Z8F54978222 Application Note TLE7250V About this document Scope and purpose This document provides application information for the transceiver TLE7250V from Infineon Technologies AG as Physical Medium Attachment within a Controller Area Network (CAN). This document contains information about: • set-ups for CAN application • mode control • fail safe behavior • power supply concepts • power consumption aspects This document refers to the data sheet of the Infineon Technologies AG CAN Transceiver TLE7250V. Note: The following information is given as a hint for the implementation of our devices only and shall not be regarded as a description or warranty of a certain functionality, condition or quality of the device. Intended audience This document is intended for engineers who develop applications. Application Note www.infineon.com 1 Rev. 1.1 2016-05-03 Application Note Z8F54978222 Table of Contents About this document . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Table of Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1 CAN Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2 2.1 2.2 TLE7250V Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Mode Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3 3.1 3.2 In Vehicle Network Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Clamp 30 and Clamp 15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Baud Rate versus Bus Length . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 4 CAN FD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 5 5.1 5.2 5.3 5.4 5.5 5.6 5.7 Pin Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 VIO Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 VCC Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 NEN Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 TxD Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 RxD Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 CANH and CANL Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 GND Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 6 6.1 6.2 6.3 6.3.1 6.3.2 6.3.3 6.3.4 6.4 6.5 6.6 6.7 Transceiver Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Voltage Regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 External Circuitry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 VIO Feature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 VIO 3.3 V - 5.5 V Power Supply Concept . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 VIO 3.3 V Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 VIO 5 V Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Dual 5 V Supply Concept . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Current Consumption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Loss of Battery (Unsupplied Transceiver) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Loss of Ground . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Ground Shift . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 7 7.1 7.2 7.3 7.4 Transceiver Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Mode Change by NEN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Mode Change Delay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Mode Change due to VCC Undervoltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Transition from Power-Save Mode to Forced-Power-Save Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 8 8.1 8.2 8.3 8.4 Failure Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 TxD Dominant Time-out Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Minimum Baud Rate and Maximum TxD Dominant Phase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Short Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 TLE7250V Junction Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Terms and Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 9 Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Application Note 2 Rev. 1.1 2016-05-03 Application Note Z8F54978222 CAN Application 1 CAN Application With the growing number of electronic modules in cars the amount of communication between modules increases. In order to reduce wires between the modules CAN was developed. CAN is a Class-C, multi master serial bus system. All nodes on the bus system are connected via a two wire bus. A termination of RT = 120 Ω or a split termination (RT/2 = 60 Ω and CT = 4.7 nF) on two nodes within the bus system is recommended. Typically an ECU consists of: • power supply • microcontroller with integrated CAN protocol controller • CAN transceiver The CAN protocol uses a lossless bit-wise arbitration method of conflict resolution. This requires all CAN nodes to be synchronized. The complexity of the network can range from a point-to-point connection up to hundreds of nodes. A simple network concept using CAN is shown in Figure 1. VBAT Power Supply VIO/VCC Transceiver CANH CANL Mode-Pin CANH TxD CANL RxD μC GND ECU CT Figure 1 ECU ECU ECU ECU RT/2 RT/2 RT/2 RT/2 CT CAN Example with Typical ECU Using TLE7250V The CAN bus physical layer has two defined states: dominant and recessive. In recessive state CANH and CANL are biased to VCC/2 (typ. 2.5 V) and