic Discharge Voltage at all
Pins
Static Latch−up at All Pins
Storage Temperature
Ambient Temperature
Maximum Junction Temperature
Note 2
Note 2
Note 2
Note 4
Note 5
Note 4
−55
−40
−40
0 < V
CC
< 5.25 V; No Time
Limit
0 < V
CC
< 5.25 V; No Time
Limit
0 < V
CC
< 5.25 V; No Time
Limit
Conditions
Min
−0.3
−50
−50
−50
−0.3
−0.3
−0.3
−300
−300
−300
−5
−750
Max
+7
+50
+50
+50
V
CC
+ 0.3
V
CC
+ 0.3
V
CC
+ 0.3
+300
+300
+300
+5
+750
120
+150
+125
+170
Unit
V
V
V
V
V
V
V
V
V
V
kV
V
mA
°C
°C
°C
Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the
Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect
device reliability.
2. Applied transient waveforms in accordance with ISO 7637 part 3, test pulses 1, 2, 3a, and 3b (see Figure 3).
3. Standardized human body model electrostatic discharge (ESD) pulses in accordance to MIL883 method 3015.7.
4. Static latch−up immunity: Static latch−up protection level when tested according to EIA/JESD78.
5. Standardized charged device model ESD pulses when tested according to EOS/ESD DS5.3−1993.
Table 4. THERMAL CHARACTERISTICS
Symbol
R
th(vj−a)
R
th(vj−s)
Parameter
Thermal Resistance from Junction−to−Ambient in SOIC−8 Package
Thermal Resistance from Junction−to−Substrate of Bare Die
Conditions
In Free Air
In Free Air
Value
145
45
Unit
k/W
k/W
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AMIS−42675
APPLICATION SCHEMATIC
VBAT
IN
5V−
reg
OUT
V
CC
STB
3
8
4
1
2
V
CC
7
CANH
60
W
47 nF
CAN
controller
PC20071005.3
RxD
TxD
AMIS−
42675
5
V
SPLIT
60
W
CAN
BUS
6
CANL
GND
GND
Figure 2. Application Diagram
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4
AMIS−42675
FUNCTIONAL DESCRIPTION
Operating Modes
AMIS−42675 provides two modes of operation as
illustrated in Table 5. These modes are selectable through
Pin STB.
Table 5. OPERATING MODES
Pin RXD
Mode
Normal
Standby
Pin STB
Low
High
Low
Bus Dominant
Wake−up Request Detected
High
Bus Recessive
No wake−up Request Detected
Normal Mode
Overtemperature Detection
In the normal mode, the transceiver is able to
communicate via the bus lines. The signals are transmitted
and received to the CAN controller via the Pins TxD and
RxD. The slopes on the bus lines outputs are optimized to
give extremely low EME.
Standby Mode
In stand−by mode both the transmitter and receiver are
disabled and a very low−power differential receiver
monitors the bus lines for CAN bus activity. The bus lines
are terminated to ground and supply current is reduced to a
minimum, typically 10
mA.
When a wake−up request is
detected by the low−power differential receiver, the signal
is first filtered and then verified as a valid wake signal after
a time period of t
BUS
, the RxD Pin is driven low by the
transceiver to inform the controller of the wake−up request.
Split Circuit
A thermal protection circuit protects the IC from damage
by switching off the transmitter if the junction temperature
exceeds a value of approximately 160°C. Because the
transmitter dissipates most of the power, the power
dissipation and temperature of the IC is reduced. All other
IC functions continue to operate. The transmitter off−state
resets when Pin TxD goes high. The thermal protection
circuit is particularly needed when a bus line short circuits.
High Communication Speed Range
The transceiver is primarily intended for industrial
applications. It allows very low baud rates needed for long
bus length applications. But also high speed communication
is possible up to 1 Mbit/s.
Fail Safe Features
The V
SPLIT
Pin is operational only in normal mode. In
standby mode this pin is floating. The V
SPLIT
is connected
as shown in Figure 2 and its purpose is to provide a stabilized
DC voltage of 0.5 x V
CC
to the bus avoiding possible steps
in the common−mode signal therefore reducing EME. These
unwanted steps could be caused by an un−powered node on
the network with excessive leakage current from the bus that
shifts the recessive voltage from its nominal 0.5 x V
CC
voltage.
Wake−up
A current−limiting circuit protects the transmitter output
stage from damage caused by accidental short circuit to
either positive or negative supply voltage, although power
dissipation increases during this fault condition.
The Pins CANH and CANL are protected from
automotive electrical transients (according to ISO 7637; see
Figure 3). Pins TxD and STB are pulled high internally
should the input become disconnected. Pins TxD, STB and
RxD will be floating, preventing reverse supply should the
V
CC
supply be removed.
Once a valid wake−up (dominant state longer than t
BUS
)
has been received during the standby mode, the RxD Pin is
driven low.
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