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19-2687; Rev 0; 11/02
80V Fault-Protected/Tolerant CAN Transceivers for In-Car Applications
General Description
The MAX3054/MAX3055/MAX3056 are interfaces between the protocol controller and the physical wires of the bus lines in a controller area network (CAN). The devices provide differential transmit capability and switch to single-wire mode if certain fault conditions occur. The MAX3054/MAX3055/MAX3056 guarantee full wake-up capability during failure modes. The extended fault-protected voltage range of CANH and CANL bus lines of 80V allows for use in 42V automotive applications. Current-limiting and thermalprotection circuits protect the transmitter output stage against overcurrent faults to prevent destruction of the transmitter output stage. The CANH and CANL lines are also protected against electrical transients that may occur in an automotive environment. The transceiver provides three low-power modes that can be entered and exited through pins STB and EN. An output INH pin can be used for deactivation of an external voltage regulator. The MAX3054/MAX3055/MAX3056 are designed to provide optimal operation for a specified data rate. The MAX3054 is ideal for high data rates of 250kbps. The MAX3055 is used for data rates of 125kbps and the MAX3056 is designed for 40kbps applications. For the 40kbps and 125kbps versions, a built-in slope-control feature allows the use of unshielded cables, and receiver input filters guarantee high noise immunity.
Features
o Pin and Functionally Compatible with TJA1054 o 80V Fault Protection Suitable for 42V Battery Systems o Low RFI/Excellent EMC Immunity o Full Wake-Up Capability During Failure Modes o Bus-Failure Management o Support Single-Wire Transmission Mode with Ground Offset Voltages Up to 1.5V o Thermally Protected o Do Not Disturb the Bus Line when Unpowered o Low-Current Sleep and Standby Mode with WakeUp Through Bus Lines o Up to 250kbps Data Rate (MAX3054)
MAX3054/MAX3055/MAX3056
Ordering Information
PART MAX3054ASD MAX3055ASD MAX3056ASD TEMP RANGE -40C to +125C -40C to +125C -40C to +125C DATA RATE 250kbps Slew control 125kbps Slew control 40kbps PINPACKAGE 14 SO 14 SO 14 SO
Applications
Automotive
Typical Operating Circuit
VBATT +12V BATTERY CAN CONTROLLER +5V 2 3 5 STB 6 EN 4 ERR 1 INH 10 VCC GND BATT RTL 9 13 14 100nF
Pin Configuration
TOP VIEW
INH 1 TXD RXD 2 3 14 BATT 13 GND 12 CANL
TXD RXD
ERR 4 STB 5 EN 6
7
WAKE
MAX305_
MAX3054 MAX3055 MAX3056
11 CANH 10 VCC 9 8 RTL RTH
RTH 8 CAN BUS
CANH CANL 11 12
WAKE 7
FAULT TO 80V
SO
________________________________________________________________ Maxim Integrated Products
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80V Fault-Protected/Tolerant CAN Transceivers for In-Car Applications MAX3054/MAX3055/MAX3056
ABSOLUTE MAXIMUM RATINGS
(All voltages are referenced to GND) Supply Voltage (VCC) ...............................................-0.3V to +6V Battery Voltage (VBATT)..........................................-0.3V to +80V TXD, RXD, ERR, STB, EN ...........................-0.3V to (VCC + 0.3V) CANH, CANL ..........................................................-80V to +80V RTH, RTL ................................................................-0.3V to +80V RTH, RTL Current ...........................................................180mA WAKE .....................................................................-0.3V to +80V INH ..........................................................-0.3V to (VBATT + 0.3V) INH Current.......................................................................-0.5mA Transient Voltage (ISO 7637)................................-200V, +200V* Continuous Power Dissipation (TA = +70C) 14-Pin SO (derate 8.3mW/C above +70C)................667mW Operating Temperature Range .........................-40C to +125C Junction Temperature ......................................................+150C Storage Temperature Range .............................-65C to +150C Lead Temperature (soldering, 10s) .................................+300C *Pending completion of testing.
Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
DC ELECTRICAL CHARACTERISTICS
(VCC = 5V 5%, VBATT = +5V to +42V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = 5V, VBATT = 14V, R1 = 100 (Figure 2), TA = +25C.) (Notes 1, 2)
PARAMETER VOLTAGE SUPPLIES Dominant normal operating mode, no load, TXD = 0 Supply Current ICC Recessive normal operating mode, TXD = VCC Low-power modes: VTXD = VCC, VBATT = 14V Battery Current Battery Power on Flag Threshold STB, EN, AND TXD High-Level Input Voltage Low-Level Input Voltage High-Level Input Current Low-Level Input Current Supply Voltage--Forced Standby Mode (Fail-Safe) RXD AND ERR High-Level Output Voltage Low-Level Output Voltage WAKE Wake-Up Threshold Voltage Low-Level Input Current VTH(WAKE) IIL(WAKE) VSTB = 0V V WAKE = 0V 2.0 -10 2.7 -4 3.4 -1 V A VOH VOL IOUT = -1mA IOUT = 7.5mA VCC - 0.5 0 VCC 0.9 V V VIH VIL IIH IIL VFS VIN = 4V VIN = 1V VBATT = 14V STB and EN TXD STB and EN TXD -200 4 -800 2.75 9 -80 8 -320 -100 4.50 2.4 0.8 20 -25 V V A A V IBATT VPWRON Low-power modes at VTRL = VBATT, VBATT = V WAKE = VINH = 5V to 27V Low-power modes 5 1.0 16 4 3 54 30 mA 10 10 125 3.5 A A V SYMBOL CONDITIONS MIN TYP MAX UNITS
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80V Fault-Protected/Tolerant CAN Transceivers for In-Car Applications
DC ELECTRICAL CHARACTERISTICS (continued)
(VCC = 5V 5%, VBATT = +5V to +42V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = 5V, VBATT = 14V, R1 = 100 (Figure 2), TA = +25C.) (Notes 1, 2)
PARAMETER INH High-Level Voltage Drop Leakage Current CANH, CANL VCC = 5V, no failures and bus failures 1, 2, 5, 9 Differential Receiver Threshold VDIFF VCC = 4.75V to 5.25V, no failures and bus failures 1, 2, 5, 9 No failures and bus failures 1, 2, 5, 9 TXD = VCC, RTH < 4k TXD = VCC, RTH < 4k TXD = 0V, R1 = 100 TXD = 0V, R1 = 100 VCANH = 0V, TXD = 0V Low-power modes, VCANH = 0V, VCC = 5V VCANL = 14V, TXD = 0V CANL Output Current Voltage Detection Threshold for Short Circuit to Battery on CANH Voltage Detection Threshold for Short Circuit to GND on CANL Voltage Detection Threshold for Short Circuit to Battery on CANL CANL Wake-Up Threshold CANH Wake-Up Threshold CANH Single-Ended Receiver Threshold (Failures 4, 6, 7) CANH Single-Ended Receiver Hysteresis IO(CANL) Low-power modes, VCANL = 42V, VBATT = 42V, RTL = open VCC = 4.75V to 5.25V Low-power modes Low-power modes Normal mode, VCC = 5V Low-power modes Low-power modes VCC = 5V VCC = 4.75V to 5.25V 0.30 VCC 1.1 2.5 6.4 2.5 1.1 1.50 0.30 VCC 10 7.3 3.2 1.8 1.70 -150 -10 75 130 20 0.37 VCC 2.5 3.9 8.2 3.9 2.5 1.85 0.37 VCC -86 VCC - 0.2 VCC - 1.4 1.4 -3.5 -3.2 -2.9 V -0.70 VCC -0.58 VCC 18 200 mV mV V V V mA A mA A V V V V V V mV VH ILEAK(INH) INH = -0.18mA, standby mode Sleep mode, VINH = 0V 0.8 5 V A SYMBOL CONDITIONS MIN TYP MAX UNITS
MAX3054/MAX3055/MAX3056
Differential Receiver Hysteresis CANH Recessive Output Voltage CANL Recessive Output Voltage CANH Dominant Output Voltage CANL Dominant Output Voltage CANH Output Current
HYST VOCH VOCL VOCHDOM VOCLDOM IO(CANH)
VDET(CANH) VDTG(CANL) VDET(CANL) VTHL(WAKE) VTHH(WAKE) VSE(CANH) HYST
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80V Fault-Protected/Tolerant CAN Transceivers for In-Car Applications MAX3054/MAX3055/MAX3056
DC ELECTRICAL CHARACTERISTICS (continued)
(VCC = 5V 5%, VBATT = +5V to +42V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = 5V, VBATT = 14V, R1 = 100 (Figure 2), TA = +25C.) (Notes 1, 2)
PARAMETER CANL Single-Ended Receiver Threshold CANL Single-Ended Receiver Hysteresis RTL AND RTH RTL to VCC Switch On-Resistance RTH to VCC Switch On-Resistance Output Current on Pin RTL RTL Pullup Current RTH Pulldown THERMAL SHUTDOWN Shutdown Junction Temperature Thermal Protection Hysteresis TJ TJF6 THYS For shutdown During failure 6--switch off CANL only 165 140 15 C C RSW(RTL) RSW(RTH) IO(RTL) |IPU(RTL)| |IPU(RTH)| IO = -10mA IO = 10mA Low-power modes, VRTL = 0 Normal and failures 4, 6, 7, RTL = 0V Normal and failures 3, 8, RTL = VCC -1.25 20 20 36 23 -0.65 107 106 100 100 -0.30 200 200 mA A A SYMBOL VSE(CANL) HYST VCC = 5V VCC = 4.75V to 5.25V Failures 3, 8 CONDITIONS MIN 3.15 TYP 3.30 MAX 3.45 UNITS V mV
0.63 VCC 10
