AN00093 TJA1020 LIN transceiver Rev. 02 — 16 September 2005 Application note Document information Info Content Keywords TJA1020, Local Interconnect Network (LIN), Transceiver, Physical Layer, ISO 9141 Abstract The TJA1020 is a low power LIN transceiver for the use in automotive and industrial applications. It supports the single wire bus signal representation being described in the LIN protocol specification for in-vehicle Class-A buses with a single master node and a set of slave nodes. Local Interconnect Network (LIN) is a serial bus protocol being primarily intended for transmission of control related data between a number of bus nodes. This application note provides information how to use the TJA1020 in LIN applications. AN00093 Philips Semiconductors TJA1020 LIN transceiver Revision history Rev Date Description 02 20050916 Section 2.5, Section 4.4, Section 5.1 and Section 6 added Section 3.2.1 updated Figure 5, Figure 6 and Figure 32 updated 01 20020128 Preliminary Application Note Contact information For additional information, please visit: http://www.semiconductors.philips.com For sales office addresses, please send an email to: [email protected] AN00093_2 Application note © Koninklijke Philips Electronics N.V. 2005. All rights reserved. Rev. 02 — 16 September 2005 2 of 44 AN00093 Philips Semiconductors TJA1020 LIN transceiver 1. Introduction The Local Interconnect Network (LIN) is a low speed (max. 20 kBaud) class-A, serial bus protocol. A LIN sub-bus is primarily intended for modules like seat, door, roof, switch panel, steering wheel, etc. Its task is to connect switches, actuators and sensors into a sub-bus that links to the main bus e.g. a CAN bus. master control unit LIN bus slave control unit 1 slave control unit 2 slave control unit n Fig 1. Single-master / multiple-slave concept The LIN protocol (Ref. 2) is based on the UART/SCI serial data link format using 8N1-coded byte fields. A LIN network consists of one master node and one or more slave nodes; the medium access is controlled by the master node. Such a single-master/multiple-slave concept is shown in Figure 1. V driver node V receiver node VBAT VBAT recessive recessive 80% 60% 40% 20% dominant dominant t t Fig 2. Voltage levels on the LIN bus line The LIN physical layer has been derived from the ISO 9141 (Ref. 3) standard but has some enhancements to meet the particular operation requirements in automotive environments such as EMC, ESD, etc. The LIN bus is a single-wire, wired AND bus with a 12 V-battery related recessive level. The voltage levels on the LIN bus line are shown in Figure 2. AN00093_2 Application note © Koninklijke Philips Electronics N.V. 2005. All rights reserved. Rev. 02 — 16 September 2005 3 of 44 AN00093 Philips Semiconductors TJA1020 LIN transceiver e.g. H-Bridge µC ECU Voltage Regulator SCI/ 3.3V/5V UART TJA1020 LIN bus line Fig 3. Typical LIN ECU This report describes the technical implementation of the TJA1020 (Ref. 1) as Physical Medium Attachment within LIN. Its focus is to provide application hints / recommendations for the design of LIN electronic control units (ECUs) using the LIN transceiver TJA1020 from Philips Semiconductors (see Figure 3). AN00093_2 Application note © Koninklijke Philips Electronics N.V. 2005. All rights reserved. Rev. 02 — 16 September 2005 4 of 44 AN00093 Philips Semiconductors TJA1020 LIN transceiver 2. General description The transceiver TJA1020 represents the Physical Medium Attachment, interfacing the LIN master/slave protocol controller to the LIN transmission medium. The transmit data stream of the protocol controller at the TXD input is converted by the LIN transceiver into a bus signal with controlled slew rate and wave shaping to minimize ElectroMagnetic Emission (EME). The receiver of the TJA1020 detects the data stream on the LIN bus line and transmits it via the RXD pin to the protocol controller. The transceiver provides low-power management (see Section 2.3), consumes nearly no current in Sleep mode (see Section 9.1) and minimizes the power consumption in failure modes (see Section 9.2). The TJA1020 transceiver is optimized for the maximum specified LIN transmission speed of 20 kBaud and is recommended for networks including up to 16 nodes (Ref. 2). The pinning of the TJA1020 is chosen to be compatible to standard K-Line transceivers. 2.1 Features The main features of the TJA1020 are: • • • • • • • • • • • • • • Baud rate up to 20 kBaud Very low ElectroMagnetic Emission (EME) due to output wave shaping Very high ElectroMagnetic Immunity (EMI) Low-slope mode for low speed applications (< 10 kBaud) to reduce EME even further Very low current consumption in Sleep mode Battery discharge protection in case of LIN to GND short-circuit Transmit data (TXD) dominant time-out function Wide battery supply operation range, up to jump start conditions (27 V) Control input and output levels compatible with devices supplied out of 3 V up to 5 V Integrated termination resistor for LIN slave applications Local and remote wake-up in Sleep mode Recognition of the wake-up source (local or remote) Fail-safe behavior in case of unpowered conditions, no reverse current paths Bus terminal protected against short-circuits and transients in the automotive environment • Direct battery operation with protection against load dump, jump start and transients • No 5 V supply required • Thermally protected AN00093_2 Application note © Koninklijke Philips Electronics N.V. 2005. All rights reserved. Rev. 02 — 16 September 2005 5 of 44 AN00093 Philips Semiconductors TJA1020 LIN transceiver 2.2 Block diagram BAT IIL(NWAKE) *NWAKE Wake Timer **NSLP Sleep/Norm Timer INH RSLP RSLAVE CONTROL IIL(LIN) Temp. Protect. TxD Time-out Timer Transmitter RTXD TXD LIN BUS Timer GND RXD RXD/ INT Filter Receiver *NWAKE = WAKE **NSLP = SLP Fig 4. Block diagram of the TJA1020 2.3 Operating modes The TJA1020 provides four operating modes: Normal-slope mode, Low-slope mode, Standby mode and Sleep mode. The operating modes are shown in Table 1 and Figure 5. Table 1: Operating modes Mode NSLP TXD RXD INH Trans- RSLAVE mitter Remarks Sleep 0 weak pull-down floating floating off current source see Section 2.3.1 Standby 0 weak pull-down if remote wake-up; low strong pull-down if local wake-up high (VBAT) off 30 kΩ see Section 2.3.2 Low-slope 1 weak pull-down high: recessive state; high low: dominant state (VBAT) on 30 kΩ see Section 2.3.4 Normalslope weak pull-down high: recessive state; high low: dominant state (VBAT) on 30 kΩ see Section 2.3.3 1 AN00093_2 Application note © Koninklijke Philips Electronics N.V. 2005. All rights reserved. Rev. 02 — 16 September 2005 6 of 44 AN00093 Philips Semiconductors TJA1020 LIN transceiver Normal slope INH: high LIN: 30k RXD: receive data output TXD: transmit data input Transmitter: on (TXD = 1) AND (NSLP = 1)2 (TXD = 1) AND (NSLP = 1)2 (NSLP = 0)1 Standby AND (TXD = 1) INH: high ( Remote Wake-up LIN: 30k 3 RXD: low OR Local Wake-up 4 ) TXD: wake source output AND (NSLP = 0) Transmitter: off Sleep INH: floating LIN: current source RXD: floating TXD: weak pull-down Transmitter: off (TXD = 0) AND (NSLP = 0)1 (NSLP = 1)2 AND (TXD = 1) (TXD = 0) AND Power-on (NSLP = 1)2 Low slope INH: high LIN: 30k RXD: receive data output TXD: weak pull-down Transmitter: on (1) t(NSLP=0) > tgotosleep (Ref. 1) (2) t(NSLP=1) > tgotonorm (Ref. 1) (3) LIN becomes dominant for t(LIN=0) > tBUS (Ref. 1) and is followed by an edge to recessive (4) NWAKE becomes low for t(NWAKE=0) > tNWAKE (Ref. 1) Fig 5. State diagram of the TJA1020 2.3.1 Sleep mode The Sleep mode of the TJA1020 provides the lowest achievable power consumption within LIN ECUs. This is achieved by a very low current dissipation of the transceiver itself and switching off the external voltage regulator through the INH output. During Sleep mode the INH output is floating. Although the power consumption is extremely low, a remote wake-up via LIN and a local wake-up via NWAKE will be recognized and results in a mode change towards Standby mode (see Section 2.3.2). Furthermore the TJA1020 provides direct control of Normal or Low-slope mode via NSLP independently of a previous wake-up event (see Section 2.3.3 AN00093_2 Application note © Koninklijke Philips Electronics N.V. 2005. All rights reserved. Rev. 02 — 16 September 2005 7 of 44 AN00093 Philips Semiconductors TJA1020 LIN transceiver and Section 2.3.4). This is useful for applications where the microcontroller supply is not controlled by the INH output and thus, the microcontroller could activate the transceiver at any time. The TJA1020 is protected against unwanted wake-up events caused by automotive transients or EMI. For this purpose the transceiver provides filters and/or timers at the input of the receiver (LIN), of the local wake-up input (NWAKE) and of the sleep control input (NSLP). Therefore all wake-up events have to maintain for a certain time period (tBUS, tWAKE and tgotonorm). The Sleep mode is entered if a low level at the sleep control input pin NSLP maintains for at least tgotosleep (Ref. 1) (see Figure 6) and no wake-up event (remote or local) happens within this time. This filter time prevents unintended transitions towards Sleep mode caused by EMI. During the mode transition it is recommended to keep TXD on high level to avoid generation of unintended wake-up events on the LIN bus. The activation of the Sleep mode is even possible, if LIN and/or NWAKE are clamped to ground, e.g. caused by a short-circuit to ground. NSLP 1 TXD high low dont care high INH dont care floating V BAT t gotosleep MODE Normal slope / Low slope Sleep 1: recommended use Fig 6. Sleep mode timing During Sleep mode, the internal slave termination resistor RSLAVE between LIN and BAT is disabled; only a weak current source is present. This minimizes the current consumption in case LIN bus is short-circuited to ground. 