LTM2889 Isolated CAN FD Module Transceiver and Power FEATURES DESCRIPTION Isolated 4Mbps CAN FD Transceiver nn 2500V RMS for 1 Minute Per UL1577 nn Isolated DC Power: 5V (Adjustable to 3.3V) nn Up to 150mA Available Isolated Power Output nn 3.3V or 5V Input Supply Voltage Options nn UL-CSA Recognized File #E151738 nn No External Components Required nn High Bus Fault Voltage Tolerance: 60V nn Low Power OFF Mode: <1A Typical nn High Common Mode Transient Immunity: 30kV/s nn Variable Slew Rate Driver with Active Symmetry Control and SPLIT Pin for Low EME nn Fully ISO 11898-2 and CAN FD Compliant nn Ideal Passive Behavior to CAN Bus with Supply Off nn Transmit Data (TXD) Dominant Timeout Function nn High ESD: 25kV CANH, CANL to GND2 and V CC2; 10kV Across Isolation Barrier nn Ambient Operation from -40C to 125C nn Low Profile 15mm x 11.25mm BGA Package The LTM(R)2889 is a complete galvanically-isolated Controller Area Network (CAN) Module(R) (micromodule) transceiver. No external components are required - a single supply powers both sides of the interface through an integrated, isolated DC/DC converter. Separate versions are available for 3.3V and 5V power supplies. The dual voltage CAN transceiver and the adjustable regulator allow 3.3V or 5V isolated power with either the 3.3V or 5V version. nn Coupled inductors and an isolation power transformer provide 2500VRMS of isolation between the line transceiver and the logic interface. This device is ideal for systems where the ground loop is broken, allowing for large common mode voltage ranges. Communication remains uninterrupted for common mode transients greater than 30kV/s. Supports up to 4Mbps CAN with Flexible Data Rate (CAN FD). A logic supply pin allows easy interfacing with different logic levels from 1.62V to 5.5V, independent of the main supply. Enhanced ESD protection allows this part to withstand up to 25kV Human Body Model (HBM) on the transceiver interface pins and 10kV HBM across the isolation barrier without latchup or damage. APPLICATIONS Isolated CAN Bus Interface Industrial Networks nn DeviceNet Applications nn nn L, LT, LTC, LTM, Linear Technology, Module and the Linear logo are registered trademarks of Analog Devices, Inc. All other trademarks are the property of their respective owners. TYPICAL APPLICATION Isolated Powered CAN Transceiver 1.62V TO 5.5V VDD VL PVCC VCC RE ON TXD S GND LTM2889 ISOLATION BARRIER RXD CAN CONTROLLER VCC2 5V OUTPUT (ADJUSTABLE) AVAILABLE CURRENT: 150mA (LTM2889-5) 100mA (LTM2889-3) PWR ADJ 3.3V (LTM2889-3) OR 5V (LTM2889-5) GND CANH SPLIT* CANL RS 60 60 LTM2889 Operating at 1Mbps with 45 kV/s Common Mode Transients Across the Isolation Barrier 2V/DIV 2V/DIV RXD TXD MULTIPLE SWEEPS OF COMMON MODE TRANSIENTS ACROSS ISOLATION BARRIER GND2 500V/DIV 2889 TA01 *USE OF SPLIT PIN IS OPTIONAL 50ns/DIV 2889 TA01a 2889fa For more information www.linear.com/LTM2889 1 LTM2889 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) VCC to GND................................................... -0.3V to 6V PVCC to GND................................................. -0.3V to 6V VL to GND..................................................... -0.3V to 6V VCC2 to GND2................................................ -0.3V to 6V Signal Voltages (ON, S, RE, RXD, TXD) to GND.................................................-0.3V to VL +0.3V Interface I/O (CANH, CANL, SPLIT) to GND2...........60V Interface I/O to Interface I/O.................................. 120V VCC2, ADJ, RS to GND2................................. -0.3V to 6V Operating Temperature Range (Note 4) LTM2889C................................................ 0C to 70C LTM2889I.............................................-40C to 85C LTM2889H.......................................... -40C to 125C Maximum Internal Operating Temperature............. 125C Storage Temperature Range................... -55C to 125C Peak Reflow Temperature (Soldering, 10 sec)........ 245C TOP VIEW 1 RE 2 3 RXD TXD 4 5 6 S ON VL 7 8 VCC PVCC A B GND C D E F G H J GND2 DNC GND2 K L CANL SPLIT CANH GND2 RS ADJ VCC2 BGA PACKAGE 32-PIN (15mm x 11.25mm x 3.42mm) TJMAX = 125C, JA = 32.2C/W, JCTOP = 27.2C/W JCBOTTOM = 20.9C/W, JB =26.4C/W, Weight = 1.1g PRODUCT SELECTION GUIDE LTM2889 I Y -3 #PBF LEAD FREE DESIGNATOR PBF = Lead Free INPUT VOLTAGE RANGE 3 = 3V to 3.6V 5 = 4.5V to 5.5V PACKAGE TYPE Y = Ball Grid Array (BGA) TEMPERATURE GRADE C = Commercial Temperature Range (0C to 70C) I = Industrial Temperature Range (-40C to 85C) H = Automotive Temperature Range (-40C to 125C) PRODUCT PART NUMBER 2889fa 2 For more information www.linear.com/LTM2889 LTM2889 ORDER INFORMATION http://www.linear.com/product/LTM2889#orderinfo PART MARKING PART NUMBER PAD OR BALL FINISH DEVICE FINISH CODE PACKAGE TYPE MSL INPUT VOLTAGE RATING RANGE LTM2889CY-3#PBF LTM2889IY-3#PBF LTM2889HY-3#PBF LTM2889CY-5#PBF LTM2889Y-3 SAC305 (RoHS) LTM2889IY-5#PBF e1 32-Lead BGA 3 LTM2889Y-5 LTM2889HY-5#PBF * Device temperature grade is indicated by a label on the shipping container. TEMPERATURE RANGE 3V to 3.6V 0C to 70C 3V to 3.6V -40C to 85C 3V to 3.6V -40C to 125C 4.5V to 5.5V 0C to 70C 4.5V to 5.5V -40C to 85C 4.5V to 5.5V -40C to 125C * Recommended BGA PCB Assembly and Manufacturing Procedures: www.linear.com/BGA-assy * Pad or ball finish code is per IPC/JEDEC J-STD-609. * BGA Package and Tray Drawings: www.linear.com/packaging * Terminal Finish Part Marking: www.linear.com/leadfree * This product is moisture sensitive. For more information, go to: www.linear.com/BGA-assy * This product is not recommended for second side reflow. For more information, go to www.linear.com/BGA-assy ELECTRICAL CHARACTERISTICS The l denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C. Unless otherwise noted, the following conditions apply: PVCC = VCC = 3.3V for the LTM2889-3, PVCC = VCC = 5V for the LTM2889-5, VL = 3.3V, GND = GND2 = S = RE = RS = 0V, ON = VL. Figure 10 applies for VCC2 = 3.3V; otherwise ADJ is floating. Figure 1 applies with RL = 60 and dominant mode measurements are taken prior to TXD dominant timeout (t < tTOTXD). (Note 2) SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Power Supplies VCC Supply Voltage ICC Supply Current PVCC Supply Voltage, Isolated Power Converter PICC Supply Current, Isolated Power Converter, (VCC2 External Load Current ILOAD = 0) VL Logic Supply Voltage IL Logic Supply Current VCC2 VCC2-3.3V l VCC2 Short Circuit Current V l 0 10 A ON = VL l 3.1 5 