AMIS-42700
Dual High Speed CAN
Transceiver
General Description
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PIN CONFIGURATION
NC
1
20
NC
EN2
2
19
CANH2
Text
3
18
CANL2
Tx0
4
17
GND
GND
5
16
GND
GND
6
15
GND
Rx0
7
14
CANL1
Vref1
8
13
CANH1
Rint
9
12
VCC
EN1
10
11
NC
AMIS−42700
Controller area network (CAN) is a serial communication protocol,
which supports distributed real−time control and multiplexing with
high safety level. Typical applications of CAN−based networks can be
found in automotive and industrial environments.
The AMIS−42700 Dual−CAN transceiver is the interface between
up to two physical bus lines and the protocol controller and will be
used for serial data interchange between different electronic units at
more than one bus line. It can be used for both 12 V and 24 V systems.
The circuit consists of following blocks:
• Two differential line transmitters
• Two differential line receivers
• Interface to the CAN protocol handler
• Interface to expand the number of CAN busses
• Logic block including repeater function and the feedback suppression
• Thermal shutdown circuit (TSD)
• Short to battery treatment circuit
Due to the wide common−mode voltage range of the receiver inputs,
the AMIS−42700 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.
SOIC 20
WC SUFFIX
CASE 751AQ
Key Features
•
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•
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•
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•
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•
•
Fully compatible with the ISO 11898−2 standard
Certified “Authentication on CAN Transceiver Conformance (d1.1)”
High speed (up to 1 Mbit/s in function of the bus topology)
Ideally suited for 12 V and 24 V industrial and automotive
applications
Low EME common−mode−choke is no longer required
Differential receiver with wide common−mode range (±35 V) for
high EMS
No disturbance of the bus lines with an un−powered node
Dominant time−out function
Thermal protection
Bus pins protected against transients in an automotive environment
Short circuit proof to supply voltage and ground
© Semiconductor Components Industries, LLC, 2009
January, 2009 − Rev. 5
1
ORDERING INFORMATION
See detailed ordering and shipping information in the package
dimensions section on page 12 of this data sheet.
Publication Order Number:
AMIS−42700/D
AMIS−42700
Table 1. Technical Characteristics
Symbol
Parameter
Conditions
Min.
Max.
Unit
VCANHx
DC voltage at pin CANH1/2
0 < VCC < 5.25 V; no time limit
−45
+45
V
VCANLx
DC voltage at pin CANL1/2
0 < VCC < 5.25 V; no time limit
−45
+45
V
42.5 W < RLT < 60 W
1.5
3
V
Vo(dif)(bus_dom)
Differential bus output voltage in dominant state
CM−range
Input common−mode range for comparator
Guaranteed differential receiver
threshold and leakage current
−35
+35
V
VCM−peak
Common−mode peak
See Figures 9 and 10 (Note 1)
−1000
1000
mV
VCM−step
Common−mode step
See Figures 9 and 10 (Note 1)
