LT1796CN8

LT1796 Overvoltage Fault Protected CAN Transceiver FEATURES s s DESCRIPTIO s s s s s s s Protected from Overvoltage Line Faults to ±60V ESD Protection to IEC-1000-4-2 Level 4 ±15kV Air Gap Test ±8kV Contact Mode Test ISO 11898 Compatible High Input Impedance Supports Up to 256 Nodes Controlled Slew Rates for EMI Emissions Control High Impedance Outputs When Off or Powered Down Short-Circuit Protection On All Outputs Thermal Shutdown Protection Pin Compatible with Philips PCA82C251 The LT®1796 CAN transceiver provides built-in fault tolerance to survive in industrial and automotive environments. Discrete protection devices are not needed. Bus interface pins can withstand voltage faults up to ± 60V with respect to ground with no damage to the device. Faults may occur while the transceiver is active, shut down or powered off. On-chip ESD protection withstands up to ±15kV air discharges and ± 8kV contact mode discharges tested per IEC-1000-4-2. Loss of power or ground connections does not damage the IC. The circuit operates with data rates up to 125kbaud. A slew control pin allows control of transmitted data pulse edges to control EMI and reflection problems on imperfectly terminated lines. High output current drive allows the use of inexpensive PVC cable with impedance as low as 72Ω. The 100kΩ input impedance allows up to 256 transceivers per data network. The LT1796 is available in 8-lead PDIP and SO packages. , LTC and LT are registered trademarks of Linear Technology Corporation. APPLICATIO S s s s Industrial Control Data Networks Automotive Systems HVAC Controls TYPICAL APPLICATIO RT 120Ω 5V 0.1µF Fault Protected CAN Bus Network RT 120Ω 5V 0.1µF 125kbps CANH and CANL Driver Output CANH-CANL 2V/DIV LT1796 7 TXD 1 D 6 RXD 4 R VREF GND 2 RS 8 5 5 6 7 LT1796 D 1 TXD CANH 2V/DIV CANL 2V/DIV TXD IN 5V/DIV 5V/DIV 1796 TA02 R VREF RS 8 GND 2 4 RXD 1796 TA01 U 1796f U U 1 LT1796 ABSOLUTE MAXIMUM RATINGS (Note 1) PACKAGE/ORDER INFORMATION ORDER PART NUMBER TOP VIEW TXD 1 D GND 2 VCC 3 RXD 4 R 7 6 5 8 RS CANH CANL VREF Supply Voltage (VCC) .............................................. 44V RS Slope Control Input Voltage ................ – 0.3V to 44V VREF Reference Output Pin ......................... – 0.3V to 7V Driver Input Voltage .................................. – 0.3V to 44V CANH, CANL Data Line Pins ...................... – 80V to 80V Receiver Output Voltages ............................– 0.3V to 7V Operating Temperature Range LT1796C .................................................. 0°C to 70°C LT1796I .............................................. – 40°C to 85°C Storage Temperature Range ................. – 65°C to 150°C Lead Temperature (Soldering, 10 sec).................. 