High Speed CAN Transceivers

A p p l i c a t i o n N o t e , V 1. 0 , J a n . 2 00 6
High speed CAN Transceivers
A p p li c a t i o n N o t e
TLE6250G
TLE6250GV33
TLE6251DS
TLE6251G
A u th o r : S té p h a n e F r ai s s é
A u to m o t i v e P o w e r
Edition 2006-04-01
Published by Infineon Technologies AG,
St.-Martin-Strasse 53,
81669 München, Germany
© Infineon Technologies AG 2006.
All Rights Reserved.
Attention please!
The information given in this Data Sheet shall in no event be regarded as a guarantee of conditions or
characteristics (“Beschaffenheitsgarantie”). With respect to any examples or hints given herein, any typical values
stated herein and/or any information regarding the application of the device, Infineon Technologies hereby
disclaims any and all warranties and liabilities of any kind, including without limitation warranties of noninfringement of intellectual property rights of any third party.
Information
For further information on technology, delivery terms and conditions and prices please contact your nearest
Infineon Technologies Office (www.infineon.com).
Warnings
Due to technical requirements components may contain dangerous substances. For information on the types in
question please contact your nearest Infineon Technologies Office.
Infineon Technologies Components may only be used in life-support devices or systems with the express written
approval of Infineon Technologies, if a failure of such components can reasonably be expected to cause the failure
of that life-support device or system, or to affect the safety or effectiveness of that device or system. Life support
devices or systems are intended to be implanted in the human body, or to support and/or maintain and sustain
and/or protect human life. If they fail, it is reasonable to assume that the health of the user or other persons may
be endangered.
High speed CAN
Revision History:
2006-04-01
Previous Version:
none
Page
Subjects (major changes since last revision)
Template: ap_a4_tmplt.fm / 2 / 2005-10-01
High speed CAN
CAN Transceiver
Application Note
4
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
1
1.1
1.2
1.3
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Recessive Level. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Dominant level. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Driver symmetry. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2
2.1
2.1.1
2.1.2
2.1.3
2.2
2.2.1
2.2.2
2.3
2.3.1
2.3.1.1
2.3.1.2
2.3.1.3
2.3.2
2.3.2.1
2.3.2.2
2.3.3
2.3.3.1
2.3.3.2
2.3.4
2.3.4.1
2.3.5
2.3.6
2.3.7
2.3.8
In Vehicle Network. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Type of supplies in the vehicle. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Unsupplied modules in the parked car. (Clamp 15) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Supplied modules in the parked car. (Clamp 30) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Mixed network. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Ground line. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
High current applications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Low current application. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
The Transceiver in the automotive environment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Low battery voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
TLE6250G. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
TLE6251DS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
TLE6251G. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
High battery voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
TLE6250G / TLE6251DS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
TLE6251G. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Reverse polarity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
TLE6250G / TLE6251DS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
TLE6251G. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Short circuit on the bus. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Termination resistors case in short circuit to Vbat. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Temperature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Ground shift. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Loss of ground. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Loss of Battery. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3
3.1
3.1.1
3.1.2
3.1.3
3.1.4
3.1.4.1
3.1.4.2
3.1.5
3.2
3.2.1
3.2.2
3.2.3
3.2.4
3.2.5
3.3
3.3.1
3.3.2
3.3.3
3.3.4
3.3.5
Power management, transceiver supply. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TLE6250G. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TLE6250G in unsupplied mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TLE6250G in inhibit mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TLE6250G in normal mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TLE6250G in fault condition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Average maximum current in fault condition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Peak maximum current and decoupling capacitor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TLE6250G junction temperature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TLE6251DS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TLE6251DS in unsupplied mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TLE6251DS in stand by mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TLE6251DS in normal mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TLE6251DS in fault condition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TLE6251DS junction temperature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TLE6251G. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TLE6251G in unsupplied mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TLE6251G in sleep mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TLE6251G in Stand by mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TLE6251G in receive only mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TLE6251G in normal mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Application Note
1
2
2
2
3
13
13
13
13
13
13
13
13
14
14
14
15
15
15
15
15
16
16
16
17
17
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
3.3.6
3.3.7
3.3.8
TLE6251G in fault condition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
TLE6251G junction temperature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Choice of the voltage regulator. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4
4.1
4.1.1
4.1.2
4.1.3
4.1.4
4.1.5
4.1.6
4.2
4.2.1
4.2.2
4.2.2.1
4.2.2.2
4.2.2.3
4.2.3
4.2.3.1
4.2.3.2
4.2.3.3
4.3
4.3.1
4.3.2
4.3.3
4.3.4
4.3.5
4.3.5.1
4.3.5.2
4.3.6
4.3.7
4.3.7.1
4.3.7.2
4.3.8
4.3.8.1
4.3.8.2
4.3.8.3
4.3.8.4
4.3.9
4.3.10
4.3.10.1
4.3.10.2
4.3.10.3
4.3.10.4
Interface with micro controller. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TLE6250G/GV33. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pin Vcc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pin RM (only for the TLE6250G version). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pin INH. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pin V33 or Vio (only for TLE6250GV33). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pin TxD. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pin RxD. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TLE6251DS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pin STB. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pin TxD. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Hardware description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Time out function. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Time out function. Baud rate limitation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pin RxD. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Hardware description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Wake up behavior. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Delay from stand by to normal mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TLE6251G. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pin TxD. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pin RxD. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pin EN. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pin NSTB. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pin VµC. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
VµC pin´s maximum current. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Vµc under voltage detection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
pin Vcc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pin NERR. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Possible bus errors cases. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pin NERR in short circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pin INH. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pin INH purpose. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pin INH power capability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pin INH driving the INH input of an Voltage regulator. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Wake up timing with pin INH. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
pin WK. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Software issues consideration for TLE6251G. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Cold start. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Hot start. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Enter the Standby mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Enter the Sleep mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
18
18
18
19
19
19
20
20
22
22
22
22
22
23
23
23
23
24
25
25
25
25
25
26
26
26
27
27
27
27
27
27
28
28
28
29
32
32
32
32
33
5
5.1
5.2
5.2.1
5.2.2
5.3
Bus pins. Terminations concepts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Termination resistors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Split pin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Recessive voltage in a mixed Clamp 15 / 30 network, without SPLIT. . . . . . . . . . . . . . . . . . . . . . .
Recessive voltage in a mixed Clamp 15 / 30 network, with SPLIT. . . . . . . . . . . . . . . . . . . . . . . . . .
CAN_H / CAN_L. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
37
37
37
37
38
40
Application Note
2
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
6
6.1
6.1.1
6.1.2
6.1.3
6.1.4
6.2
6.3
6.3.1
6.3.2
6.3.3
6.4
6.5
ESD Aspects. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ESD tests definition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Human Body Model test. (MIL-STD 883). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Gun test. (IEC 61000-4-2). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Charged Device Model (CDM). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Machine Model (MM). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ESD protection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Modules under ESD gun test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Device without any external protection circuitry. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ESD level reached with a choke coil. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ESD level reached with a choke coil and ESD diode or varistor. . . . . . . . . . . . . . . . . . . . . . . . . . .
PCB layout. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Conclusion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
41
41
41
41
42
43
43
43
44
45
45
47
47
7
7.1
7.2
7.2.1
7.2.2
7.3
7.3.1
7.3.1.1
7.3.1.2
7.3.2
7.3.2.1
7.3.2.2
7.3.2.3
7.3.2.4
7.3.3
7.4
EMC aspect. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
EM Immunity against transcients. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
EM Immunity against RF disturbances. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The Stripline test. ISO 11452-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The Bulk Current Injection test. (BCI). ISO 11452-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Infineon transceivers in the EMI disturbances. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Immunity against transcients. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Damage test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Malfunction test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Immunity against RF disturbances. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
BCI test limitation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Principle of the DPI test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Results of Infineon’s transceiver under DPI test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Improvement of the DPI result. Use of choke coil. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Emission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Conclusion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
49
49
49
49
49
49
49
49
50
50
50
50
51
52
53
55
8
Products summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
9
References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Application Note
3
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
Application Note
4
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9
Figure 10
Figure 11
Figure 12
Figure 13
Figure 14
Figure 15
Figure 16
Figure 17
Figure 18
Figure 19
Figure 20
Figure 21
Figure 22
Figure 23
Figure 24
Figure 25
Figure 26
Figure 27
Figure 28
Figure 29
Figure 30
Figure 31
Figure 32
Figure 33
Figure 34
Figure 35
Figure 36
Figure 37
Figure 38
Figure 39
Figure 40
Figure 41
Figure 42
Figure 43
Figure 44
Figure 45
Figure 46
Figure 47
Figure 48
Figure 49
Figure 50
Figure 51
Typical high speed CAN signal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Dominant level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Common mode voltage definition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Typical Clamp 15 application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Typical Clamp 30 application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Mixed CL15 and CL30 network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Typical high current application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Undervoltage detection mechanism for Vs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Current in the termination resistors in case of short circuit to Vbat. . . . . . . . . . . . . . . . . . . . . . . . . . 9
System with one ground shift event . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Typical DC ground shift signal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
CAN signals with AC ground shift. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Loss of ground with inductive load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Buffer capacitor in function of the baud rate. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Quiescent current computation in stand by mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Quiescent current computation in sleep mode, with and without inhibit functionnality. . . . . . . . . . 16
Block diagram of TLE6250G/ TLE6250GV33. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Module connection verification, using receive only mode functionnality. . . . . . . . . . . . . . . . . . . . . 19
parasitic delay in case of serial resistor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
receiver timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Typical application for TLE6250G. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Typical application for TLE6250GV33. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Pin out comparison TLE6251DS and TLE6250G . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Permanent dominant time out feature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Wake up timing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Delay from stand by to normal mode timing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Typical application for the TLE6251DS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Pin out comparison TLE6251DS and TLE6251G . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
TLE6251G Mode state diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Possible failure cases failures on the bus word list. (According ISO 11898) . . . . . . . . . . . . . . . . . 27
Circuitry for the INH output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Possible wake up circuitries.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Wake up timing with INH function. Cold start. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Typical application circuit for TLE6251G, with separate 3.3V VµC and 5V Vcc supply . . . . . . . . . 31
Flow diagram for an ECU cold start.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Flow diagram for an ECU warm start.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Flow diagram to enter Stand by mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Flow diagram to enter Sleep mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Application circuitry for the split pin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Equivalent electrical schematic for a mixed network without split pin. . . . . . . . . . . . . . . . . . . . . . . 38
Equivalent electrical schematic for a mixed network with SPLIT pin . . . . . . . . . . . . . . . . . . . . . . . 38
Recessive level for different configurations in a mixed network with split. . . . . . . . . . . . . . . . . . . . 39
Current flowing in the TLE6250G ground, function of the ESD voltage. Device unsupplied . . . . . 41
Comparison of the current between HBM and gun test.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
ESD test equipement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Standard and Infineon ESD protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Schematic of the test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Positive ESD discharge, device supplied. Read out of the ground and supply current. . . . . . . . . . 44
Negative ESD discharge, device supplied. Read out of the ground and supply current. . . . . . . . . 45
ESD discharge, device supplied. Read out of the ground current. With choke coil.. . . . . . . . . . . . 45
Positive ESD discharge, device supplied. Read out of the ground current. With varistor. . . . . . . . 46
Application Note
1
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
Figure 52
Figure 53
Figure 54
Figure 55
Figure 56
Figure 57
Figure 58
Figure 59
Figure 60
Figure 61
Negative ESD discharge, device supplied. Read out of the ground current. With varistor. . . . . . .
Bad PCB example for ESD. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Good PCB design for ESD robustness. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
BCI test limitation example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DPI test set up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DPI test results example : The TLE6250G . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Choke coil principle. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DPI test results with choke coil for the TLE6250G. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
EME test results with TLE6250G, without chock coil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
EME test results with TLE6250G with and without chock coil . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Application Note
2
46
47
48
50
51
52
53
53
54
54
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
Table 1
Table 2
Table 3
Table 4
DC parameters for recessive output of CAN node . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
DC parameters for dominant output of CAN node . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Driver symmetry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Damage test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Application Note
1
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
Introduction. Recessive Level.
1
Introduction.
The increasing number of electronics equipment in todays cars implies a lot of information exchange. To avoid a
massive usage of wires between modules, a digital protocol has been created. This protocol has been named CAN
for Controller Area Network. CAN allows communication, to a speed up to 1Mbit/s. To avoid noisy communication
in terms of electromagnetic emission, the medium is a twisted pair and the electrical signal is differential. Figure 1
shows the typical signal of high speed CAN, and the basic reason for low electro-magnetic emission. When
CAN_H rises, some parasitic are emitted. In the same time, CAN_L goes down, in the same proportion. The sum
of these parasitics are 0, so to say the electromagnetic emission is limited.