2.3.2 Standby mode The Standby mode is an intermediate mode that is entered only, if a remote or local wake-up occurs while the TJA1020 is in its Sleep mode. In Standby mode the INH pin outputs a battery related high level and therefore can activate an external voltage regulator. In addition the internal slave termination resistor RSLAVE between LIN and BAT is activated. The TJA1020 signals the Standby mode with a low level at the RXD pin. This can be used as wake-up interrupt request for a microcontroller. Furthermore the wake-up source is signalled by the pull-down condition at the TXD pin. A remote wake-up event results in a AN00093_2 Application note © Koninklijke Philips Electronics N.V. 2005. All rights reserved. Rev. 02 — 16 September 2005 8 of 44 AN00093 Philips Semiconductors TJA1020 LIN transceiver weak pull-down and a local wake-up event results in a strong pull-down at TXD. Depending on the used microcontroller an external pull-up resistor could be necessary (see Section 3.2.2). LIN recessive dominant recessive tBUS INH VBAT floating 1 RXD high low TXD1 high MODE Sleep Standby 1: only if a pull-up reference is present Fig 7. Standby mode timing of remote bus wake-up NWAKE INH VBAT low V floating BAT 1 high low 1 high low RXD TXD t MODE NWAKE Sleep Standby 1: only if a pull-up reference is present Fig 8. Standby mode timing of local wake-up AN00093_2 Application note © Koninklijke Philips Electronics N.V. 2005. All rights reserved. Rev. 02 — 16 September 2005 9 of 44 AN00093 Philips Semiconductors TJA1020 LIN transceiver Figure 7 and Figure 8 show the timing of a remote and local wake-up and their particular outputs at RXD and TXD. A remote wake-up via LIN bus is detected, if the LIN wire becomes continuously dominant for at least tBUS (Ref. 1) followed by an edge to recessive bus level. A falling edge at the NWAKE pin results in a local wake-up if the low level maintains for at least tNWAKE (Ref. 1). 2.3.3 Normal-slope mode The Normal-slope mode is used to transmit and receive data via the LIN bus line. The bus data stream is converted by the receiver into a digital bit stream and output at the RXD to the microcontroller. A high level on the RXD pin represents a recessive level on the LIN bus line and a low level on the RXD pin represents a dominant LIN bus line. The transmitter of the TJA1020 converts the data stream of the microcontroller at the TXD input into a wave shaped LIN bus signal to minimize the EME. A low level TXD input results in a dominant LIN bus level while a high level input results in a recessive bus level. In Normal-slope mode the internal slave termination resistor RSLAVE (Ref. 1) pulls the LIN bus pin high. The INH pin provides a battery related high level to keep an external voltage regulator on. The Normal-slope mode is entered setting NSLP and TXD high for at least tgotonorm,max (Ref. 1). The mode transition is executed when tgotonorm (Ref. 1) is expired. Figure 9 shows the timing of a transition from Sleep or Standby mode to Normal-slope mode. NSLP TXD low high high don't care t gotonorm,min t MODE don't care Sleep / Standby gotonorm,max mode transition Normal slope Fig 9. Normal-slope mode timing 2.3.4 Low-slope mode The Low-slope mode can be used within LIN systems below 10 kBaud and allows a further reduction of the EME compared to the already very low EME of the Normal-slope mode. So the only difference compared to Normal-slope mode is the bus signal transition time. For the Low-slope mode, the transition time is about two times longer than for the Normal-slope mode (see Figure 10). The Low-slope mode can be entered only coming from the Sleep or Standby mode. A direct transition from Normal-slope to Low-slope mode is not possible. AN00093_2 Application note © Koninklijke Philips Electronics N.V. 2005. All rights reserved. Rev. 02 — 16 September 2005 10 of 44 AN00093 Philips Semiconductors TJA1020 LIN transceiver V LIN Low slope mode Normal slope mode t Fig 10. Reduced LIN bus slope in Low-slope mode The Low-slope mode is entered by a low level on the TXD pin in conjunction with a high level on the NSLP pin maintained for at least tgotonorm,max (Ref. 1). The mode transition is executed when tgotonorm (Ref. 1) is expired. The timing of a transition from Sleep or Standby mode to Low-slope mode is shown in Figure 11. NSLP TXD low high low don't care t gotonorm,min t MODE don't care Sleep / Standby gotonorm,max mode transition Low slope Fig 11. Low-slope mode timing 2.4 Compatibility to 3.0 V to 5 V microcontroller devices The TJA1020 is designed to support the increasing demand for lower supply voltages than 5 V within automotive applications. It provides reduced input thresholds at the input pins TXD and NSLP and open drains at the output pins RXD and TXD. So it is compatible to 3.0 V/3.3 V supplied microcontroller as well as to 5 V supplied devices. There is no 5 V tolerant behavior of interface pins between the TJA1020 and the host microcontroller needed and furthermore no extra VCC supply for the transceiver itself required. To achieve a suitable high level at RXD and TXD an external pull-up resistor might be required in case such a pull-up resistor is not part of the microcontroller port pin itself. 2.5 ISO 9141 compatibility The Standard ISO 9141-2 ‘Road Vehicles – Diagnostic Systems – Part 2’ (Ref. 3) specifies the interchange of digital (diagnostic) information between on-board ECUs of road vehicles and a scan/test tool. The appropriate bus is the so-called ‘K-Line Bus’. AN00093_2 Application note © Koninklijke Philips Electronics N.V. 2005. All rights reserved. Rev. 02 — 16 September 2005 11 of 44 AN00093 Philips Semiconductors TJA1020 LIN transceiver Although the LIN physical layer (Ref. 2) has been derived from the ISO 9141 (Ref. 3) standard it has some differences such as shown in Table 2. Table 2: Comparison ISO9141 (K-Line) with LIN Description ISO9141 (Ref. 3) LIN (Ref. 2) Compliance Operating voltage range VB 8 V to 16 V 7.3 V to 18 V √ Receiver high state > 70 % VB > 60 % VB √ Receiver low state < 30 % VB < 40 % VB √ Temperature range 0 °C to 50 °C −40 °C to 125 °C √ Diagnose tester / LIN master < 2 nF - √ ECU / LIN slave < 500 pF < 250 pF Not compliant! But the TJA1020 can be used with the ISO 9141 ECU capacitance load Wiring < 2 nF < 6 nF √ Total < 9.6 nF < 10 nF √ Diagnose tester / LIN master 510 Ω 0.9 kΩ to 1.1 kΩ Not compliant! But the TJA1020 can be used with the ISO 9141 diagnose tester pull-up. ECU / LIN slave > 100 kΩ 20 kΩ to 60 kΩ Not compliant! LIN transceivers are typically implemented with an integrated LIN slave resistor. Transmission rate 10.4 kbit/s 1 kbit/s to 20 kbit/s √ Slew rate / slope time < 10 % TBIT = 9.6 µs 0.5 V/µs to 3 V/µs; 3.5 µs to 22.5 µs Not compliant! The timing of TJA1020 is according to LIN (Ref. 2), which results in better EMC compared to ISO 9141 (Ref. 3). Capacitance Resistance Timings Although the LIN physical layer is not fully compatible to the ISO standard, in practice a LIN transceiver can be used in K-Line networks. Only the number of K-Line nodes could be limited, if LIN transceivers have been applied. In a K-Line bus the overall network load is mainly caused by the diagnose tester (the master in a K-Line bus (Ref. 3)), which is terminated with a pull-up of RTESTER = 510 Ω. But each LIN transceiver with integrated LIN slave resistor RSLAVE, like the TJA1020, will cause a decrease of the K-Line network resistance. The K-Line network resistance reduction can be calculated with following equation: Minimum K-Line network load: R K ( BUS – BAT ),min R SLAVE,min R TESTER,min × --------------------------N = ---------------------------------------------------------------R SLAVE,min R TESTER,min + --------------------------N with AN00093_2 Application note © Koninklijke Philips Electronics N.V. 2005. All rights reserved. Rev. 02 — 16 September 2005 12 of 44 AN00093 Philips Semiconductors TJA1020 LIN transceiver RTESTER = minimum diagnose tester pull-up resistor RSLAVE,min = minimum LIN slave pull-up resistor N = number of transceivers with integrated LIN slave resistor Thus the maximum number of LIN transceivers in a K-Line bus is limited by the strength of the weakest bus driver. The TJA1020 is specified for the minimum network resistance of RL(LIN-BAT) = 500 Ω (Ref. 1). Nevertheless the bus driver of the TJA1020 can drive a lower network resistance. The minimum bus resistance is RL(BUS-BAT),min = 450 Ω, which is derived from the minimum bus driver current limitation IO(SC) (Ref. 1). Though there are some deviations between the LIN and the ISO 9141 specification, the TJA1020 is able to support the K-Line bus from functional point of view. From a formal point of view, no LIN transceiver supports by 100 % the original ISO 9141-2 specification (Ref. 3). AN00093_2 Application note © Koninklijke Philips Electronics N.V. 2005. All rights reserved. Rev. 02 — 16 September 2005 13 of 44 AN00093 Philips Semiconductors TJA1020 LIN transceiver 3. Slave application 3.1 Set-up A slave application of the LIN transceiver TJA1020 is shown in Figure 12. The protocol controller (e.g. microcontroller) is connected to the LIN transceiver via a UART/SCI based interface or standard I/O port pins. The TXD pin of the TJA1020 is the transmit data input and the RXD pin is the receive data output. The sleep control input NSLP of the LIN transceiver can be controlled by a microcontroller port pin. The TJA1020 provides an internal slave termination resistor. Thus for a slave application no extra LIN bus termination resistor is needed. The capacitor CSLAVE in Figure 12 is recommended in order to improve the EME as well as EMI performance of the LIN system (see also Section 4.4). BAT 3.0V CBAT RWAKE1 ... 