300°C LT1796CN8 LT1796CS8 LT1796IN8 LT1796IS8 S8 PART MARKING 1796 1796I N8 PACKAGE S8 PACKAGE 8-LEAD PDIP 8-LEAD PLASTIC SO TJMAX = 150°C, θJA = 130°C/W (N8) TJMAX = 150°C, θJA = 150°C/W (S8) Consult LTC Marketing for parts specified with wider operating temperature ranges. DC ELECTRICAL CHARACTERISTICS SYMBOL VCANH VCANL VOD PARAMETER CANH Output Voltage CANL Output Voltage Dominant State Differential Output Voltage The q denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VCC = 4.75V to 5.25V, VRS = 0V unless otherwise noted. CONDITIONS VTXD = 0V, No Load VTXD = 0V, RL = 60Ω VTXD = 0V, No Load VTXD = 0V, RL = 60Ω VTXD = 0V, No Load, VCC = 4.75V VTXD = 0V, RL = 60Ω, VCC = 4.75V VTXD = 0V, RL = 36Ω, VCC = 4.75V VTXD = 5V, RL = 60Ω VTXD = 5V, RL = 60Ω, VCC = 5V RL = 60Ω, VCC = 5V q q q q q q q q q q q q MIN 3.8 2.8 0 0 3.0 1.5 1.2 – 10 2.7 2 2.8 TYP 4.4 3.5 0.5 1.3 3.6 2.0 1.7 0 3 2.5 MAX 5.0 4.6 0.9 1.6 5.0 4.2 4.2 10 3.5 3 2 UNITS V V V V V V V mV V V V V µA mA mA mA mA mA mA mA mA kΩ kΩ mA mA mA VREC VCMR VCMD VIH VIL IIN1 ISCH Recessive State Differential Output Voltage Recessive State Common Mode Output Voltage Dominant State Common Mode Output Voltage TXD Input High Voltage TXD Input Low Voltage TXD Input Current CANH Short-Circuit Current, Dominant Mode 0 < VTXD < VCC VCANH = 0V, VCC = 5.25V VCANH = – 36V, VCC = 5.25V VCANH = – 60V, VCC = 5.25V VCANH = 60V, VCC = 5.25V VCANL = 5V, VTXD = 0V, VCC = 5.25V VCANL = 36V, VTXD = 0V, VCC = 5.25V VCANL = 60V, VTXD = 0V, VCC = 5.25V VCANL = – 60V, VTXD = 0V, VCC = 5.25V VTXD = 5V, – 7V < VCANH, VCANL < 12V VTXD = 5V, – 7V < VCANH, VCANL< 12V VRS = 5V, – 60V < VCANH, VCANL < 60V VTXD = 5V, – 60V < VCANH, VCANL < 60V VCC = 0V, – 60V < VCANH, VCANL < 60V q q q q q q q q q q q q q q –5 – 250 – 10 – 10 0 60 0 0 – 10 140 70 –3 –3 –3 –1 –1 1 1 1 –1 240 120 5 – 60 0 0 10 250 10 10 0 350 175 3 3 3 ISCL CANL Short-Circuit Current, Dominant Mode RIND Differential Input Resistance CANH, CANL Input Resistance Input Fault Current (CANH, CANL) 2 U W U U WW W 1796f LT1796 DC ELECTRICAL CHARACTERISTICS SYMBOL VTH ∆VTH VOH VOL ISCR VREF VREFSC VRSSB IRS PARAMETER Differential Input Threshold Voltage for Receiver Receiver Input Hysteresis Receiver Output High Voltage Receiver Output Low Voltage Receiver Short-Circuit Current Reference Output Voltage Reference Output Short-Circuit Current RS Pin Standby Threshold RS Input Current The q denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VCC = 4.75V to 5.25V, VRS = 0V unless otherwise noted. CONDITIONS VRS = 0V, – 7V < VCM < 12V VRS = 5V, – 7V < VCM < 12V – 7V < VCM < 12V VCC = 4.75V, IO = – 400µA, VID = 500mV VCC = 4.75V, IO = 1.6mA, VID = 900mV 0V < VO < VCC , VCC = 5.25V – 100µA < IREF < 100µA 0 < VREF < VCC VCC = 5V VRS = 5V, VCC = 5V VRS = 0V, VCC = 5V RS = 47k, VCC = 5V Dominant Recessive Standby No Load, VRS = 0V, VTXD = 0V, VCC = 5.25V RL = 60Ω, VRS = 0V, VTXD = 5V, VCC = 5.25V RL = 60Ω, VRS = 5V, VCC = 5.25V q q q q q q q q q q q q q q MIN 0.5 0.5 TYP MAX 0.9 0.9 UNITS V V mV V 70 3 7 2.25 – 20 2.5 – 270 – 90 2.8 0.1 – 200 – 60 4.3 3.8 0.8 3.6 0.15 20 2.5 0.4 85 2.7 20 4 10 – 140 – 40 7 7 1.5 V mA V mA