0.69 VCC
AC ELECTRICAL CHARACTERISTICS
(VCC = 5V 5%, VBATT = +5V to +42V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = 5V, VBATT = 14V, R1 = 100 (Figure 2), TA = +25C.) (Notes 1, 2)
PARAMETER TRANSITION TIME CANL and CANH Bus Output Transition Time Recessive to Dominant (10% to 90%) CANL and CANH Bus Output Transition Time Dominant to Recessive (10% to 90%) CL = 330pF, MAX3054 (250kbps) t(r-d) CL = 220pF to 3.3nF, MAX3055 (125kbps) CL = 560pF to 10nF, MAX3056 (40kbps) CL = 330pF, MAX3054 (250kbps) t(d-r) CL = 220pF to 1nF, MAX3055 (125kbps) CL = 560pF to 3.3nF, MAX3056 (40kbps) No failures, CL = 330pF, MAX3054 (250kbps) Bus failures 1, 2, 5, 9, CL = 330pF, MAX3054 (250kbps) No failures and bus failures 1, 2, 5, 9, CL = 1nF, MAX3055 (125kbps) No failures and bus failures 1, 2, 5, 9, CL = 3.3nF, MAX3056 (40kbps) 200 0.5 100 0.7 130 1200 2.8 38 700 3.3 ns s ns s SYMBOL CONDITIONS MIN TYP MAX UNITS
PROPAGATION DELAY TXD TO RXD LOW--DOMINANT TRANSMISSION (Figures 1, 2) 600 ns 750 1.5 s 4.7 Differential Reception tPDLD
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80V Fault-Protected/Tolerant CAN Transceivers for In-Car Applications
AC ELECTRICAL CHARACTERISTICS (continued)
(VCC = 5V 5%, VBATT = +5V to +42V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = 5V, VBATT = 14V, R1 = 100 (Figure 2), TA = +25C.) (Notes 1, 2)
PARAMETER SYMBOL CONDITIONS Bus failures 3, 4, 6, 7, 8, CL = 330pF, MAX3054 (250kbps) Single-Ended Reception tPDLSE Bus failures 3, 4, 6, 7, 8, CL = 1nF, MAX3055 (125kbps) Bus failures 3, 4, 6, 7, 8, CL = 3.3nF, MAX3056 (40kbps) PROPAGATION DELAY TXD TO RXD HIGH--RECESSIVE TRANSMISSION (Figures 1, 2) No failures and bus failures 1, 2, 5, 9, CL = 330pF, MAX3054 (250kbps) Differential Reception tPDHD No failures and bus failures 1, 2, 5, 9, CL = 1nF, MAX3055 (125kbps) No failures and bus failures 1, 2, 5, 9, CL = 3.3nF, MAX3056 (40kbps) Bus failures 3, 4, 6, 7, 8, CL = 330pF, MAX3054 (250kbps) Single-Ended Reception tPDHSE Bus failures 3, 4, 6, 7, 8, CL = 1nF, MAX3055 (125kbps) Bus failures 3, 4, 6, 7, 8, CL = 3.3nF, MAX3056 (40kbps) WAKE-UP TIMING Minimum Time for Wake-Up on CANL and CANH or WAKE FAILURES TIMING Failures 3 and 8 Detection Time Normal and low-power mode MAX3054 (250kbps), MAX3055 (125kbps) MAX3056 (40kbps) Failures 4 and 7 Detection Time tDET Normal and low-power mode MAX3054 (250kbps), MAX3055 (125kbps) MAX3056 (40kbps) Failure 6 Detection Time Normal mode MAX3054 (250kbps), MAX3055 (125kbps) MAX3056 (40kbps) 1.9 5.5 0.3 1.0 0.35 0.93 5.7 16.5 1 3.2 1.1 2.97 9.5 27.0 1.9 5.5 1.85 5.00 ms t WAKE 8 38 s 950 1.9 s 5.95 950 1.9 s 5.95 ns ns MIN TYP MAX 750 1. 5 s 4.7 UNITS ns
MAX3054/MAX3055/MAX3056
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80V Fault-Protected/Tolerant CAN Transceivers for In-Car Applications MAX3054/MAX3055/MAX3056
AC ELECTRICAL CHARACTERISTICS (continued)
(VCC = 5V 5%, VBATT = +5V to +42V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = 5V, VBATT = 14V, R1 = 100 (Figure 2), TA = +25C.) (Notes 1, 2)
PARAMETER Failures 3 and 8 Recovery Time SYMBOL CONDITIONS Normal and low-power mode MAX3054 (250kbps), MAX3055 (125kbps) MAX3056 (40kbps) MAX3054 (250kbps) Normal mode Failures 4 and 7 Recovery Time tREC Low-power mode MAX3055 (125kbps) MAX3056 (40kbps) MAX3054 (250kbps), MAX3055 (125kbps) MAX3056 (40kbps) Failure 6 Recovery Time Minimum Hold Time of Go-to-Sleep Command Disable Time of TXD Permanent Dominant Timer Pulse Count Difference for Failures 1, 2, 5, 9 Detection (ERR Becomes Low) Count Pulse Count Difference for Failures 1, 2, 5, 9 Recovery (ERR Becomes High) 3 4 5 Normal mode MAX3054 (250kbps), MAX3055 (125kbps) MAX3056 (40kbps) tHMIN MAX3054 (250kbps), MAX3055 (125kbps) MAX3056 (40kbps) MIN 0.36 1.0 1.7 7 22 0.35 1.0 150 390 5 0.9 2.34 4 TYP 1.14 3.2 5.6 23 70 1.1 3.2 525 1445 MAX 1.90 5.5 9.5 38 119 1.85 5.5 900 2500 50 4.5 12.50 s s ms s UNITS ms
tDIS(TXD)
VTXD = 0
ms
Note 1: All currents into the device are positive; all currents out of the device are negative. All voltages are referenced to device ground, unless otherwise noted. Note 2: Failure modes 1 through 9 are explained in Table 1 and in the Detailed Description section.