mA LTM2889-3 l 3.0 3.3 3.6 LTM2889-5 l 4.5 V 5.0 5.5 V l 0 10 A 34 60 mA Recessive: ON = VL, TXD = VL and/or S = VL LTM2889-3 l LTM2889-5 l 32 50 mA Dominant: ON = VL, TXD = S = 0 LTM2889-3 l 140 225 mA LTM2889-5 l l 1.62 94 130 mA 3.3 5.5 V OFF: ON = 0V, TXD = VL l 0 10 A Recessive: ON = VL, TXD = VL l 0 10 A Dominant: ON = VL, TXD = S = 0V l 6 50 A No Load, TXD = VL Regulated VCC2 Output Voltage to GND2, 3.3V Output 5.5 OFF: ON = 0V OFF: ON = 0V Regulated VCC2 Output Voltage to GND2 3.0 l 4.75 5.0 5.25 V ILOAD = 100mA, TXD = VL LTM2889-3 l 4.75 5.0 5.25 V ILOAD = 150mA, TXD = VL LTM2889-5 l 4.75 5.0 5.25 V l 3.1 3.3 3.5 V ILOAD = 100mA, (Fig. 10) LTM2889-3 l 3.0 3.3 3.5 V ILOAD = 150mA, (Fig. 10) LTM2889-5 l 3.0 3.3 3.5 V No Load, (Fig. 10) VCC2 = 0V, TXD = VL 200 mA 2889fa For more information www.linear.com/LTM2889 3 LTM2889 ELECTRICAL CHARACTERISTICS The l denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C. Unless otherwise noted, the following conditions apply: PVCC = VCC = 3.3V for the LTM2889-3, PVCC = VCC = 5V for the LTM2889-5, VL = 3.3V, GND = GND2 = S = RE = RS = 0V, ON = VL. Figure 10 applies for VCC2 = 3.3V; otherwise ADJ is floating. Figure 1 applies with RL = 60 and dominant mode measurements are taken prior to TXD dominant timeout (t < tTOTXD). (Note 2) SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Control Inputs S, ON, RE: VIH HIGH-level Input Voltage VL 2.35V l 0.7 * VL VL + 0.3 1.62V VL < 2.35V l 0.75 * VL VL + 0.3 V VIL LOW-level Input Voltage VL 2.35V l -0.3 0.3 * VL V 1.62V VL < 2.35V l -0.3 0.25 * VL V IIH HIGH-level Input Current ON = S = RE = VL l IIL LOW-level Input Current ON = S = RE = 0V l VL 2.35V l 1.62V VL < 2.35V 11 V 25 A 1 A 0.7 * VL VL + 0.3 V l 0.75 * VL VL + 0.3 V VL 2.35V l -0.3 0.3 * VL V 1.62V VL < 2.35V l -0.3 0.25 * VL V 5 A -50 -2 A CAN Transmit Data Input Pin TXD VIH VIL HIGH-level Input Voltage LOW-level Input Voltage IIH HIGH-level Input Current TXD = VL l IIL LOW-level Input Current TXD = 0V l CIN Input Capacitance (Note 6) 5 pF CAN Receive Data Output Pin RXD IOH IOL HIGH-level Output Current RXD = VL - 0.4V LOW-level Output Current 3V VL 5.5V l -4 mA 1.62V VL < 3V l -1 mA RXD = 0.4V, Bus Dominant 3V VL 5.5V l 4 mA 1.62V VL < 3V l 1 mA TXD = 0V, t< tTOTXD VCC2 = 5V l 2.75 3.6 4.5 V VCC2 = 3.3V l 2.15 2.9 3.3 V VCC2 = 5V l 0.5 1.4 2.25 V VCC2 = 3.3V l 0.5 0.9 1.65 V Bus Driver Pins CANH, CANL VO(D) Bus Output Voltage (Dominant) to GND2 CANH CANL VO(R) TXD = 0V, t< tTOTXD Bus Output Voltage (Recessive) to GND2 VCC2 = 5V, No Load (Figure 1) l 2 2.5 3 V VCC2 = 3.3V, No Load (Figure 1) l 1.45 1.95 2.45 V 2.2 3 V VOD(D) Differential Output Voltage (Dominant) RL = 50 to 65 (Figure 1) l 1.5 VOD(R) Differential Output Voltage (Recessive) No Load (Figure 1) l -500 0 50 mV VOC(D) Common Mode Output Voltage (Dominant) to GND2 VCC2 = 5V, (Figure 1) l 2 2.5 3 V VCC2 = 3.3V, (Figure 1) l 1.45 1.95 2.45 V Bus Output Short-Circuit Current CANH (Dominant) CANH CANH = 0V to GND2 l -100 -75 CANH = 60V to GND2 l -100 CANL CANL = 5V to GND2 l CANL CANL = 60V to GND2 l IOS(D) 75 -3 mA 3 mA 110 mA 100 mA 2889fa 4 For more information www.linear.com/LTM2889 LTM2889 ELECTRICAL CHARACTERISTICS The l denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C. Unless