CAN_H
5V
2.5V
= 0 emission
CAN_L
Recessive state
Figure 1
Dominant state
Typical high speed CAN signal
This application note is intended to present the high speed CAN application and the usage of Infineon CAN
transceivers in these applications. This document refers to international standard ISO 11898-2 [5], SAE J2284,
ISO 11898-5 [6], and well as to the TLE6250G [1],TLE6251DS [2], and TLE6251G [3] datasheets.
First part of the document will describes high speed CAN network in the automotive environnement. Then it will
focus on transceivers itself for easy interfacing with micro-controller, and will conclude by application hints to
successfully reach the challenges of such networks require.
1.1
Recessive Level.
During the recessive state, the signal is specified by the ISO 11898-2 [5]and ISO11898-5 [6]. The Table 1 gives
the parameters (extract of the ISO11898-2 [5] table 4).
Table 1
DC parameters for recessive output of CAN node
Parameter
Notation
Unit
min
Nom Max
Condition
Output bus voltage
VCAN_H
V
2,0
2,5
3
no load
VCAN_L
V
2,0
2,5
3
Differential output bus voltage
Vdiff
mV
-500 0
50
Differential input voltage
Vdiff
V
-1
0,5
1.2
no load
Dominant level.
During the dominant state, the signal is specified by the ISO 11898-2 [5] and ISO11898-5 [6]. The Figure 2 shows
the definition of the parameters, described in Table 2 (extract of the ISO11898-2 [5] table 5).
Application Note
2
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
Introduction. Driver symmetry.
5V
4.5V
CAN_H
2.75V
Vdiff = VCANH - VCANL
2.5V
2.25V
CAN_L
0.5V
Dominant state
Figure 2
Dominant level
Table 2
DC parameters for dominant output of CAN node
Parameter
Notation
Unit
min
Output bus voltage
VCAN_H
V
2,75 3,5
4,5
VCAN_L
V
0,5
1,5
2,25
Differential output bus voltage
Vdiff
V
1,5
2
3
load RL / 2
Differential input voltage
Vdiff
V
-0,9
5
load RL / 2
1.3
Nom Max
Condition
load RL / 2
Driver symmetry.
In the ISO11898-5 [6], the driver symmetry is specified. This is to improve the EMC behaviour. The Figure 3
shows the definition of the parameter, unsymmetry appears often when CAN_H and CAN_L are not perfectly
synchronized. The Table 3 gives the specified values.
V SYM
CAN_H+CAN_L
5V
CAN_H
2.5V
CAN_L
Recessive state
Dominant state
Figure 3
Common mode voltage definition.
Table 3
Driver symmetry
Prameter
Notation
Unit
Min
Nom Max
Condition
Driver symmetry
VSYM
V
0,9
1
Load = 120Ω, 4.7nF
F = 250kHz,
Application Note
3
1,1
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
In Vehicle Network. Type of supplies in the vehicle.
2
In Vehicle Network.
2.1
Type of supplies in the vehicle.
According to car makers requirements, the modules can be supplied or not supplied when car is parked. Main
reason for unsupplied modules is current saving for the car’s battery, when supplied modules can quickly wake up
on CAN request, or monitoring discretes inputs like switches.
2.1.1
Unsupplied modules in the parked car. (Clamp 15)
Unsupplied modules are mainly under hood applications as engine control unit. When the car is parked, a main
switch cut the battery supply off (see Figure 4). This supply line is often called Clamp 15 or KL15 (Klemme 15 in
German). Since the battery isn’t present, the voltage regulator is off and the transceiver is unsupplied. We will see
later on (Chapter 5.2) the basic requirements of such applications for the transceivers.
Main switch e.g ignition key
KL 15
ECU 1
Battery
ECU 2
ECU n
CAN wires network
Figure 4
Typical Clamp 15 application
2.1.2
Supplied modules in the parked car. (Clamp 30)
Supplied modules, even when car is parked are mainly requested in the body of the vehicle, as door modules, RF
keyless receiver, etc... The battery voltage comes directly to the module. This supply line is often called Clamp 30
or KL30 (Klemme 30 in German). Since the battery is present, the LDO is or can be ON, and the transceiver is or
can be supplied. We will see in the Chapter 5.2 the basic requirements of such applications for the transceivers.
KL 30
Battery
ECU 1
ECU 2
ECU n
CAN wires network
Figure 5
Typical Clamp 30 application
Application Note
4
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
In Vehicle Network. Ground line.
2.1.3
Mixed network.
It´s also possible to mix the two solutions. Some modules are CAN or discretes switches wakeable, some are only
supplied by a main switch. Figure 6 shows the application principle. The Chapter 5.2 describes the challenges to
achieve with this kind of mixed network.
KL 30
Battery
ECU30_1
ECU30_ 2
ECU30_n
CAN wires network
ECU15_1
Main switch
e.g ignition key
Figure 6
Mixed CL15 and CL30 network
2.2
Ground line.
ECU15_2
ECU15_m
KL 15
The ground line has a big influence on the electronic equipment, especially for communication purposes, since
the physical layer depends on voltage level. The 0V reference is the chassis of the vehicle. The ground pin of the
module might not be at this chassis reference. If the ground is shifted between modules, each transceivers are at
different ground level and so communication mismatch might occurs.
The ground line also influences the EMC and ESD performance of the module and of the vehicle. See Chapter 6
and Chapter 7.
2.2.1
High current applications.
The ground reference of the vehicle is the chassis. Some applications like power-steering, starter-alternator, etc...
have a huge current to ground (80Amps or even higher). Moreover, the current is often not DC. Special
consideration should be taken with respect to ground cable and its resistor, as well as its inductance has to be
taken into account. Figure 7 shows a typical high current module. Wiring companies often give the resistance of
the cable, in Ω/km. A standard 1mm² cross section cable has a resistance of about 20 Ω/km. A 80 Amps
application with a 1m cable means then a ground shift of about 1.6V, without considering the connectors, and PCB
traces resistance. This voltage drop cannot be neglected. The Figure 7 also shows a possible voltage drop, inside
the module due to the PCB trace. This will mainly affect the ESD and EMC robustness. Please refer to the
Chapter 6 and Chapter 7.
Application Note
5
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
In Vehicle Network. The Transceiver in the automotive environment.
LDO
e.g TL7469G
Phase 1
VS
3
phases
Motor
µC
Phase 1
e.g XC164
Three phase
motor driver
Phase 2
Phase 2
e.g
TLE6280GP
Phase 3 SPB80N03S2-03
Transceiver
CAN_H
e.g TLE6250G
Phase 3
CAN_L
E.g 100mA
PCB traces
impedance
E.g 100mA
E.g 80A
GND
Ground shift voltage
Ground wire to chassis with
impedance, function of the lenght
E.g 80A
Figure 7
Typical high current application
2.2.2
Low current application.
Most of applications are low current applications, where the voltage drop in the ground wire is close to zero and
so the ground current can be neglected.
2.3
The Transceiver in the automotive environment.
This chapter describes the behavior of the transceivers in the automotive environment, meaning for example, loss
of ground, low battery voltage, cranking pulse, load dump, etc... Each car maker (OEM) specify its own
environmental specification so that application note cannot cover all cases, but gives application hints on how to
deal with these issues.
2.3.1
Low battery voltage.
This situation happens mainly during the cranking of the engine. Except for the TLE6251G, the transceivers are
not directly connected to the battery voltage. The transceiver is then mainly dependant on the voltage regulator
behavior. Please refers to Chapter 3.3.8, for the voltage regulator’s choice.
2.3.1.1
TLE6250G.
The TLE6250G has no special under voltage function integrated. To get the device working and warranted, the
Vcc pin should be higher than the minimum operating voltage specified in the data sheet [1] so 4.5V. Below this
value, it is observed that the device is still working, sending and receiving data, but the parameters are not
warranted and not compliant to the ISO standard. The recessive voltage is proportional to the Vcc, typical half Vcc.
For example, with a Vcc of 4V, the recessive voltage will be 2V typical. It is then recommended to monitor the
battery voltage by an external circuitry or early warning function of the voltage regulator, to avoid
miscommunication during this time.
When the Vcc voltage is too low, typical 3V, the device is in OFF state, comparable to unsupplied.
Application Note
6
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
In Vehicle Network. The Transceiver in the automotive environment.
2.3.1.2
TLE6251DS.
The TLE6251DS doesn’t integrate any under voltage function and behaves as the TLE6250G. Please refers to
Chapter 2.3.1.1.
2.3.1.3
TLE6251G.
The TLE6251G integrates undervoltage detection for all supply pins, Vs, Vcc and VµC. If one of these pins see a
voltage below the specified minimum values (see [3]) , the device goes after a filtering blanking time to standby
mode, in case Vs is in undervoltage , or to Sleep Mode in case of undervoltage detection on Vcc or VµC. Please
refers to Figure 8 for explanation of Vs. Please also refers to Chapter 4.3.5.2, for undervoltage detection on Vµc/
Vcc.
Vs
V s, P off
tUV,t min
tUV,t min
Normal mode
Figure 8
Standby mode
Undervoltage detection mechanism for Vs.
Since the undervoltage mechanism is below the minimum operating voltage (for production spread and
temperature dependancy reasons), between these under voltage states and minumum operation, the device is
active and operates, without warranted conformity to the ISO standard. Last but not least, the Vs undervoltage
detection threshold is buffered with an hysteresis.
2.3.2
High battery voltage.
We discuss here all high battery voltage conditions, like jump start, load dump, or highest nominal battery voltage.
The voltage should not exceed the absolute maximum rating. Otherwise, the device could be damaged or
destroyed. The high battery voltage as well as load dump are voltage regulator issues. Since the dissipated power
in the LDO is directly proportional to the input voltage, (see Equation (1)), the issue is to get rid of the power in
the LDO.
Power loss in a LDO: Ploss = (Vbat - Vcc) * I out + Vbat * Iq
(1)
Iout is the output current of the LDO.
Iq is the current consumption of the LDO (values can be found in the LDO datasheet).
If the power dissipation challenge is passed, the application will work properly.
Application Note
7
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
In Vehicle Network. The Transceiver in the automotive environment.
2.3.2.1
TLE6250G / TLE6251DS.
For 12V applications, the concern of the high operating battery voltage is limited to two very special cases, double
failure (CAN_H or CAN_L shorted to battery and high voltage operation). The absolute maximum rating warranties
no destruction of the device because the highest voltage seen is the 34V load dump.
The only concerns is the power dissipation, when CAN_L is shorted to battery. The device limits the current, but
with battery voltage, the temperature will increase dramatically and the device might go into thermal shutdown.
(failure case 3 and 6, see Figure 30).
2.3.2.2
TLE6251G.
In addition to the TLE6250G and TLE6251DS (see Chapter 2.3.2.1) remarks, the TLE6251G includes an high
side switch. In case of high battery voltage, the power loss in the switch cannot be neglected and so it is
recommended to not connect a low ohmic load on the INH output. The INH pin should be considered as a high
voltage signal only. See also Chapter 4.3.8.
2.3.3
Reverse polarity.
Same remark as for the Chapter 2.3.2. The issue is mainly carried by the voltage regulator. Anyway, some
possible current path exists and has to be described in the following sections.
2.3.3.1
TLE6250G / TLE6251DS.
A possible failure would be a current flowing into the CAN_L output stage DMOS, due to its parasitic body diode.
To avoid this, the TLE6250G and TLE6251DS includes in serial a diode on the bus output lines. Please see block
diagrams of the devices in the data sheets [1] [2] [3].
2.3.3.2
TLE6251G.
The TLE6251G includes a P channel DMOS high side switch (pin INH). The maximum reverse battery voltage the
device can withstand is very small (-300mV)[3]. It is then necessary to protect the Vs pin of the TLE6251G with a
diode, preferably Schottky diode to get rid of the low voltage issue (Chapter 2.3.1). The power loss in this diode
is negligible, since the Vs pin doesn’t need a high current, whatever the mode the device is. It is then suggested
to use the diode in common with the voltage regulators.
2.3.4
Short circuit on the bus.
Unfortunatly, the short circuit is a problem which can occur in the vehicle when the signal goes out the electronic
module. All cases of short circuit are described in the Figure 30. The transceiver family from Infineon withstand
all these cases, but communication cannot be warranted anymore. The Chapter 3 describes in details the
resulting current to be handled by the voltage regulator.