the differential output voltage VDiff is below 0.5 V. A “low” signal applied to TxD pin generates a dominant state on CANH and CANL. The voltage on CANH changes towards VCC and CANL goes towards GND. The differential voltage VDiff is higher than 0.9 V. Application Note 3 Rev. 1.1 2016-05-03 Application Note Z8F54978222 CAN Application CANH CANL 5V “recessive” “dominant” “recessive” 2,5V t VDiff 5V “dominant” 0,9V 0,5V “recessive” t -1V Figure 2 Voltage Levels according to ISO 11898-2 Table 1 Voltage Levels according to ISO 11898-2 Parameter Symbol Values Unit Note or Test Condition Min. Typ. Max. 2.0 2.5 3.0 V No load Differential Output Bus Voltage VDiff_R_NM -500 – 50 mV No load Differential Input Bus Voltage VDiff_R_Range -1.0 – 0.5 V – VCANH 2.75 3.5 4.5 V 50 Ω < RL < 65 Ω VCANL 0.5 1.5 2.25 V 50 Ω < RL < 65 Ω Differential Output Bus Voltage VDiff_D_NM 1.5 2.0 3.0 V 50 Ω < RL < 65 Ω Differential Input Voltage 0.9 – 5.0 V – Recessive State Output Bus Voltage VCANL,H Dominant State Output Bus Voltage VDiff_D_Range The CAN physical layer is described in ISO 11898-2. The CAN transceiver TLE7250V fulfills all parameters defined in ISO 11898-2. This document describes CAN applications with the TLE7250V. It provides application hints and recommendations for the design of CAN electronic control units (ECUs) using the CAN transceiver TLE7250V from Infineon Technologies AG. Application Note 4 Rev. 1.1 2016-05-03 Application Note Z8F54978222 TLE7250V Description 2 TLE7250V Description The transceiver TLE7250V represents the physical medium attachment, interfacing the CAN protocol controller to the CAN transmission medium. The transmit data stream of the protocol controller at the TxD input is converted by the CAN transceiver into a bus signal. The receiver of the TLE7250V detects the data stream on the CAN bus and transmits it via the RxD pin to the protocol controller. 2.1 Features The main features of the TLE7250V are: • Baud rate up to 2 Mbit/s • Very low Electromagnetic Emission (EME) and high Electromagnetic Immunity (EMI) • Excellent ESD performance according to HBM (+/-9 kV) and IEC (+/-8 kV) • Very low current consumption in Power-save mode • Transmit data (TxD) dominant time-out function • Supply voltage range 4.5 V to 5.5 V • Control input levels compatible with 3.3 V and 5 V devices • Thermal shutdown protection 2.2 Mode Description The TLE7250V supports three different modes of operation. The mode of operation depends on the status of the reference power supply and the status of the mode selection pin NEN, : • Normal-operating mode: Used for communication on the HS CAN bus. Transmit and receive data on the bus. • Power-save mode: Reduces current consumption in afterrun when there is no communication on the HS CAN bus with ECU still active. Emergency undervoltage state, when the microcontroller detects undervoltage and starts saving internal information. In order to reduce current consumption the transceiver is set to Power-save mode. • Forced-power-save mode: Same behavior as Power-save mode implemented as a fail-safe mode for VCC undervoltage condition. Reduces current consumption in afterrun when there is no communication on the HS CAN bus with ECU still active. Emergency undervoltage state when the microcontroller detects undervoltage and starts saving internal information. TxD 1 8 NEN GND 2 7 CANH VCC 3 6 CANL RxD 4 5 TxD 1 8 NEN GND 2 7 CANH VCC 3 6 CANL RxD 4 5 PAD VIO (Top-side x-ray view) Figure 3 VIO Pin Configuration of the TLE7250V Application Note 5 Rev. 1.1 2016-05-03 Application Note Z8F54978222 In Vehicle Network Applications 3 In Vehicle Network Applications The TLE7250/51-Family offers a perfect match for various ECU requirements. For partially supplied ECUs (Clamp 15) the TLE7250V is suitable. According to the requirements of automobile manufacturers, the modules can either be permanently supplied or unsupplied during the car is parked. The main reason for unsupplied modules is saving battery energy. Permanently supplied modules can wake up quickly via CAN message. 3.1 Clamp 30 and Clamp 15 Clamp 30: Permanently supplied modules, even when the car is parked are required by body applications such as door modules, RF keyless entry receivers, etc. Modules are directly connected to the battery. This supply line is called clamp 30. As battery voltage is present permanently, the voltage regulator, transceiver and microcontroller are always supplied. Therefore voltage regulator, transceiver and microcontroller need to be set to low-power mode in order to reduce current consumption to a minimum. Clamp 15: Partially supplied modules are typically used in under hood applications such as ECUs. When the car is parked a main switch or ignition key switches off the battery supply. This supply line is called clamp 15. When the battery voltage is not present, the voltage regulator and transceiver are switched off. Clamp 30 Clamp 15 VBAT ECU with TLE7251 CT Figure 4 ECU with ECU with ECU with ECU with TLE7251 TLE7251 TLE7250/51 TLE7250/51 RT/2 RT/2 RT/2 RT/2 CT CAN with ECUs Using TLE7250V In Clamp 15 applications