−250
250
mV
1. The parameters VCM−peak and VCM−step guarantee low EME.
VCC
12
Thermal
shutdown
Timer
14
Driver
control
Vcc/2
Ri(cm)
+
COMP
19
Timer
Feedbeck Surpression
CANL1
clock
AMIS−42700
13
Feedbeck Surpression
CANH1
POR
Logic
Unit
18
Driver
control
Ri(cm)
+
COMP
Ri(cm)
Vcc/2
Ri(cm)
VCC
8
VREF
VCC
10
VCC
VCC
3
ENB1 Text
7
4
Rx0
Tx0
9
Rint
2
5
ENB2
Figure 1. Block Diagram
Typical Application
Application Description
• Dual CAN
• A CAN−bus extender
• A CAN−bus repeater
AMIS−42700 is especially designed to provide the link
between a CAN controller (protocol IC) and two physical
busses. It is able to operate in three different modes:
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2
6
15
GND
16
17
CANH2
CANL2
AMIS−42700
Application Schematics
VBAT
CAN BUS 1
5V−reg
CAN BUS 2
CD
100 nF
Vref
VCC
8 13 CANH1
EN1 10 12
EN2 2
Rx0 7
Tx0
Text
Rint
RLT
AMIS−42700
4
14
19
CANL1
60 W
CANH2
RLT
3
9
5
18
6 15 16 17
CANL2
60 W
GND
Figure 2. Application Diagram CAN−bus Repeater
VBAT
CAN BUS 1
5V−reg
CD
CD
100 nF
100 nF
VCC
VCC
EN1 10
EN2 2
Rx0
mC
CAN
con−
troller
Tx0
Text
Rint
7
4
Vref
8 13 CANH1
12
RLT
AMIS−42700
14
19
CANL1
CANH2
RLT
3
9
60 W
5
6 15 16 17
18
CANL2
60 W
GND
GND
Figure 3. Application Diagram Dual−CAN
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3
CAN BUS 2
AMIS−42700
VBAT
CAN BUS 1
5V−reg
CD
CD
100 nF
100 nF
VCC
8 13 CANH1
EN1 10 12
EN2 2
mC
Rx0 7
Tx0
CAN
con−
troller
Text
Rint
+5
Vref
VCC
RLT
AMIS−42700
4
CAN BUS 2
14
19
CANL1
60 W
CANH2
RLT
3
9
5
18
6 15 16 17
CANL2
GND
GND
60 W
+5
CAN BUS 3
CD
100 nF
Vref
VCC
8 13 CANH1
EN1 10 12
EN2 2
Rx0
Tx0
Text
Rint
7
4
RLT
AMIS−42700
14
19
CANL1
CANH2
RLT
3
9
60 W
5
6 15 16 17
18
CANL2
60 W
GND
Figure 4. Application Diagram CAN−bus Extender
Table 2. Pin Out
Pin
Name
Description
1
NC
2
ENB2
Not connected
3
Text
Multi−system transmitter Input; internal pull−up
4
Tx0
Transmitter input; internal pull−up
5
GND
Ground connection (Note 2)
6
GND
Ground connection (Note 2)
7
Rx0
Receiver output
8
VREF1
9
Rint
10
ENB1
11
NC
Enable input, bus system 2; internal pull−up
Reference voltage
Multi−system receiver output
Enable input, bus system 1; internal pull−up
Not connected
12
VCC
13
CANH1
Positive supply voltage
CANH transceiver I/O bus system 1
14
CANL1
CANL transceiver I/O bus system 1
15
GND
Ground connection (Note 2)
16
GND
Ground connection (Note 2)
17
GND
Ground connection (Note 2)
18
CANL2
CANL transceiver I/O bus system 2
19
CANH2
CANH transceiver I/O bus system 2
20
NC
Not connected
2. In order to ensure the chip performance, all these pins need to be connected to GND on the PCB.
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4
CAN BUS 4
AMIS−42700
Functional Description
Overall Functional Description
not connected or is accidentally interrupted. A dominant
state on the bus line is represented by a low-level at the
digital interface; a recessive state is represented by a
high-level.
Dominant state received on any bus (if enabled) causes a
dominant state on both busses, pin Rint and pin Rx0.
Dominant signal on any of the input pins Tx0 and Text
causes transmission of dominant on both bus lines (if
enabled).
Digital inputs Tx0 and Text are used for connecting the
internal logic’s of several IC’s to obtain versions with more
than two bus outputs (see Figure 4: Application Diagram
CAN-bus Extender). They have also a direct logical link to
pins Rx0 and Rint independently on the EN1x pins −
dominant on Tx0 is directly transferred to both Rx0 and Rint
pins, dominant on Text is only transferred to Rx0.
AMIS−42700 is specially designed to provide the link
between the protocol IC (CAN controller) and two physical
bus lines. Data interchange between those two bus lines is
realized via the logic unit inside the chip. To provide an
independent switch−off of the transceiver units for both bus
systems by a third device (e.g. the mC), enable−inputs for the
corresponding driving and receiving sections are provided.