5V CVDD LIN BUS LINE VBAT MICROCONTROLLER RWAKE2 R* RX VDD R* TX INH RX0 RXD TX0 TXD Px.x NSLP GND NWAKE BAT TJA1020 LIN TRANSCEIVER LIN GND ** CSLAVE * optional ** recommended Fig 12. TJA1020 application example 3.2 Detailed pin description 3.2.1 NSLP pin The sleep control pin NSLP provides an internal pull-down resistor RSLP to support a defined input level in case of open circuit failures. A low level results in the Sleep mode and reduces the power dissipation to a minimum. The range of the input threshold is chosen to support 5 V as well as 3.0 V/3.3 V supplied devices. A typical NSLP pin application is shown in Figure 13. AN00093_2 Application note © Koninklijke Philips Electronics N.V. 2005. All rights reserved. Rev. 02 — 16 September 2005 14 of 44 AN00093 Philips Semiconductors TJA1020 LIN transceiver µC TJA1020 Px.x NSLP V I R SLP Fig 13. Typical NSLP pin application The minimum drive capability of the microcontroller port pin for the NSLP pin can be calculated with the following equation: Min. high level port pin strength at VµC > VIH(SLP),min: V IH ( SLP ),min I HIGH ( µC ), min = ------------------------------ + I IL ( SLP ),max R SLP,min with (Ref. 1) VIH(SLP),min = minimum NSLP HIGH-level input voltage RSLP,min = minimum NSLP pull-down resistor IIL(SLP),max = maximum NSLP LOW-level input current The LIN slope operation modes (see Section 2.3), such as Normal and Low-slope mode, depend on NSLP and TXD. Hence, it is recommended to connect NSLP to a microcontroller port pin. Due to the undefined power-on rise timing between TXD and a VCC source, NSLP connected to a VCC source would result in an undefined LIN slope operation mode. Therefore, it is dissuaded to connect NSLP directly to a VCC supply source. 3.2.2 TXD pin 3.2.2.1 Wake-up source recognition The TXD pin is a bi-directional pin. In Normal-slope and Low-slope mode it is used as transmit data input whereas in Standby mode the wake-up source is signalled. Here an active low output of the TXD pin indicates a local wake-up event on the NWAKE pin. If a local wake-up source at the NWAKE pin is used, a pull-up behavior at pin TXD is required. This pull-up can be achieved in two ways: 1. The microcontroller port pin provides an integrated pull-up RTX(µC) (see Figure 14a) 2. An external pull-up resistor RTX(ext) towards the local VCC is connected (see Figure 14b) In case no local wake-up source is present (NWAKE is unused), no external pull-up resistor is required. Then TXD will never be pulled to a strong low level by the TJA1020. If the local wake-up feature (NWAKE) of the TJA1020 is used, the required pull-up strength of the external pull-up RTX is defined by: 1. The drive capability of the integrated wake-up source transistor pulling TXD to low in case of a local wake-up event and 2. The integrated TXD pull-down resistor RTXD (Ref. 1) of the TJA1020 AN00093_2 Application note © Koninklijke Philips Electronics N.V. 2005. All rights reserved. Rev. 02 — 16 September 2005 15 of 44 AN00093 Philips Semiconductors TJA1020 LIN transceiver The required strength of the microcontroller port pin as well as the value of the pull-up resistor RTX can be calculated by the following equations: Min. high level pull-up current at VTX(µC) > VIH(TXD),min: V IH ( TXD ),min I HIGH ( RTX ),min = ------------------------------- + I IL ( TXD ),max R TXD,min Max. low level pull-up current at VTX(uC) < VIL(TXD),max: V IL ( TXD ),max I LOW ( RTX ),max = -------------------------------I OL ( TXD ),min with VTXD = 0.4 V V TXD Range of pull-up resistor: R TX ,min < R TX < R TX ,max with VCC max – V IL ( TXD ),max VCC min – V IH ( TXD ),min and R TX ,max = --------------------------------------------------------R TX ,min = ---------------------------------------------------------I LOW ( RTX ),max I HIGH ( RTX ),min with (Ref. 1) VIH(TXD),min = minimum TXD HIGH-level input voltage VIL(TXD), max = maximum TXD Low-level input voltage RTXD,min = minimum TXD pull-down resistor IIL(TXD),max = maximum TXD LOW-level input current IOL(TXD),min = minimum TXD LOW-level output current Remark: For LIN the signal symmetry of the falling and rising transition on TXD has an impact on the overall system tolerances. Thus it is recommended to keep the RC-load time constant on the TXD input as small as possible. Example: If the supply voltage of the microcontroller (VCC = VCCmin = VCCmax) is 5 V, then the range of the pull-up resistor RTX is: VCC max – V IL ( TXD ),max = 1.4 kΩ with R TX ,min = ---------------------------------------------------------I LOW ( RTX ),max V IL ( TXD ),max I LOW ( RTX ),max = -------------------------------I OL ( TXD ),min = 3 mA V TXD VCC min – V IH ( TXD ),min R TX ,max = ---------------------------------------------------------- ≈ 140 kΩ with I HIGH ( RTX ),min V IH ( TXD ),min I HIGH ( RTX ),min = ------------------------------- + I IL ( TXD ),max = 21 µA R TXD,min A recommended value for the pull-up resistor RTX is 2.2 kΩ. AN00093_2 Application note © Koninklijke Philips Electronics N.V. 2005. All rights reserved. Rev. 02 — 16 September 2005 16 of 44 AN00093 Philips Semiconductors TJA1020 LIN transceiver µC VCC TJA1020 µC TJA1020 VCC R R TX(ext) TX(uC) TXD TXD VI TX TX VI RTXD RTXD a. for µC with internal programmable pull-up b. for µC without internal pull-up Fig 14. Typical TXD pin application The open drain output as well as the maximum value of the input threshold VIH(TXD) (Ref. 1) are designed to support 3.0 V/3.3 V as well as 5 V microcontroller derivatives. Thus 3.0 V/3.3 V microcontroller derivatives without 5 V tolerant ports can be used for the TJA1020. 3.2.2.2 Open circuit handling The TXD pin provides an internal weak pull-down resistor RTXD (Ref. 1) to ensure a defined input level in case of open circuit failures. Although this TXD input level is dominant, the TXD dominant time-out function prevents the LIN bus from being clamped to a dominant level by disabling the transmitter. Furthermore the weak pull-down allows providing an output level free TXD pin. 3.2.3 RXD pin The receive data output RXD provides an open drain behavior in order to get an output level, which can be adapted to the microcontroller supply voltage. Thus 3.0 V/3.3 V microcontroller derivatives without 5 V tolerant ports can be used. In case the microcontroller port pin does not provide an integrated pull-up, an external pull-up resistor connected to the microcontroller supply voltage VCC is required. In Figure 15 typical RXD applications are shown. µC VCC TJA1020 µC TJA1020 VCC R R RX(ext) RX(uC) RXD RXD RX RX a. for µC with internal programmable pull-up b. for µC without internal pull-up Fig 15. Typical RXD pin application The minimum pull-up resistor RRX,min is defined by the drive capability of the TJA1020’s RXD output pin. The maximum pull-up resistor RRX,max depends on the maximum delay of the rising edge trPropRX caused by the RC-load on RXD: AN00093_2 Application note © Koninklijke Philips Electronics N.V. 2005. All rights reserved. Rev. 02 — 16 September 2005 17 of 44 AN00093 Philips Semiconductors TJA1020 LIN transceiver Range of pull-up resistor: R RX ,min < R RX < R RX ,max with VCC max – V LOW ( RX ),max V RXD R RX ,min = -------------------------------------------------------------- × ------------------------------- , V RXD = 0.4 V and V LOW ( RX ),max I OL ( RXD ),min t rPropRX ,max R RX ,max = --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------, VCC min ( C RX ( ext ),max + C RX ( µC ),max + C RXD,max ) × 1n ------------------------------------------------------------- VCC min – V HIGH ( RX ),min VCC min – V HIGH ( RX ),min where R RX ,max ≤ -------------------------------------------------------------- , t rPropRX ,max = 3 µs and C RXD,max = 5 pF I LH ( RXD ),max with ILH(RXD),max = maximum RXD HIGH-level leakage current (Ref. 1) IOL(RXD),min = minimum RXD LOW-level output current (Ref. 1) VHIGH(RX),min = minimum µC port pin (RX) HIGH-level input voltage VLOW(RX),max = maximum µC port pin (RX) LOW-level input voltage CRX(µC),max = maximum µC port pin (RX) capacitance CRX(ext), max = maximum external capacitance Remark: For LIN the signal symmetry of the falling and rising transition on RXD has an impact on the overall system tolerances. Thus it is recommended to keep the RC-load time constant on the RXD output as small as possible, but due to the driver strength of the RXD output the pull-up resistor RRX should not be below 1 kΩ. Example: If the supply voltage of the microcontroller (VCC = VCCmin = VCCmax) is 5 V, the microcontroller port input threshold voltage range is from VLOW(RX),max = 0.8 V to VHIGH(RX),min = 2 V and the microcontroller port capacitance is CRX,max = CRX(µC),max + CRX(ext),max = 15 pF, then the range of the pull-up resistor RRX is: VCC max – V LOW ( RX ),max V RXD R RX ,min = -------------------------------------------------------------- × ------------------------------- = 1.4 kΩ V LOW ( RX ),max I OL ( RXD ),min t rPropRX ,max R RX ,max = --------------------------------------------------------------------------------------------------------------------------------------- ≈ 290 kΩ VCC min ( C RX ,max + C RXD,max ) × ln -------------------------------------------------------------- VCC min – V HIGH ( RX ),min VCC min – V HIGH ( RX ),min R RX ,max = 290 kΩ ≤ -------------------------------------------------------------- ≈ 600 kΩ I LH ( RXD ),max A recommended value for the pull-up resistor RRX is 2.2 kΩ in order to keep the RC-load time constant low at the RXD pin. 3.2.4 NWAKE pin The local wake-up input NWAKE is used to detect local wake-up events using a falling edge. This falling edge has to be followed by a continuous low level of at least tNWAKE in order to successfully