there is no need to use transceivers with bus wake-up feature. Therefore TLE7250V offers three different modes, that make applications more flexible (see Chapter 2.2). For applications that do not use the bus wake-up feature, the TLE7250V offers the Power-save mode with very low current consumption. There is also the possibility to reduce the current consumption of the ECU more by disconnecting the TLE7250V from the power supply. If communication is still on the HS CAN bus, then the TLE7250V has a perfect passive bus behavior in order not to affect CAN bus communication, while the TLE7250V is switched off. Application Note 6 Rev. 1.1 2016-05-03 Application Note Z8F54978222 In Vehicle Network Applications VBAT Power VCC Supply VIO Mode μC TLE7250V RxD TxD CANH CANL Figure 5 Example ECU with TLE7250V 3.2 Baud Rate versus Bus Length Table 2 Recommended Baud Rate versus Bus Length Baud Rate (kbit/s) Bus Length (m) Maximum Distance between two Nodes 1000 10 500 40 250 120 125 500 50 1000 Baud rate is limited by: • bus length • ringing • propagation delay of cables • propagation delay of the CAN controller of the transceiver The two most distant nodes (A and B) in a CAN network are the limiting factor in transmission speed. The propagation delays must be considered because a round trip has to be made from the two most distant CAN controllers on the bus. Worst case scenario: When node A starts transmitting a dominant signal, it takes a certain period of time (t = tCANcontroller + tTransceiver + tCable) until the signal arrives at node B. The propagation delay is estimated by: CAN controller delay, transceiver delay, bus length delay. Assumption: 70 ns for CAN controller, 255 ns for transceiver, 5 ns per meter of cable. Example with 50 m cable length: tprop = tCANcontroller + tTransceiver + tCable + tCANcontroller + tTransceiver + tCable = 70 ns + 255 ns + 50 m × 5 ns/m + 70 ns + 255 ns + 50 m × 5 ns/m = 1150 ns Some other factors of great influence on the maximum baud rate are cable capacitance, oscillator tolerance, ringing and reflection effects depending on the network topology. In addition to theoretical maximum propagation delay all other effects must be taken into account and an additional margin of safety must be added. Wire resistance increases with bus length and therefore the bus signal amplitude may be degraded. Application Note 7 Rev. 1.1 2016-05-03 Application Note Z8F54978222 CAN FD 4 CAN FD CAN FD (Flexible Data Rate) is the advanced version of classical CAN. Classical CAN is specified by ISO 11898-2 for data transmission rate up to 1 Mbit/s. For CAN FD with higher data transmission rate (2 Mbit/s) ISO 118982 specifies additional timing parameters. CAN FD uses the same physical layer as classical CAN does, but allows higher data transmission rate and increased payload per message. During the arbitration phase and checksum the data transmission rate is the same as for classical CAN (1 Mbit/s). As soon as one node in the CAN FD network starts transmitting the payload, the data rate increases (2 Mbit/s). The increase in baud rate is possible as only one node transmits during the data transmission phase. All other nodes listen to the data on the CAN bus. Instead of 8 bytes per message (classical CAN) payload is increased up to maximum 64 byte per message. Using CAN FD saves transmission time and allows increased data payload. In order to ensure reliable data transmission, CAN FD requires a CAN transceiver with full ISO 11898-2 specification for Flexible Data rate up to 2 Mbit/s. The TLE7250V from Infineon Technologies AG is the perfect match for CAN FD networks. TLE7250V fulfills or exceeds all classical CAN and CAN FD parameters of ISO 11898-2 in order to enable smooth and safe usage within applications. Classical CAN: 8 Byte Message SOF Arbitration CTR Payload (Data) CRC ACK EOF 1 Mbit/s CAN FD: 8 Byte Message CAN FD: Increased Payload SOF Arbitration CTR 1 Mbit/s Payload (Data) CRC ACK EOF 2 Mbit/s 1 Mbit/s SOF Arbitration CTR 1 Mbit/s Payload (Data) CRC 2 Mbit/s ACK EOF 1 Mbit/s t Figure 6 Classical CAN Data Rate and CAN FD Data Rate Application Note 8 Rev. 1.1 2016-05-03 Application Note Z8F54978222 Pin Description 5 Pin Description 5.1 VIO Pin The VIO pin is needed for the operation with a microcontroller that is supplied by VIO < VCC, to get the correct level between microcontroller and transceiver. It can also be used to decouple microcontroller and transmitter supply. This concept improves EMC performance and the transmitter supply VCC can be switched off separately. The digital reference supply voltage VIO has two functions: • supply of the internal logic of the transceiver (state machine) • voltage adaption for external microcontroller (3.0 V < VIO < 5.5 V) As long as VIO is supplied (VIO > 3.0 V) the state machine of the transceiver works and mode changes can be performed. If a microcontroller uses low VIO < VCC = 5 V, then the VIO pin must be connected to the power supply of the microcontroller. Due to this feature, the TLE7250V can work with various microcontroller supplies. If VIO is available, then both transceiver and microcontroller are fully functional. Below VIO < 3.0 V the TLE7250V is in Power On Reset state. To enter Normal-operating mode VIO > 3.0 V is required. 