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80V Fault-Protected/Tolerant CAN Transceivers for In-Car Applications
Timing Diagram/Test Circuits
+5V
MAX3054/MAX3055/MAX3056
VTXD
VCC GND
10 VCC 7 2 WAKE TXD
6 EN
5 STB RTH CANL 8 12 R1 CL
VCANL VCANH
5V 3.6V 1.4V 0 2.2V
MAX305_
-3.2V VDIFF VRXD VCC/2
CBYPASS ERR 4 GND 13 RXD 3 1 VBATT 14 BATT RTL 9 R1 CL INH CANH 11
-5V
tPDL VDIFF = CANH - CANL
tPDH
CX = 15pF PROBE CAP INCLUDED
Figure 1. Timing Diagram for Dynamic Characteristics
Figure 2. Test Circuit for Dynamic Characteristics
+5V
+5V
10 VCC 7 WAKE
6 EN
5 STB RTH 8 125 CL 7
10 VCC WAKE
6 EN
5 STB RTH 8 125 1nF
511 2 TXD CANL 12 2 TXD CANL
511 1nF 12 GENERATOR
MAX305_
1 INH CANH 11 1 INH
MAX305_
CANH 11
1nF
+12V 14 CBYPASS ERR 4 GND 13 RXD 3 BATT RTL 9
511
+12V 14 BATT ERR 4 GND 13 RTL RXD 3 9
511
125
CL
CBYPASS
125
1nF
CX = 15pF PROBE CAP INCLUDED
CX = 15pF PROBE CAP INCLUDED
Figure 3. Test Circuit for Typical Operating Characteristics
Figure 4. Test Circuit for Automotive Transients
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80V Fault-Protected/Tolerant CAN Transceivers for In-Car Applications MAX3054/MAX3055/MAX3056
Typical Operating Characteristics
(VCC = 5V, VBATT = +12V, RTL = RTH = 511, R1 = 125, and TA = +25C; see Figure 3.)
SLEW RATE vs. TEMPERATURE RECESSIVE TO DOMINANT
MAX3054/MAX3055/MAX3056 toc01
MAX3054 SUPPLY CURRENT vs. DATA RATE
MAX3054/MAX3055/MAX3056 toc02
MAX3055 SUPPLY CURRENT vs. DATA RATE
MAX3054/MAX3055/MAX3056 toc03
20 MAX3055 15 SLEW RATE (V/s)
37 TA = +125C 36 SUPPLY CURRENT (mA) TA = +25C
37
36 SUPPLY CURRENT (mA)
TA = +125C TA = +25C TA = -40C
35 TA = -40C 34
35
10
34
5
MAX3056
33
33
0 -40 -7 26 59 92 125 TEMPERATURE (C)
32 0 50 100 150 200 250 300 350 400 450 500 DATA RATE (kbps)
32 0 25 50 75 100 125 DATA RATE (kbps)
MAX3056 SUPPLY CURRENT vs. DATA RATE
MAX3054/MAX3055/MAX3056 toc04
MAX3054 RECEIVER PROPAGATION DELAY vs. TEMPERATURE
CL = 330pF RECEIVER PROPAGATION DELAY (ns) 400 RECESSIVE 350
MAX3054/MAX3055/MAX3056 toc05
MAX3055 RECEIVER PROPAGATION DELAY vs. TEMPERATURE
RECEIVER PROPAGATION DELAY (ns) CL = 1nF 500 RECESSIVE 400
MAX3054/MAX3055/MAX3056 toc06
38 TA = +125C
450
600
37 SUPPLY CURRENT (mA)
36
TA = +25C
35
TA = -40C
DOMINANT
300 DOMINANT
34
300
250
33 0 10 20 DATA RATE (kbps) 30 40
200 -50 -15 20 55 90 125 TEMPERATURE (C)
200 -50 -15 20 55 90 125 TEMPERATURE (C)
MAX3056 RECEIVER PROPAGATION DELAY vs. TEMPERATURE
MAX3054/MAX3055/MAX3056 toc07
MAX3054 DRIVER PROPAGATION DELAY vs. TEMPERATURE
MAX3054/MAX3055/MAX3056 toc08
MAX3055 DRIVER PROPAGATION DELAY vs. TEMPERATURE
CL = 1nF DRIVER PROPAGATION DELAY (s) DOMINANT 600
MAX3054/MAX3055/MAX3056 toc09
2.0 CL = 3.3nF RECEIVER PROPAGATION DELAY (s) DOMINANT 1.5
200 CL = 330pF RECEIVER PROPAGATION DELAY (ns) 175
700
DOMINANT
1.0 RECESSIVE 0.5
150 RECESSIVE 125
500 RECESSIVE 400
0 -50 -15 20 55 90 125 TEMPERATURE (C)
100 -50 -15 20 55 90 125 TEMPERATURE (C)
300 -50 -15 20 55 90 125 TEMPERATURE (C)
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80V Fault-Protected/Tolerant CAN Transceivers for In-Car Applications
Typical Operating Characteristics (continued)
(VCC = 5V, VBATT = +12V, RTL = RTH = 511, R1 = 125, and TA = +25C; see Figure 3.)