pass the integrated EMI filter. The NWAKE pin provides an internal weak pull-up current source IIL(NWAKE) (Ref. 1) towards battery, which defines a high pin level in case of open circuit failures. It is recommended to connect an external pull-up resistor RWAKE1 to provide sufficient current for an external wake-up switch or transistor. In AN00093_2 Application note © Koninklijke Philips Electronics N.V. 2005. All rights reserved. Rev. 02 — 16 September 2005 18 of 44 AN00093 Philips Semiconductors TJA1020 LIN transceiver case the wake-up source (switch or transistor) at NWAKE has a different ground path than the TJA1020, it is recommended to add a series resistor RWAKE2 between the NWAKE pin and the wake-up source. If the ECU has lost its ground while the wake-up source is still connected to ground, the series resistor RWAKE2 protects the ECU against a reverse current supply through the internal protection diodes of NWAKE. Figure 16a shows a typical NWAKE pin application for local wake-up via external switch. The pull-up resistor RWAKE1 depends only on the required current of the wake-up source (switch or transistor), whereas the series resistor RWAKE2 is mainly defined by the applications ground shift between the ECU and the external wake-up source. The following equations show how to calculate the recommended series resistor: Range of series resistor: V BAT ,max R wake2,min < R WAKE2 < R WAKE 2,max with R WAKE 2,min = --------------------------- and I NWAKE,min V IL ( NWAKE ),max – V GND – shift with e.g. V GND – shift = 1.5 V R WAKE2,max = ---------------------------------------------------------------------------I IL ( NWAKE ),min with (Ref. 1) VIL(NWAKE),max = maximum NWAKE LOW-level input voltage IIL(NWAKE),min = minimum NWAKE pull-up current INWAKE,min = minimum NWAKE output current (limiting value) Example: For a maximum ground-shift of VGND-shift = 1.5 V and a battery voltage range of VBAT = 5 V to 27 V is the range of RWAKE2: V BAT ,max R WAKE2,min = --------------------------- = 1.8 kΩ I NWAKE,min V IL ( NWAKE ),max – V GND – shift R WAKE2,max = ---------------------------------------------------------------------------- ≈ 6.6 kΩ I IL ( NWAKE ),min Therefore a typical value for the series resistor RWAKE2 is 3 kΩ. If no local wake-up is required for the application the NWAKE pin can be left open, due to the internal pull-up and filter behavior. Nevertheless it is recommended to connect the NWAKE pin directly to the BAT pin (see Figure 16b), if not used. TJA1020 BAT VBAT RWAKE1 VBAT IIL RWAKE2 NWAKE TJA1020 BAT IIL VI a. for local wake-up via external switch NWAKE VI b. for applications without local wake-up Fig 16. Typical NWAKE pin application AN00093_2 Application note © Koninklijke Philips Electronics N.V. 2005. All rights reserved. Rev. 02 — 16 September 2005 19 of 44 AN00093 Philips Semiconductors TJA1020 LIN transceiver The TJA1020 provides also hardware compatibility to other LIN transceiver implementations, which have a VCC supply input instead of a local wake-up input at pin 3. Therefore the wake-up threshold of the NWAKE input is defined to be above 5 V. Thus this pin can be connected to the applications VCC supply without forcing a wake-up event in case VCC drops down (e.g. system Sleep mode). Nevertheless this would cause a small extra current consumption IIL(NWAKE) (Ref. 1) (internal weak current source) of the system. 3.2.4.1 Wake-up after power-on After power-on the TJA1020 enters directly the Sleep mode keeping INH on floating condition and thus the supply of the LIN node disabled. This behavior reduces the total power-on peak current of a LIN sub-system. Nevertheless in some applications a LIN node needs to be waked up autonomously after powering-up. This can be achieved with a RC-combination on NWAKE (see Figure 17b). During power-on such an RC-combination can generate a local wake-up by keeping the NWAKE input voltage VNWAKE below VIL(NWAKE),max (Ref. 1) for at least tNWAKE,max (Ref. 1). The circuit in Figure 17a provides a solution for both, a local wake-up via external switch and an autonomous wake-up after power-on. For the calculation of RWAKE1 and RWAKE2 see Section 3.2.4. IIL RWAKE2 VI IIL NWAKE VI CWAKE CWAKE NWAKE TJA1020 BAT VBAT RWAKE RWAKE1 TJA1020 BAT VBAT a. for local wake-up via external switch b. for applications without local wake-up Fig 17. Typical NWAKE pin application to wake-up after power-on Figure 18 shows the relation between the battery voltage VBAT and the resulting NWAKE voltage VNWAKE during power-on, and it shows its constraints to wake-up the TJA1020. The RC-combination can be calculated by the following rule: RC time constant to wake-up after power-on: R WAKE × C WAKE = t BAT – ON ,max > 2t NWAKE,max with tNWAKE,max = maximum dominant time to wake-up via NWAKE (Ref. 1) tBAT-ON,max = maximum power-on ramp-up time of VBAT Example: Assuming the maximum power-on ramp-up time tBAT-ON,max is 1 ms and the pull-up resistor RWAKE should be 10 kΩ, then CWAKE is: t BAT – ON ,max C WAKE = ------------------------------- = 100 nF with t BAT – ON ,max = 1 ms > 2t NWAKE,max = 100 µs R WAKE AN00093_2 Application note © Koninklijke Philips Electronics N.V. 2005. All rights reserved. Rev. 02 — 16 September 2005 20 of 44 AN00093 Philips Semiconductors TJA1020 LIN transceiver V W N V W N E K A < ax ,m E) K A V I L( VBAT VNWAKE V IL(NWAKE),max t t BAT-ON,max t @(VNWAKE < VIL(NWAKE),max) > tNWAKE,max tNWAKE,max tNWAKE,min Sleep mode transion Standby Fig 18. Timing to wake-up after power-on 3.2.5 INH pin 3.2.5.1 INH controlled voltage regulator The output pin INH is a battery related open drain output to control an external voltage regulator. Therefore an external pull-down resistor RINH connected to ground is necessary. This pull-down is typically integrated within the voltage regulator itself. A typical INH pin application is shown in Figure 19a. Voltage Regulator V INPUT VBAT TJA1020 BAT Voltage Regulator VBAT TJA1020 BAT VINPUT INH INH INH RINH a. for voltage regulators with inhibit input b. for voltage regulators without inhibit input Fig 19. Typical INH pin application AN00093_2 Application note © Koninklijke Philips Electronics N.V. 2005. All rights reserved. Rev. 02 — 16 September 2005 21 of 44 AN00093 Philips Semiconductors TJA1020 LIN transceiver The range of the pull-down resistor RINH can be calculated with the equations below: Range of pull-down resistor: V BAT ,max R INH ,min < R INH < R INH ,max with R INH ,min = ---------------------- for IINH,max see Section 3.2.5.2. I INH ,max V LOW ( VoltReg ),max R INH ,max = -------------------------------------------I LH ( INH ),max with ILH(INH),max = maximum INH HIGH-level leakage current (Ref. 1) VLOW(VoltReg),max = maximum inhibit LOW-level input voltage (volt regulator) 3.2.5.2 Direct voltage regulator supply Due to the INH drive capability, the TJA1020 is able to supply a voltage regulator directly. Figure 19b shows the typical INH pin application of such a slave application. The maximum supply current through the INH pin IINH,max for the voltage regulator and the maximum voltage drop VDROP can be calculated by the equations below: Max. voltage regulator supply current through INH: I INH ,max = P max – P Q,max – P TX ,max ------------------------------------------------------------- with I INH ,max ≤ 50 mA R SW ( INH ),max T vj,max – T amb,max P max = --------------------------------------------R th ( j – a ) Max. voltage drop at INH: V DROP = R SW ( INH ),max × I INH ,max with PQ,max = maximum quiescence power dissipation (Normal-slope mode, bus recessive, VINH = VBAT), see Figure 20 PTX,max = maximum transmitter power dissipation (Normal-slope mode, transmission duty cycle = 50 %, VINH = VBAT), see Figure 20 RSW(INH),max = maximum switch-on resistance between BAT and INH (Ref. 1) and Tvj,max = maximum virtual junction temperature (K) (Ref. 1) Tamb,max = maximum ambient temperature (K) Rth(j-a) = thermal resistance (K/W) (Ref. 1) Remark: Independently from the above calculation the current through the INH pin IINH should not exceed 50 mA. The power dissipation depends on the supply voltage VBAT and the baud rate. Figure 20 shows the quiescence power dissipation PQ and the transmitter power dissipation PTX of the TJA1020 as the function of the supply voltage VBAT. A worst case duty cycle of 50 % and a worst case LIN bus load (RL = 500 Ω, CL = 10 nF) are used for the transmitter power dissipation PTX in Figure 20. AN00093_2 Application note © Koninklijke Philips Electronics N.V. 2005. All rights reserved. Rev. 02 — 16 September 2005 22 of 44 AN00093 Philips Semiconductors TJA1020 LIN transceiver The thermal resistance Rth(j-a) (Ref. 1) is the ability of an IC package to conduct heat to its environment and is typically specified for free air conditions. Within real applications the use of large copper planes attached to pin GND can reduce the thermal resistance and therefore increase the maximum INH current IINH,max. P [mW] 140 PTX,max @ 20kBaud 120 100 PTX,max @ 10kBaud 80 PTX,max @ 5kBaud 60 PQ,max 40 20 0 5 10 15 20 25 30 VBAT [V] Fig 20. Power dissipation in Normal-slope mode 3.2.6 LIN pin The pin LIN is used to transmit and receive data on the LIN bus line. A low side switch with controlled wave shaping is used for bit transmission while an integrated receive comparator (receiver) converts the LIN bus voltage back to a binary signal. The threshold of the receiver Vth(rx) (Ref. 1) is battery related and has a hysteresis of Vthr(hys) (Ref. 1). The LIN pin has a weak pull-up current source of IIL(LIN) (Ref. 1) and a slave termination resistor of RSLAVE (Ref. 1) in parallel to BAT. The slave termination resistor and the current source as well as the low side switch are implemented with a reverse current diode (see also Figure 21). Thus no external components are required. Nevertheless, improvement of EME and EMI can be achieved by applying a capacitive load at the LIN bus line as shown in Figure 12. The current source of IIL(LIN) (Ref. 1) is used as an additional weak pull-up, because the slave termination resistor RSLAVE (Ref. 1) is switched off in Sleep mode. Thus a transition into the Sleep mode minimizes the current consumption in case of LIN short-circuit to ground (see Section 9.2). AN00093_2 Application note © Koninklijke Philips Electronics N.V. 2005. All rights reserved. Rev. 02 — 16 September 2005 23 of 44 AN00093 Philips Semiconductors TJA1020 LIN transceiver 4. Master application A master application differs from a slave application mainly with respect to the external master termination resistor RMASTER (Ref. 2). The capacitance load CMASTER (Ref. 2) is recommended in order to improve EME as well as EMI (see also Section 4.4). The TJA1020 provides several master application solutions, which are described in Section 4.1 to Section 4.4. 