5.2 VCC Pin The VCC pin supplies the transmitter output stage. The transmitter operates according to data sheet specifications in the voltage range of 4.5 V < VCC < 5.5 V. Voltage VCC > 6 V can damage the device. If VCC < VCC_UV, then the transmitter is disabled. The undervoltage threshold VCC_UV is in the range from 3.65 V to 4.3 V. If VCC_UV < VCC < 4.5 V, then the transmitter is enabled and can then send data to the bus, but parameters may be outside the specified range. 5.3 NEN Pin The NEN pin sets the mode of TLE7250V and is usually directly connected to an output port of a microcontroller. For a disconnected NEN pin or microcontroller ports in “tristate” the TLE7250V has an integrated pull-up resistor to VIO, by default the device is in Power-save mode in order to enable low current consumption. This reduces disturbance to the HS CAN bus. Table 3 shows mode changes via the NEN pin, assuming VIO > VIO_UV. Features and modes of operation are described in Chapter 2. Table 3 Mode Selection via NEN Mode of operation NEN VCC Comment Power-Save Mode “high” “X” If NEN is set to "high", then the TLE7250V is in Power-save mode, Independent of VCC. Forced-Power-Save Mode “low” < VCC_UV Same as Power-save mode Normal-Operating Mode “low” > VCC_UV If VCC > VCC_UV, then the transmitter is enabled. The Power-save mode and Forced-power-save mode are the low-power modes of TLE7250V. In these modes both the transmitter and the receiver are disabled and current consumption is reduced to a minimum. The user can deactivate transmitter and receiver of TLE7250V either by setting the NEN pin to “low” or by switching off VCC. This can be used to implement two different fail safe paths in case a failure is detected in the ECU. Application Note 9 Rev. 1.1 2016-05-03 Application Note Z8F54978222 Pin Description 5.4 TxD Pin TxD is an input pin. TxD pin is used to receive the data stream from the microcontroller. If VIO > VIO_UV, then the data stream is transmitted to the HS CAN bus. A “low” signal causes a dominant state on the bus and a “high” signal causes a recessive state on the bus. The “high” signal must be adapted according to the voltage on the VIO pin. This means the “high” level must not exceed VIO voltage. The TxD input pin has an integrated pull-up resistor to VIO. If TxD is permanently “low”, for example due to a short circuit to GND, then the TxD time-out feature will block the signal on the TxD input pin (see Chapter 8.1). It is not recommended to use a series resistor within the TxD line between transceiver and microcontroller. A series resistor may add delay, which degrades the performance of the transceiver, especially in high data rate applications. The data stream sent from the microcontroller to the TxD pin of the transceiver is only transmitted to the HS CAN bus in Normaloperating mode. In all other modes the TxD input pin is blocked. 5.5 RxD Pin RxD is an output pin. The data stream received from the HS CAN bus is displayed on the RxD output pin in Normal-operating mode. It is not recommended to use a series resistor within the RxD line between transceiver and microcontroller. A series resistor may add delay, which degrades the performance of the transceiver, especially in high data rate applications. 5.6 CANH and CANL Pins CANH and CANL are the CAN bus input and output pins. The TLE7250V is connected to the bus via pin CANH and CANL. Transmitter output stage and receiver are connected to CANH and CANL. Data on the TxD pin is transmitted to CANH and CANL and is simultaneously received by the receiver input and signalled on the RxD output pin. For achieving optimum EME (Electromagnetic Emission) performance, transitions from dominant to recessive and from recessive to dominant are done as smooth as possible also at high data rate. Output levels of CANH and CANL in recessive and dominant state are described in Table 1. Due to the excellent ESD performance on CANH and CANL no external ESD components are necessary to fulfill OEM requirements. 5.7 GND Pin The GND pin must be connected as close as possible to module ground in order to reduce ground shift. It is not recommended to place filter elements or an additional resistor between GND pin and module ground. GND must be the same for transceiver, microcontroller and HS CAN bus system. Application Note 10 Rev. 1.1 2016-05-03 Application Note Z8F54978222 Transceiver Supply 6 Transceiver Supply The internal logic of TLE7250V is supplied by the VIO pin. The VCC pin 5 V supply is used to create the CANH and CANL signal. The transmitter output stage as well as the main CAN bus receiver are supplied by the VCC pin. This chapter describes aspects of power consumption and voltage supply concepts of TLE7250V. 6.1 Voltage Regulator It is recommended to use one of the following Infineon low drop output (LDO) voltage regulators, depending on the VIO power supply concept: • 3.3 V VIO power supply: TLS850D0TAV33 (500mA)1), TLS850F0TAV33 (500mA)1), TLS810B1LDV332) (100mA), TLE4266-2GS V33 (150mA), • 5 V VIO and VCC power supply: TLS850D0TAV501) (500mA), TLS850F0TA V50 (500mA), TLS810D1EJV50 (100mA), TLS810B1LDV50 (100mA), TLE4266-2 (150mA) • 3.3 V and 5 V dual voltage power supply: TLE4476D • Dual 5V voltage power supply: TLE4473GV55 Please refer to Infineon Linear Voltage Regulators for the Infineon voltage regulator portfolio, data sheets and application notes. 