otherwise noted, the following conditions apply: PVCC = VCC = 3.3V for the LTM2889-3, PVCC = VCC = 5V for the LTM2889-5, VL = 3.3V, GND = GND2 = S = RE = RS = 0V, ON = VL. Figure 10 applies for VCC2 = 3.3V; otherwise ADJ is floating. Figure 1 applies with RL = 60 and dominant mode measurements are taken prior to TXD dominant timeout (t < tTOTXD). (Note 2) SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS 36 V Bus Receiver Pins CANH, CANL VCM Bus Common Mode Voltage to GND2 = (CANH + CANL)/2 for Data Reception VCC2 = 5V l VCC2 = 3.3V l 25 V VTH+ Bus Input Differential Threshold Voltage (Positive-Going) VCC2 = 5V, -36V VCM 36V l 775 900 mV VCC2 = 3.3V, -25V VCM 25V l 775 900 mV Bus Input Differential Threshold Voltage (Negative-Going) VCC2 = 5V, -36V VCM 36V l 500 625 mV VCC2 = 3.3V, -25V VCM 25V l 500 625 mV - VTH VTH Bus Input Differential Hysteresis Voltage VCC2 = 5V, -36V VCM 36V 150 mV VCC2 = 3.3V, -25V VCM 25V 150 mV RIN Input Resistance (CANH and CANL) to GND2 RIN = V/I; I = 20A l 25 40 50 k RID Differential Input Resistance RIN = V/I; I = 20A l 50 80 100 k RIN Input Resistance Matching RIN (CANH) to RIN (CANL) 1 % CIH Input Capacitance to GND2 (CANH) (Note 6) 32 pF CIL Input Capacitance to GND2 (CANL) (Note 6) 8 pF CID Differential Input Capacitance (Note 6) 8.4 pF IBL Bus Leakage Current (VCC2 = 0V) (I-Grade) CANH = CANL = 5V, T 85C l 10 A Bus Leakage Current (VCC2 = 0V) (H-Grade) CANH = CANL = 5V, T 125C l 40 A -500A I(SPLIT) VCC2 = 5V 500A VCC2 = 3.3V l 1.5 2.5 3.5 V l 0.9 1.9 2.9 V -60V SPLIT 60V to GND2 l 3 mA Bus Common Mode Stabilization Pin SPLIT VO_SPLIT IOS_SPLIT SPLIT Output Voltage to GND2 SPLIT Short-Circuit Current Logic/Slew Control Input RS VIH_RS High Level Input Voltage to GND2 l VIL_RS Low Level Input Voltage to GND2 l IIN_RS Logic Input Current 0 RS VCC2 l 0.9 * VCC2 V 0.5 * VCC2 -170 0 V 10 A ESD (HBM) (Note 3) Isolation Boundary GND2 to GND 10 kV CANH, CANL, SPLIT Referenced to GND2 or VCC2 25 kV All Other Pins Referenced to GND, GND2, or VCC2 4 kV 2889fa For more information www.linear.com/LTM2889 5 LTM2889 SWITCHING CHARACTERISTICS The l denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C. Unless otherwise noted, the following conditions apply: PVCC = VCC = 3.3V for the LTM2883-3, PVCC = VCC = 5V for the LTM2883-5, VL = 3.3V, GND = GND2 = S = RE = RS = 0V, ON = VL. Figure 2 applies with RL = 60, CL = 100pF, RSL = 0. Figure 10 applies for VCC2 = 3.3V; otherwise ADJ is floating. SYMBOL PARAMETER CONDITIONS MIN TYP MAX 105 165 UNITS Transceiver Timing fMAX Maximum Data Rate tPTXBD TXD to Bus Dominant Propagation Delay (Figure 3) tPTXBR TXD to Bus Recessive Propagation Delay (Figure 3) tPTXBDS tPTXBRS l 4 VCC2 = 3.3V l 55 VCC2 = 5V l 50 100 150 ns VCC2 = 3.3V l 100 145 205 ns VCC2 = 5V l 80 115 155 ns RSL = 200k (Figure 3) VCC2 = 3.3V l 200 565 1255 ns VCC2 = 5V l 220 585 1225 ns TXD to Bus Recessive Propagation Delay, Slow RSL = 200k Slew (Figure 3) VCC2 = 3.3V l 420 985 2035 ns VCC2 = 5V l 490 1065 2245 ns l 40 65 100 ns TXD to Bus Dominant Propagation Delay, Slow Slew tPBDRX Bus Dominant to RXD Propagation Delay (Figure 3) tPBRRX Bus Recessive to RXD Propagation Delay (Figure 3) tPTXRXD TXD to RXD Dominant