As long as both lines are enabled, they appear as one logical
bus to all nodes connected to either of them.
The bus lines can have two logical states, dominant or
recessive. A bus is in the recessive state when the driving
sections of all transceivers connected to the bus are passive.
The differential voltage between the two wires is
approximately zero. If at least one driver is active, the bus
changes into the dominant state. This state is represented by
a differential voltage greater than a minimum threshold and
therefore by a current flow through the terminating resistors
of the bus line. The recessive state is overwritten by the
dominant state.
In case of a fault (like short circuit) is present on one of the
bus lines, it remains limited to that bus line where it occurs.
Data interchange from the protocol IC to the other bus
system and on this bus system itself can be continued.
AMIS−42700 can be also used for only one bus system. If
the connections for the second bus system are simply left
open it serves as a single transceiver for an electronic unit.
For correct operation, it is necessary to terminate the open
bus by the proper termination resistor.
Transmitters
The transceiver includes two transmitters, one for each
bus line, and a driver control circuit. Each transmitter is
implemented as a push and a pull driver. The drivers will be
active if the transmission of a dominant bit is required.
During the transmission of a recessive bit all drivers are
passive. The transmitters have a built−in current limiting
circuit that protects the driver stages from damage caused by
accidental short circuit to either positive supply voltage or
to ground. Additionally a thermal protection circuit is
integrated.
The driver control circuit ensures that the drivers are
switched on and off with a controlled slope to limit EME.
The driver control circuit will be controlled itself by the
thermal protection circuit, the timer circuit and the logic
unit.
The enable signal ENBx allows the transmitter to be
switched off by a third device (e.g. the mC). In the disabled
state (ENBx = high) the corresponding transmitter behaves
as in the recessive state.
Logic Unit and CAN Controller Interface
The logic unit inside AMIS−42700 provides data transfer
from/to the digital interface to/from the two busses and from
one bus to the other bus. The detailed function of the logic
unit is described in Table 3.
All digital input pins, including ENBx, have an internal
pull-up resistor to ensure a recessive state when the input is
Table 3. Function of the Logic Unit (bold letters describe input signals)
EN1B
EN2B
TX0
TEXT
Bus 1 State
Bus 2 State
RX0
RINT
0
0
0
0
dominant
dominant
0
0
0
0
0
1
dominant
dominant
0
0
0
0
1
0
dominant
dominant
0
1
0
0
1
1
recessive
recessive
1
1
0
0
1
1
dominant (Note 3)
dominant
0
0
0
0
1
1
dominant
dominant (Note 3)
0
0
0
1
0
0
dominant
recessive
0
0
0
1
0
1
dominant
recessive
0
0
0
1
1
0
dominant
recessive
0
1
0
1
1
1
recessive
recessive
1
1
0
1
1
1
dominant (Note 3)
recessive
0
0
3. Dominant detected by the corresponding receiver.
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AMIS−42700
Table 3. Function of the Logic Unit (bold letters describe input signals)
EN1B
EN2B
TX0
TEXT
Bus 1 State
Bus 2 State
RX0
RINT
0
1
1
1
recessive
dominant (Note 3)
1
1
1
0
0
0
recessive
dominant
0
0
1
0
0
1
recessive
dominant
0
0
1
0
1
0
recessive
dominant
0
1
1
0
1
1
recessive
recessive
1
1
1
0
1
1
dominant (Note 3)
recessive
1
1
1
0
1
1
recessive
dominant (Note 3)
0
0
1
1
0
0
recessive
recessive
0
0
1
1
0
1
recessive
recessive
0
0
1
1
1
0
recessive
recessive
0
1
1
1
1
1
recessive
recessive
1
1
1
1
1
1
dominant (Note 3)
recessive
1
1
1
1
1
1
recessive
dominant (Note 3)
1
1
3. Dominant detected by the corresponding receiver.
Receivers
on that bus line, on which a dominant is actively transmitted.