6.2 External Circuitry In order to reduce EME and to improve the stability of input voltage level on VCC and VIO of the transceiver, it is recommended to place capacitors on the PCB. During sending a dominant bit to the HS CAN bus, current consumption of TLE7250V is higher than during sending a recessive bit. Data transmission can change the load profile on VCC. Changes in load profile may reduce the stability of VCC. If several CAN transceivers are connected in parallel, and if these CAN transceivers are supplied by the same VCC and/or VIO power supply (for example LDO), then the impact on the stability of VCC is even stronger. It is recommended to place a 100 nF capacitor as close as possible to VCC and VIO pin. The output of the VCC and VIO power supply (for example LDO) must be stabilized by a capacitor in the range of 1 to 50 µF, depending on the load profile. Ceramic capacitors are recommended for low ESR. 6.3 VIO Feature TLE7250V offers a VIO supply pin, which is a voltage reference input for adjusting the voltage levels on the digital input and output pins to the voltage supply of the microcontroller. In order to use the VIO feature, connect the power supply of the microcontroller to the VIO input pin. Depending on the voltage supply of the microcontroller, TLE7250V can operate with the VIO reference voltage input within the voltage range from 3.0 V to 5.5 V. 6.3.1 VIO 3.3 V - 5.5 V Power Supply Concept The VIO pin supplies the internal logic of the TLE7250V. TLE7250V can operate with the VIO reference voltage input in the range from 3.0 V to 5.5 V. The VCC pin (typ. = 5 V) supplies the transmitter of TLE7250V. Therefore the VCC supply input pin must be connected to a 5 V voltage regulator. Competitor devices use VCC to supply the internal logic and the transmitter output stage and VIO as a simple level shifter. Infineon’s HS CAN transceivers can work in VCC undervoltage condition or even with VCC completely switched off in Forcedpower-save mode and Power-save mode. 1) Planned SOP Q2 2016 2) Planned SOP Q4 2016 Application Note 11 Rev. 1.1 2016-05-03 Application Note Z8F54978222 Transceiver Supply 6.3.2 VIO 3.3 V Power Supply In order to reduce power consumption of ECU, the microcontroller might not be supplied by VCC but by a lower voltage (for example 3.3 V). Therefore the TLE7250V offers a VIO supply pin, which is a voltage reference input in order to adjust the voltage levels on the digital input and output pins to the voltage supply of the microcontroller. The VIO feature enables the TLE7250V to operate with a microcontroller, which is supplied by a voltage lower than VCC. With the VIO reference voltage input the TLE7250V can operate from 3.0 V to 5.5 V. VBAT 3.3V LDO VIO VIO μC VIO VCC VCC 5V LDO TLE7250V Figure 7 3.3 V Power Supply Concept 6.3.3 VIO 5 V Supply TLE7250V can also operate with a 5 V supply because of the VIO input voltage range from 3.0 V to 5.5 V. If the microcontroller uses VCC = 5 V supply, then VIO is connected to VCC. The VIO input must be connected to the supply voltage of the microcontroller. VBAT 5V LDO VIO μC VIO VCC TLE7250V Figure 8 5 V Power Supply Concept 6.3.4 Dual 5 V Supply Concept In order to decouple the microcontroller and the HS CAN Bus from each other with respect to noise and disturbances, it is possible to use a dual 5 V voltage regulator like TLE4473GV55. In this case two independent 5 V LDOs supply VIO and VCC. This power supply concept improves EMC behavior and reduces noise. Application Note 12 Rev. 1.1 2016-05-03 Application Note Z8F54978222 Transceiver Supply VBAT VIO 5V LDO VIO μC VCC 5V LDO VIO VCC TLE7250V Figure 9 Dual 5 V Power Supply Concept Application Note 13 Rev. 1.1 2016-05-03 Application Note Z8F54978222 Transceiver Supply 6.4 Current Consumption Current consumption depends on the mode of operation: • Normal-operating mode: Maximum current consumption of TLE7250V on the VCC supply is specified as 60 mA in dominant state and 4 mA in recessive state. Maximum current consumption of TLE7250V on the VIO supply is specified as 1 mA. To estimate theoretical current consumption in Normal-operating mode, a duty cycle of 50% can be assumed, with fully loaded bus communication of 50% dominant and 50% recessive. In Normal-operating mode the TLE7250V consumes in worst case maximum: ICC_AVG = (ICC_REC + ICC_DOM) / 2 + IIO = 32.5 mA Typically the current consumption is less than 15 mA. • Power-save mode and Forced-power-save mode: In Power-save mode most of the functions are turned off. VCC can be switched off. The maximum current consumption is specified as 8 µA. 6.5 Loss of Battery (Unsupplied Transceiver) When TLE7250V is unsupplied, CANH and CANL act as high impedance. The leakage current ICANH,lk, ICANL,lk at CANH pin or CANL pin is limited to +/- 5 µA in worst case. When unsupplied, TLE7250V behaves like a 1 MΩ resistor towards the bus. Therefore the device perfectly fits applications that use both Clamp 15 and Clamp 30. 