4.1 Master termination directly to BAT This master application is realized by a reverse current diode in series with the resistor RMASTER (Ref. 2) connected between LIN and BAT as shown in Figure 21. Such a master application solution does not provide fail-safe system behavior in case the LIN bus is erroneously shorted to ground. This short-circuit current cannot be switched off, and will discharge the battery continuously. LIN RSLAVE RMASTER IIL CMASTER * LIN BUS LINE TJA1020 BAT VBAT Filter Vthr *recommended Fig 21. Typical master termination 4.2 Master termination towards INH For fail-safe reasons the TJA1020 supports an advanced master application solution using the INH pin to drive the master termination resistor RMASTER (Ref. 2). As shown in Figure 22 the master termination resistor in series with a reverse current diode is connected to the INH pin instead of the BAT pin. The advantage of this application solution is the ability to switch off the master termination by a transition into the Sleep mode, thus solving the above mentioned short-circuit condition of LIN and ground. Whenever the applications microcontroller detects a permanent dominant level on the LIN bus line caused by a ground short-circuit, the microcontroller is able to minimize the power dissipation by selecting the Sleep mode. Thus a transition into the Sleep mode switches off the external voltage regulator, the master termination RMASTER (Ref. 2) as well as the internal slave termination RSLAVE (Ref. 1). Only the internal weak pull-up current source IIL(LIN) (Ref. 1) and the internal current consumption of the TJA1020 determine the remaining current consumption of a LIN node in such a failure case (see also Section 9.2). AN00093_2 Application note © Koninklijke Philips Electronics N.V. 2005. All rights reserved. Rev. 02 — 16 September 2005 24 of 44 AN00093 Philips Semiconductors TJA1020 LIN transceiver VBAT Voltage Regulator BAT TJA1020 INH RSLAVE IIL LIN Vthr Filter CMASTER* LIN BUS LINE RMASTER INH *recommended Fig 22. Advanced master termination through the INH pin 4.3 Master termination split between INH and BAT Since the advanced master termination in Section 4.2 provides a fail-safe system behavior but high LIN bus impedance in Sleep mode, a combination of the terminations concepts in Section 4.1 and Section 4.2 can be an option, if a higher short-circuit current at the LIN bus can be tolerated (see Figure 23). BAT VBAT Voltage Regulator TJA1020 INH IIL CMASTER* LIN RSLAVE RMASTER-INH RMASTER-BAT LIN BUS LINE INH Filter Vthr *recommended Fig 23. Trimmed master termination The resistors RMASTER-BAT and RMASTER-INH in parallel determine the master termination while the TJA1020 is in its modes: Standby, Normal-slope and Low-slope. In Sleep mode the master termination is determined by RMASTER-BAT. Therefore the maximum LIN bus short-circuit current ISC,max can be trimmed by RMASTER-BAT: AN00093_2 Application note © Koninklijke Philips Electronics N.V. 2005. All rights reserved. Rev. 02 — 16 September 2005 25 of 44 AN00093 Philips Semiconductors TJA1020 LIN transceiver V BAT ,max R MASTER – BAT = ---------------------I SC ,max R MASTER – BAT × R MASTER R MASTER – INH = ---------------------------------------------------------------with R MASTER = 1 kΩ R MASTER – BAT – R MASTER 4.4 Master termination for LIN networks with different supplied LIN nodes In mixed-supplied LIN networks, where the supply of some slave nodes are ignition key controlled (clamp 15) while others are permanently connected to battery (clamp 30), unsupplied slave nodes (ignition key off) represent pull-down loads on the LIN bus. Thus it is recommended to apply the trimmed master termination (see Figure 23). With the trimmed master termination the pull-up during Sleep mode RMASTER-BAT can be adapted to the pull-down behavior of unsupplied slaves. For the LIN bus an unsupplied TJA1020 represents in worst case a pull-down load of a diode with a forward biased voltage of VDS = 2 V in series with a high-impedance resistor of RS = 300 kΩ. Figure 24 shows an example of a mixed-supplied network with two unsupplied slave nodes with TJA1020 transceiver applied. BAT Unsupplied TJA1020 VBattery TJA1020 LIN VDS RS TJA1020 IIL RSLAVE INH RMASTER-INH BAT Unsupplied VDM BAT LIN CMASTER* Unsupplied Slave Node RMASTER-BAT RS VDP LIN BUS LINE VDS SLAVE NODE POWER LINE LIN Master Node *recommended Unsupplied Slave Node Fig 24. Different supplied slave nodes (simplified transceiver circuitry) The maximum master termination resistor RMASTER-BAT can be calculated with the following equation: AN00093_2 Application note © Koninklijke Philips Electronics N.V. 2005. All rights reserved. Rev. 02 — 16 September 2005 26 of 44 AN00093 Philips Semiconductors TJA1020 LIN transceiver ( V Battery – V DP – V DM – V LIN ,rec ) × R S 1 R MASTER – BAT ≤ min -------------------------------------------------------------------------------------------------- × ---- , where V DS = 2 V N V LIN ,rec – V DS + R S × I LEAK and R S = 300 kΩ with VDP = forward biased voltage of protection diode VDM = forward biased voltage of reverse current master diode VLIN,rec = recessive LIN bus voltage ILEAK = leakage current from LIN bus to ground (e.g. plug leakage current) N = number of unsupplied slaves nodes Example: In a mixed-supplied LIN network with 2 unsupplied TJA1020 connected to the LIN bus it is assumed that both diodes, the protection diode as well as the reverse current diode, have a forward biased voltage of VDP = VDM = 1 V, and the recessive LIN bus voltage VLIN,rec shall remain above 0.75 VBAT (VBAT = VBattery − VDP). A LIN bus leakage current to ground of ILEAK ≤ 10 µA per unsupplied node is expected. Then for the battery voltage range of VBattery = 8 V to 18 V the maximum master termination resistor is: ( V Battery – V DP – V DM – V LIN ,rec ) × R S 1 R MASTER – BAT ≤ min -------------------------------------------------------------------------------------------------- × ---- = 18 kΩ N V LIN ,rec – V DS + R S × I LEAK AN00093_2 Application note © Koninklijke Philips Electronics N.V. 2005. All rights reserved. Rev. 02 — 16 September 2005 27 of 44 AN00093 Philips Semiconductors TJA1020 LIN transceiver 5. EMC aspects 5.1 EME - network design hints The LIN physical layer is a single-wire, wired AND bus with a battery related recessive level. Here, no compensation effect of the electromagnetic field is present as known from dual-wire concepts making use of differential signals (e.g. high-speed CAN). Thus a smooth output wave shaping becomes more important. The ElectroMagnetic Emission EME depends mainly on the falling and rising slope of the LIN bus waveform. The smoother these slopes are the more EME reduction can be achieved. The TJA1020 provides a slope control adjustment by modifying the capacitive load (CMASTER (Ref. 2) or CSLAVE (Ref. 2)) on the LIN bus. The slope decreases with increasing capacitive load. Therefore increasing the total network capacitance (CBUS = CMASTER + n × CSLAVE + CLINE (Ref. 2)) can further reduce the EME. For very high bit rates close to 20 kBaud the LIN bus slope times have also impacts to system tolerances such as ground shift. Thus the time constant τ of the overall system shall not exceed its specified maximum τmax (Ref. 2). Further it is not recommended to make use of the maximum allowed capacitive load CBUS,max (Ref. 2) at very high bit rates in order to keep some safety margin for the system. V Battery Slave 1 MASTER Master R 1k R R SLAVE SLAVE TJA1020 LINE SLAVE C' C TJA1020 SLAVE C MASTER C TJA1020 R SLAVE Slave N Fig 25. LIN network loads In a LIN network the master resistor RMASTER (Ref. 2) and the slave resistors RSLAVE (Ref. 2) are accurately defined by the LIN standard (Ref. 2). No variation is allowed. Also the specified slave capacitance CSLAVE (Ref. 2) provides almost no room for network optimizations. Only the master capacitor CMASTER (Ref. 2) can be used to tune the LIN bus signal in either way. For EME as well as for EMI a big network capacitance is of advantage. Thus the maximum master capacitance CMASTER,max is of interest. CMASTER,max can be calculated with following equations: AN00093_2 Application note © Koninklijke Philips Electronics N.V. 2005. All rights reserved. Rev. 02 — 16 September 2005 28 of 44 AN00093 Philips Semiconductors TJA1020 LIN transceiver τ max C MASTER,max = ---------------------- – N × C SLAVE – LEN BUS × C′ LINE with R BUS,max R SLAVE ,max R BUS,max = R MASTER,max || ---------------------------N+1 with τmax = maximum time constant of overall LIN network (Ref. 2) RMASTER,max = maximum LIN master termination resistor (Ref. 2) RSLAVE,max = maximum LIN slave termination resistor (Ref. 1) CSLAVE = LIN slave capacitance (Ref. 2) C’LINE = LIN bus line capacitance (Ref. 2) LENBUS = overall bus line length (Ref. 2) N = number of slaves nodes Example: Assuming a 6-node LIN network with a capacitance of 220 pF per slave and an overall network length of 8 m with a line capacitance of 80 pF/m. It results in a maximum master capacitance of R SLAVE ,max R BUS,max = R MASTER,max || ---------------------------- = 965 Ω N+1 τ max C MASTER,max = ---------------------- – N × C SLAVE – LEN BUS × C′ LINE = 3.44 nF R BUS,max In this example a master capacitor of CMASTER = 3.3 nF is recommended. 