V µA µA µA mA mA mA ICC Supply Current SWITCHI G CHARACTERISTICS SYMBOL tBIT FMAX tTXDON tTXDOFF tLBON tLBOFF tRXDOFF tRXDON tRXDOFFSB tRXDONSB tWAKE SR + SR – PARAMETER Minimum Bit Time Maximum Data Rate Driver Input to Bus Active Driver Input to Bus Inactive Loopback Delay Active Loopback Delay Inactive Receiver Delay Off Receiver Delay On Receiver Delay Off, Standby Receiver Delay On, Standby Wake-Up Delay from Standby Positive Slew Rate Negative Slew Rate The q denotes the specifications which apply over the full operating temperature range. VRS = 0V unless otherwise noted. (Note 2) CONDITIONS (Note 3) (Note 3) Figures 1, 2 Figures 1, 2 Figures 1, 3 Figures 1, 3 Figures 1, 4 Figures 1, 4 VRS = 4V, Figures 1, 4 VRS = 4V, Figures 1, 4 Figures 1, 5 RS = 0k RS = 47k RS = 0k RS = 47k RS = 0k RS = 47k RS = 0k RS = 47k q q q q q q q q q q q q q q q q q Note 1: Absolute Maximum Ratings are those values beyond which the life of the device may be impaired. Note 2: Unless otherwise specified, testing done at VCC = 5V, TA = 25°C. U MIN 125 TYP MAX 8 UNITS µs kbps ns ns ns ns µs µs ns ns µs µs µs V/µs V/µs V/µs V/µs 300 350 500 600 0.6 1.5 400 300 1.5 1 1 5 2 5 2 12 7 36 5 500 1000 1000 1500 1.5 3 600 600 4 4 15 65 30 65 15 Note 3: Bit time and data rate specifications are guaranteed by driver and receiver delay time measurements. 1796f 3 LT1796 TYPICAL PERFOR A CE CHARACTERISTICS Dominant State Bus Voltage vs RL 3.0 2.5 2.0 VOD (V) TA = 25° C SUPPLY CURRENT (mA) 1.5 1.0 0.5 0 0 50 RS Pin Current vs RS 250 TA = 25° C SLEW CONTROL CURRENT (µA) 200 150 SR+ (V/µs) SR– (V/µs) 100 50 0 0 20 40 RS (kΩ) 60 80 1796 G04 Transmitter Propagation Delay vs Temperature 700 600 tTXDOFF AND tTXDON (ns) 500 tTXDOFF 300 200 100 0 –50 tTXDON ISC (mA) –40 –60 –80 ISC (mA) 400 –25 0 25 50 TEMPERATURE (°C) 4 UW 75 1796 G07 Supply Current vs Data Rate Transmitting, 50% Duty Cycle 24 TA = 25° C 23 22 21 20 100 150 RL (Ω) 200 250 1796 G01 0 50 150 100 DATA RATE (Kbps) 200 250 1796 G03 Positive Slew Rate vs RS 15 TA = 25° C 40 Negative Slew Rate vs RS TA = 25° C 30 10 20 5 10 0 0 0 20 40 RS (kΩ) 60 80 1796 G05 0 20 40 RS (kΩ) 60 80 1796 G06 CANH Short-Circuit Current vs Voltage 20 0 –20 TA = 25° C 90 80 70 60 50 40 30 20 10 CANL Short-Circuit Current vs Voltage TA = 25° C –100 –120 –60 0 100 –40 –20 0 20 VCANH (V) 40 60 1796 G08 –10 –60 –40 –20 0 20 VCANL (V) 40 60 1796 G09 1796f LT1796 TYPICAL PERFOR A CE CHARACTERISTICS Receiver Thresholds vs Temperature 0.80 0.75 VTH RISING tRXDOFF AND tRXDON (ns) VTH (V) 0.70 VTH FALLING 0.65 0.60 –50 –25 PI FU CTIO S TXD (Pin 1): Driver Input. Logic-level thresholds are set by VREF. A logic input level higher than VREF turns the driver outputs off, releasing control of the CANH and CANL lines. A logic input less than VREF turns the driver outputs on, pulling CANH high and CANL low. An open TXD input will float high, turning the driver outputs off. The TXD input pin can withstand voltages