6.6 Loss of Ground If loss of ground occurs, then the transceiver is unsupplied and behaves like in unpowered state. In applications with inductive load connected to the same GND, for example a motor, the transceiver can be damaged due to loss of ground. Excessive current can flow through the CAN transceiver when the inductor demagnetizes after loss of ground. The ESD structure of the transceiver cannot withstand that kind of Electrical Overstress (EOS). In order to protect the transceiver and other components of the module, an inductive load must be equipped with a free wheeling diode. VBAT VBAT Voltage Regulator Voltage Regulator VCC Inductive load VCC CAN Transceiver CAN Transceiver CANH CANL GND Figure 10 GND Loss of GND with Inductive Load Application Note 14 Rev. 1.1 2016-05-03 Application Note Z8F54978222 Transceiver Supply 6.7 Ground Shift Due to ground shift the GND levels of CAN transceivers within a network may vary. Ground shift occurs in high current applications or in modules with long GND wires. The receiver input stage acts like a resistor (Ri) to GND. Because the transmitting node has its GND shifted to VShift, the recessive voltage level Vrec from the chassis ground is no longer 2.5 V but Vrec + Vshift. The same ground shift voltage VShift must be taken into account for the dominant signal. Because CAN uses a differential signal and because of the wide common mode range of +/12 V for Infineon transceivers, any CANH and CANL DC value within absolute maximum ratings works. The recessive CAN bus level Vrec during a ground shifted node transmitting is equal to the average recessive voltage level of all transceivers: Vrec = [(Vrec_1 + VShift_1) + (Vrec_2 + VShift_2) + (Vrec_3 + VShift_3) + ... + (Vrec_n + VShift_n)]/n n: number of connected CAN nodes Vrec_1, Vrec_2, .., Vrec_n: specific recessive voltage level of the transceiver at nodes 1, 2, .. n VShift_1, VShift_2, ..., VShift_n: specific ground shift voltage level of the transceiver at nodes 1, 2, .. n The supply current of a ground shifted transceiver increases by ICC_Shift = VShift / (Ri_n / n), assuming all input resistances at CANH and CANL of the transceivers are identical. Application Note 15 Rev. 1.1 2016-05-03 Application Note Z8F54978222 Transceiver Control 7 Transceiver Control The modes of the TLE7250V are controlled by the pin NEN and by transmitter voltage VCC. 7.1 Mode Change by NEN The mode of operation is set by the mode selection pin NEN. By default the NEN input pin is “high” due to the internal pull-up resistor to VIO. The TLE7250V is in Power-save mode independent of the status of VCC. In order to change the mode to Normaloperating mode, NEN must be switched to “low” and VCC must be available. 7.2 Mode Change Delay The HS CAN transceiver TLE7250V changes the mode of operation within the transition time period tMode. The transition time period tMode must be considered in developing software for the application. During the mode change from Power-save mode to a non-low power mode the receiver and/or transmitter is enabled. During the period tMode the RxD output pin is permanently set to “high” and does not reflect the status on the CANH and CANL input pins. In addition, during tMode, the TxD path is blocked as well. When the mode change is completed, the TLE7250V releases the RxD output pin. Figure 11 shows this scenario. CANH CANL t RxD blocked RxD released RxD t NEN t Power-save mode Mode change tMode Normal-operating Mode¹ 1) Assuming VCC > VCC_UV Figure 11 RxD Behavior during Mode Change Application Note 16 Rev. 1.1 2016-05-03 Application Note Z8F54978222 Transceiver Control tMode Figure 12 Communication on the CAN Bus: RxD Behavior during Mode Change (Power-Save Mode to Normal-Operating Mode) Application Note 17 Rev. 1.1 2016-05-03 Application Note Z8F54978222 Transceiver Control 7.3 Mode Change due to VCC Undervoltage A mode change due to VCC undervoltage is only possible in Normal-operating mode. If VCC undervoltage persists longer than tDelay(UV), then the TLE7250V changes from Normal-operating mode to Forced-power-save mode. As soon as TLE7250V detects an undervoltage, it disables the transmitter output stage so that no faulty data is sent to the HS CAN bus. In order to reduce current consumption during VCC < VCC(UV) fault condition, the TLE7250V has a optimized current consumption in Forced-power-save mode. If VCC recovers, then VCC > VCC_UV triggers a mode change back to Normal-operating mode. VCC VCC_UV tDelay(UV) tDelay(UV) tDelay(UV) t Normal-operating mode Figure 13 Forced power-save mode Normal-operating mode VCC Undervoltage and Recovery tDelay_(UV) Figure 14 Recovery of VCC in Forced Power-Save Mode Application Note 18 Rev. 1.1 2016-05-03 Application Note Z8F54978222 Transceiver Control 7.4 Transition