MAX3054/MAX3055/MAX3056
MAX3056 DRIVER PROPAGATION DELAY vs. TEMPERATURE
MAX3054/MAX3055/MAX3056 toc10
RECEIVER OUTPUT LOW vs. OUTPUT CURRENT
MAX3054/MAX3055/MAX3056 toc11
RECEIVER OUTPUT HIGH vs. OUTPUT CURRENT
MAX3054/MAX3055/MAX3056 toc12
3.5 CL = 3.3nF DRIVER PROPAGATION DELAY (s) 3.0
3.0 2.5 TA = +125C VOLTAGE RXD (V) 2.0 1.5 TA = +25C 1.0 0.5 TA = -40C
3.0
2.4 VOLTAGE RXD (V) TA = +125C 1.8 TA = +25C 1.2
RECESSIVE
2.5 DOMINANT 2.0
0.6 TA = -40C 0 0 5 10 15 20 25 30 0 3 6 9 12 15 18 OUTPUT CURRENT (mA) OUTPUT CURRENT (mA)
1.5 -50 -15 20 55 90 125 TEMPERATURE (C)
0
DIFFERENTIAL VOLTAGE vs. LOAD RESISTANCE
MAX3054/MAX3055/MAX3056 toc13
MAX3054 RECEIVER PROPAGATION DELAY
MAX3054/MAX3055/MAX3056 toc14
5
DIFFERENTIAL VOLTAGE (V)
4
TA = +25C
TA = +125C
DIFFERENTIAL INPUT 5V/div
3 TA = -40C 2
1
RXD 5V/div
0 0 100 200 300 400 500 200ns/div LOAD RESISTANCE ()
MAX3055 RECEIVER PROPAGATION DELAY
MAX3054/MAX3055/MAX3056 toc15
MAX3056 RECEIVER PROPAGATION DELAY
MAX3054/MAX3055/MAX3056 toc16
DIFFERENTIAL INPUT 5V/div
DIFFERENTIAL INPUT 5V/div
RXD 5V/div
RXD 5V/div
400ns/div
1s/div
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80V Fault-Protected/Tolerant CAN Transceivers for In-Car Applications MAX3054/MAX3055/MAX3056
Typical Operating Characteristics (continued)
(VCC = 5V, VBATT = +12V, RTL = RTH = 511, R1 = 125, and TA = +25C; see Figure 3.)
DRIVER PROPAGATION DELAY RECESSIVE TO DOMINANT
MAX3054/MAX3055/MAX3056 toc17
DRIVER PROPAGATION DELAY DOMINANT TO RECESSIVE
MAX3054/MAX3055/MAX3056 toc18
TXD-TO-RXD PROPAGATION DELAY DOMINANT TO RECESSIVE
MAX3054/MAX3055/MAX3056 toc19
TXD 5V/div MAX3054
TXD 5V/div
TXD
MAX3056 MAX3055 MAX3055 MAX3054 MAX3056 MAX3056 MAX3055 MAX3054 1s/div 1s/div 1s/div
TXD-TO-RXD PROPAGATION DELAY RECESSIVE TO DOMINANT
MAX3054/MAX3055/MAX3056 toc20
MAX3056 CAN BUS AT 40kbps
MAX3054/MAX3055/MAX3056 toc21
TXD CANH - CANL 5V/div MAX3054
MAX3055 FFT 1V/div MAX3056 1s/div 4s/div
MAX3055 CAN BUS AT 125kbps
MAX3054/MAX3055/MAX3056 toc22
MAX3054 CAN BUS AT 250kbps
MAX3054/MAX3055/MAX3056 toc23
CANH - CANL 5V/div
CANH - CANL 10V/div
FFT 1V/div
FFT 1V/div
2s/div
400ns/div
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80V Fault-Protected/Tolerant CAN Transceivers for In-Car Applications
Pin Description
PIN 1 2 3 4 5 6 7 8 9 10 11 12 13 14 NAME INH TXD RXD ERR STB EN WAKE RTH RTL VCC CANH CANL GND BATT Transmit Data Input Receive Data Output Error. Wake-up and power-on indication output; active low in normal operating mode when the bus has a failure and in low-power modes (wake-up signal or power-on standby). Standby. The digital control signal input (active low) defines, together with input signal on pin EN, the state of the transceiver (in normal and low-power modes). Enable. The digital control signal input defines, together with input signal on pin STB, the state of the transceiver (in normal and low-power modes). Wake-Up. Local wake-up signal input; falling and rising edges are both detected. Termination Resistor. Termination resistor connection for CANH bus. Termination Resistor. Termination resistor connection for CANL bus. Supply Voltage. Bypass to ground with a 0.1F capacitor. High-Level Voltage Bus Line Low-Level Voltage Bus Line Ground Battery Supply. Bypass to ground with a 0.1F capacitor. FUNCTION Inhibit Output. Inhibit output is for switching an external voltage regulator if a wake-up signal occurs.
