AMIS-4168x Fault Tolerant CAN Transceiver
Data Sheet
1.0 General Description
The new AMIS-41682 and AMIS-41683 are interfaces between the protocol controller and the physical wires of the bus lines in a
control area network (CAN). AMIS-41683 is identical to the AMIS-41682 but has a true 3.3V digital interface to the CAN controller. The
device provides differential transmit capability but will switch in error conditions to a single-wire transmitter and/or receiver. Initially it will
be used for low speed applications, up to 125kBaud, in passenger cars.
Both AMIS-41682 and AMIS-41683 are implemented in I2T100 technology enabling both high-voltage analog circuitry and digital
functionality to co-exist on the same chip.
These products consolidate the expertise of AMIS for in-car multiplex transceivers and support together with AMIS-30522 (VAN),
AMIS-30660 and AMIS-30663 (CAN high speed) and AMIS-30600 (LIN) another widely used physical layer.
2.0 Key Features
•
•
Fully compatible with ISO11898-3 standard
Optimized for in-car low-speed communication
o
Baud rate up to 125kBaud
o
Up to 32 nodes can be connected
o
Due to built-in slope control function and a very good matching of the CANL and CANH bus outputs, this device
realizes a very low electromagnetic emission (EME)
o
Fully integrated receiver filters
o
Permanent dominant monitoring of transmit data input
o
Differential receiver with wide common-mode range for high electromagnetic susceptibility (EMS) in normal- and low-
power modes
o
True 3.3V digital I/O interface to CAN controller for AMIS-41683 only
Management in case of bus failure
o
In the event of bus failures, automatic switching to single-wire mode, even when the CANH bus wire is short circuited
to VCC
o
The device will automatically reset to differential mode if the bus failure is removed
o
During failure modes there is full wake-up capability
o
Un-powered nodes do not disturb bus lines
o
Bus errors and thermal shutdown activation is flagged on ERRB pin
Protection issues
o
Short circuit proof to battery and ground
o
Thermal protection
o
The bus lines are protected against transients in an automotive environment
o
An un-powered node does not disturb the bus lines
Support for low power modes
o
Low current sleep and standby mode with wake-up via the bus lines
o
Power-on flag on the output
o
Two-edge sensitive wake-up input signal via pin WAKEB
I/Os
The un-powered chip cannot be parasitically supplied either from digital inputs or from digital outputs
•
•
•
•
3.0 Technical Characteristics
Table 1: Technical Characteristics
Symbol
Parameter
V
CANH
DC voltage at pin CANH, CANL
Vbat
Voltage at pin Vbat
Condition
0 < VCC < 5.25V; no time limit
Load-dump
Max.
-40
Max.
+40
+40
Unit
V
V
AMI Semiconductor
– Jun. 07, Rev. 3.0
www.amis.com
1
AMIS-4168x Fault Tolerant CAN Transceiver
Data Sheet
4.0 Ordering Information
Table 2: Ordering Information
Marketing Name
AMIS41682NGA
AMIS41683NGA
Package
SOIC-14 GREEN
SOIC-14 GREEN
Temp. Range
-40°C…125°C
-40°C…125°C
5.0 Block Diagram
VBAT
INH
1
14
VCC
10
POR
Vcc (
*
)
Mode &
wake-up
control
STB
EN
W AKE
5
6
7
9
RTL
CANH
CANL
RTH
Vcc (
*
)
Thermal
shutdown
11
Driver
control
12
8
TxD
2
Timer
GND
ERR
13
4
Failure
handling
Receiver
Filter
RxD
3
AMIS-4168x
(
*
) For AMIS-41682 pull up to Vcc.