from – 0.3V to 44V with no damage. GND (Pin 2): Ground. VCC (Pin 3): Positive Supply Input. Normal operation is with a 4.75V to 5.25V supply. Operation with supplies up to 44V is possible with unterminated bus lines. Operation at high voltages with normally terminated busses will result in excessive power dissipation and activation of the thermal shutdown circuit. VCC should be decoupled with a 0.1µF low ESR capacitor placed as close to the supply pin as possible. RXD (Pin 4): Receiver TTL Level-Logic Output. A high level output indicates a recessive state (zero-volt differential) bus. A dominant state forces a low receiver output. VREF (Pin 5): Reference Output. The reference voltage sets the TXD input threshold and the recessive bus common mode voltage at CANH and CANL. VREF is approximately VCC/2 for low voltage operation. When VCC > 7.5V, VREF maintains a 3.5V level. CANL (Pin 6): CAN Bus Low Data Line. The CANL pin is one input to the receiver and the low driver output. In the dominant state (TXD low), the driver pulls the CANL pin to within 1V of GND. In the recessive state (TXD high), the driver output stays high impedance. The CANL pin is protected from voltage faults from – 60V to 60V in dominant, recessive, standby or powered off modes. On-chip ESD protection meets IEC-1000-4-2 levels. CANH (Pin 7): CAN Bus High Data Line. The CANH pin is one input to the receiver and the high driver output. In the dominant state (TXD low), the driver pulls the CANH pin to within 1V of VCC. In the recessive state (TXD high), the driver output stays high impedance. The CANH pin is protected from voltage faults from – 60V to 60V in dominant, recessive, standby or powered off modes. On-chip ESD protection meets IEC-1000-4-2 levels. RS (Pin 8): Slope Control. This pin is a multifunction control pin. When RS is high (VRS > 4V), the circuit goes into a low power standby mode. In standby, the driver always stays in a high impedance (recessive) state. The receiver operates in a low power (slow) monitoring mode. Received data may be used to “wake-up” the system to full functionality. Full speed normal operation occurs if RS is tied low through a resistance of less than 3k. The current out of RS will be limited to about 500µA in the low state. Controlling the current out of RS with a resistor greater than 3k or by using a current source allows slew rate control of the data output onto CANH and CANL. 1796f UW Receiver Propagation Delay vs Temperature 400 350 tRXDOFF 300 tRXDON 250 0 25 50 TEMPERATURE (°C) 75 100 1796 G10 200 –50 –25 0 25 50 TEMPERATURE (°C) 75 100 1796 G11 U U U 5 LT1796 BLOCK DIAGRA TXD 1 RS RXD VREF 8 SLOPE/ STANDBY 7 CANH CANL RX 6 REFERENCE VOLTAGE 4 5 TI I G DIAGRA S 5V TXD 0V VDIFF = VCANH – VCANL VDIFFHI VDIFF VDIFFLO 25% tTXDOFF 50% RXD 0V 2V 0.8V tLBON 5V 2.5V Figure 2. Driver Delay Waveforms 3.5V CANH 2.5V CANL = 2.5V RXD 2V 0.8V tRXDON tRXDOFF 3V 3V Figure 4. Reciever Delay Waveforms