MAX3054/MAX3055/MAX3056
Detailed Description
The MAX3054/MAX3055/MAX3056 interface between the protocol controller and the physical wires of the bus lines in a CAN. The devices provide differential transmit capability and switch to single-wire mode if certain fault conditions occur (see the Failure Management section). The MAX3054/MAX3055/MAX3056 guarantee full wakeup capability during failure modes. The extended fault-protection range of CANH and CANL bus lines (80V) allows for use in 42V automotive applications. A current-limiting circuit protects the transmitter output stage against overcurrent faults. This feature prevents destruction of the transmitter output stage. If the junction temperature exceeds a value of approximately +165C, the transmitter output stages are disabled. The CANH and CANL lines are also protected against electrical transients, which can occur in an automotive environment. The transceiver provides three low-power modes that can be entered and exited through pins STB and EN. An output INH pin can be used for deactivation of an external voltage regulator. The MAX3054/MAX3055/MAX3056 are designed to provide optimal operation for a specified data rate. The
MAX3054 is ideal for high data rates of 250kbps. The MAX3055 is used for data rates of 125kbps, and the MAX3056 is designed for 40kbps applications. For the 40kbps and 125kbps versions, the built-in slope-control feature allows the use of unshielded cables and receiver input filters guarantee high noise immunity.
Normal Operation Mode
Transmitter The transmitter converts a single-ended input (TXD) from the CAN controller to differential outputs for the bus lines (CANH, CANL). Receiver The receiver takes differential input from the bus lines (CANH, CANL) and converts this data as a singleended output (RXD) to the CAN controller. It consists of a comparator that senses the difference V = (CANH CANL) with respect to an internal threshold. BATT The main function of BATT is to supply power to the device when vehicle battery voltage is supplied. BATT can handle up to +80V making it ideal for 42V automotive systems allowing power-up of the device when the ignition is turned on.
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11
80V Fault-Protected/Tolerant CAN Transceivers for In-Car Applications MAX3054/MAX3055/MAX3056
BATT
10
VCC
INH 1 WAKE 7 STB 5 EN 6 WAKE-UP STANDBY CONTROLLER THERMAL SHUTDOWN
9 11
RTL CANH CANL
TXD 2 DRIVER 4ms 8 RTH 12
FILTER
ERR 4 FAULT DETECTION GND
IPD
RXD 3
RECEIVER
MAX305_
Figure 5. Block Diagram
INH Inhibit is an output that allows for the control of an external voltage regulator. On a wake-up request or power-up on BATT, the transceiver sets the output INH high. This feature enables the external voltage regulator to be shut down during sleep mode to reduce power consumption. INH is floating while entering the sleep mode and stays floating during the sleep mode. If INH is left floating, it is not set to a high level again until the following events occur: * Power-on (VBATT switching on at cold start) * Rising or falling edge on WAKE * Dominant signal longer than 38s during EN or STB at low level The signals on STB and EN are internally set to a low level when VCC is below a certain threshold voltage providing fail-safe functionality. After power-on (VBATT switched on) the signal on INH becomes HIGH and an internal power-on flag is set. This flag can be read in the power-on standby mode through ERR (STB = 1, EN = 0) and is reset by entering the normal operating mode.
12
ERR ERR is a wake-up and power-on indicator, as well as an error detector. Upon power-up, wake-up, or when a bus failure is detected, the output signal on ERR becomes LOW. Upon error recovery, the output signal on ERR is set HIGH. STB STB is the standby digital control signal into the logic controller. This is an active-low input that is used with EN to define the status of the transceiver in normal and low-power modes. EN EN is the enable digital control signal into the logic controller used in conjunction with STB to define the status of the transceiver in normal and low-power modes. WAKE WAKE is an input to the logic controller within the device to signal a wake-up condition. If WAKE receives a positive or negative pulse for a period longer than tWAKE, wake-up occurs.
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80V Fault-Protected/Tolerant CAN Transceivers for In-Car Applications
Driver Output Protection
Thermal Shutdown If the junction temperature exceeds +165C, the driver is switched off. Thermal hysteresis is 15C, disabling thermal shutdown once the temperature reaches +150C. Overcurrent Protection A current-limiting circuit protects the transmitter output stage against a short circuit to a positive and negative battery voltage. Although the power dissipation increases during this fault condition, this feature prevents destruction of the transmitter output stage.
Failure Management
The failure detector is fully active in normal operating mode. After the detection of a single failure, the detector switches to the appropriate state (see Table 1). The differential receiver threshold voltage is set to -3.2V typically (VCC = 5V). This ensures correct reception with a noise margin as high as possible in the normal operating mode and in the event of failures 1, 2, 5, and 9. If any of the wiring failures occur, the output signal on pin ERR becomes LOW after detection. On error recovery, the output signal on pin ERR becomes HIGH.