5.2 EME - Low-slope mode The curve shaping of the LIN bus signal in Normal-slope mode is optimized for the maximum specified LIN transmission speed of 20 kBaud. Thus for low speed LIN applications (e.g. 4.8 kBaud) the curve shaping in Normal-slope mode has unnecessary steep slopes. Therefore the TJA1020 provides the Low-slope mode (see Section 2.3.4) with reduced slopes (see Figure 10). These reduced slopes result in a further reduction of EME. 5.3 EMI - capacitive load A capacitor on the LIN bus pin reduces the impact of RF-interferences. Thus it is recommended to provide a capacitor (e.g. CMASTER/SLAVE = 220 pF) from LIN to ground at each node. AN00093_2 Application note © Koninklijke Philips Electronics N.V. 2005. All rights reserved. Rev. 02 — 16 September 2005 29 of 44 AN00093 Philips Semiconductors TJA1020 LIN transceiver 6. ESD - aspects 6.1 General design hints for ESD levels beyond ±4 kV HBM The on-chip ESD protection of pin LIN of the TJA1020 is designed to withstand Vesd(HBM) = ±4 kV according to the Human Body Model (HBM) JESD22-A114-B (100 pF / 1.5 kΩ). External ESD protection on the LIN bus connection is recommended if the TJA1020 is subjected to ESD-pulses of more than Vesd(HBM) = ±4 kV (Ref. 1) or if another ESD Model (e.g. IEC 61000-4-2 (Ref. 4)) is applied. Figure 26 shows a set-up for such external ESD protection. The clamping voltage VCLAMP of the ESD protection diodes should be chosen above the maximum battery voltage in order not to be damaged, in case the LIN bus line is shorted to the battery line. Furthermore, the positive clamping voltage VCLAMP-POS should be below the maximum LIN bus voltage VLIN,max = 40 V (Ref. 1) and the negative clamping voltage VCLAMP-NEG should be above the minimal LIN bus voltage VLIN,min = −27 V (Ref. 1). According to the LIN Specification Rev. 1.3 (Ref. 2), the LIN slave node capacitance shall be less than CSLAVE,max = 250 pF to ground. Together with the inherent capacitance of an ESD-protection device (e.g. suppressor diode) this requirement (< 250 pF) must be fulfilled. The ferrite LFERRITE between LIN capacitor and the ESD protection diodes serves for minimizing the current of the first ESD peak. The suppressor diodes DPOS and DNEG should be placed as close as possible to the connectors, whereas the LIN node capacitor CMASTER/SLAVE and the ferrite LFERRITE should be placed close to the LIN transceiver’s bus pin. Power Application (e.g. electro motor, inductive loads) ** Application (e.g. voltage regulator + microcontroller) BAT LFERRITE* LIN TJA1020 CMASTER/SLAVE GND DPOS* DNEG* LIN Node Connector CBAT * optional ** recommended Fig 26. External ESD-protection set-up AN00093_2 Application note © Koninklijke Philips Electronics N.V. 2005. All rights reserved. Rev. 02 — 16 September 2005 30 of 44 AN00093 Philips Semiconductors TJA1020 LIN transceiver 6.2 ESD protection example for ESD model according to IEC 61000-4-2 (Ref. 4) The maximum peak current an ESD protection diode has to withstand depends on the maximum ESD voltage and the applied ESD model. Thus, with a capacitor of 150 pF charged to 10 kV and a discharge resistor of 330 Ω a theoretical peak current of 30 A occurs. The discharge time constant will be about 50 ns. Table 3 shows the ESD results achieved with the respective proposed protection elements. The protection is based on the ESD protection diode PESD1LIN (Ref. 5), which is especially designed to fulfill the demands of LIN bus lines. The PESD1LIN contains the two diodes DPOS and DNEG (see Figure 26) in one package. In Table 3 VESD corresponds to the ESD voltage the TJA1020 withstands without being damaged. Table 3: ESD voltage the TJA1020 withstands without being damaged VESD (150 pF / 330 Ω) Applied components CMASTER/SLAVE LFERRITE DPOS - - PESD1LIN (Philips) ±5.0 kV - BLM18BD102SH1 (muRata) PESD1LIN (Philips) ±7.5 kV - MMZ1608Y102B (TDK) PESD1LIN (Philips) ±7.0 kV 220 pF - PESD1LIN (Philips) ±5.5 kV 220 pF BLM18BD102SH1 (muRata) PESD1LIN (Philips) ±7.5 kV 220 pF MMZ1608Y102B (TDK) PESD1LIN (Philips) ±7.0 kV 220 pF MMZ2012Y202B (TDK) PESD1LIN (Philips) ±8.5 kV AN00093_2 Application note DNEG © Koninklijke Philips Electronics N.V. 2005. All rights reserved. Rev. 02 — 16 September 2005 31 of 44 AN00093 Philips Semiconductors TJA1020 LIN transceiver 7. Transceiver control The modes of the TJA1020 are controlled by the pins NSLP and TXD. The following chapters describe the mode control of TJA1020 and how to deal with LIN bus failures. The transceiver control can be split into two basic applications: • The microcontroller power supply is controlled via the INH pin of the TJA1020 • Independent of the TJA1020’s modes the microcontroller is permanently supplied 7.1 INH controlled microcontroller power supply After a local or remote wake-up the Standby mode is entered automatically. As a result the INH pin outputs a battery related high level and thus switches on the external voltage regulator. In consequence the microcontroller becomes supplied and starts with its initialization. The TJA1020 indicates the wake-up event by an active low at RXD. Depending on the use of the NWAKE pin two different software-flows for mode control are recommended: 7.1.1 Applications using NWAKE The TJA1020 allows distinguishing between different wake-up sources using the TXD pin. Thus the TXD pin needs to be applied with a pull-up behavior as described in Section 3.2.2. This pull-up behavior is required to sense the TJA1020’s pull-down transistor at TXD, which becomes active after a local wake-up event via NWAKE. Thus the wake-up source can be distinguished by reading the TJA1020’s TXD pin. To distinguish between Normal-slope mode and Low-slope mode the TJA1020’s TXD pin is used. The Normal-slope mode is entered if TXD carries a high level after NSLP is set high. TXD gets high automatically after a local wake-up event if the corresponding microcontroller port pin is configured to be input (weak high) because the wake-up source information is cleared immediately with setting NSLP to high level. The mode change itself is performed holding NSLP high for at least tgotonorm (Ref. 1) (see also the timing in Figure 9). Remark: There is no software timing constraint required for setting the microcontroller port pin TX to high output after setting NSLP to high, because the local wake-up source information at TXD is cleared immediately with setting NSLP to high level, whereas the mode transition itself executes after tgotonorm (Ref. 1). To enter the Low-slope mode the microcontroller TX port pin is simply set low before the NSLP input pin of the TJA1020 gets a high level. Figure 27 shows the related software flow of a Standby to Normal/Low-slope transition. AN00093_2 Application note © Koninklijke Philips Electronics N.V. 2005. All rights reserved. Rev. 02 — 16 September 2005 32 of 44 AN00093 Philips Semiconductors TJA1020 LIN transceiver Wake-up Event: VCC µC RTX TJA1020 sets INH TJA1020 to HIGH (Standby mode) TXD TX R TXD VCC ramps up Px.x NSLP µC starts RSLP operation Note: High-ohmic pull-up Set TX as The time the TX pin of the microcontroller input behavior for TX Input (see also the note) is program m ed to be input, it behaves high-ohm ic . S o t he ext ernal pull-up behavior is required to pull this pin high in Read TX Input case a remote wake-up has occurred via LIN. Normal slope Read wake-up source Low slope Mode? Executes mode Set Px.x to Set TX to transition via NSLP HIGH output LOW output Prepares TX to enter Low slope mode Prepares TX for Set TX to Set Px.x to Executes mode data transmission HIGH output HIGH output transition via NSLP TJA1020 is in Set TX to Prepares TX for Normal slope HIGH output data transmission mode TJA1020 is in Low slope mode Fig 27. Flow diagram of Standby to Normal/Low-slope transition, using NWAKE 7.1.2 Applications without using NWAKE In case no local wake-up source is present the hardware becomes simpler because the TXD pin of the TJA1020 behaves as input only. Thus the weak pull-up behavior as described in Section 7.1.1 is not required. The software flow is shown within Figure 28. Here the TXD input of the TJA1020 defines the next mode before the NSLP input is set to a high-level. AN00093_2 Application note © Koninklijke Philips Electronics N.V. 2005. All rights reserved. Rev. 02 — 16 September 2005 33 of 44 AN00093 Philips Semiconductors TJA1020 LIN transceiver Wake-up Event: µC TJA1020 sets INH TJA1020 to HIGH (Standby mode) TX TXD RTXD VCC ramps up Px.x NSLP RSLP µC starts operation Normal slope Low slope Mode? Prepares TX to enter Normal slope mode Set TX to Set TX to HIGH output LOW output Prepares TX to enter Low slope Set Px.x to Executes mode HIGH transition via NSLP mode Prepares TX for data Set TX to transmission (only required HIGH output for Low slope mode) TJA1020 is in Normal slope or Low slope mode Fig 28. Flow diagram of Standby to Normal/Low-slope transition, NWAKE not used 7.2 Permanently supplied microcontroller In some applications the TJA1020 is not used to control the power supply of the microcontroller. Thus the INH pin is unused, respectively used for another purpose. For such applications the TJA1020 allows a direct transition