FU CTIO TABLES Driver Output INPUTS TXD 0 0 1 1 RS VRS < 3V VRS > 4V VRS < 3V VRS > 4V BUS TERMINALS CANH High Hi-Z Hi-Z Hi-Z CANL Low Hi-Z Hi-Z Hi-Z OPERATING STATE Dominant Standby Recessive Standby 6 W W VCC 3 DRIVER 2 GND 1796 BD TEST CIRCUIT 5V 0.1µF 3 1 TXD CANH 7 60Ω 4 RXD CANL 6 100pF 30pF GND VREF RS 2 5 8 RS 1796 F01 Figure 1. Switching Test Circuit U UW U 2.5V TXD 0V 2.5V 2.5V tTXDON 1796 F02 tLBOFF 1796 F03 Figure 3. Loopback Delay Waveforms 5V RS 0V 2.5V RXD tWAKE 0.8V 1796 F05 1796 F04 Figure 5. Wake Up from Standby Waveforms Receiver Output BUS VOLTAGE VBUS = VCANH – VCANL VBUS < 0.5V 0.5V ≤ VBUS ≤ 0.9V VBUS > 0.9V VBUS < 0.5V 0.5V ≤ VBUS ≤ 0.9V VBUS > 0.9V RS < 3V < 3V < 3V > 4V > 4V > 4V RXD High Indeterminate Low High Indeterminate Low RESPONSE TIME Fast Fast Fast Slow Slow Slow 1796f LT1796 PACKAGE DESCRIPTIO U N8 Package 8-Lead PDIP (Narrow .300 Inch) (Reference LTC DWG # 05-08-1510) .400* (10.160) MAX 8 7 6 5 .255 ± .015* (6.477 ± 0.381) 1 .300 – .325 (7.620 – 8.255) 2 3 4 .130 ± .005 (3.302 ± 0.127) .045 – .065 (1.143 – 1.651) .065 (1.651) TYP .120 (3.048) .020 MIN (0.508) MIN .018 ± .003 (0.457 ± 0.076) N8 1002 .008 – .015 (0.203 – 0.381) ( +.035 .325 –.015 8.255 +0.889 –0.381 ) .100 (2.54) BSC INCHES MILLIMETERS *THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .010 INCH (0.254mm) NOTE: 1. DIMENSIONS ARE S8 Package 8-Lead Plastic Small Outline (Narrow .150 Inch) (Reference LTC DWG # 05-08-1610) .045 ±.005 .050 BSC 8 N N .245 MIN .160 ±.005 .228 – .244 (5.791 – 6.197) 1 .030 ±.005 TYP 2 3 N/2 N/2 .150 – .157 (3.810 – 3.988) NOTE 3 .189 – .197 (4.801 – 5.004) NOTE 3 7 6 5 RECOMMENDED SOLDER PAD LAYOUT 1 2 3 4 .010 – .020 × 45° (0.254 – 0.508) .008 – .010 (0.203 – 0.254) 0°– 8° TYP .053 – .069 (1.346 – 1.752) .004 – .010 (0.101 – 0.254) .016 – .050 (0.406 – 1.270) NOTE: 1. DIMENSIONS IN INCHES (MILLIMETERS) 2. DRAWING NOT TO SCALE 3. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm) .014 – .019 (0.355 – 0.483) TYP .050 (1.270) BSC SO8 0502 1796f Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. 7 LT1796 TYPICAL APPLICATIO 5V 0.1µF 3 LT1796 7 TXD 1 D 6 RXD 4 R VREF GND 2 RS 8 47k 5 5 VREF RS 8 6 7 0.1µF RELATED PARTS PART NUMBER LTC485 LTC491 LTC1483 LTC1485 LTC1487 LT1785/LT1791 DESCRIPTION Low Power RS485 Interface Transceiver Differential Driver and Receiver Pair Ultralow Power RS485 Low EMI Transceiver RS485 Differential Bus Transceiver Ultralow Power RS485 with Low EMI, Shutdown and High Input Impedance 60V Fault-Protected RS485/RS422 Transceivers COMMENTS ICC = 300µA Typ ICC = 300µA Typ Controlled Driver Slew Rate 10Mbaud Operation Up to 256 Transceivers On the Bus 15kV ESD Protected 8 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 q FAX: (408) 434-0507 q U Low EMI, Slew Limited CANBUS Network RT 120Ω RT 120Ω 5V 3 LT1796 D 1 TXD R 4 RXD GND 2 1796 TA03 47k 1796f LT/TP 0203 2K • PRINTED IN THE USA www.linear.com © LINEAR TECHNOLOGY CORPORATION 2001