For AMIS-41683 pull up to Vcc/2
AMIS-41682
VCC
AMIS-41683
ERR
4
Failure
handling
VCC
ERR
4
Failure
handling
RxD
3
RxD
3
PC20050610.3
Figure 1: Block Diagram
AMI Semiconductor
– Jun. 07, Rev. 3.0
www.amis.com
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AMIS-4168x Fault Tolerant CAN Transceiver
Data Sheet
6.0 Typical Application Schematic
6.1 Application Schematic
OUT
5V-reg
IN
VBAT
*
VCC
EN
6
ERR
4
VCC INH
10
1
VBAT
14
WAKE
7
9
RTL
CANL
CANH
CAN
controller
STB
RxD
12
5
3
AMIS-41682
11
TxD
2
13
8
RTH
GND
GND
PC20050610.1
*
optional
CAN BUS LINE
Figure 2: Application Diagram AMIS-41682
OUT
3.3V-
reg
IN
O UT
5V-reg
IN
VBAT
*
4.7 kΩ
4.7 kΩ
VC C
EN
6
VCC
10
IN H
1
VBAT
14
W AKE
7
9
R TL
CANL
CANH
3.3V CAN
controller
ERR
4
STB
5
3
12
AM IS-41683
11
RxD
TxD
2
13
8
R TH
GND
G ND
PC 20050610.2
*
optional
C AN BUS LINE
Figure 3: Application Diagram AMIS-41683
AMI Semiconductor
– Jun. 07, Rev. 3.0
www.amis.com
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AMIS-4168x Fault Tolerant CAN Transceiver
6.2 Pin Description
6.2.1. Pin Out (Top View)
Data Sheet
INH
TxD
RxD
ERR
STB
EN
WAKE
1
14
VBAT
GND
CANL
CANH
VCC
RTL
RTH
AMIS-4168x
2
3
4
5
6
7
13
12
11
10
9
8
PC20041029.1
Figure 4: Pin Configuration
6.2.2. Pin Description
Table 3: Pin Description
Pin
Name
1
INH
2
TxD
3
RxD
4
ERR-B
5
STB-B
6
EN
7
WAKEB
8
RTH
9
RTL
10
Vcc
11
CANH
12
CANL
13
GND
14
BAT
Description
Inhibit output for external voltage regulator
Transmit data input; internal pull-up current
Receive data output
Error; wake-up and power-on flag; active low
Standby digital control input; active low; pull-down resistor
Standby digital control input; active high; pull-down resistor
Enable digital control input; falling and rising edges are both detected
Pin for external termination resistor at CANH
Pin for external termination resistor at CANL
5V supply input
Bus line; high in dominant state
Bus line; low in dominant state
Ground
Battery supply
The functional description and characteristics are made for AMIS-41682 but are also valid for AMIS-41683. Differences between the
two devices will be explicitly mentioned in the text.
AMI Semiconductor
– Jun. 07, Rev. 3.0
www.amis.com
4
AMIS-4168x Fault Tolerant CAN Transceiver
Data Sheet
7.0 Functional Description
7.1 Description
AMIS-41682 is a fault tolerant CAN transceiver which works as an interface between the CAN protocol controller and the physical wires
of the CAN bus (see Figure 2). It is primarily intended for low speed applications, up to 125kBaud, in passenger cars. The device
provides differential transmit capability to the CAN bus and differential receive capability to the CAN controller.
The AMIS-41683 has open-drain outputs (RXD and ERR-B pins), which allow the user to use external pull-up resistors to the required
supply voltage; this can be 5V or 3.3V.
To reduce EME, the rise and fall slope are limited. Together with matched CANL and CANH output stages, this allows the use of an
unshielded twisted pair or a parallel pair of wires for the bus lines.
The failure detection logic automatically selects a suitable transmission mode, differential or single-wire transmission. Together with the
transmission mode, the failure detector will configure the output stages in such a way that excessive currents are avoided and the
circuit returns to normal operation when the error is removed.
A high common-mode range for the differential receiver guarantees reception under worst case conditions and together with the
integrated filter the circuit realizes an excellent immunity against EMS. The receivers connected to pins CANH and CANL have
threshold voltages that ensure a maximum noise margin in single-wire mode.
A timer has been integrated at pin TXD. This timer prevents the AMIS-41682 from driving the bus lines to a permanent dominant state.
7.2 Failure Detector
The failure detector is fully active in the normal operating mode. After the detection of a single bus failure the detector switches to the
appropriate mode. The different wiring failures are depicted in Figure 5. The figure also indicates the effect of the different wiring
failures on the transmitter and the receiver. The detection circuit itself is not depicted.
The differential receiver threshold voltage is typically set at 3V (VCC = 5V). This ensures correct reception with a noise margin as high
as possible in the normal operating mode and in the event of failures 1, 2, 4, and 6a. These failures, or recovery from them, do not
destroy ongoing transmissions. During the failure, reception is still done by the differential receiver and the transmitter stays fully active.
To avoid false triggering by external RF influences the single-wire modes are activated after a certain delay time. When the bus failure
disappears for another time delay, the transceiver switches back to the differential mode. When one of the bus failures 3, 5, 6, 6a, and
7 is detected, the defective bus wire is disabled by switching off the affected bus termination and the respective output stage. A wake-
up from sleep mode via the bus is possible either by way of a dominant CANH or CANL line. This ensures that a wake-up is possible
even if one of the failures 1 to 7 occurs. If any of the wiring failure occurs, the output signal on pin ERRB will become low. On error
recovery, the output signal on pin ERRB will become high again.
During all single-wire transmissions, the EMC performance (both immunity and emission) is worse than in the differential mode. The
integrated receiver filters suppress any HF noise induced into the bus wires. The cut-off frequency of these filters is a compromise
between propagation delay and HF suppression. In the single-wire mode, LF noise cannot be distinguished from the required signal.
AMI Semiconductor
– Jun. 07, Rev. 3.0
www.amis.com
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