2.3.4.1
Termination resistors case in short circuit to Vbat.
In case CAN_H is in short circuit to Vbat, (failure case 6, see Figure 30), the power loss in the termination resistors
has to be taken into account. The Figure 9 shows the path of the current, in the case the termination is splitted
(2x60Ω or 120Ω). Purpose of the Split is described in Chapter 5.2. The transceiver will limit the current to the
ICANL_SC value, if the battery voltage is higher than 12V.
Power loss in the resistor : 1/2 x Rtermination x ICANL_SC².
(2)
The coefficient 1/2 comes to the ratio recessive dominant. See also Chapter 3.1.4
According to Equation (2), the power loss in the 60Ω resistors will be at an average of 300mW and in the 120Ω
resistor an average of 600mW. This power has to be taken into account when designing the network termination
resistors.
Application Note
8
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
In Vehicle Network. The Transceiver in the automotive environment.
Vbat
60 Ω
ICA NL_S C/2
I CA NL_S C/2
120 Ω
4.7nF
TLE6251G
TLE6250G
60 Ω
ICA NL_S C
Figure 9
Current in the termination resistors in case of short circuit to Vbat.
Please also notice that in case of CAN_H shorted to Vbat, due to the voltage drop in the resistors, it is possible to
see an “appearing” permanent dominant signal.
2.3.5
Temperature.
The Infineon transceiver family is qualified from -40°C to 150°C, as required by the automotive standard. The
Chapter 3 will show the power consumption of the devices, in the different cases.
2.3.6
Ground shift.
In the Chapter 2.2 we have seen the influence on the ground line for the module. We will now describe the
application of interfacing an high current application and a low current application. Figure 10 shows an application
with one ground shift module, in connection with one not connected. We limit the drawing to two modules for
simplification purpose, the description remains valid with several modules.
Vbat
TLE 625x
VCC
TLE 625x
CANH
Output
Stage
VCC
CANH
CANL
Output
Stage
CANL
=
=
Receiver
Receiver
*
*
GND
GND
V shift
Figure 10
System with one ground shift event
When the module subjected to a ground shift is transmitting, the CAN_H and CAN_L output stages of receiving
nodes are OFF. In other words, the receivers for both CAN_H and CAN_L are modeled as resistors to ground.
Application Note
9
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
In Vehicle Network. The Transceiver in the automotive environment.
The values can be found in the datasheet of the respective products considered, under the name Ri. Since the
sender has its ground shifted to a Vshift value, the recessive level Vrec seen from the chassis ground is no longer
2.5V typical but Vrec + Vshift. The same shift has to be taken into account for the dominant signal. This voltage is
the voltage seen by the receiver. The Infineon transceivers are differential transceivers, with a wide common mode
range. The CAN_H and CAN_L DC value are not of primary importance, if below the absolute maximum rating.
Only the difference voltage (CAN_H - CAN_L) is taken into account by the receiver. Figure 11 shows a typical
CAN signal with a DC ground shift of +2V, and Figure 12 shows a rough ground shift due to high inrush in the
application load. In both cases, the communication remains excellent.
The recessive system level when the ground shifted module is sending, is equaled to the mean value of all
transceivers recessive voltages. Equation (3) gives the value of the system recessive voltage in that case.
Vrec = [(Vrec_1+ Vshift_1) + (Vrec_2 + Vshift_2) + ... (Vrec_n + Vshift_n)] / n
(3)
n is the number of connected modules.
Vrec_1, 2..n are the specific recessive level of the transceiver on nodes 1, 2, ...n
Vshift_1, 2, ... n are the specific ground shift on nodes 1, 2, ...n.
Zone A
Zone C
CAN_H
CAN_L
Zone B
Ground shift value
Chassis ground
Figure 11
Typical DC ground shift signal.
Zone A : Shows the recessive voltage of the system, so close to the nominal recessive value of 2.5V
Zone B : When the transmitter starts to communicate (zone B), the signal grows quickly, and load the capacitors
of the system. (parasitics of the wiring, terminations capacitors, ...).
Zone C : The communication is stabilized, and the recessive voltage is reaching the value, as computed on
Equation (3).
It is important to notice that the supply current of the transceiver will increase.
If n represents the number of nodes on the network,
Ri_n is the impedance to ground of the CAN_H / CAN_L input for each nodes,
Vshift is the ground shift voltage,
The extra supply current is : Icc_shift = Vshift / (Ri_n / n), assuming all input resistances identical
Application Note
10
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
In Vehicle Network. The Transceiver in the automotive environment.
CAN_H
Vdiff
GND shift
CAN_L
Figure 12
CAN signals with AC ground shift.
2.3.7
Loss of ground.
In case of loss of ground, the voltage regulator output (Vcc) might goes to the battery voltage. It means the Vcc input
of the transceiver might be at the 12V battery potential. The transceiver is of course no longer supplied, so it
behaves as unpowered state, but brings a pull-up to battery to the bus, via the input resistors of the receiver. From
a system point of view, the behavior is like a short circuit to battery via a weak pull up, the transceiver is the weak
pull-up. The CAN signals are no more in conformance with the ISO standard but the communication between the
non-affected module remains OK, since the high speed CAN protocol is differential and a limp home functionnality
is possible.
Application Note
11
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
In Vehicle Network. The Transceiver in the automotive environment.
I
Inductive load application
Module with ground
Voltage
Regulator
VCC
VCC
TLE625x
TLE625x
CAN_H
CAN_H
CAN_L
CAN_L
Motor
I motor
GND
GND
Figure 13
Loss of ground with inductive load
If the application is using an inductive load, a risk of destruction is possible, if the inductive load has no
freewheeling diode. Figure 13 shows the issue. When the ground disconnects, the coil has to be demagnetized
and the current is flowing in the less ohmic path available. One of the lowest ohmic path on the application is the
CAN transceiver. The inductive load increases the voltage until turning on the ESD protection and the current is
flowing. The ESD protection isn´t designed to withstand such a long energy and the transceiver is very quickly
destroyed by E.O.S. (Electrical Over Stress). The only solution is to plan a free wheehling diode on the inductive
load. No protection can be done at the transceiver level.
2.3.8
Loss of Battery.
In case of loss of battery, no issue can be expected, and the device behaves as in unsupplied state. Please refers
to the Chapter 3.1.1 (TLE6250G), Chapter 3.2.1 (TLE6251DS) and Chapter 3.3.1 (TLE6251G) for additional
information on the behavior of the device, when unsupplied.
Application Note
12
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
Power management, transceiver supply.TLE6250G.
3
Power management, transceiver supply.
Each transceiver product has its own power management features, from the basic features of the TLE6250G to
the complex power management of the TLE6251G. The following chapter will describe which power consumption
on the different supplies pin will be achieved with the different devices.
3.1
TLE6250G.
The TLE6250G is the first High Speed Transceiver product Infineon has introduced the market. This part has no
power management. Anyhow, the part includes an inhibit functionality, to switch the device completly. This device
is perfectly matching application on the KL15 powernet, so unsupplied when the vehicle is parked.
3.1.1
TLE6250G in unsupplied mode.
When the TLE6250G is unsupplied, it brings on the bus an pull down resistors specified in the datasheet
(parameter Ri)
3.1.2
TLE6250G in inhibit mode.
In inhibit mode, the power consumption on the Vcc, (specified in [1] ICC, STB) is below 10µA. The complete device
is disabled. The TLE6250G brings on the bus an pull down resistors specified in the datasheet (parameter Ri).
3.1.3
TLE6250G in normal mode.
In normal mode, the device needs a current on the Vcc of maximum 70mA in dominant state, and 10mA on
recessive state [1]. To estimate the power consumption in normal mode, a cyclic ratio of 50% can be assumed,
because we can consider the communication is overall 50% dominant, 50% recessive. In normal mode, the device
will need a maximum average current of:
ICC, AVG = (ICC,REC + ICC, DOM) / 2 = 40mA.
3.1.4
TLE6250G in fault condition.
3.1.4.1
Average maximum current in fault condition.
In presence of bus failure, the Vcc supply current for the transceiver can increase significantly, in case of CAN_H
shorted to ground. (case 4, see Figure 30). It is recommended to dimension the Voltage regulator for the worst
case, especially when the Vcc also supplies the micro controller. It is important to notice the Vcc supply current
increase only in dominant state, the recessive current remains almost unchanged. With the same assumption as
the Chapter 3.1.3, the average fault current will be:
ICC, AVG, fault = (ICC,REC + ICANH, SC) / 2 = 105,5mA
This current is the maximum average current the device will demand on the Vcc supply line.
3.1.4.2
Peak maximum current and decoupling capacitor.
The peak current is higher than described in Chapter 3.1.4.1, and it is recommended to filter the maximum peak
current by the decoupling capacitor’s the Voltage regulator needs for stability reason. The worst case scenario is
to have 17 dominant bits in a row. At the moment the CAN controller starts a transmission, the dominant Start Of
Frame bit is not fed back to RxD and thus forces an Error Frame due to the bit failure condition. The first bit of the
error frame again is not reflected at RxD and forces the next error frame (Tx Error Counter + 8). Latest after 17bit
times, depending on the TX Error Counter Level before starting this transmission, the CAN controller reaches the
error passive limit and stops sending dominant bits. During this 17bits, the maximum current will be ICANH, SC. To
filter this peak current, we need first to compute the delta current the capacitor should deliver.
∆ ICC MAX, SC = ICANH, SC - ICC,REC= 190mA.
Application Note
13
V1.0, 2005-11-08
High speed CAN
CAN Transceiver
Power management, transceiver supply.TLE6251DS.
The worst case bypass capacitor then calculates to:
Cbuff = ∆ ICC, MAX, SC x t DOM, MAX / ∆ Vmax
Figure 14 gives the result, function of the baud rate of the decoupling capacitor value, with an allowed ∆ Vmax of
200mV. This value is an excess value, since the voltage regulator will react. This reaction time is only dependant
on the device used and so cannot be described here.
Figure 14
Buffer capacitor in function of the baud rate.
3.1.5
TLE6250G junction temperature.
In the Chapter 3.1.3, we have seen the worst case current consumption in normal condition, with a 5V supply.
This leads to a nominal power dissipation of : 0,5 x (70mA x 3,5V + 10mA x 5V) = 150mW. The SO8 package
offers an Rthja of 185K/W in the worst case. The junction temperature is then increased by 28K worst case. In
case of short circuit, the power dissipation will increase of course. The transceiver might go to thermal shutdown.
In that case, the receiver is still active, only the power stage is disabled, behavior is identical to receive only mode.
3.2
TLE6251DS.
TLE6251DS offers a standby mode. In this mode, the device is still able to receive some data, with the target to
wake up a micro controller. This device is then compliant to Clamp 15 as well as Clamp 30 (see Chapter 2.1)
powernets and thanks to the very high ohmic behavior in unsupplied mode (Chapter 3.2.1), perfectly suitable for
the Clamp 15 part of a mixed KL15 / KL30 network.
3.2.1
TLE6251DS in unsupplied mode.
TLE6251DS has an improved behavior during unsupplied case. The Ri resistors of the receivers are cutted, and
the current flowing into the pin CAN_H / CAN_L is limited. The datasheet [2] gives the value (paramater ICANH, L,
lk) to 5µA worst case. It leads to a equivalent resistor of 1MΩ minimum. Thanks to this, the device perfectly fits the
request of the Clamp 15 mixed with Clamp 30. The pull down resistor will be limited, compared to the TLE6250G.
Application Note
14
V1.0, 2005-11-08
High speed CAN
CAN Transceiver
Power management, transceiver supply.TLE6251G.
3.2.2
TLE6251DS in stand by mode.
In that mode, the TLE6251DS needs a maximum current supply ICC, STB of 30µA, 20µA typical [2]. Figure 15 shows
how to compute the quiescent current of the application, (actuators excluded).
Vbat
Total quiescent current = q,LDO
I
+ ICC,
Vcc
LDO
Iq,
LDO
TLE6251DS
ICC,
Figure 15
STB + Iq, µC
Micro
controller
in
stop
mode
Iq,
µC
STB
Quiescent current computation in stand by mode.
It is important to notice that in this quiescent current “grand total”, the biggest part is often the Voltage regulator
contribution (Iq, LDO), if the Voltage regulator is designed in standard bipolar technology. (TLE42xx or TLE44xx
Infineon products). To get rid of this issue, it is recommended to use the new Voltage regulator family from
Infineon, in the SPT5 technology, (TLE72xx and TLE74xx). For example, the supply current of the TLE4275 is
worst case 200µA [7] at 25°C when the TLE7270 is 30µA [8], for similar maximum output current and functions.
