MCP2004

MCP2003/4 LIN J2602 Transceiver Features • The MCP2003 and MCP2004 are compliant with LIN Bus Specifications 1.3, 2.0 and 2.1 and are compliant to SAE J2602 • Support Baud Rates up to 20 Kbaudwith LIN-compatible output driver • 43V load dump protected • Very low EMI meets stringent OEM requirements • Very high ESD immunity: - >20kV on VBB (IEC 61000-4-2) - >14kV on LBUS (IEC 61000-4-2) • Very high immunity to RF disturbances meets stringent OEM requirements • Wide supply voltage, 6.0V-27.0V continuous • Extended Temperature Range: -40 to +125°C • Interface to PIC® MCU EUSART and standard USARTs • Local Interconnect Network (LIN) bus pin: - Internal pull-up resistor and diode - Protected against battery shorts - Protected against loss of ground - High current drive • Automatic thermal shutdown • Low-power mode: - Receiver monitoring bus and transmitter off, ( 5 µA) Description This device provides a bidirectional, half-duplex communication physical interface to automotive and industrial LIN systems to meet the LIN bus specification Revision 2.1 and SAE J2602. The device is short circuit and overtemperature protected by internal circuitry. The device has been specifically designed to operate in the automotive operating environment and will survive all specified transient conditions while meeting all of the stringent quiescent current requirements. MCP200X family members: • 8-pin PDIP, DFN and SOIC packages: - MCP2003, LIN-compatible driver, with WAKE pins - MCP2004, LIN-compatible driver, with FAULT/TXE pins Package Types MCP2003 PDIP, SOIC RXD 1 CS 2 WAKE 3 TXD 4 8 VREN 7 VBB MCP2004 PDIP, SOIC RXD 1 CS 2 8 VREN 7 VBB 6 LBUS 5 VSS 6 LBUS FAULT/TXE 3 5 VSS TXD 4 MCP2003 4x4 DFN* RXD 1 CS 2 WAKE 3 TXD 4 EP 9 8 VREN 7 VBB 6 LBUS 5 VSS MCP2004 4x4 DFN* RXD 1 CS 2 FAULT/TXE 3 TXD 4 EP 9 8 VREN 7 VBB 6 LBUS 5 VSS * Includes Exposed Thermal Pad (EP); see Table 1-1.  2010 Microchip Technology Inc. DS22230A-page 1 MCP2003/4 MCP2003 Block Diagram VREN Ratiometric Reference WAKE Wake-Up Logic and Power Control VBB RXD CS TXD OC ~30 k LBUS VSS Thermal Protection Short Circuit Protection MCP2004 Block Diagram VREN Ratiometric Reference Wake-Up Logic and Power Control RXD CS TXD FAULT/TXE Thermal Protection Short Circuit Protection OC ~30 k VBB LBUS VSS DS22230A-page 2  2010 Microchip Technology Inc. MCP2003/4 1.0 DEVICE OVERVIEW 1.2.3 THERMAL PROTECTION The MCP2003/4 provides a physical interface between a microcontroller and a LIN bus. This device will translate the CMOS/TTL logic levels to LIN logic level, and vice versa. It is intended for automotive and industrial applications with serial bus speeds up to 20 Kbaud. LIN specification 2.1 requires that the transceiver of all nodes in the system is connected via the LIN pin, referenced to ground and with a maximum external termination resistance of 510 from LIN bus to battery supply. The 510 corresponds to 1 master and 15 slave nodes. The VREN pin can be used to drive the logic input of an external voltage regulator. This pin is high in all modes except for Power Down mode. The thermal protection circuit monitors the die temperature and is able to shut down the LIN transmitter. There are two causes for a thermal overload. A thermal shut down can be triggered by either, or both, of the following thermal overload conditions. • LIN bus output overload • Increase in die temperature due to increase in environment temperature Driving the TXD and checking the RXD pin makes it possible to determine whether there is a bus contention (Rx = low, Tx = high) or a thermal overload condition (Rx = high, Tx = low). After a thermal overload event, the device will automatically recover once the die temperature has fallen below the recovery temperature threshold. See Figure 1-1. 1.1 1.1.1 External Protection REVERSE BATTERY PROTECTION FIGURE 1-1: THERMAL SHUTDOWN STATE DIAGRAM LIN bus Shorted to VBB Operation Mode Transmitter Shutdown An external reverse-battery-blocking diode should be used to provide polarity protection (see Example 1-1). 1.1.2 TRANSIENT VOLTAGE PROTECTION (LOAD DUMP) An external 43V transient suppressor (TVS) diode, between VBB and ground, with a 50 transient protection resistor (RTP) in series with the battery supply and the VBB pin serve to protect the device from power transients (see Example 1-1) and ESD events. While this protection is optional, it is considered good engineering practice. Temp < SHUTDOWNTEMP 1.2 1.2.1 Internal Protection ESD PROTECTION For component-level ESD ratings, please refer to the maximum operation specifications. 