from Power-Save Mode to Forced-Power-Save Mode From Normal-operating mode the TLE7250V enters Forced-power-save mode on detecting VCC undervoltage. However, in Power-save mode VCC undervoltage detection is disabled. With VCC below the undervoltage threshold VCC_UV in Power-save mode, when EN is switched from "high" to "low" the TLE7250V changes to Normal-operating mode. In Normal-operating-mode VCC undervoltage detection is enabled, and thus the undervoltage event is detected. This in turn triggers a mode change to Forced-power-save mode. The overall transition time period from Power-save mode to Forced-power-save Mode is t < tMode. During the mode change from Power-save mode to Forced-power-save mode the RxD output pin is permanently set to “high” and does not reflect the status of the CANH and CANL input pins. After the mode change to Forced-power-save mode is completed, the TLE7250V releases the RxD output pin. Normal-operating mode NEN VCC VIO 0 “on” “on” VCC “off” ForcedPower-save mode Power-down state NEN VCC VIO “X” “X” “off” NEN “0” NEN VCC VIO 0 “off” “on” Power-save mode Figure 15 NEN VCC VIO 1 “X” “on” Power-Save Mode to Forced-Power-Save Mode Application Note 19 Rev. 1.1 2016-05-03 Application Note Z8F54978222 Failure Management 8 Failure Management This chapter describes typical bus communication failures. 8.1 TxD Dominant Time-out Detection The TxD dominant time-out detection of TLE7250V protects the CAN bus from being permanently driven to dominant level. When detecting a TxD dominant time-out, the TLE7250V disables the transmitter in order to release the CAN bus. Without the TxD dominant time-out detection, a CAN bus would be clamped to the dominant level and therefore would block any data transmission on the CAN bus. This failure may occur for example due to TxD pin shorted to ground. The TxD dominant time-out detection can be reset after a dominant to recessive transition at the TxD pin. A “high” signal must be applied to the TxD input for at least tTXD_release = 200 ns to reset the TxD dominant timer. TxD t t > tTxD_release t > tTxD t < tTxD_release CANH CANL t RxD t TxD time-out Figure 16 TxD time–out released Resetting TxD Dominant Time-out Detection If a TxD Dominant Time-out is present, then a mode change to Power-save mode clears the TxD dominant timer state. 8.2 Minimum Baud Rate and Maximum TxD Dominant Phase Due to the TxD dominant time-out detection of the TLE7250V the maximum TxD dominant phase is limited by the minimum TxD dominant time-out time tTxD = 4.5ms. The CAN protocol allows a maximum of 11 subsequent dominant bits at TxD pin (worst case dominant bits followed immediately by an error frame). With a minimum value of 4.5 ms given in the datasheet and maximum possible 11 dominant bits, the minimum baud rate of the application must be higher than 2.44 kbit/s. Application Note 20 Rev. 1.1 2016-05-03 Application Note Z8F54978222 Failure Management 8.3 Short Circuit Figure 17 shows short circuit types on the HS CAN bus. The CANH and CANL pins are short circuit proof to GND and to supply voltage. A current limiting circuit protects the transceiver from damage. If the device heats up due to a permanent short at CANH or CANL, then the overtemperature protection switches off the transmitter. Depending on the type of short circuit on CANH and CANL, communication might be still possible. If only CANL is shorted to GND or only CANH is shorted to VBAT, then dominant and recessive states may be recognized by the receiver. Timings and/or differential output voltages might be not valid according to ISO11898 but still in the range for the receiver working properly. Case 1 VBAT Case 3 VCC CANH Case 5 Case 2 VBAT Case 4 Case 7 VCC CANL Case 6 Figure 17 HS CAN Bus Short Circuit Types Communication on the HS CAN bus is blocked in the following cases: • CANH and CANL shorted (Case7) • CANH shorted to GND (Case 5) • CANL shorted to VBAT (Case 2) or VCC (Case 4) If a short circuit occurs, then the VCC supply current for the transceiver can increase significantly. It is recommended to dimension the voltage regulator for the worst case, especially when VCC also supplies the microcontroller. VCC supply current only increases in dominant state. The recessive current remains almost unchanged. CANH shorted to GND The datasheet specifies a maximum short circuit current of 100mA. When transmitting a dominant state to the bus, 5V is shorted to GND through the transmitter output stage. Power dissipation with 10% duty cycle (DCD) is: P = DCD x U x I = 0.1 x 5V x 100mA = 0.05W. The average fault current with worst case parameters and assuming a realistic duty cycle of 10% is: ICC,Fault = ICC,rec x 0.9 + I CANH,SC x 0.1 = 13.6mA. CANL shorted to VBAT If CANL is shorted to VBAT, then the current through the CANL output stage is even higher and the device heats up faster. The datasheet specifies a maximum short circuit current of 100mA. When transmitting a dominant state to the bus, VBAT is shorted to GND through the transmitter output stage. Assuming a realistic duty cycle of 10% for this case and the power dissipation