With an SPT5 Voltage regulator and TLE6251DS, the leakage current the module will need in a parked car should
be in the range of 70µA (depending on the micro controller stop mode supply current).
3.2.3
TLE6251DS in normal mode.
In normal mode, the TLE6251DS behaves as the TLE6250G. Please refers to Chapter 3.1.3
3.2.4
TLE6251DS in fault condition.
Please refer to Chapter 3.1.4.
3.2.5
TLE6251DS junction temperature.
Please refer to Chapter 3.1.5.
3.3
TLE6251G.
The TLE6251G has an enhanced energy management, allowing the device to control the entire supply chain of
the electronic module, targeting to achieve the lowest quiescent current. It perfectly fits the Clamp 30 application.
There’s no voltage supply sequencing. Vcc, VµC and Vs can be powered in indifferent orders.
Application Note
15
V1.0, 2005-11-08
High speed CAN
CAN Transceiver
Power management, transceiver supply.TLE6251G.
3.3.1
TLE6251G in unsupplied mode.
Same remarks as for the TLE6251DS, see Chapter 3.2.1.
3.3.2
TLE6251G in sleep mode.
In sleep mode, the quiescent current of the device is 25µA typical, 35µA worst case on the Vs pin [3]. If the Vcc
and VµC are OFF, using the INH functionality (see also Chapter 4.3.8), then the entire module will need no more
current (actuators excluded).
Vbat
Vbat
INH
Iq, INH
LDO
VµC
LDO
Iq
VµC
µC
INH
Iq,µC
µC
Iq
LDO
Iq, INH
LDO VCC
VCC
INH
IVS, sleep
TLE6251G
IVS, sleep
Figure 16
TLE6251G
Icc+µC, sleep
Quiescent current computation in sleep mode, with and without inhibit functionnality.
In case the Vcc and / or VµC are supplied, an extra leakage current has to be taken into account, and the overall
quiescent current of the module will increase dramatically. Figure 16 shows the two cases. The Iq, INH values are
given in the data sheet and are typically in the range of one µA.
3.3.3
TLE6251G in Stand by mode.
The stand-by mode is entered at power up or after under voltage as Vs. Compared to sleep mode, the TLE6251G
turns ON the high side switch of the INH output so an extra leakage current has to be taken into account. 25µA
maximum to turn ON and supply the high side internally [3]. It is also necessary to compute the extra current of
the INH load which is connected to the INH output, which is application dependant.
The TLE6251G includes a under voltage detection on its three supply pins, Vs, Vcc and Vµc. In case the application
requires to keep the device in standby mode for a long time (higher than the minimum under voltage blanking time,
see also Chapter 4.3.5.2), then, both Vcc and VµC have to be present. Otherwise, the TLE6251G will go
automatically to sleep mode. It means the quiescent current of an application with TLE6251G remaining in stand
by mode is bigger than the sleep mode, since the voltage regulators must remains ON, even if no or few current
are consumed.
Application Note
16
V1.0, 2005-11-08
High speed CAN
CAN Transceiver
Power management, transceiver supply.TLE6251G.
3.3.4
TLE6251G in receive only mode.
In receive only mode, the device is functional and needs the same current as in normal mode, recessive state.
3.3.5
TLE6251G in normal mode.
In the normal mode, the TLE6251G behaves as the TLE6250G so please refers to Chapter 3.1.3, with the correct
values given in the data sheet [3].
3.3.6
TLE6251G in fault condition.
As for the TLE6250G and TLE6251DS, the current consumption on the Vcc pin will increase dramatically. Please
refer to chapter Chapter 3.1.4. Since the bus error management is only valid after four transitions of bus (from
recessive to dominant), the worst case scenario with 17 consecutive bits dominant has to be taken into account
as well.
3.3.7
TLE6251G junction temperature.
In normal condition, the device needs 40mA on the 5V Vcc supply. The SO14 package offers a RTHJA of maximum
120K/W, leading to a junction temperature increase of 24K, compared to the ambient temperature.
3.3.8
Choice of the voltage regulator.
The voltage regulator has to be chosen in the family of the low drop output (LDO), as the Infineon’s TLE42xx,
TLE44xx, TLE72xx and TLE74xx. These LDOs families allow input voltage down to 5.5V at their input pin. To filter
the bounces on the battery supply line, the application requires a big input capacitor. This capacitor has to be
protected against reverse polarity by adding a diode. This diode has to be chosen with the lowest voltage drop
(Schottky diode, typical 200mV) in its forward path. So to say that the LDO delivers a proper 5V with a minimum
of 5.7V battery voltage. Below, the 5V cannot be warranted anymore, and the LDO follows the battery voltage. For
the transceiver it means as well the level will be smaller, and follows the battery line, until a threshold when the
communication will stop completly. It should be able to deliver 40mA DC current (see Chapter 3.1.3), only for the
transceiver. The LDO should also allow to work with a peak current of 105mA (see Chapter 3.1.4.1) for the
transceiver. Since the 105mA are not DC condition after a while, the Error Frame counter will stop the
communication, it is not needed to warranty 105mA DC condition. The decoupling capacitor at the output of the
LDO is described in Chapter 3.1.4.2. If the LDO is used only to supply the transceiver, the TLE4266-2G.[9],
offering a minimun of 150mA peak current, an INH input, in SOT223, fits perfectly.
Application Note
17
V1.0, 2005-11-08
High speed CAN
CAN Transceiver
Interface with micro controller. TLE6250G/GV33.
4
Interface with micro controller.
A CAN transceiver is the physical layer between the protocol controller (micro controller, state machine), to the
physical transmission medium. Following is a description, of TLE6250 and TLE6251 family, of the interface
between the micro controller and the Infineon’s used transceiver.
4.1
TLE6250G/GV33.
Figure 17 shows the pin out and a brief description of the logic pins of the TLE6250G and TLE6250GV33, adapted
to 3.3V logic level. Following is a description of the logical pin and Figure 21 and Figure 22 gives the standard
schematic of the application.
TLE 6250 G
3
TLE 6250 G V33
VC C
5
1
Mode Control
8
5
4
1
TxD
INH
Mode Control
8
V33
TxD
INH
RM
RxD
4
RxD
TLE6250G BLOCK DIAGRAM.VSD
Figure 17
Block diagram of TLE6250G/ TLE6250GV33
4.1.1
Pin Vcc
The pin Vcc gives the proper 5V supply to build the CAN_H and CAN_L signal, as well as the receiver supply and
internal voltage reference supply to build the recessive state level. In case of TLE6250G use, the logic pins are
pulled up to Vcc. Chapter 3.3.8 gives additional information about how to size correctly the voltage regulator
supply.
Application Note
18
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
Interface with micro controller. TLE6250G/GV33.
4.1.2
Pin RM (only for the TLE6250G version).
The pin RM or Receive only Mode is a special feature from the TLE6250G. This pin allows to inhibit the data
streaming on the TxD pin, which blocks the transmission. Main functionality of the receive only mode is to allow
diagnostic (to avoid the aknowledge bit realized by software), to check modules connections, see Figure 18, or to
avoid miss-communication on the medium due to a micro controller failure. To enter the Receive-only Mode, a
logical zero has to be applied on the pin. To set the device in normal operation, so to activate the data streaming
from the micro controller on the TxD pin, the RM pin has to be set to a logical 1. Since the TLE6250G integrates
a pull up resistor, by default the device is in normal operation. In case the Receive only mode is not used, the pin
can to be left opened.
Example : Checking connection between module 1 and 8.
1
2
3
4
5
6
7
8
Set pin RM of module 2, 3, ..7 to Receive only mode.
Module 1 send a test message.
Module 8 :
1/ Acknowledges the reception. Connection is OK
2/ Doesn´t acknowledge the reception. Connection is NOK.
Module 2...7 also acknowledge the message but thanks to
receive only mode, the software is bypassed
Figure 18
Module connection verification, using receive only mode functionnality
4.1.3
Pin INH.
The pin INH is used to set the device in stand by mode or normal operation. The stand by mode is used to reach
the lowest quiescent current possible on the Vcc pin. To enter the stand by operation mode, the pin has to be at
a logical 1. As the device integrates an internal pull up, by default, the device is in stand by mode.
To enter the normal operation, a logical 0 has to be applied. In that case, the maximum current flowing out the INH
pin is 525µA. In case the INH mode is not needed, the pin has to be set to ground directly.
4.1.4
Pin V33 or Vio (only for TLE6250GV33).
The pin V33 or Vio is needed for operation with 3.3V I/O micro controllers to get the correct level between the micro
controller and transceiver. This pin needs some current, mainly to supply the RxD pin (see Chapter 4.1.6). This
pin can also be supplied by a 5V voltage regulator of course, when the application is requesting a separate supply
for the micro controller and the transceiver. In case the Vio voltage is 0V, the TxD pin is 0V as well and the risk is
to have a permanent dominant signal on the bus. The TLE6250GV33 includes the functionnality to not react to the
TxD pin if Vio is 0V. In that case, the CAN_H and CAN_L output switches are OFF and the device is recessive. In
the opposite case, if Vcc is OFF, and Vio is ON, the RxD might be permanently low (dominant), and could trouble
the software. To avoid this, in case Vcc = 0V, the RxD pin is permanently high (recessive).
Application Note
19
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
Interface with micro controller. TLE6250G/GV33.
4.1.5
Pin TxD.
The transceiver receives the digital bit stream to be transmitted from micro controller onto the bus via the pin TxD.
Sometimes, the signal at TxD show steep edges at bit transitions, likely to degrade the EMC performance of the
total module. In this case it is recommended to place or to plan a serial 1kΩ resistor into the TxD line between the
transceiver and the micro controller. Along with the TLE6250G internal capacitance (value) this would help to
smooth the edges to some degree. For high speed communication up to 1Mbit/s, the resistor might generates on
extra delay and this has to be taken into account, please refers to Figure 19. The parasitic capacitor CTxD is not
specified, for testing reasons. The standard value used for the Infineon’s transceiver is 10pF, 15pF to consider the
worst case.
VµC
TLE6250
TLE6251
VµCTx D
1kΩ
TxD
µC TxD
Transceiver TxD
Internal
transceiver TxD
C TxD
Micro
controller
VTranscieverTxD
Parasitic delay
Figure 19
parasitic delay in case of serial resistor.
4.1.6
Pin RxD.
The analog bit stream received from the bus is output at pin RXD for further processing within the micro controller.
As with pin TXD a series resistor of about 1kΩ can be used to smooth the edges at bit transitions. Again the
additional delay within RXD has to be taken into account, if high bus speeds close to 1Mbit/s are used. The output
stage of the RxD pin is a push pull stage. The output is not protected against over-current. Nevertheless, in case
the RxD pin is in short circuit, a current of about 15mA typical can flow in or out (depends on short to ground or
short to Vcc). This typical failure happens when the pin is forced to ground or 5V. The pin RxD follows the bus,
meaning it also repeats what the TxD pin sends. The Figure 20 shows the propagation delay concept.
TxD
Td(H), T
Td(L), T
t
Vdiff = CAN_H -CAN_L
t
RxD
Td(L), TR
Td(H ), TR
t
Figure 20
receiver timing
Application Note
20
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
Interface with micro controller. TLE6250G/GV33.
Vbat
Main switch
Some pins are missing, for simplification purposes
TLE 6250 G
8
GPIO
INH
RxD
4
1kΩ
1
(1)
µP
TxD
RM
GND
2
VC C
5
GND
e. g. TLE 4270
+
GND
Figure 21
(1) Optional, to improve EMC
performance
5V
VQ1
VI
GPIO
3
Typical application for TLE6250G
Vbat
Some pins are missing, for simplification purposes
Main switch
TLE 6250 G V33
8
INH
RxD
4
1kΩ (1)
1
TxD
V33 V
GND
2
VCC
e. g. TLE 4476
VQ1
VI
5
3
GND
(1) Optional, to improve EMC
performance
5V
3.3 V
VQ2
GND
Figure 22
µP
3.3 V
+
+
Typical application for TLE6250GV33.
Application Note
21
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
Interface with micro controller. TLE6251DS.
4.2
TLE6251DS.
Compared to the TLE6250G, TLE6251DS has almost the same pin out (see Figure 23). The TLE6251DS is able
to wake up the micro controller on bus activities. We will now describe the logic pins of the TLE6251DS. Figure 27
describes the typical application interface between TLE6251DS and micro controller. TLE6251DS fits only to 5V
micro controller interface.