from Sleep mode into Normal-slope mode or Low-slope mode. Depending on the use of the NWAKE pin two different software-flows for mode control are recommended: 7.2.1 Application using NWAKE Here the same flow is used as described within Section 7.1.1. The only difference is that no initialization phase is performed, because the microcontroller is already running. Figure 29 shows the related software flow diagram with respect to the pin description of TXD in Section 3.2.2. AN00093_2 Application note © Koninklijke Philips Electronics N.V. 2005. All rights reserved. Rev. 02 — 16 September 2005 34 of 44 AN00093 Philips Semiconductors TJA1020 LIN transceiver TJA1020 is in VCC µC RTX TJA1020 Sleep mode High-ohmic input (TX is set as behavior for TX Input) TXD TX VCC RRX RTXD Read RX Input Read wake-up flag on RXD RXD RX No wake-up event RX LOW? Wake-up event NSLP Px.x Read TX Input RSLP Normal slope Read wake-up source on TXD Low slope Mode? Executes mode Set Px.x to Set TX to transition via NSLP HIGH output LOW output Prepares TX to enter Low slope mode Prepares TX for Set TX to Set Px.x to Executes mode data transmission HIGH output HIGH output transition via NSLP TJA1020 is in Set TX to Prepares TX for Normal slope HIGH output data transmission mode TJA1020 is in Low slope mode Fig 29. Flow diagram of Sleep to Normal/Low-slope transition, using NWAKE 7.2.2 Application without using NWAKE Here the same flow is used as described within Section 7.1.2. The only difference is that no initialization phase is performed, because the microcontroller is already running. The corresponding software flow diagram is shown in Figure 30. AN00093_2 Application note © Koninklijke Philips Electronics N.V. 2005. All rights reserved. Rev. 02 — 16 September 2005 35 of 44 AN00093 Philips Semiconductors TJA1020 LIN transceiver µC TJA1020 TXD TX VCC RRX RTXD RXD RX TJA1020 is in Sleep mode NSLP Px.x RSLP Read RX Input Normal slope Read wake-up flag on RXD Low slope Mode? Prepares TX to enter Normal slope mode Set TX to Set TX to HIGH output LOW output Prepares TX to enter Low slope Set Px.x to Executes mode HIGH transition via NSLP Set TX to HIGH output mode Prepares TX for data transmission (only required for Low slope mode) TJA1020 is in Normal slope or Low slope mode Fig 30. Flow diagram of Sleep to Normal/Low-slope transition, NWAKE not used 7.3 Transition from Normal-slope/Low-slope into Sleep mode The TJA1020 enters its Sleep mode if the NSLP input is becoming low for at least tgotosleep (Ref. 1). Depending on the use of the NWAKE pin two different software-flows for mode control are recommended: 7.3.1 Application using NWAKE If the NWAKE input of the TJA1020 is in use, the microcontroller port pin (e.g. TX) driving the TXD pin of the TJA1020 should be configured as input or bi-directional before the mode transition is executed by setting a low level on NSLP. This provides pull-up behavior at pin TXD in case of wake-up events via NWAKE during mode transition towards Sleep mode. Figure 31 shows the software flow diagram of a transition from Normal-slope mode or Low-slope mode into Sleep mode with NWAKE support. AN00093_2 Application note © Koninklijke Philips Electronics N.V. 2005. All rights reserved. Rev. 02 — 16 September 2005 36 of 44 AN00093 Philips Semiconductors TJA1020 LIN transceiver VCC µC TJA1020 RTX TJA1020 is in Normal slope or Low slope mode TXD TX RTXD VCC Set TX as R RX High-ohmic input Input RXD behavior for TX RX Executes mode Set Px.x to transition towards LOW output Sleep mode via NSLP NSLP Px.x RSLP Read wake-up flag Read RX Input Wake-up event on RXD No wake-up event RX LOW? Restart Software TJA1020 disables external voltage regulator via INH Fig 31. Flow diagram of Normal/Low-slope to Sleep transition, using NWAKE 7.3.2 Application without using NWAKE In case the NWAKE pin is unused and no TXD pull-up behavior is provided (see also Section 3.2.2.1), only the NSLP input should become low (see Figure 32). The ‘Set TX as input’ step within the software flow diagram in Figure 31 should not be performed, since the weak pull-down RTXD (Ref. 1) would cause a low level on TXD if the microcontroller port pin TX is set into a high-impedance state without pull-up behavior. This would result in a dominant level on the LIN bus until NSLP is set low or the TXD dominant time-out phase is passed. Instead it is recommended to set TXD to high level via the microcontroller port pin (e.g. TX). AN00093_2 Application note © Koninklijke Philips Electronics N.V. 2005. All rights reserved. Rev. 02 — 16 September 2005 37 of 44 AN00093 Philips Semiconductors TJA1020 LIN transceiver TJA1020 is in µC TJA1020 Normal slope or Low slope mode TXD TX VCC Set TX to RTXD Stop transmission HIGH output RRX RXD RX Executes mode Set Px.x to transition towards LOW output Sleep mode via NSLP NSLP Px.x RSLP Read wake-up flag Read RX Input Wake-up event on RXD No wake-up event RX LOW? Restart Software TJA1020 disables external voltage regulator via INH Fig 32. Flow diagram of Normal/Low-slope to Sleep transition, NWAKE not used AN00093_2 Application note © Koninklijke Philips Electronics N.V. 2005. All rights reserved. Rev. 02 — 16 September 2005 38 of 44 AN00093 Philips Semiconductors TJA1020 LIN transceiver 8. Failure management 8.1 LIN bus short-circuit to ground In case the LIN bus is shorted to ground a continuous current flows out of VBAT due to the LIN termination. The TJA1020 allows to reduce this short-circuit current to a minimum using its integrated termination control. LIN bus short-circuit detected with RXD dominant time-out via µC-software RXD permanent dominant is caused by short-circuit: high short-circuit current battery becomes discharged bus termination and voltage Set TJA1020 into Sleep mode regulator are switched off: low current consumption battery is protected Fig 33. Failure management if LIN bus is shorted to ground Once the LIN bus is shorted to ground this can be detected in software monitoring the continuous dominant level on RXD. In order to reduce this failure current the TJA1020 is simply put into its Sleep mode, if not needed anymore. This results in disabling the slave termination resistor RSLAVE (Ref. 1) as well as the external master termination resistor RMASTER if connected to INH. Only an internal weak pull-up current source IIL(LIN) (Ref. 1) remains active for the case of a LIN bus failure recovery. So the INH-controlled master termination resistor RMASTER optimizes the system with respect to fail-safe behavior. Thus the system enters its Low-power mode (VCC off). The remaining short-circuit current is the amount of the internal bias current and the pull-up current source IIL(LIN) (Ref. 1). Figure 33 shows the corresponding failure management flow. 8.2 TXD dominant failure Usually in case a TXD pin is shorted to ground, the LIN bus is clamped to the dominant level and therefore overrules any transmission on the LIN bus. To protect the LIN bus from being continuously driven to the dominant level, the TJA1020 has an integrated TXD dominant timer. Thus the transmitter of the TJA1020 is disabled, if a TXD dominant failure is detected and the LIN bus is released again. Due to the integrated pull-down TXD resistor RTXD (Ref. 1), an open TXD pin results also in a continuous dominant situation. In such a case the TXD open failure is detected by the integrated TXD dominant timer and disables the transmitter stage of the TJA1020. Both failures, the TXD dominant failure as well as the TXD open failure, are detected, if the TXD input maintains dominant for at least tDOM (Ref. 1). As a consequence the LIN transmission speed is limited to a minimum baud rate. Its calculation is shown in Section 8.3. AN00093_2 Application note © Koninklijke Philips Electronics N.V. 2005. All rights reserved. Rev. 02 — 16 September 2005 39 of 44 AN00093 Philips Semiconductors TJA1020 LIN transceiver Furthermore if one of the above failures is present, a change of the NSLP input signal does not modify the TXD dominant timer state and therefore makes sure that no dominant LIN signal is driven to the bus by the TJA1020 (fail-safe behavior). 8.3 Minimum baud rate and maximum TXD dominant phase Due to the TXD dominant failure detection of the TJA1020 the maximum TXD dominant phase is limited by the minimum TXD dominant time-out time tDOMmin (Ref. 1). As a consequence the transmission speed is also limited to a minimum baud rate. 8.3.1 Minimum baud rate of a master node The maximum dominant phase of the LIN protocol (Ref. 2) is the maximum SYNCH BREAK LOW PHASE TSYNBRK,max (Ref. 2) of the SYNCH BREAK FIELD. The SYNCH BREAK FIELD is part of the message frame HEADER, which is only sent by the master node. The maximum SYNCH BREAK LOW PHASE TSYNBRK,max (Ref. 2) represents the maximum number of dominant bits sent by the master. Depending on the length of the maximum SYNCH BREAK LOW PHASE TSYNBRK,max (Ref. 2) and the minimum TXD dominant time out time tDOMmin (Ref. 1) the minimum baud rate for the master node can be calculated by the following equation: T SYNBRK ,max baudrate min,MASTER = ------------------------------t DOM ,min with TSYNBRK,max > TSYNBRK,min where TSYNBRK,min is specified in (Ref. 2) Thus with a maximum SYNCH BREAK LOW PHASE of TSYNBRK,max = 14.4 the TJA1020 allows operating within master application down to 2.4 kBaud. 