Propagation Delay (Figure 3) tPTXRXR TXD to RXD Recessive Propagation Delay (Figure 3) Mbps ns l 45 70 115 ns VCC2 = 3.3V l 120 170 240 ns VCC2 = 5V l 110 165 225 ns VCC2 = 3.3V l 160 215 275 ns VCC2 = 5V l 140 185 245 ns TXD to RXD Dominant Propagation Delay, Slow Slew RSL = 200k (Figure 3) VCC2 = 3.3V l 210 550 1170 ns VCC2 = 5V l 240 580 1150 ns tPTXRXRS TXD to RXD Recessive Propagation Delay, Slow Slew RSL = 200k (Figure 3) VCC2 = 3.3V l 450 990 1960 ns VCC2 = 5V l 500 1070 2150 ns tTOTXD TXD Timeout Time (Figure 4) l 0.5 2 4 ms VCC2 = 3.3V l 400 455 550 ns VCC2 = 5V l 400 475 550 ns VCC2 = 5V l 200 225 275 ns tPTXRXDS tBIT(RXD),2M Receiver Output Recessive Bit Time, 2Mbps, Loop Delay Symmetry (Figure 8) tBIT(RXD),4M Receiver Output Recessive Bit Time, 4Mbps (Figure 8) tZLR Receiver Output Enable Time (Figure 5) l 20 ns tLZR Receiver Output Disable Time (Figure 5) l 30 ns tENRSRX RXD Enable from Shutdown Time (Figure 6) l 40 s tENRSTX TXD Enable from Shutdown TIme (Figure 7) (Note 5) l 40 s tSHDNRX Time to Shutdown, Receiver (Figure 6) l 3 s tSHDNTX Time to Shutdown, Transmitter (Figure 7) l 250 ns No load, ON , VCC2 to 4.5V l 5 ms 500 mV Power Supply Generator tENPS VCC2 Supply Start-Up Time 2.3 Transmitter Drive Symmetry (Common Mode Voltage Fluctuation) VSYM Driver Symmetry (CANH + CANL - 2VO(R)) (Dynamic Peak Measurement) RL = 60/Tol. < 1%, CSPLIT = 4.7nF/5%, fTXD = 250kHz, Input Impedance of Oscilloscope: 20pF/1M (Figure 2) l 2889fa 6 For more information www.linear.com/LTM2889 LTM2889 ISOLATION CHARACTERISTICS SYMBOL PARAMETER VISO Rated Dielectric Insulation Voltage VIORM TA = 25C CONDITIONS MIN TYP MAX 1 Second (Notes 7, 8, 9) 3000 VRMS 1 Minute, Derived from 1 Second Test (Note 9) 2500 VRMS Common Mode Transient Immunity LTM2889-3 VCC = 3.3V, LTM2889-5 VCC = 5.0V, VL = ON = 3.3V, V(GND2-GND) = 1kV, t = 33ns (Note 3) 30 Maximum Working Insulation Voltage (Notes 3,10) 560 Partial Discharge VPD = 1060 VPEAK (Note 7) 50 kV/s VPEAK, VDC VRMS 400 CTI DTI UNITS Comparative Tracking Index IEC 60112 (Note 3) Depth of Erosion IEC 60112 (Note 3) Distance Through Insulation (Note 3) 5 600 pC VRMS 0.017 mm 0.06 mm 109 Input to Output Resistance (Notes 3, 7) Input to Output Capacitance (Notes 3, 7) 6 pF Creepage Distance (Notes 3, 7) 9.5 mm Note 1. Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2. All currents into device pins are positive; all currents out of device pins are negative. All voltages are referenced to device ground unless otherwise specified. Note 3. Not tested in production. Note 4. This module includes overtemperature protection that is intended to protect the device during momentary overload conditions. Junction temperature exceeds 150C when overtemperature protection is active. Continuous operation above the specified maximum operating temperature may result in device degradation or failure. Note 5. TXD must make a high to low transition after this time to assert a bus dominant state. Note 6. Pin capacitance given for reference only and is not tested in production. Note 7. Device considered a 2-terminal device. Pin group A1 through B8 shorted together and pin group K1 through L8 shorted together. Note 8. The Rated Dielectric Insulation Voltage should not be interpreted as a continuous voltage rating. Note 9. In accordance with UL1577, each device is proof tested for the 2500VRMS rating by applying an insulation test voltage of 3000VRMS for 1 second. Note 10. Maximum Working Insulation Voltage is for continuous or repeated voltage applied across the isolation boundary. Refer also to relevant equipment level safety specifications which may reduce VIORM depending on application conditions. 