TxD
1
8
GND
2
VC C
3
7
TLE 6251 DS
(P-DSO-8) 6
RxD
4
5
TxD
1
8
CANH
GND
2
CANL
VCC
3
TLE 6250G 7
(P-DSO-8)
6
SPLIT
RxD
4
5
STB
Figure 23
Pin out comparison TLE6251DS and TLE6250G
4.2.1
Pin STB.
INH
CANH
CANL
RM
The STB pin (STand By) is used to set the TLE6251DS in the standby or normal mode. To set the device to normal
operation, a logical 0 has to be applied. (and logical 1 to set the device to standby mode). As the pin has an
integrated pull-up, by default the device is in standby mode. In case the standby feature isn’t needed, the pin
should be connected to ground.
4.2.2
Pin TxD.
4.2.2.1
Hardware description.
Please refers to the Chapter 4.1.5, description of the TxD of the TLE6250G.
4.2.2.2
Time out function.
The TLE6251DS has a permanent dominant disable time. Figure 4.2.3 describes this feature. It´s used in case
the micro controller goes to faulty condition and sets the TxD pin to a permanent 0 logic level. In that case, the bus
is permanently dominant and the entire network is down due to the faulty micro controller. To avoid this, the
permanent dominant disable time will automatically relax the bus to recessive level if the TxD pin is low for more
than t TxD. The value can be found in the TLE6251DS data sheet [2]. To come back to normal operation, the TxD
pin has to go back to a logical 1. No special filter timing for the recovery is applied. It means there’s no constrained
on the minimum time TxD pin has to be at logical 1 to leave the permanent dominant disable function. Anyway,
the function is realized with a flip flop so the reset pulse should be longer than the propagation delay in the flip flop
cell, so 20ns.
TxD
Time out release pulse
t TX D
CAN_H
CAN_L
Normal mode
Figure 24
Time out
Normal mode
Permanent dominant time out feature.
Application Note
22
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
Interface with micro controller. TLE6251DS.
4.2.2.3
Time out function. Baud rate limitation.
This feature limits the minimum possible baud rate. According to the CAN protocol a maximum of eleven
successive dominant bits is allowed on TXD only (worst case of five successive dominant bits followed
immediately by an error frame). With a minimum value given in the data sheet for TxD of 300µs [2], so to say that
11 bits should be faster than 300µs, the baud rate of the application must be higher than 36.6kbit/s to be sure to
comply to the CAN protocol. Min baud rate = max dominant bits / t TXD.
4.2.3
Pin RxD.
4.2.3.1
Hardware description.
The RxD pin is as for the TLE6250G, see Chapter 4.1.6, a push pull stage. In case of short circuit to ground or
Vcc, the current is limited to maximum 20mA ( see datasheet [2] IscRxD).
4.2.3.2
Wake up behavior.
The RxD pin is used to wake the micro controller up. To realize the wake up mechanism, the micro controller
should be in stop mode and the RxD pin should be an interrupt input in order to wake. Figure 25 gives the timing
of the wake function. The parameter tWU is given in the data sheet of the TLE6251DS [2] and is directly copied
from the ISO 11898-5 norm[6]. It has to be understood as:
1. In case the pulse on the bus is shorter than the minimum value of tWU, the device will/has to never wake up.
This is to avoid parasitic wakes up due to Electro Magnetic disturbances for example.
2. In case the pulse on the bus is in between the minimum value and the maximum value, the device might wake
up, depending on the temperature, production spread, etc....
3. In case the pulse on the bus is longer than the maximum value of tWU, the device will/has to wake up.
4. Since the application micro controller might missed the first edge, the TLE6251DS is following the bus toggling.
Recessive level sets by
the module who wants to
wake the TLE6251DS
tWU
t WU
tWU
CAN_H
3
CAN_L
(1 and 2) Too
short
wake pulse
RxD
STB
tS TA RTµC
(4) Wake up pulse missed
by microcontroller
TLE6251DS
state
Microcontroller
state
Stand by mode
Stop mode
Normal mode
Start up
Normal mode
Microncontroller Sets STB pin to 0
Figure 25
Wake up timing.
Application Note
23
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
Interface with micro controller. TLE6251DS.
4.2.3.3
Delay from stand by to normal mode.
To achieve a very good quiescent current in standby mode, the TLE6251DS has two receivers, a low power mode
and a normal mode. When the micro controller set the device to normal operation with the STB pin, and the bus
is dominant, a parasitic pulse on the RxD pin is observed. This is due to the commutation from the low power
receiver to the normal receiver. Figure 26 describes the timing of this possible parasitic pulse. Unless this parasitic
pulse maximum duration isn´t specified, it is never longer than 50µs.
CAN_H
CAN_L
Parasitic TLE6251DS reset pulse
STB
tWU
tWU
RxD
Stand by mode
Figure 26
Transition
Normal mode
Delay from stand by to normal mode timing.
Some pins are missing, for simplification purposes
Vbat
TLE 6251DS
STB
RxD
TxD
8
GPIO
4
1kΩ (1)
1
µP
GPIO
GND
VCC
3
VCC
GND
2
e. g. TLE 7270
VQ1
VI
GND
Figure 27
(1) Optional, to improve EMC
performance
5V
+
Typical application for the TLE6251DS.
Application Note
24
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
Interface with micro controller. TLE6251G.
4.3
TLE6251G.
TLE6251G has the same pin-out compared to TLE6251DS (see Figure 28), with inverse logic for the STB pin,
and with additional functionalities. The TLE6251G is able to wake a micro controller, as well as the power supplies
on bus activities. We will now describe the logic pins of the TLE6251G. Figure 34 describes the typical application
interface between TLE6251G and the micro controller.
TLE 6251 DS
(P-DSO-8-3)
TLE 6251 G
(P-DSO-14-13)
TxD
1
14
NSTB
TxD
1
8
STB
GND
2
13
CANH
GND
2
7
CANH
VCC
3
12
CANL
VCC
3
6
CANL
RxD
4
11
SPLIT
RxD
4
5
SPLIT
VµC
5
10
VS
EN
6
9
WK
INH
7
8
NERR
Figure 28
Pin out comparison TLE6251DS and TLE6251G
4.3.1
Pin TxD.
Please refer to Chapter 4.2.2
4.3.2
Pin RxD.
Please refer to Chapter 4.2.3, TLE6251DS without the wake behavior.
4.3.3
Pin EN.
The EN pin (enable) is used to set the TLE6251G to normal operation. The device is disabled with a logical 0, and
enabled with a logical 1. The EN pin has a pull down integrated. By default, the device is disabled.
4.3.4
Pin NSTB.
The NSTB pin is used to switch the device to receive only mode (See Chapter 4.1.2) and also used to bring the
device to sleep mode via the go-to-sleep state. Figure 29 shows the different operating mode of the TLE6251G
can be. The NSTB pin has an integrated pull down. By default, the device is in stand-by mode.
Application Note
25
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
Interface with micro controller. TLE6251G.
Start Up
Power Up
Power Down
Normal Mode
EN
NSTB
INH
1
1
High
Undervoltage
at VS
Go to Sleep
EN
NSTB
1
0
Receive-Only
Stand-By
EN
NSTB
INH
EN
NSTB
INH
0
1
High
0
0
High
t < thS LP
Wake-Up:
t > tWK
t > tWU
Undervoltage
at V CC / VµC
for t > t UV ,t
Sleep
t > thS LP
EN
NSTB
INH
0
0
Float.
TLE6251G STATE DIAGRAM.VSD
Figure 29
TLE6251G Mode state diagram
4.3.5
Pin VµC.
The VµC pin is used to supply the pins in direct contact with the micro controller, to get the voltage reference of the
micro controller threshold, in order to use the device both with 3.3V and 5V micro controller. In case the micro
controller has the same supply as the CAN transceiver, the VµC and Vcc should be connected together.
4.3.5.1
VµC pin´s maximum current.
The push-pull for the RxD, as well as the NERR pin are supplied by VµC. In case the RxD pin and/or the NERR
are in short circuit to ground, a non-negligible current (please refers to TLE6251G data sheet [3], ISC_NERR, ISC_RxD)
will be demanded to the micro controller supply.
4.3.5.2
Vµc under voltage detection.
The VµC voltage level is monitored by the TLE6251G. Benefit of this solution is to avoid any undesired
communication on the bus when Vcc is present but the micro controller is down. In case of under voltage detection
on pin VµC, the device is going to sleep mode. Since the device can command the micro controller supply, with the
Application Note
26
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
Interface with micro controller. TLE6251G.
INH output pin, a quite long filter time is implemented (refer to TLE6251G data sheet), to allow the micro controller
supply to rise the voltage. There’s no sequencing requested with the others voltage supply (Vcc and Vs).
4.3.6
pin Vcc.
The Vcc pin is used to supply the IC to get the proper CAN signal on the bus, the voltage reference and receiver
stage when the IC is in normal mode. The Vcc voltage is monitored as the VµC pin. Please refer also to
Chapter 4.3.5.2. There’s no sequencing requested with the others voltage supply (VµC and Vs).
4.3.7
Pin NERR.
The NERR pin is used as flag indicator of a failure event on the bus. The output stage is a push-pull, connected
to VµC. The following section will describe the NERR behavior.
4.3.7.1
Possible bus errors cases.
Figure 30 gives the all possible failures that can be encount by the bus wiring. In case one or several of these
failures occur, the pin NERR is set to a logical 0. It’s important to notice that some errors can only be detected
after certain amount of transition recessive to dominant states. For example, a CAN_L shorted to ground (case 5)
failure cannot be detected as long as the bus is dominant. While some events can be detected by the protocol
(cases 1, 2, 3, 4, 7), some others are only detectable by this transceiver feature (5 and 6)
4.3.7.2
Pin NERR in short circuit.
In case the NERR pin is shorted to ground, as the output stage is a push-pull, a high current can flow out. This
current is internally limited. Please refer to TLE6251G’s data sheet [3] parameter ISC_NERR. This current has to be
taken into account when dimensioning the Vµc supply for a safe design. (see Chapter 4.3.5.1)
Vbat
Vcc
Case 2
Case 6a
Case 6
CAN_H
Case 4
Vbat
Case 1
Case 3
Case 7
Vcc
Case 3a
CAN_L
Case 5
Figure 30
Possible failure cases failures on the bus word list. (According ISO 11898)
4.3.8
Pin INH.
The INH pin is not a real logical pin. The function of this pin is mainly digital and described in the following section.
This pin is not a power output. It is a P channel DMOS switch to gives a “high voltage logic” indication.
4.3.8.1
Pin INH purpose.
Main purpose of the INH pin is to indicate a wake event from either the WK pin or the CAN line. The INH pin is
always high, meaning equal to the battery voltage, minus a voltage drop (please refer to TLE6251G data sheet
[3]) except during sleep mode condition. In that case, the pin is high ohmic.
Application Note
27
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
Interface with micro controller. TLE6251G.
4.3.8.2
Pin INH power capability.
The pin is not suitable to drive a low ohmic load, and the output current should not exceed 5mA. It is then
impossible to drive the input of a voltage regulator (LDO) directly but should be used to drive the inhibit input of
the LDO. The INH input isn’t protected against short circuit to ground and so should not be connected outside the
E.C.U. In the case of a short to ground, or overload, the protection will be the thermal shutdown.
4.3.8.3
Pin INH driving the INH input of an Voltage regulator.
All Infineon LDO family are active when their INH input is high and OFF when the INH input is low. Since they all
have an integrated pull down, it´s normally not necessary to add an external one. Anyway, for EMC issue, it´s
reasonable to plan an external resistor with a value of 10kΩ, in case of parasitics coming into the INH pin.
Figure 31 shows the recommended circuitry for the pin INH.
VBAT
Vs
LDO
INH
INH
TLE4xxx
TLE7xxx
10k Ω optional
TLE6251G
Figure 31
Circuitry for the INH output
4.3.8.4
Wake up timing with pin INH.
Using the INH pin to drive the voltage regulator INH, the wake up timing is shown on Figure 33. Please note the
time scale isn’t linear. The start up of a voltage regulator takes several ms when the logical signal are in ns. In
some applications, only the inhibit input of the micro-controller voltage regulator, or the voltage regulator for the
CAN transceiver is driven by theTLE6251G. The Vcc line necessary for proper supply of the transceiver, or the
VµC for proper supply of the micro-controller is switched on by the micro-controller. If we assume a 2ms activation
time for each LDO ( see Equation (4)), and the necessary start-up time of the microcontroller, the time to go to
normal operation increased significantly, like 10 to 40ms normally. Whenever this time is below 50ms (see [3],
parameter t UV,t), the undervoltage mechanism is inhibited. It gives the time to react without entering into the sleep
mode again, which will inhibit the microcontroller LDO and so entering infinite cyclic wakes.