8.3.2 Minimum baud rate of a slave node A slave node sends the RESPONSE part (Ref. 2) of the LIN message frame only, which has a maximum dominant phase of 9 bits (start bit + 8 data bits). As a result the minimum baud rate of a slave can be calculated by the following equation: 9 + n safe baudrate min,SLAVE = --------------------t DOM ,min with nsafe as safety margin Thus with a safety margin of nsafe = 1.8 the TJA1020 allows operating within slave application down to 1.8 kBaud. AN00093_2 Application note © Koninklijke Philips Electronics N.V. 2005. All rights reserved. Rev. 02 — 16 September 2005 40 of 44 AN00093 Philips Semiconductors TJA1020 LIN transceiver 9. Power consumption During design of the TJA1020 special care has been taken on system power consumption since this is a key for introduction of this new LIN sub bus system within automotive applications. The TJA1020 achieves lowest power consumption not only within a failure free system but also during bus failure situations on the LIN bus line. Even with the extremely low system power consumption the TJA1020 provides full wake-up capability via the LIN bus as well as via local events keeping a high immunity against electromagnetic disturbances. 9.1 Sleep mode power consumption The TJA1020 provides very low power consumption in Sleep mode. If the transceiver is used to control the ECU supply via INH pin the only remaining system current flows into the BAT pin (IBAT(sleep) (Ref. 1)). All other pins do not sink or source any extra current (see Figure 34). V Sleep mode: IBAT 3.3V NSLP µA Floating: 0 Px.x Low: 0 µA TXD µA LIN Recessive: 0 RXD RX0 voltage regulator INH IIL(LIN) TXD TX0 Low: 0 µA inhibit of R VDD IIL(NWAKE) RSLAVE Low: 0 SLP µA MICROCONTROLLER BAT NWAKE RWAKE2 ... 5V Supply Off: 0 µA R voltage regulator High: 0 RMASTER BAT inhibit of RWAKE1 BAT µA GND TJA1020 GND Fig 34. Current consumption in Sleep mode 9.2 Sleep mode power consumption at presence of LIN bus short-circuit In case of a LIN short-circuit to ground the power consumption of the TJA1020 keeps also very low if the Sleep mode is selected. Since the termination of the system becomes nearly disabled during Sleep, the resulting short-circuit current is defined by the internal bias current and the remaining pull-up current source for failure recovery (see Figure 35). AN00093_2 Application note © Koninklijke Philips Electronics N.V. 2005. All rights reserved. Rev. 02 — 16 September 2005 41 of 44 AN00093 Philips Semiconductors TJA1020 LIN transceiver V Supply: 100 RWAKE1 BAT BAT 3.3V µA BAT NWAKE RWAKE2 ... 5V NSLP µA Px.x Low: 0 µA RX0 TXD µA voltage regulator INH IIL(LIN) TXD TX0 Low: 0 µA inhibit of R VDD Floating: 0 RSLAVE MICROCONTROLLER Low: 0 SLP µA IIL(NWAKE) LIN R Supply Off: 0 High: 0 RMASTER inhibit of voltage regulator µA Dominant: IIL(LIN) RXD GND TJA1020 GND Fig 35. Typical short-circuit current consumption in Sleep mode 10. References [1] Data Sheet TJA1020, LIN Transceiver, Philips Semiconductors, Jan. 2004 [2] LIN Specification Package, LIN Protocol Specification – Revision 1.3, LIN Consortium, Dec. 2002 [3] International Standard ISO 9141, Road Vehicles – Diagnostic Systems – Requirement for Interchange of Digital Information, International Standardization Organization, 1989 [4] International Standard IEC 61000-4-2, Electromagnetic Compatibility – Testing and Measurement Techniques – Electrostatic Discharge Immunity Test, International Electrotechnical Commission, 2001 [5] Data Sheet PESD1LIN, LIN Bus ESD Protection Diode, Philips Semiconductors, Oct. 2004 AN00093_2 Application note © Koninklijke Philips Electronics N.V. 2005. All rights reserved. Rev. 02 — 16 September 2005 42 of 44 AN00093 Philips Semiconductors TJA1020 LIN transceiver 11. Disclaimers Life support — These products are not designed for use in life support appliances, devices, or systems where malfunction of these products can reasonably be expected to result in personal injury. Philips Semiconductors customers using or selling these products for use in such applications do so at their own risk and agree to fully indemnify Philips Semiconductors for any damages resulting from such application. Right to make changes — Philips Semiconductors reserves the right to make changes in the products - including circuits, standard cells, and/or software - described or contained herein in order to improve design and/or performance. When the product is in full production (status ‘Production’), relevant changes will be communicated via a Customer Product/Process Change Notification (CPCN). Philips Semiconductors assumes no responsibility or liability for the use of any of these products, conveys no license or title under any patent, copyright, or mask work right to these products, and makes no representations or warranties that these products are free from patent, copyright, or mask work right infringement, unless otherwise specified. Application information — Applications that are described herein for any of these products are for illustrative purposes only. Philips Semiconductors make no representation or warranty that such applications will be suitable for the specified use without further testing or modification. 12. Trademarks Notice — All referenced brands, product names, service names and trademarks are the property of their respective owners. AN00093_2 Application note © Koninklijke Philips Electronics N.V. 2005. All rights reserved. Rev. 02 — 16 September 2005 43 of 44 AN00093 Philips Semiconductors TJA1020 LIN transceiver 13. Contents 1 2 2.1 2.2 2.3 2.3.1 2.3.2 2.3.3 2.3.4 2.4 2.5 3 3.1 3.2 3.2.1 3.2.2 3.2.2.1 3.2.2.2 3.2.3 3.2.4 3.2.4.1 3.2.5 3.2.5.1 3.2.5.2 3.2.6 4 4.1 4.2 4.3 4.4 5 5.1 5.2 5.3 6 6.1 6.2 7 7.1 7.1.1 7.1.2 7.2 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 General description . . . . . . . . . . . . . . . . . . . . . . 5 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Operating modes . . . . . . . . . . . . . . . . . . . . . . . 6 Sleep mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Standby mode. . . . . . . . . . . . . . . . . . . . . . . . . . 8 Normal-slope mode . . . . . . . . . . . . . . . . . . . . 10 Low-slope mode . . . . . . . . . . . . . . . . . . . . . . . 10 Compatibility to 3.0 V to 5 V microcontroller devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 ISO 9141 compatibility . . . . . . . . . . . . . . . . . . 11 Slave application . . . . . . . . . . . . . . . . . . . . . . . 14 Set-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Detailed pin description . . . . . . . . . . . . . . . . . 14 NSLP pin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 TXD pin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Wake-up source recognition . . . . . . . . . . . . . . 15 Open circuit handling . . . . . . . . . . . . . . . . . . . 17 RXD pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 NWAKE pin . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Wake-up after power-on . . . . . . . . . . . . . . . . . 20 INH pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 INH controlled voltage regulator . . . . . . . . . . . 21 Direct voltage regulator supply . . . . . . . . . . . . 22 LIN pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Master application . . . . . . . . . . . . . . . . . . . . . . 24 Master termination directly to BAT . . . . . . . . . 24 Master termination towards INH . . . . . . . . . . . 24 Master termination split between INH and BAT 25 Master termination for LIN networks with different supplied LIN nodes . . . . . . . . . . . . . . . . . . . . . 26 EMC aspects. . . . . . . . . . . . . . . . . . . . . . . . . . . 28 EME - network design hints . . . . . . . . . . . . . . 28 EME - Low-slope mode . . . . . . . . . . . . . . . . . 29 EMI - capacitive load . . . . . . . . . . . . . . . . . . . 29 ESD - aspects . . . . . . . . . . . . . . . . . . . . . . . . . . 30 General design hints for ESD levels beyond 4 kV HBM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 ESD protection example for ESD model according to IEC 61000-4-2 (Ref. 4) . . . . . . . . . . . . . . . . 31 Transceiver control . . . . . . . . . . . . . . . . . . . . . 32 INH controlled microcontroller power supply . 32 Applications using NWAKE. . . . . . . . . . . . . . . 32 Applications without using NWAKE . . . . . . . . 33 Permanently supplied microcontroller. . . . . . . 34 7.2.1 7.2.2 7.3 7.3.1 7.3.2 8 8.1 8.2 8.3 8.3.1 8.3.2 9 9.1 9.2 10 11 12 Application using NWAKE . . . . . . . . . . . . . . . 34 Application without using NWAKE . . . . . . . . . 35 Transition from Normal-slope/Low-slope into Sleep mode . . . . . . . . . . . . . . . . . . . . . . . . . . 36 Application using NWAKE . . . . . . . . . . . . . . . 36 Application without using NWAKE . . . . . . . . . 37 Failure management . . . . . . . . . . . . . . . . . . . . 39 LIN bus short-circuit to ground . . . . . . . . . . . . 39 TXD dominant failure . . . . . . . . . . . . . . . . . . . 39 Minimum baud rate and maximum TXD dominant phase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 Minimum baud rate of a master node. . . . . . . 40 Minimum baud rate of a slave node . . . . . . . . 40 Power consumption . . . . . . . . . . . . . . . . . . . . 41 Sleep mode power consumption . . . . . . . . . . 41 Sleep mode power consumption at presence of LIN bus short-circuit . . . . . . . . . . . . . . . . . . . . 41 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 Disclaimers . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 Trademarks . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 © Koninklijke Philips Electronics N.V. 2005 All rights are reserved. Reproduction in whole or in part is prohibited without the prior written consent of the copyright owner. The information presented in this document does not form part of any quotation or contract, is believed to be accurate and reliable and may be changed without notice. No liability will be accepted by the publisher for any consequence of its use. Publication thereof does not convey nor imply any license under patent- or other industrial or intellectual property rights. Date of release: 16 September 2005 Document number: AN00093_2 Published in The Netherlands