The reception becomes active again only with certain delay
after the dominant transmission on this line is finished.
Two bus receiving sections sense the states of the bus
lines. Each receiver section consists of an input filter and a
fast and accurate comparator. The aim of the input filter is
to improve the immunity against high−frequency
disturbances and also to convert the voltage at the bus lines
CANHx and CANLx, which can vary from –12 V to +12 V,
to voltages in the range 0 to 5 V, which can be applied to the
comparators.
The output signal of the comparators is gated by the ENBx
signal. In the disabled state (ENBX = high), the output signal
of the comparator will be replaced by a permanently
recessive state and does not depend on the bus voltage. In the
enabled state the receiver signal sent to the logic unit is
identical to the comparator output signal.
Power−on−Reset (POR)
While Vcc voltage is below the POR level, the POR
circuit makes sure that:
• The counters are kept in the reset mode and stable state
without current consumption
• Inputs are disabled (don’t care)
• Outputs are high impedant; only Rx0 = high−level
• Analog blocks are in power down
• Oscillator not running and in power down
• CANHx and CANLx are recessive
• VREF output high impedant for POR not released
Time−out Counters
To avoid that the transceiver drives a permanent dominant
state on either of the bus lines (blocking all communication),
time−out function is implemented. Signals on pins Tx0 and
Text as well as both bus receivers are connected to the logic
unit through independent timers. If the input of the timer
stays dominant for longer than parameter tdom, it’s replaced
by a recessive signal on the timer output.
Over Temperature Detection
Feedback Suppression
Fault Behavior
The logic unit described in Table 3 constantly ensures that
dominant symbols on one bus line are transmitted to the
other bus line without imposing any priority on either of the
lines. This feature would lead to an “interlock” state with
permanent dominant signal transmitted to both bus lines, if
no extra measure is taken.
Therefore a feedback suppression is included inside the
logic unit of the transceiver. This block masks−out reception
A fault like a short circuit is limited to that bus line where
it occurs; hence data interchange from the protocol IC to the
other bus system is not affected.
When the voltage at the bus lines is going out of the normal
operating range (−12 V to +12 V), the receiver is not allowed
to erroneously detect a dominant state.
A thermal protection circuit is integrated to prevent the
transceiver from damage if the junction temperature
exceeds thermal shutdown level. Because the transmitters
dissipate most of the total power, the transmitters will be
switched off only to reduce power dissipation and IC
temperature. All other IC functions continue to operate.
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AMIS−42700
Short Circuits
Reverse Electronic Unit (ECU) Supply
As specified in the maximum ratings, short circuits of the
bus wires CANHx and CANLx to the positive supply
voltage Vbat or to ground must not destroy the transceiver.
A short circuit between CANHx and CANLx must not
destroy the IC as well.
The dedicated comparator (L2VBAT) on CANL pin
detects the short to battery and after debounce time−out
switches off the affected driver only. The receiver of the
affected driver has to operate normally.
If the connections for ground and supply voltage of an
electronic unit (ECU) (max. 50 V) which provides Vcc for
the transceiver are exchanged, this transceiver has a ground
potential which may be up to 50 V higher than that of the
other transceivers. In this case no transceiver must be
destroyed even if several of them are connected via the bus
system.
Any exchange among the six connections CANH1,
CANH2, CANL1, CANL2, ground, and supply voltage of
the electronic unit at the connector of the unit must never
lead to the destruction of any transceiver of the bus system.
Faulty Supply
In case of a faulty supply (missing connection of the
electronic unit or the transceiver to ground, missing
connection of the electronic unit to Vbat or missing
connection of the transceiver to Vcc), the power supply
module of the electronic unit will operate such that the
transceiver is not supplied, i.e. the voltage Vcc is below the
POR level. In this condition the bus connections of the
transceiver must be in the POR state.