Start up time of an Voltage regulator formula:
Tmax = Cmax x Vcc /(Imin- I start_up)
(4)
Tmax represents the longest time needed to reach the regulated voltage (5 or 3.3V)
Cmax is the total capacitance on the regulated voltage. (With capacitance tolerance)
Vcc is the regulated voltage (5 or 3.3V)
Imin is the minimum current the voltage regulator is able to drive as maximum.
Application Note
28
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
Interface with micro controller. TLE6251G.
Istart_up is the current the application (e.g micro controller) need during start up phase.
Example, with the TLE4278G.
The TLE4278G is a 5V Voltage regulator. Data sheet [4] specifies a minimum value for the maximum current the
Voltage regulator is able to drive of Imin = 200mA. Assuming :
CMAX = 60µF (20% tolerance on a 47µF capacitor) decoupling capacitors on the Vcc,
Istart_up = 20mA to supply the application (microcontroller, logical circuitries...) the maximum time the Voltage
regulator needs to reach 5V, starting from 0V is then:
Tmax = 60 x10-6 x 5 / (200 10-3 - 20 10-3)= 1,7ms.
4.3.9
pin WK.
The WK pin (Wake) is also a high voltage pin. It is used mainly to signal a local wake up event on the transceiver.
A signal change is only necessary to wake up the device. There´s no pull-up or pull-down, so it can be used to
wake via a switch to ground, or via a switch to battery. The wake up pin is sensible to voltage edges. In case the
Wake pin is unused, it is recommended to connect the pin directly to ground. (to avoid parasitic wake up). See
Figure 32 for possible usage description.
(*) optionnal
Vbat
Vbat
WK switch
RWK *
RS W
TLE6251G
WK
WK switch
RS W
TLE6251G
WK
Low side wake up
High side wake up
Figure 32
RWK*
Possible wake up circuitries.
RWK should be planned, to improve the robustness to ISO pulses. If the ISO pulses test shows good results
without, RWK is useless, because the absolute maximum rating (see [3]) allows enough safety margin. RSW is
necessary, to polarize the WK pin to the sleeping state. The value of RSW should be set according to the cleaning
current of the switch.
Application Note
29
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
Interface with micro controller. TLE6251G.
CAN_H
CAN_L
WAKE
PATTERN
Communication
starts
BUS
WAIT
BUS
OFF
Vdiff
INH
tWU
DEVICE
WAKES
Vcc/Vio
ECU WAKES
LDO RAMP UP
µC P.O.R.
RxD
NERR
NSTB/EN
µC sets TLE6251G to
normal operation
Normal mode
Figure 33
Wake up timing with INH function. Cold start.
Application Note
30
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
Interface with micro controller. TLE6251G.
Vs
E.g
TLE4266
CVs
CVcc
INH
Vs
INH
Vcc
10kΩ
(1)
E.g
TLE7273GV33
CVµC
INH
Vµc
TLE6251G
µC supply
EN
GPIO
NSTB
GPIO
Vµc
NERR
IRQ
Microcontroller with
on chip CAN module
e.g C164, C167
XC164
TC17xx
Vµc
1kΩ (1)
TxD
TxD
Vµc
CAN
controller
1kΩ (1)
RxD
(1)
Figure 34
RxD
Optional. To improve EMC performance
Typical application circuit for TLE6251G, with separate 3.3V VµC and 5V Vcc supply
Application Note
31
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
Interface with micro controller. TLE6251G.
4.3.10
Software issues consideration for TLE6251G.
4.3.10.1
Cold start.
The power ON flag of the TLE6251G indicates to the microcontroller whether a microcontroller cold start was
caused by a wakeup from Sleep mode or by a first battery power application. This information is often needed for
the application to initiate some possible calibration procedures upon first battery power application.
The pin NERR reflects the power ON flag when entering the power ON /Receive only mode from stand by, sleep
or go to sleep mode. Moreover, in case of wake up from Sleep Mode, the TLE6251G provides information on the
wake up source. Entering the Normal mode the pin NERR reflects the wake up source flag. A logical 0 signal
indicates a local wake up via the WK pin whereas a logical 1 indicates a remote wakeup via the bus.
In case battery power is applied the first time, an internal hardware reset is given to the transceiver for initialization.
Subsequently, the power ON flag is set and the pin INH is pulled to Vbat, activating the voltage regulator(s) and
ramping up the Vcc supply. See also Chapter 4.3.8. Along with the Vcc the pins RxD and NERR go to logical 1.
With ramping up Vcc, the micro controller comes up. As almost all micro controllers feature a weak pull down or
floating behaviour at their port pins, the TLE6251G comes up in stand by mode after first battery power up. See
also Chapter 4.3.2 and Chapter 4.3.7. This is the starting point for the application program taking over the control
now. If the microcontroller comes up with a logical 1 at its port pins, the TLE6251G enters the normal mode and
the power ON flag information is irretrievably lost. Please refer to the Figure 33 for timing characteristics.
Figure 35 suggests a software flow for an ECU cold start. It considers primarily the issues related to the
TLE6251G rather than representing a complete software flow. After the transceiver and microcontroller have
performed their initialization, the transceiver is put in power ON / Receive Only Mode for reading the power ON
flag. If a logical 0 signal is read on the pin NERR, the ECU cold start was initiated by the first battery power up.
The microcontroller performs the correspnding system startup procedure. If a logical 1 is read, the cold start was
initiated by a wake up from sleep mode. In order to get information on the wake up source, the Normal mode is
selected. If reading of the pin NERR yields a logical 0, there was a local wake up via the pin wake. If reading yields
a logical 1 signal, the wake up came via the bus. Afterwards, the cold start procedure is finished and normal
operation is ongoing.
4.3.10.2
Hot start.
A warm start up is performed when the ECU wakes up from Sleep Mode. Figure 36 suggests a software flow for
an ECU warm start. The starting point assumes a TLE6251G transceiver in its Sleep Mode and the host
microcontroller in a dedicated power down mode. If the transceiver receives a wake up either via the pin WK, the
internal wake up flag is set and signalled at the pin NERR and RxD. These signals can be used for wakeup of the
microcontroller from its power down mode. The starting application program can now take control over the
transceiver. If the power ON flag is of interest, the microcontroller can force the transceiver into Power ON /
Receive Only Mode for reading the Power ON flag. Otherwise the microcontroller can force the transceiver directly
into Normal mode for reading the wake up Source flag at the pin NERR.
As the microcontroller remains powered by the Vcc supply, the microcontroller can monitor its port pins for possible
wake up events. Upon detection of a wake up event the microcontroller can initiate a wakeup by forcing the
transceiver directly into normal mode. Then reading of the Power ON flag or wake up Source, flag is not necessary.
4.3.10.3
Enter the Standby mode.
When the network management decides to put the bus system into standby, each ECU must receive the
appropriate standby command. The flow diagram seen in Figure 37 shows the different steps in order to put the
TLE6251G into Standby mode. Upon receiving a standby command (like a CAN message), the microcontroller
has to stop all CAN transmission. In order to ensure that no CAN communication is present on the bus anymore,
caused by other nodes, the bus must have been recessive for a suitable time before the TLE6251G is put in
Standby Mode by setting NSTB and EN to logical 0. If there is no system dependant “waiting period”, implemented
there would be the risk that a node sends out a last message while another one is already on the way towards
Application Note
32
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
Interface with micro controller. TLE6251G.
Standby mode. This would cause a wake up event thus making it impossible to enter a system wide low power
state.
4.3.10.4
Enter the Sleep mode.
The procedure to put an ECU into sleep mode is shown in Figure 38 it is similar to the previous one for entering
the Standby mode. Upon receiving a sleep command the microcontroller has to stop all CAN transmission. In order
to ensure that no CAN communication is present on the bus anymore, the bus must have been recessive for
suitbale time before the TLE6251G is put into Sleep Mode by selecting NSTB to logical 0 and EN to logical 1. The
difference now is that the microcontroller checks periodically for a wake up as long as Vcc is not yet down. This is
necessary since it might happen that a wake up event just appears while the Go To Sleep Command is processed.
In this case the INH of the TLE6251G will keep high and the Vcc will not drop down. Instead the wake up request
is forwarded to the application via RxD and NERR. Without this check the microcontroller would assume that a
sleep phase follows with disabled Vcc, thus waiting forever for a power ON reset caused by a wakeup which will
never happen.
Application Note
33
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
Interface with micro controller. TLE6251G.
VBAT and GND connected
INH = High
NSTB, EN held LOW
during the Vcc ramping up
Cold Start
Select
power ON/ Receive only mode
Set NSTB to 1
EN to 0
Optional
If power ON flag is not an interest
Wait 10µs
Power ON flag
0 = First Vbat application
1= Wake up from Sleep mode
Read NERR
Yes (first Vbat app)
NERR = 0
No (sleep wake)
Select normal mode
Set NSTB to 1
System start up
procedure
Optional
If wake origin
is not an interest
Wait 10µs
Set NSTB to 1
EN to 1
Wake up source flag
0 = local wake up
1 Wake up via bus
Read NERR
End of Cold Start
Figure 35
Flow diagram for an ECU cold start.
Application Note
34
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
Interface with micro controller. TLE6251G.
Transceiver in Stand by
µC in Power Down
Vcc available.
Microcontroller initiates
the wake up
Warm start
Wake up event
RxD and NERR goes to 0
Local or Remote wake up
Set NSTB to 1
EN to 1
Select normal mode
Set NSTB to 1
EN to 1
Wait 10µs
Wake up source Flag
0 : Local wake up
1 wake up via bus
Activate CAN controller
Read NERR
Release CAN reset
End of Warm Start
Figure 36
Flow diagram for an ECU warm start.
TLE6251G
Normal mode
Standby command
received
Stop all CAN
transmission
Wait suitable time for
bus recessive
Select Stand by mode
Set NSTB to 0
EN to 0
Standby mode
Figure 37
Flow diagram to enter Stand by mode
Application Note
35
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
Interface with micro controller. TLE6251G.
TLE6251G
Normal mode
Sleep command
received
Stop all CAN
transmission
Wait suitable time for
bus recessive
Select Go-to sleep mode
Check for wake up
Set NSTB to 0
EN to 1
Read NERR / RxD
Yes
NERR / RxD= 0 ?
No
Vcc not down.
Vcc down.
Wake up
Restart
Standby mode
Figure 38
Flow diagram to enter Sleep mode
Application Note
36
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
Bus pins. Terminations concepts. Termination resistors.
5
Bus pins. Terminations concepts.
The transceiver is connected to the bus via the pin CAN_H and CAN_L. Some concept also includes a so called
SPLIT pin. The purpose of this pin is to improve EMC behavior of transceiver, by increasing the symmetry between
CAN_H and CAN_L. See Figure 1.
5.1
Termination resistors.
The ISO 11898-2 [5] and ISO 11898-5 [6] request for the system a 60Ω resistor bus termination. This bus
termination resistor is needed to reduce the reflexions on the bus. Where and how to apply this 60Ω resistor is up
to the OEM, several concepts are possible and used today, depending on the usage, the topology, etc... Some
applications have only one termination resistor, mainly for stars topology. Some applications have two termination
resistors of 120Ω, for linear topology, and some even have one termination resistor on each nodes, the total
impedance should be equaled to 60Ω. However, it is recommended to put a weak termination resistor of 1kΩ at
least for EMC improvements of the system, in terms of emission. It is important to not forget the short circuit issue,
described in the Chapter 2.3.4.1.
5.2
Split pin.
The recommended application circuitry is described on Figure 39.
CAN_H
CAN_H
1k Ω (1)
60Ω
TLE6251G
TLE6251DS
SPLIT
4.7nF
4.7nF
(1)
1kΩ (1)
60Ω
CAN_L
(1)
SPLIT
TLE6251G
TLE6251DS
(1)
CAN_L
Suggested value, has to be according to the car maker requirements.
Figure 39
Application circuitry for the split pin.
5.2.1
Recessive voltage in a mixed Clamp 15 / 30 network, without SPLIT.
When the system requires two types of modules, some connected to the CL15 (see Chapter 2.1.1), some
connected to the CL30 (see Chapter 2.1.2), the unsupplied modules bring to the bus an extra impedance to
ground. The result is the recessive voltage tends to go to 0V.
The recessive voltage with a mixed network, without split pin can be computed with the Equation (5), with the
usage of the TLE6250G.