MAX3054/MAX3055/MAX3056
Table 1. Failure States
FAILURE 1 2 3 4 5 6 7 8 9 CANH wire interrupted CANL wire interrupted CANH short circuited to battery CANL short circuited to ground CANH short circuited to ground CANL short circuited to battery CANL mutually short circuited to CANH CANH short circuited to VCC CANL short circuited to VCC DESCRIPTION MODE Normal Normal All All Normal Normal All All Normal
Failure 1--CANH Wire Interrupted (Normal Mode Only)
MODE Detection Receiver Driver Recovery DESCRIPTION The external termination resistance connected to the RTH pin provides an instantaneous pulldown of the open CANH line to GND. Detection is provided, sensing the pulse-count difference between CANH and CANL (pulse count = 4). The receiver remains in differential mode. No received data lost. Driver remains in differential mode. No transmission data lost. Recovery is provided sensing the pulse-count difference between CANH and CANL after the detection of four consecutive pulses.
Failure 2--CANL Wire Interrupted (Normal Mode Only)
MODE Detection Receiver Driver Recovery DESCRIPTION The external termination resistance connected to the RTL pin provides an instantaneous pullup of the CANL line to VCC. Detection is provided, sensing the pulse-count difference between CANL and CANH (pulse count = 4). The receiver remains in differential mode. No received data lost. Driver remains in differential mode. No transmission data lost. Recovery is provided, sensing the pulse-count difference between CANL and CANH after the detection of four consecutive pulses.
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80V Fault-Protected/Tolerant CAN Transceivers for In-Car Applications MAX3054/MAX3055/MAX3056
Table 1. Failure States (continued) Failure 3--CANH Short Circuited to Battery
MODE Detection Receiver Driver Recovery Receiver switches to single ended on CANL. CANH and RTH are both switched off (high impedance) and transmission continues on CANL after timeout. When the short is removed, the recessive bus voltage is restored. If the differential voltage remains below the recessive threshold level for the timeout period, reception and transmission switch back to the differential mode. DESCRIPTION Sensing a permanent dominant condition on CANH for a timeout period.
Failure 4--CANL Short Circuited to GND
MODE Detection Receiver Driver Recovery Receiver switches to single ended on CANH. CANL and RTL are both switched off (high impedance) and transmission continues on CANH after timeout. When the short is removed, the recessive bus voltage is restored. If the differential voltage remains below the recessive threshold level for the timeout period, reception and transmission switch back to the differential mode. DESCRIPTION Sensing a permanent dominant condition for a timeout period.
Failure 5--CANH Short Circuited to Ground or Below Ground (Normal Mode Only)
MODE Detection Receiver Driver Recovery DESCRIPTION Detection is provided, sensing the pulse-count difference between CANH and CANL (pulse count = 4). Receiver remains in differential mode. No received data lost. RTH remains on and CANH remains enabled. Recovery is provided, sensing the edge-count difference between CANH and CANL after the detection of four consecutive pulses.
Failure 6--CANL Short Circuited to Battery (Normal Mode Only)
MODE Detection Receiver Driver Recovery DESCRIPTION Detected by a comparator for CANL > 7.3V after a timeout period. Receiver switches to single ended on CANH after timeout. RTL is switched off after timeout. CANH remains active. Sensing CANL < 7.3V after the timeout period.
Failure 7--CANL Mutually Short Circuited to CANH
MODE Detection Receiver Driver Recovery DESCRIPTION Sensing a permanent dominant condition on the differential comparator (CANH - CANL > -3.2V) for the timeout period. Receiver switches to CANH single-ended mode after timeout. CANL and RTL are both switched off after timeout. Transmission remains ongoing on CANH. When the short is removed, the recessive bus voltage is restored (RTL on if CANH - CANL < -3.2V) but CANL still remains disabled and ERR = 0. If the differential voltage remains below the recessive threshold level (CANH CANL < -3.2V) for the timeout period, reception and transmission switch back to the differential mode.
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80V Fault-Protected/Tolerant CAN Transceivers for In-Car Applications MAX3054/MAX3055/MAX3056
Table 1. Failure States (continued) Failure 8--CANH Short Circuited to Vcc
MODE Detection Receiver Driver Recovery Receiver switches to single ended on CANL. CANH and RTH are both switched off (high impedance) and transmission continues on CANL after timeout. When the short is removed, the recessive bus voltage is restored. If the differential voltage remains below the recessive threshold level for the timeout period, reception and transmission switch back to the differential mode. DESCRIPTION Sensing a permanent dominant condition on CANH for a timeout period.
Failure 9--CANL Short Circuited to Vcc (Normal Mode Only)
MODE Detection Receiver Driver Recovery DESCRIPTION Detection is provided, sensing the pulse-count difference between CANL and CANH (pulse count = 4). Receiver remains in differential mode. No received data lost. Driver remains in differential mode. No transmission data lost. Recovery is provided, sensing the pulse-count difference between CANL and CANH after the detection of four consecutive pulses.