If the ground line of the electronic unit is interrupted, Vbat
may be applied to the Vcc pin (measured relative to the
original ground potential, to which the other units on the bus
are connected).
Electrical Characteristics
Definitions
All voltages are referenced to GND. Positive currents
flow into the IC. Sinking current means that the current is
flowing into the pin. Sourcing current means that the current
is flowing out of the pin.
Absolute Maximum Ratings
Stresses above those listed in Table 4 may cause
permanent device failure. Exposure to absolute maximum
ratings for extended periods may affect device reliability.
Table 4. Absolute Maximum Ratings
Symbol
VCC
Conditions
Supply voltage
Min.
Max.
Unit
−0.3
+7
V
VCANHx
DC voltage at pin CANH1/2
0 < VCC < 5.25 V; no time limit
−45
+45
V
VCANLx
DC voltage at pin CANL1/2
0 < VCC < 5.25 V; no time limit
−45
+45
V
VdigIO
DC voltage at digital IO pins (EN1B, EN2B,
Rint, Rx0, Text, Tx0)
−0.3
VCC + 0.3
V
VREF
DC voltage at pin VREF
−0.3
VCC + 0.3
V
Vtran(CANHx)
Transient voltage at pin CANH1/2
(Note 4)
−150
+150
V
Vtran(CANLx)
Transient voltage at pin CANL1/2
(Note 4)
−150
+150
V
ESD voltage at CANH1/2 and CANL1/2 pins
(Note 5)
(Note 7)
−4
−500
+4
+500
kV
V
ESD voltage at all other pins
(Note 5)
(Note 7)
−2
−250
+2
+250
kV
V
Static latch−up at all pins
(Note 6)
100
mA
Vesd(CANLx/CANHx)
Vesd
Latch−up
4.
5.
6.
7.
Parameter
Tstg
Storage temperature
−55
+155
°C
Tamb
Ambient temperature
−40
+125
°C
Tjunc
Maximum junction temperature
−40
+150
°C
Applied transient waveforms in accordance with “ISO 7637 part 3”, test pulses 1, 2, 3a, and 3b (see Figure 5).
Standardized human body model (HBM) ESD pulses in accordance to MIL883 method 3015. Supply pin 8 is ±2 kV.
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.
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AMIS−42700
Table 5. Thermal Characteristics
Symbol
Parameter
Conditions
Value
Unit
Rth(vj−a)
Thermal resistance from junction to ambient in SO20 package
In free air
85
K/W
Rth(vj−s)
Thermal resistance from junction to substrate of bare die
In free air
45
K/W
Table 6. DC and Timing Characteristics (VCC = 4.75 to 5.25 V; Tjunc = −40 to +150°C; RLT = 60 W unless specified otherwise.)
Symbol
Parameter
Conditions
Min.
Typ.
Max.
Unit
45
137.5
19.5
mA
4.7
V
SUPPLY (pin VCC)
ICC
PORL_VCC
Supply current, no loads on digital
outputs, both busses enabled
Dominant transmitted
Recessive transmitted
Power−on−reset level on VCC
2.2
DIGITAL INPUTS (Tx0, Text, EN1B, EN2B)
VIH
High−level input voltage
0.7 x VCC
−
VCC
V
VIL
Low−level input voltage
−0.3
−
0.3 x
VCC
V
IIH
High−level input current
VIN = VCC
−5
0
+5
mA
IIL
Low−level input current
VIN = 0 V
−75
−200
−350
mA
Ci
Input capacitance
Not tested
−
5
10
pF
DIGITAL OUTPUTS (pin Rx0, Rint)
Ioh
High−level output current
Vo = 0.7 x VCC
−5
−10
−15
mA
Iol
Low−level output current
Vo = 0.3 x VCC
5
10
15
mA
Reference output voltage
−50 mA < IVREF < +50 mA
0.45 x
VCC
0.50 x
VCC
0.55 x
VCC
V
Reference output voltage for full
common mode range
−35 V