AMIS-42671 High-Speed CAN Transceiver
For Long Networks
Data Sheet
1.0 General Description
The AMIS-42671 CAN transceiver with autobaud is the interface between a controller area network (CAN) protocol controller and the
physical bus. It may be used in both 12V and 24V 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-
42671 is able to reach outstanding levels of electromagnetic susceptibility (EMS). Similarly, extremely low electromagnetic emission
(EME) is achieved by the excellent matching of the output signals.
The AMIS-42671 is primarily intended for industrial network 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-42671 allows low transmit data rates down 10 Kbit/s or lower. The autobaud function allows the CAN controller to determine the
incoming baud rate without influencing the CAN communication on the bus.
2.0 Key Features
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Fully compatible with the ISO 11898-2 standard
Autobaud function
Wide range of bus communication speed (0 up to 1 Mbit/s)
Allows low transmit data rate in networks exceeding 1 km
Ideally suited for 12V and 24V industrial and automotive applications
Low electromagnetic emission (EME) common-mode choke is no longer required
Differential receiver with wide common-mode range (+/- 35V) for high EMS
No disturbance of the bus lines with an un-powered node
Thermal protection
Bus pins protected against transients
Silent mode in which the transmitter is disabled
Short circuit proof to supply voltage and ground
Logic level inputs compatible with 3.3V devices
ESD protection for CAN bus at ± 8 kV
3.0 Technical Characteristics
Table 1: Technical Characteristics
Symbol
Parameter
V
CANH
DC voltage at pin CANH
V
CANL
DC voltage at pin CANL
V
i(dif)(bus_dom)
Differential bus output voltage in dominant state
t
pd(rec-dom)
Propagation delay TxD to RxD
t
pd(dom-rec)
Propagation delay TxD to RxD
C
M-range
Input common-mode range for comparator
V
CM-peak
V
CM-step
Common-mode peak
Common-mode step
Conditions
0 < V
CC
< 5.25V; no time limit
0 < V
CC
< 5.25V; no time limit
42.5Ω < R
LT
< 60Ω
See Figure 8
See Figure 8
Guaranteed differential receiver threshold and
leakage current
See Figure 9 and Figure 10 (Notes)
See Figure 9 and Figure 10 (Notes)
Min.
-45
-45
1.5
70
100
-35
-500
-150
Max.
+45
+45
3
245
245
+35
500
150
Unit
V
V
V
ns
ns
V
mV
mV
Note: The parameters V
CM-peak
and V
CM-step
guarantee low electromagnetic emission.
4.0 Ordering Information
Ordering Code (Tubes)
0ICAB-001-XTD
Ordering Code (Tape)
0ICAB-001-XTP
Marketing Name
AMIS 42671AGA
Package
SOIC-8 GREEN
Temp. Range
-40°C…125°C
AMI Semiconductor
– Oct. 07, Rev. 1.0
www.amis.com
Specifications subject to change without notice
1
AMIS-42671 High-Speed CAN Transceiver
For Long Networks
Data Sheet
5.0 Block Diagram
V
CC
AUTB
8
Thermal
shutdown
V
CC
3
TxD
1
Slope
Control
7
Driver
control
6
CANH
CANL
Auto-
baud
Control
AMIS-42671
COMP
RxD
V
REF
4
R
i(cm)
+
V
cc
/
2
5
R
i(cm)
2
PC20070930.2
GND
Figure 1: Block Diagram
6.0 Typical Application
6.1 Application Schematic
VBAT
IN
5V-reg
OUT
V
CC
AUTB
3
8
4
7
60
Ω
60
Ω
47 nF
V
CC
CANH
VREF
CANL
60
Ω
GND
CAN
controller
RxD
TxD
AMIS-
42671
2
5
6
CAN
BUS
1
60
Ω
47 nF
GND
PC20071001.1
Figure 2: Application Diagram
AMI Semiconductor
– Oct. 07, Rev. 1.0
www.amis.com
Specifications subject to change without notice
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AMIS-42671 High-Speed CAN Transceiver
For Long Networks
6.2 Pin Description
6.2.1. Pin Out (Top View)
Data Sheet
TxD
GND
V
CC
RxD
1
8
AUTB
CANH
CANL
V
REF
AMIS-
42671
Figure 3: Pin Configuration
2
3
4
7
6
5
PC20070929.1
6.3 Pin Description
Table 2: Pin Out
Pin
Name
1
TxD
2
GND
3
V
CC
4
RxD
5
V
REF
6
CANL
7
CANH
8
AUTB
Description
Transmit data input; low input
→
dominant driver; internal pull-up current
Ground
Supply voltage
Receive data output; dominant transmitter→ low output
Reference voltage output
Low-level CAN bus line (low in dominant mode)
High-level CAN bus line (high in dominant mode)
Autobaud mode control input; internal pull-down current
AMI Semiconductor
– Oct. 07, Rev. 1.0
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www.amis.com
Specifications subject to change without notice
AMIS-42671 High-Speed CAN Transceiver
For Long Networks
Data Sheet
7.0 Functional Description
7.1 Operating Modes
The behavior of AMIS-42671 under various conditions is illustrated in Table 3 below. In case the device is powered, one of two
operating modes can be selected through pin AUTB.