Vrec = Vref x m / (m+n)
(5)
m represents the number of nodes supplied and enable (CL30)
n represents the number of unsupplied nodes. (CL15)
Vref is the recessive voltage when the device is alone. See Table 1. Typically Vcc / 2
The equivalent DC electrical schematic of the system is given on Figure 40, assuming (for simplification) all
internal impedances and voltage regulators identical. Figure 42 gives the voltage value, for m=2, function of n.
Application Note
37
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
Bus pins. Terminations concepts. Split pin.
m nodes
n nodes
R CM
RCM
R termination total
60 Ohm=120Ohm//120Ohm
R CM
RCM
VRef
OV
Figure 40
Equivalent electrical schematic for a mixed network without split pin
5.2.2
Recessive voltage in a mixed Clamp 15 / 30 network, with SPLIT.
TLE6251DS and TLE6251G integrate a SPLIT pin. The internal schematic of the split pin is quite complex, but can
be simplified as a voltage regulator at VSPLIT with an internal resistor RSPLIT, [2] [3]. The purpose of the SPLIT pin
is to improve the symetry of the signal, by maintaining the recessive voltage at mid value of the dominant voltage
of CAN_H and CAN_L.
Using the SPLIT pin, the equivalent DC circuitry looks like Figure 41. The recessive voltage with a mixed network,
with SPLIT pin can be computed with the Equation (6), assuming all devices identical (for simplification
purposes).
s nodes
t nodes
m nodes
RW
RT
R CM
RCM
R SPLIT
R SPLIT
R CM
VRef
Figure 41
n nodes
R CM
RW
RT
VSPLIT
VSPLIT
OV
Equivalent electrical schematic for a mixed network with SPLIT pin
m represents the number of supplied and enabled nodes with and without split pin.(min 2)
t represents the number of SPLIT nodes with RT = 60Ω termination resistors (min 0, max 2)
s represents the number of SPLIT nodes with RW > 1kΩ weak termination resistors
Application Note
38
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
Bus pins. Terminations concepts. Split pin.
n represents the number of unsupplied nodes.
(6)
1
Vrec = Vref × ------------------------------------------------------------------------------------n
1 + -------------------------------------------------------------------------Rc
Rc
------------------ + s × --------------------m+t×
Rs + Rt
Rw + Rs
The influence of the SPLIT is seen, since Rc >> Rs, Rw or Rt.
Figure 42 gives the System recessive level, for several conditions. Worst case of two nodes in communications,
others are disabled.
It is important to notice that both TLE6251DS and TLE6251G offer a very weak connection to gournd when they
are unsupplied (specified in the datasheet [2] [3] as a current ICANHL_lk) of about 1MΩ so to say the problem is less
forseen for an application using these devices unsupplied.
Last but not least, a capacitor of about 4.7nF as shown on Figure 39 but without connection to the SPLIT pin
circuitry shows improve as well the recessive level value.
recessive level
3,00
2,50
Vrec (V)
2,00
1,50
1,00
0,50
0,00
0
1
t= 0, s= 0
Figure 42
2
3
4
5
6
7
8
9
10
Number of unsupplied node
t= 0, s= 1
t= 1, s= 0
t= 2, s= 0
Recessive level for different configurations in a mixed network with split.
t=0, s=0 corresponds to the case without split termination concept. (Equation (5))
t=0, s=1 correesponds to the case with a split pin at a weak termination resistor (1kΩ)
t=1, s=0 corresponds to the case with a split pin at the bus termination resistor (60Ω)
t=2, s=0 corresponds to the case with a split pin at both bus termination resistor.
Application Note
39
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
Bus pins. Terminations concepts. CAN_H / CAN_L.
5.3
CAN_H / CAN_L.
The CAN_H and CAN_L are the interface to the bus network. The challenge for these pins are multiples. EMC,
ESD, that we will see in Chapter 6 and Chapter 7. The challenge is also regarding short circuit discussed in the
Chapter 3.1.4 mainly. Last but not least, the CAN_H and CAN_L have parasitic capacitors to ground, due to the
DMOS cells as well as the ESD structure. These parasitics capacitors are not specified, due to testing issues but
the maximum observed value are in the range of 50pF for CAN_H, half of it for CAN_L for the TLE6250G. The
reason for this unsymmetry is that CAN_L is a N channel, when the CAN_H is a P channel output stage. As a rule
of thumb, the P channel cell is twice bigger to get the same Rdson.
Application Note
40
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
ESD Aspects. ESD tests definition.
6
ESD Aspects.
Among all the disturbances a CAN transceiver can encounter in a vehicle, the ESD discharge is one of the most
critical. Since the basic application of networking is to be present in the whole vehicle, the risk of ESD discharge
is very important. To get an impression of the issue, the Figure 43 shows the current flowing into the TLE6250G,
function of the ESD HBM discharge voltage; The ESD pulse is applied on the CAN_H pin, and the current is
measured on the ground line. The device is unsupplied. ESD robustness is strongly dependant to the air humidity
condition. ESD robustness is increasing with air humidity.
Figure 43
Current flowing in the TLE6250G ground, function of the ESD voltage. Device unsupplied
6.1
ESD tests definition.
6.1.1
Human Body Model test. (MIL-STD 883).
The HBM test is a modification of the Method 3015.7, MIL-STD-883. The test is realized on one pin, versus all the
others. The semiconductor industry is keen to specify the ESD with HBM, because it represents the typical
aggression during the processing of the module, of the operator in the facility touching the device. The model is
equivalent to a capacitor of 100pF loaded to the ESD voltage. The discharge is applied via a 1.5kΩ resistor (1500Ω
is your standard resistance value...). This test doesn´t represents the normal ESD aggression during the life of the
vehicle or during the car manufacturing, because the risk of somebody touching the device when the module is
built is very low. Figure 45 shows the test protocol. Infineon realize the HBM test inhouse. The HBM values are
specified in all Infineon’s datasheet. The standard value is +/-2kV, but can reach higher values for the off board
pins.
6.1.2
Gun test. (IEC 61000-4-2).
The IEC 61000-4-2 ESD test represents the typical case of somebody carrying a metallic object (screw drivers,
pliers...),touching the connectors or the housing of the module. It´s also called gun or pistol test. It applies the same
Application Note
41
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
ESD Aspects. ESD tests definition.
voltage, as the HBM but loaded into 150pF and discharged via 330Ω. This test is more representative of the real
ESD disturbance during the car manufacturing. The Figure 44 shows the difference between the HBM and the
gun test, for same voltage level. It´s obvious that the IEC61000-4-2 is a much more severe test in terms of energy.
The test is realized on all the off board pins (CAN_H, CAN_L, Wake and Vs pin) versus ground. Figure 45 shows
the test protocol. For communication applications, as CAN and LIN physical layer, Infineon is performing the test
in an external independant test facility (I.B.E.E. in Zwickau, Germany). The value isn’t specified in the Infineon’s
datasheet, because the test is also application’s dependant. Values reached can be given, on request.
I (A)
1ns
+8kV applied
30
25
20
15
10
IEC1000-4-2
HBM
5
30
60
90
120
150
T (ns)
Figure 44
Comparison of the current between HBM and gun test.
R
C
Figure 45
ESD test equipement
6.1.3
Charged Device Model (CDM).
D.U.T
R
C
HBM
1500 Ω
100pF
IEC
330 Ω
150pF
A device may also become charged. If it then contacts the insertion head or another conductive surface, a rapid
discharge may occur from the device to the metal object. This event is known as the Charged Device Model (CDM)
event, and can be more destructive than the HBM for some devices. Although the duration of the discharge is very
short (often less than one nanosecond) the peak current can reach several tens of Ampere.
Application Note
42
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
ESD Aspects. ESD protection.
6.1.4
Machine Model (MM).
A discharge similar to the HBM event also can occur from a charged conductive object, such as a metallic tool or
fixture. Originating in Japan as the result of trying to create a worst-case HBM event, the model is known as the
Machine Model. This ESD model consists of a 200pF capacitor discharged directly into a component with no series
resistor. As a worst-case human body model, the Machine Model may be over severe. However, there are realworld situations that this model represents, for example the rapid discharge from a charged board assembly or
from the charged cables of an automatic tester.
6.2
ESD protection.
All infineon’s product includes an internal ESD protection. The concept of the Infineon’s ESD protection differs
from the others silicon supplier. The ESD protection is turned ON as soon as the voltage reach a certain values.
This values is actually specified in the datasheet [1], [2]and [3], as the absolute maximum rating. The avalanche
voltage of the technology has to be higher than the ESD protection threshold.
The Figure 46 shows the ESD proctection behavior. The standard protection is the most commonly used by
semiconductors suppliers. The improved ESD protection is the typical behavior of the ESD protection all new
Infineon’s transceiver includes. Compared to the standard protection, it reduces the energy and heat into the
device. Moreover, the Infineon’s SPT technology allows low thermal resistance to the leadframe. The heat is then
spread into the whole device, reducing the risk of hot spots (local overheat).
Standard ESD protection
TLE6250G
I (A)
Ideal ESD protection
Symbolic representation of
the ESD protection
TLE6251DS
TLE6251G
ESD protection
V
Snap back parasitic effect
Figure 46
Standard and Infineon ESD protection
6.3
Modules under ESD gun test.
Figure 47 shows the test set up for the following section, with the respective external component.
Application Note
43
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
ESD Aspects. Modules under ESD gun test.
TLE 6250 G
Driver
CANH
7
CANL
Vcc
3
6
Output
Stage
1
Temp.Protection
TxD
Mode
Control
*
8
INH
5
RM
VCC
Receiver
4
*
*
RxD
2
GND
*
(*) Shunts for current measurements
Figure 47
Schematic of the test
6.3.1
Device without any external protection circuitry.
The Figure 48 and Figure 49 shows the measurement realized at the ground line and Vcc line (device is supplied
to the 5V), with 1kV gun test for the TLE6250G. The ESD discharge is applied on CAN_H.
Figure 48
Positive ESD discharge, device supplied. Read out of the ground and supply current.
Application Note
44
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
ESD Aspects. Modules under ESD gun test.
Figure 49
Negative ESD discharge, device supplied. Read out of the ground and supply current.
6.3.2
ESD level reached with a choke coil.
The purpose of the choke coil is described in the Chapter 7. The Figure 50 shows the typical current flowing into
the ground line during the ESD discharge. The measurements show that the choke coil has no real influence on
the results and could not be considered as an efficient solution for ESD protection.
TLE6250G
+ 4kV ESD discharge applied on CAN_H.
Current measured on the ground line.
Device supplied
Without coil
B82790S513 (Epcos)
MMZ2012Y202B (TDK)
Figure 50
ESD discharge, device supplied. Read out of the ground current. With choke coil.
6.3.3
ESD level reached with a choke coil and ESD diode or varistor.
The Figure 51 and Figure 52 show the results on an ESD positive and negative discharges on the pin CAN_H,
device supplied. The influence is clearly seen, when using both varistor and choke coil. Using the varistor alone
doesn’t influence too much the results, because the varistor isn’t fast enough. Using these external components,
Application Note
45
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
ESD Aspects. Modules under ESD gun test.
the current is no more flowing in the device but in the external protection circuitry. In this condition, the ESD
robustness can reach very high values like 20kV.
+4kV ESD discharge applied on CAN_H
Current measured on the ground line
Device supplied
without
In serial
In serial
Figure 51
Positive ESD discharge, device supplied. Read out of the ground current. With varistor.
-1kV ESD discharge applied on CAN_H.
Current measured on the ground line.
Device supplied
without
In serial
In serial
Figure 52
Negative ESD discharge, device supplied. Read out of the ground current. With varistor
Application Note
46
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
ESD Aspects. PCB layout.
6.4
PCB layout.
Knowing all this, and applying the good protection corresponding to the ESD requirement of the application, it is
not given to pass successfully the ESD test. We saw in the Chapter 6.3 that the ESD current is flowing in the
ground of the device (or in the ground of the external protection). But the ground of the device can be something
else than the ground of the module. To equal the two grounds, the PCB layout has to be designed with care.
The Figure 53 shows the typical case where the ESD discharge is becoming an issue for the module.
TLE6250G
TLE6251G / DS
CANH
CANL
7
RxD
6
µP
TxD
V CC
GND
GND
2
V Drop
GND
VI
VQ
5V
e.g. TLE 4270
GND
Figure 53
Bad PCB example for ESD.
In the case of the ESD discharge on CAN_H or CAN_L pin, if the ground connector is situated far from the
transceiver, and with digital components as microcontroller in between, the ground line resistance cannot be
neglicted. The resultance is an overvoltage, locally on the ground pin of the micro controller, and it can be easily
destroyed !