1.2.2 GROUND LOSS PROTECTION The LIN Bus specification states that the LIN pin must transition to the recessive state when ground is disconnected. Therefore, a loss of ground effectively forces the LIN line to a high-impedance level.  2010 Microchip Technology Inc. DS22230A-page 3 MCP2003/4 1.3 Modes of Operation For an overview of all operational modes, refer to Table 1-1. the TXD pin is held low when CS goes high, the device will transition to Transmitter Off mode instead of Operation mode. 1.3.1 POWER-DOWN MODE 1.3.3 OPERATION MODE In Power Down mode, the transmitter and VREN are both off. Only the receiver section and the wake-up circuits are operational. This is the lowest power mode. On bus activity (e.g. a BREAK character), CS going to a high level, or on a falling edge on WAKE, the device will immediately enter Ready mode. If CS is held high as the device transitions from Power Down to Ready mode, the device will transition to Operation mode as soon as internal voltages stabilize. Note: Bus activity is defined as LBUS dropping below VIL(LBUS) for longer than the Bus Activity Debounce time (tBDB). In this mode, all internal modules are operational. The MCP2003/4 will go into the Power Down mode on the falling edge of CS. The MCP2003/4 will enter Transmitter Off mode in the event of a Fault condition. These include: thermal overload, bus contention and TXD timer expiration. The MCP2004 device can also enter Transmitter Off mode if the FAULT/TXE pin is pulled low 1.3.4 TRANSMITTER OFF MODE 1.3.2 READY MODE Transmitter Off mode is reached whenever the transmitter is disabled either due to a Fault condition or pulling the nFAULT/TXE pin low on the MCP2004. The fault conditions include: thermal overload, bus contention or TXD timer expiration. The MCP2003/4 will go into Power Down mode on falling edge of CS, or return to Operation mode if all faults are resolved and the FAULT/TXE pin on the MCP2004 is high. Upon entering the Ready mode, VREN is enabled and the receiver detect circuit is powered up. The transmitter remains disabled and the device is ready to receive data but not to transmit. Upon VBB supply pin power-on, the device will remain in Ready mode as long as CS is low. If CS transitions high, the device will enter Operation mode. However, if FIGURE 1-2: POR VREN OFF RX OFF TX OFF OPERATIONAL MODES STATE DIAGRAM – MCP2003 Ready Mode VREN ON R X ON TX OFF VBB > 5.5V CS = 1 and TXD = 1 C S = 1 and TXD = 0 CS = 1 and TXD = 1 and No Fault Fault (Thermal or Timer) Falling edge on LIN or C S = 1 TOFF Mode VREN ON RX ON TX OFF Operation Mode VREN ON RX ON TX ON CS=0 CS=0 Sleep Mode VREN OFF RX OFF TX OFF DS22230A-page 4  2010 Microchip Technology Inc. MCP2003/4 FIGURE 1-3: P OR VREN OFF RX OFF TX OFF OPERATIONAL MODES STATE DIAGRAM – MCP2004 Ready Mode VREN ON R X ON TX OFF VBB > 5.5V C S = 1 and (TXE = 0 or TXD = 0) CS = 1 and TXD = 1 and TXE = 1 Falling edge on LIN or CS = 1 TOFF Mode V REN ON RX ON TX OFF CS = 1and TXE = 1 and TXD = 1 and No Fault Fault (Thermal or Timer) o r TXE=0 Operation Mode VREN ON RX ON TX ON CS = 0 CS = 0 Sleep Mode VREN OFF RX OFF TX OFF Note: While the MCP2003/4 is in thermal shutdown, TXD should not be actively driven high or it may power internal logic through the ESD diodes and may damage the device. TABLE 1-1: State POR Ready Operation OVERVIEW OF OPERATIONAL MODES Transmitter Receiver OFF OFF ON OFF ON ON Vren OFF ON ON Operation Read CS, if low, then Ready; if high, Operational mode If CS high level, then Operation mode Bus Off state If CS low level, then Power Down; Normal Operation If FAULT/TXE low level, then Transmitter Off mode mode On LIN bus falling, go to Ready mode. On CS Low Power mode high level, go to Operation mode If CS low level, then Power Down; FAULT/TXE only If FAULT/TXE and TXD high, then Operation available on mode MCP2004 Comments Power Down Transmitter Off OFF OFF Activity Detect ON OFF ON  2010 Microchip Technology Inc. DS22230A-page 5 MCP2003/4 1.4 Typical Applications TYPICAL MCP2003 APPLICATION +12 50 43V +12 EXAMPLE 1-1: 1.0 µF (See Note) 220 K VDD TXD RXD I/O VOLTAGE REG VREN VBB Master Node Only +12 TXD RXD CS WAKE Wake-up 100 nF LBUS 1 K LIN Bus 27V VSS Note: For applications with current requirements of less than 20 mA, the connection to +12V can be deleted, and voltage to the regulator supplied directly from the VREN pin. EXAMPLE 1-2: TYPICAL MCP2004 APPLICATION +12 50 43V +12 Wake-up 220 K VDD TXD RXD I/O I/O VOLTAGE REG VREN 1.0 µF Master Node Only +12 VBB 1 K LBUS 27V LIN Bus TXD RXD CS FAULT/TXE 100 nF VSS DS22230A-page 6  2010 Microchip Technology Inc. MCP2003/4 EXAMPLE 1-3: TYPICAL LIN NETWORK CONFIGURATION 40m + Return LIN bus 1 k VBB LIN bus MCP200X LIN bus MCP200X Slave 1 µC Master µC LIN bus MCP200X Slave 2 µC LIN bus MCP200X Slave n