Table 3: Functional table of AMIS-42671 when not connected to the bus; X = don’t care
VCC
pin TxD
pin AUTB
pin CANH
pin CANL
Bus state
pin RxD
4.75 to 5.25.V
4.75 to 5.25.V
4.75 to 5.25.V
VCC<PORL (unpowered)
PORL<VCC<4.75V
0
X
1 (or floating)
X
>2V
0 (or floating)
1
X
X
X
High
VCC/2
VCC/2
0V<CANH<VCC
0V<CANH<VCC
Low
VCC/2
VCC/2
0V<CANL<VCC
0V<CANL<VCC
Dominant
Recessive
Recessive
Recessive
Recessive
0
1
1
1
1
7.1.1. High-Speed Mode
If pin AUTB is pulled low (or left floating), the transceiver is in its high-speed mode and 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 line outputs are optimized
to give extremely low electromagnetic emissions.
7.1.2. Autobaud Mode
If pin AUTB is pulled high, AMIS-42671 is in Autobaud mode. The transmitter is disabled while the receiver remains active. All other IC
functions also continue to operate. Normal bus activity can be monitored at the RxD pin and transmit data on TxD is looped back to
RxD without influencing the CAN communication.
TxD
CANH
CANL
RxD
AUTB
PC20071002.4
Figure 4: Simplified Schematic Diagram of Autobaud Function
In Autobaud mode the local CAN controller is able to detect the used communication speed of other transmitting network nodes. Bus
communication is received and via the RxD pin sent to the CAN controller. If the CAN controller operates at the wrong baud rate, it will
transmit an error frame. This message will be looped back to the CAN controller which will increment its error counter. The CAN
controller will be reset with another baud rate. When an error-free message is received, the correct baud rate is detected. A logic low
may now be applied to pin AUTB, returning to the High-Speed Mode.
7.2 Over-temperature Detection
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 necessary when a bus line short-circuits.
AMI Semiconductor
– Oct. 07, Rev. 1.0
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Specifications subject to change without notice
AMIS-42671 High-Speed CAN Transceiver
For Long Networks
7.3 High Communication Speed Range
Data Sheet
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 1Mbit/s.
7.4 Fail-safe Features
A current-limiting circuit protects the transmitter output stage from damage caused by an 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 5). Pin TxD is
pulled high internally should the input become disconnected.
8.0 Electrical Characteristics
8.1 Definitions
All voltages are referenced to GND (pin 2). Positive currents flow into the IC. Sinking current means the current is flowing into the pin;
sourcing current means the current is flowing out of the pin.
8.2 Absolute Maximum Ratings
Stresses above those listed in the following table may cause permanent device failure. Exposure to absolute maximum ratings for
extended periods may affect device reliability.
Table 4: Absolute Maximum Ratings
Symbol
Parameter
V
CC
Supply voltage
V
CANH
DC voltage at pin CANH
V
CANL
DC voltage at pin CANL
V
TxD
DC voltage at pin TxD
V
RxD
DC voltage at pin RxD
V
AUTB
DC voltage at pin AUTB
V
REF
DC voltage at pin V
REF
V
tran(CANH)
Transient voltage at pin CANH
V
tran(CANL)
Transient voltage at pin CANL
V
esd
Latch-up
T
stg
T
amb
T
junc
Notes:
1.
2.
3.
4.
Conditions
0 < V
CC
< 5.25V; no time limit
0 < V
CC
< 5.25V; no time limit
Electrostatic discharge voltage at all pins
Static latch-up at all pins
Storage temperature
Ambient temperature
Maximum junction temperature
Note 1
Note 1
Note 2
Note 4
Note 3
Min.
-0.3
-45
-45
-0.3
-0.3
-0.3
-0.3
-150
-150
-4
-500
-55
-40
-40
Max.
+7
+45
+45
V
CC
+ 0.3
V
CC
+ 0.3
V
CC
+ 0.3
V
CC
+ 0.3
+150
+150
+4
+500
100
+155
+125
+150
Unit
V
V
V
V
V
V
V
V
V
kV
V
mA
°C
°C
°C
Applied transient waveforms in accordance with ISO 7637 part 3, test pulses 1, 2, 3a, and 3b (see Figure 4).
Standardized human body model ESD pulses in accordance to MIL883 method 3015.7.
Static latch-up immunity: static latch-up protection level when tested according to EIA/JESD78.
Standardized charged device model ESD pulses when tested according to EOS/ESD DS5.3-1993.
8.3 Thermal Characteristics
Table 5: Thermal Characteristics
Symbol
Parameter
R
th(vj-a)
Thermal resistance from junction to ambient in SO8 package
R
th(vj-s
)
Thermal resistance from junction to substrate of bare die
Conditions
In free air
In free air
Value
150
45
Unit
K/W
K/W
AMI Semiconductor
– Oct. 07, Rev. 1.0
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www.amis.com
Specifications subject to change without notice