The Figure 54 shows the proper PCB design to avoid these issues. The ground connector has to be as close as
possible to the transceiver.
6.5
Conclusion.
For the application targeting to have a good ESD robustness, layout of the board is very important. Providing
external ESD protection described in Chapter 6.3.3 can allow even more robust design. As the external protection
is influencing the terminations concept, it is also necessary to check the Chapter 5 to comply the bus
requirements. In case of varistor usage, a choke coil or at least two coils are necessary. It´s tempting to reduce
the varistor threshold voltage. This will improve the ESD robustness of course, but the EMI (Chapter 7) results will
be definitly jeopardized.
Application Note
47
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
ESD Aspects. Conclusion.
TLE6250G
TLE6251G / DS
CANH
CANL
7
RxD
6
µP
TxD
V CC
GND
GND
2
GND
Vs
VI
VQ
5V
e.g. TLE 4270
GND
Figure 54
Good PCB design for ESD robustness
Application Note
48
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
EMC aspect. EM Immunity against transcients.
7
EMC aspect.
The Electro-Magnetic-Compatibility is a challenge to achieve with CAN applications. Main reason is the wiring
harness of the CAN system running into the complete vehicle. The chance to encounter interferences, or to create
interferences in the neighbor of the cables is very high without any design care. In EMC, two domains are
considered, immunity (EMI) and emission (EME).
7.1
EM Immunity against transcients.
The transcients that the transceivers are facing are mainly defined in the international standard ISO 7637 part 1
and 2. It consists on checking whether the device is still running properly, or withstand the disturbances and goes
back to normal operation afterwards, or might be destroyed. The behavior requested is up to the OEM. The ISO
pulses 1, 2 and 3 are representing the disconnection of an inductive load in the wiring harness.
7.2
EM Immunity against RF disturbances.
The RF disturbances can be tested by several means. They are described in the ISO11452.
7.2.1
The Stripline test. ISO 11452-5.
The stripline test provides a uniform transverse electromagnetic field with the electric field across the strips and
the magnetic field parallel to them. Parallel-plate or co-planar lines are used with the lower plate bounded to the
shielded enclosure in which the test takes place. Such lines allow units to be subjected to plane waves over a wide
frequency range, and with high field strengths.
7.2.2
The Bulk Current Injection test. (BCI). ISO 11452-4.
Bulk Current Injection (BCI) is a test technique pioneered in the aircraft industry which uses current probes (both
pick-up and injection) to couple a 50Ω test and measurement system to a conductor or bundle of conductors such
as a vehicle wiring harness. The probes themselves are RF transformers. An injection probe is driven from the
output of an RF amplifier and couples the current into the harness of the equipment under test by acting as the
primary of a transformer - the single turn of the harness acting as the secondary. Pick-up probes act in a similar
way but this time allow the bulk current in a harness to be monitored using a power meter.
7.3
Infineon transceivers in the EMI disturbances.
7.3.1
Immunity against transcients.
The device design is optimized to withstand the ISO pulses. To check it, all devices are checked by an
independant laboratory, the IBEE. They do apply two tests, the damage and the malfunction test.
7.3.1.1
Damage test.
Purpose of the damage test is to check whether or not the device withstands the ISO pulses, without any
destruction. The levels of voltage applied are indicated in the Table 4. All infineon high speed transceivers
withstand the distrubances, without destruction.
Table 4
Damage test
Test pulse Vs max (V)
Pulse repetition
frequency (Hz)
Test duration (mn)
Remarks
1
-100
2
10
t2 = 0s
2a
+100
2
10
t2 = 0s
3a
-150
10
10
3b
+150
10
10
Application Note
49
V1.0, 2006-04-01
High speed CAN
CAN Transceiver
EMC aspect. Infineon transceivers in the EMI disturbances.
7.3.1.2
Malfunction test.
During the malfunction test the voltage is increased, for each pulses, until the device is definitively broken.
The reached values can be given, on request.
7.3.2
Immunity against RF disturbances.
The TEM cell, as well as the BCI tests, are tests at module’s level. The results are stongly dependant on the
application. It would be possible to test the device in these condition, but the interpretation of the device robustness
would be impossible, since there’s as much set-up as there are applications. To avoid this and to get the
information on the RF disturbances robustness, the Direct Power Injection (DPI) test is implemented.
7.3.2.1
BCI test limitation
The Figure 55 shows the typical case of the limitation of BCI, for component test. The transceiver is alone on the
board (for component test). The current probe is injecting 200mA for example. In that case, and assuming the
device is recessive or OFF, so having an impedance of 30kΩ as a minimum, the voltage on the pins CAN_H and
CAN_L will reach 100mA x 30kΩ = 3000 V theoretical (In practice the ESD diode is turning ON). The question is
no more to know if the device will be perturbated, but to know if it can overcome the test ! As soon as a capacitor
is present, this computation isn´t relevant anymore. But then, it´s no more component test but a test at module’s
level.
Test PCB
200mA
Termination
RF current
generator
Figure 55
BCI test limitation example
7.3.2.2
Principle of the DPI test.
The DPI test is, from a principle point of view, similar to the BCI test. The principle is to inject a certain AC voltage,
modulated or not, and to check the integrity of the signal (via the RxD pin or the NERR pin of the transceiver). The
test set up consists of 3 identical transceivers, soldered on a defined PCB. CAN bus is traced on the PCB. Instead
of a current injection, the power is injected via a capacitor (C5 and C6 on Figure 56), and measured in dBm, or
Watt. As for the BCI, the power injected is monitored to check the possible reflexions on the bus. One of the main
benefit of the DPI method is to allow comparison between different supplier’s design on an identical test bench,
via a consortium as the ICT for example.
Application Note
50
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High speed CAN
CAN Transceiver
EMC aspect. Infineon transceivers in the EMI disturbances.
Figure 56
DPI test set up
From the DPI results, the BCI and TEM cell result can be easily assessed. The DPI shows the results we can reach
with a perfect module design, on BCI and TEM cell.
7.3.2.3
Results of Infineon’s transceiver under DPI test.
The results can be given on request. The Figure 57 shows a typical DPI result curve on the well known
TLE6250G. Others transceivers are available on request. On the X axis, we can find the frequency range. On the
Y left axe, we can find the maximum power injected without failure. An ideal transceiver would have a straight
curve, so 36dBm injected without any failure. On the Y right axe, we can find the voltage in Volt RMS of the power
injected, reflecting the reflexions of the line.
Application Note
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High speed CAN
CAN Transceiver
EMC aspect. Infineon transceivers in the EMI disturbances.
Figure 57
DPI test results example : The TLE6250G
7.3.2.4
Improvement of the DPI result. Use of choke coil.
When the transceiver shows weaknesses from the DPI test, a solution is to use a choke coil. The Figure 58 shows
the principle of the choke coil. The operation current ΙO induces a magnetic flow φO. The sum of both induced
magnetic flow is φO - φO =0. So the common mode choke doesn´t influence the signal current at all. The common
mode interference induces a flow φi that sums up to a flow φi + φi =2 φi. This magnetic flow „sees“ a strong damping
by the system inductance of the magnetic ring (high permeability) and so it is also damping the resulting
interference current of the system. The choke coil should be chosen within a high µ (L=11, 22, 33, 51µH), a low Q
factor, very low (100...300mΩ) resistance and a high resonnance frequency. And of course, the coil should
withstand the short circuit current so 200mA. The B82790S513 (51µH) from Epcos or the MMZ2012Y202B (51µH)
from TDK for instance are matching these requirements.
It is important to notice the choke coil filters the parasitics coming in the module, as well as the eventual parasitics
created by the transceiver itself, only if the disturbances are on both channels (like BCI and TEM cell). In case only
CAN_H or CAN_L is disturbed / is disturbing, the choke coil is useless. To get rid of such parasitics, it´s preferable
to use a capacitor and / or a coil.
Application Note
52
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High speed CAN
CAN Transceiver
EMC aspect. Infineon transceivers in the EMI disturbances.
IO
U Operation
IO = operation current
φO = magnetic flow
φi
φO
φO
U interference
φi
RLOAD
Ii
Ii = interference current
φi = magnetic flow
Figure 58
Choke coil principle
The Figure 59 shows the results, witht the same set up as on the Figure 57, adding a chock coil, suppressing the
traditionnal weakness at low frequency.
Figure 59
DPI test results with choke coil for the TLE6250G.
7.3.3
Emission
As well as for the immunity test, the emission can be performed on the same test bench as for the DPI method.
To get emission, it is necessary the transceiver is emitting. The ICT has stated two test pulses. The first one is a
square wave of 250kHz matching an high baudrate application. The second test signal is a 90% duty cycle, at a
frequency of 50kHz, matching a low baudrate application. The Figure 60 shows the results of the TLE6250G
under these conditions. The disturbances are measured on the Y axe in dBµV, the X axe is showing the frequency.
Application Note
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High speed CAN
CAN Transceiver
EMC aspect. Infineon transceivers in the EMI disturbances.
Figure 60
EME test results with TLE6250G, without chock coil
As well as for the immunity, a choke coil can be used. The Figure 61 shows the benefit of the chock coil for the
test signal 1 (square wave of 250kHz). At least 10dBµV reduction can be observed.
Figure 61
EME test results with TLE6250G with and without chock coil
Application Note
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High speed CAN
CAN Transceiver
EMC aspect. Conclusion.
7.4
Conclusion.
As well as for the ESD, the EMC performance of the application is strongly dependant on the design care. It is
recommended to plan a choke coil, even if the EMC module test shows good results without. All Infineon’s
transceiver are tested according to the method described in this chapter and the reports for each particular parts
are available on request. Similar to the comparison between the component test and the module test, the result
of car test is difficult to predict.
Application Note
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High speed CAN
CAN Transceiver
Products summary
8
Products summary
Functionality TLE6250G TLE6250GV33 TLE6251DS TLE6251G Unit
Vcc supply
[4,5;5,5]
[4,5;5,5]
[4,75;5,25]
[4,75;5,25] V
Vio
no
[3.0 ;5,5]
no
[3.0 ; 5,25] V
Vs
no
no
no
[5 ; 40]
Enable
Yes
Yes
Yes
Yes
Bus wake up No
No
Yes
Yes
Bus bias in
unpowered
mode
GND
GND
weak GND
weak GND
SPLIT pin
no
no
Yes
Yes
ESD
6
6
6
6
INH output
no
no
no
Yes
Bus time out
no
no
yes
yes
comments
V
(+/-) kV
Abbreviation Meaning
Comment
BCI
Bulk Current Injection
CAN
Controller Area Network
CDM
Charged Device Model
ESD test
DPI
Direct Power Injection
EMC test
DUT
Device Under Test
EMC
Electro-magnetic Compatibility
EME
Electro-magnetic Emission
EMI
Electro-magnetic Immunity
EOS
Electrical Over Stress
ESD
Electro Static Discharge
HBM
Human Body model
HS CAN
High Speed CAN transceiver
IBEE
IngenieurBurö für industrielle Electrotechnik / Electronik
ICT
International Conformance and Testing
IEC
International Electrotechnical Commision
INH
Inhibit
ISO
International Standard Organization
LDO
Low Drop Output
Other name for Voltage regulator
MM
Machine Model
ESD test
OEM
Original Equipement Manufacturer
In the frame of this document, it means
car maker
SC
Short Circuit
SPT
Smart Power Technology
Application Note
Bipolar CMOS and DMOS technology
developped by Infineon
56
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CAN Transceiver
References.
9
References.
[1]
Data Sheet High speed CAN, TLE6250G Infineon Technologies AG - Version 3.8
[2]
Data Sheet High speed CAN, TLE6251DS Infineon Technologies AG - Version 3.0
[3]
Data Sheet High speed CAN, TLE6251G Infineon Technologies AG - version 3.1
[4]
Data Sheet, TLE4278G Infineon Technologies AG - version
[5]
International Standard ISO 11898-2, Road Vehicles - Controller Area Network (CAN) part 2 High speed
medium access unit.
[6]
International Standard ISO 11898-5, Road Vehicles - Controller Area Network (CAN) part 5 High speed
medium access unit.
[7]
Data Sheet, Voltage regulator TLE4275G Infineon Technologies AG version 1.4
[8]
Data Sheet, Voltage regulator TLE7270G Infineon Technologies AG version 0.21
[9]
Data Sheet, Voltage regulator TLE4266-2G Infineon Technologies AG version 1.2
Application Note
57
V1.0, 2006-04-01
www.infineon.com
Published by Infineon Technologies AG