is: P = DCD x U x I = 0.1 x VBAT x 100mA = 0.1 x 18V x 100mA = 0.18W. CANH shorted to VBAT Short circuit of CANH to VBAT can result in a permanent dominant state on the HS CAN bus, due to the voltage drop at the termination resistor. Therefore the termination resistor has to be chosen accordingly. If a short Application Note 21 Rev. 1.1 2016-05-03 Application Note Z8F54978222 Failure Management circuit of CANH to VBAT occurs, then the power loss in the termination resistor must be taken into account. Figure 18 shows the current in case CANH is shorted to VBAT. When transmitting a dominant state to the bus, the current flows through the termination resistor an CANL to GND. Power loss in the termination resistor and CANL assuming a battery voltage of 18 V and a duty cycle of 10% is: PLoss_Termination = 0.1 x (RTermination x ICANL,SC)x ICANL,SC= (60Ω x 100mA) x 100mA = 0.6W PLoss_CANL = 0.1 x (VBAT - (RTermination x ICANL,SC)) x ICANL,SC)= 0.1 x (18V-6V) x 100mA = 0.1 x 12V x 100mA = 0.12W CANH shorted to VBAT CANH CANH ICANL_SC CAN Transceiver CAN Transceiver 60Ω CANL CANL Figure 18 Current Flowing in Case of a Short Circuit CANH to VBAT 8.4 TLE7250V Junction Temperature In Normal-operating mode highest power dissipation occurs with 50% duty cycle (D) at an ambient temperature of 150 °C: PNM,MAX = D × (ICC_R × VCC,max) + D × (ICC_D x VCC,max) + (IO × VIO,max) = = 0.5 × (4 mA × 5.5 V) + 0.5 x (60 mA × 5.5 V) + (1.5 mA × 5.5 V) = 184.25 mW. Junction temperature increases due to power dissipation and depending on the package. However, typical conditions are more like this: ambient temperature is below 150 °C, overall duty cycle is less than 50%, and supply voltages VCC and VIO have their typical values instead of maximum values. Power dissipation is much lower for such typical conditions: PNM,AVG = D × (ICC_R,Typ × VCC,AVG) + D × (ICC_D,Typ x VCC,AVG) + (IO,Typ × VIO,AVG) = = 0.9 × (2 mA × 5 V) + 0.1 x (38 mA × 5 V) + (1 mA × 3.3 V) = 23.3 mW. Table 4 Increase of Junction Temperature ∆Tj Package Rthja ∆Tj Conditions PG-DSO-8 120 K/W 22.1 K PG-TSON-8 65 K/W 12 K PNM,MAX = 184.25 mW; Tamb = 150 °C; 50% duty cycle; VCC = VCC,max; VIO = VIO,max PG-DSO-8 120 K/W 2.8 K PG-TSON-8 65 K/W 1.5 K PG-DSO-8 120 K/W 6K PG-TSON-8 65 K/W 3.25K PG-DSO-8 120 K/W 21.62K PG-TSON-8 65 K/W 11.72K Application Note 22 PNM,AVG = 23.3 mW; Tamb = 80 °C; 10% duty cycle; VCC = VCC,typ; VIO = VIO,typ Short Circuit CANH to GND 10% duty cycle; Short Circuit CANL to VBAT 10% duty cycle; Rev. 1.1 2016-05-03 Application Note Z8F54978222 Failure Management If a short circuit occurs, then the TLE7250V heats up. The higher the duty cycle, the higher the power dissipation and thermal shutdown can occur due to high temperature. The receiver is still enabled with only the transmitter disabled. The behavior is identical to Receive-only mode. Application Note 23 Rev. 1.1 2016-05-03 Application Note Z8F54978222 Terms and Abbreviations Table 5 Terms and Abbreviations CMC Common mode choke EMC Electromagnetic compatibility EME Electromagnetic emission EMI Electromagnetic interference EOS Electrical overstress ESD Electrostatic discharge ESR Equivalent Series Resistance “high” logical high “low” logical low Application Note 24 Rev. 1.1 2016-05-03 Application Note Z8F54978222 Revision History 9 Revision History Revision Date Changes 1.1 2016-05-03 TxD Dominant time-out detection updated Figure 16; 1.0 2016-01-25 Application Note created Application Note 25 Rev. 1.1 2016-05-03 Please read the Important Notice and Warnings at the end of this document Trademarks of Infineon Technologies AG µHVIC™, µIPM™, µPFC™, AU-ConvertIR™, AURIX™, C166™, CanPAK™, CIPOS™, CIPURSE™, CoolDP™, CoolGaN™, COOLiR™, CoolMOS™, CoolSET™, CoolSiC™, DAVE™, DI-POL™, DirectFET™, DrBlade™, EasyPIM™, EconoBRIDGE™, EconoDUAL™, EconoPACK™, EconoPIM™, EiceDRIVER™, eupec™, FCOS™, GaNpowIR™, HEXFET™, HITFET™, HybridPACK™, iMOTION™, IRAM™, ISOFACE™, IsoPACK™, LEDrivIR™, LITIX™, MIPAQ™, ModSTACK™, my-d™, NovalithIC™, OPTIGA™, OptiMOS™, ORIGA™, PowIRaudio™, PowIRStage™, PrimePACK™, PrimeSTACK™, PROFET™, PRO-SIL™, RASIC™, REAL3™, SmartLEWIS™, SOLID FLASH™, SPOC™, StrongIRFET™, SupIRBuck™, TEMPFET™, TRENCHSTOP™, TriCore™, UHVIC™, XHP™, XMC™. Trademarks updated November 2015 Other Trademarks All referenced product or service names and trademarks are the property of their respective owners. Edition 2016-05-03 Published by Infineon Technologies AG 81726 Munich, Germany © 2006 Infineon Technologies AG. All Rights Reserved. Do you have a question about any aspect of this document? Email: [email protected] Document reference Z8F54978222 IMPORTANT NOTICE The information contained in this application note is given as a hint for the implementation of the product only and shall in no event be regarded as a description or warranty of a certain functionality, condition or quality of the product. Before implementation of the product, the recipient of this application note must verify any function and other technical information given herein in the real application. 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