Table 2. Summary of the Driver Outputs and Internal Switches State During Fault Conditions
FAILURE NO. No failure No failure 1 2 3 4 5 6 7 8 9 DESCRIPTION -- -- CANH wire interrupted CANL wire interrupted CANH short to BATT CANL short to GND CANH short to GND CANL short to BATT CANL short to CANH CANH short to VCC CANL short to VCC MODE Normal Low power Normal Normal All All Normal Normal All All Normal INTERNAL SWITCHES STATE RTH, RTL on RTH, I_RTL on RTH, RTL on RTH, RTL on RTH off RTL or I_RTL off RTH, RTL on RTL off, RTH on RTL or I_RTL off RTH off RTH, RTL on DRIVER OUTPUTS STATE CANH Enabled Disabled Enabled Enabled Disabled Enabled Enabled Enabled Enabled Disabled Enabled CANL Enabled Disabled Enabled Enabled Enabled Disabled Enabled Enabled Disabled Enabled Enabled
Note: The RTH-pulldown current switch and the RTL-pullup current switch are closed in normal mode with or without fault conditions, open in sleep mode.
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80V Fault-Protected/Tolerant CAN Transceivers for In-Car Applications MAX3054/MAX3055/MAX3056
Low-Power Modes
The transceiver provides three low-power modes that can be entered or exited through pins STB and EN (Table 3). Sleep Mode The sleep mode is the mode with the lowest power consumption. INH is switched to high impedance for deactivation of the external voltage regulator. CANL is biased to the battery voltage through RTL. If the supply voltage is provided, RXD and ERR signal the wake-up interrupt. Standby Mode The standby mode reacts the same as the sleep mode, but with a HIGH level on INH. Standby mode can be used when the external voltage regulator needs to be kept active during low-power operation. Power-On Standby Mode The power-on standby mode behaves similarly to the standby mode with the battery power-on flag of the wake-up interrupt signal on ERR. This mode is only for reading the power-on flag. INH can be high or low in the power-on standby mode. When the device goes from standby mode to power-on standby mode, INH is HIGH. When the device goes from sleep mode to power-on standby mode, INH is low. Wake-Up Wake-up requests are recognized by the transceiver when a dominant signal is detected on either bus line or if WAKE detects a pulse for more than 38s. On a wake-up request, INH is set high to activate an external voltage regulator. If VCC is provided, the wake-up request can be read on the ERR or RXD outputs. To prevent false wake-up due to transients or RF fields, the wake-up voltage levels have to be maintained for more than 38s. In the low-power modes, the failure detection circuit remains partly active to prevent increased power consumption in the event of failures 3, 4, 7, and 8.
Applications Information
The MAX3054/MAX3055/MAX3056 are capable of sustaining a network of up to 32 transceivers on a single bus. The fault-tolerant transceivers are designed to operate at a total termination resistance of 100. Both CANH and CANL lines are terminated with 100. Since the total termination resistance of the system is distributed over the entire bus, each of the transceivers contributes only part of the total 100 termination. The values of the termination resistors RTL and RTH vary according to the size of the system and need to be calculated. It is not required that each transceiver be terminated with the same value, the total termination need only be a total 100. The minimum termination resistor value allowed for each transceiver is 500, due to the driving capability of RTH and RTL. This makes it impossible to achieve a total termination resistance of 100 for systems smaller than five transceivers. Typically this does not create a problem because smaller systems usually have shorter bus cables and have no problem with higher total termination resistance. To reduce EMI in the case of an interrupted bus wire it is recommended not to exceed 6k termination resistance at a single transceiver even though a higher value is specified.
Table 3. Low-Power Modes
MODE Go-to-Sleep Command Sleep Standby Power-On Standby Normal Operating STB 0 0 0 1 EN 1 0 (Note 1) 0 0 VBATT power-on flag Error flag -- Wake-up interrupt signal (Notes 2 and 3) Dominant received data -- Recessive received data VBATT ERR LOW Wake-up interrupt signal (Notes 2 and 3) HIGH LOW Wake-up interrupt signal (Notes 2 and 3) RXD HIGH RTL SWITCHED TO
--
--
VBATT
1
1
No error flag
VCC
Note 1: In case the go-to-sleep command was used before. Note 2: If the supply voltage VCC is present. Note 3: Wake-up interrupts are released when entering the normal operating mode. 16 ______________________________________________________________________________________
80V Fault-Protected/Tolerant CAN Transceivers for In-Car Applications
Reduced EMI and Reflections
Due to internal slope control for the MAX3055/ MAX3056, the CANH and CANL outputs are slew-rate limited. This minimizes EMI and reduces reflections caused by improperly terminated cables. In general, a transmitter's rise time relates directly to the length of an unterminated stub, which can be driven with only minor waveform reflections. The following equation expresses this relationship conservatively: Length = tRISE / (15ns/ft) where tRISE is the transmitter's rise time. The MAX3054/MAX3055/MAX3056 require no special layout considerations beyond common practices. Bypass VCC to GND with a 0.1F ceramic capacitor mounted close to the IC with short lead lengths and wide trace widths.
MAX3054/MAX3055/MAX3056
Chip Information
TRANSISTOR COUNT: 1300 PROCESS: BiCMOS
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80V Fault-Protected/Tolerant CAN Transceivers for In-Car Applications MAX3054/MAX3055/MAX3056
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.)
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
18 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 2002 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
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