2889fa For more information www.linear.com/LTM2889 7 LTM2889 TEST CIRCUITS LTM2889 TXD RXD RXD VL 3.3V ON VCC PVCC VCC 15pF 47F 0.1F CANH ISOLATION BARRIER TXD GND S RE 1/2RL 1% CANH SPLIT CM VOD 1/2RL 1% CANL RS CANL VOC GND2 RSL GND RSL = 0 EXCEPT AS NOTED 2889 TC01 Figure 1. Electrical Characteristic Measurements of Bus Pins CANH, CANL LTM2889 TXD RXD RXD VL 3.3V ON VCC PVCC VCC 15pF 47F 0.1F CANH ISOLATION BARRIER TXD GND S RE 1/2RL 1% CANH CL SPLIT RS GND2 VOD 1/2RL 1% CANL CANL RSL RSL = 0 EXCEPT AS NOTED GND 2889 TC02 Figure 2. All Bus Pin Switching Characteristic Measurements Except Receiver Enable/Disable Times 2889fa 8 For more information www.linear.com/LTM2889 LTM2889 TEST CIRCUITS HIGH TXD 1/2 VL 1/2 VL LOW CANH CANL DOMINANT 0.9V VOD 0.5V RECESSIVE HIGH RXD 1/2 VL tPTXBD tPTXBDS 1/2 VL tPTXBR tPTXBRS tPBDRX tPTXRXD tPTXRXDS LOW tPBRRX tPTXRXR tPTXRXRS 2889 TC03 Figure 3. CAN Transceiver Data Propagation Timing Diagram HIGH TXD 1/2 VL LOW CANH CANL DOMINANT 0.9V VOD 0.5V tTOTXD RECESSIVE 2889 TC04 Figure 4. TXD Dominant Timeout Time 2889fa For more information www.linear.com/LTM2889 9 LTM2889 LTM2889 VL RXD ISOLATION BARRIER VL RXD 500 TXD ON VCC PVCC VCC 15pF 47F 0.1F GND S RE CANH SPLIT CANL + V 1.5V - RS GND2 GND RE HIGH RE 1/2 VL RXD 1/2 VL 1/2 VL LOW HIGH 1/2 VL tZLR LOW tLZR 2889 TC05 Figure 5. Receiver Output Enable and Disable Timing VL RXD RXD 500 TXD ON VCC PVCC VCC 15pF 47F 0.1F GND S RE ISOLATION BARRIER LTM2889 VL CANH SPLIT CANL + V 1.5V - RS RS GND2 GND HIGH RS 0.6VCC2 RXD 0.9VCC2 1/2 VL tENRSRX LOW HIGH 1/2 VL tSHDNRX LOW 2889 TC06 Figure 6. RXD Enable and Disable Timing from Shutdown 2889fa 10 For more information www.linear.com/LTM2889 LTM2889 TEST CIRCUITS HIGH RS 0.6VCC2 TXD 0.9VCC2 LOW HIGH 1/2 VL LOW CANH CANL DOMINANT 0.9V VOD 0.5V tENRSTX RECESSIVE tSHDNTX 2889 TC07 tPTXBD Figure 7. TXD Enable and Disable Timing from Shutdown TXD 5 * tBIT(TXD) tBIT(TXD) RXD tBIT(RXD) 2889 TC08 Figure 8. Loop Delay Symmetry 2889fa For more information www.linear.com/LTM2889 11 LTM2889 TYPICAL PERFORMANCE CHARACTERISTICS Unless otherwise noted, the following conditions apply: TA = 25C, PVCC = VCC = 3.3V for the LTM2889-3, PVCC = VCC = 5.0V for the LTM2889-5, VL = 3.3V, GND = GND2 = S = RE = 0V, ON = VL. Driver Differential Output Voltage (Dominant) vs Temperature Common Mode Output Voltage (Dominant) vs Temperature Driver Differential Output Voltage (Dominant) vs Output Current 2.7 2.7 2.5 2.5 VCC = 5V 2.3 2.1 1.9 1.5 -50 -25 4.0 VCC = 5V 3.5 2.3 2.1 VCC = 3.3V 100 -25 0 25 50 75 TEMPERATURE (C) 100 2889 G01 100 CANH -50 -40 -20 0 20 OUTPUT VOLTAGE (V) VL = 1.8V 0.5 0.4 VL = 2.5V 0.3 0.2 VL = 3.3V 0.1 2.2 tPTXRXD (ns) 1.8 1.6 1.4 VCC = 3.3V 1.2 1.0 0.8 0.6 -50 -25 25 50 75 0 TEMPERATURE (C) 100 125 2889 G07 VL = 3.3V VL = 2.5V 2 0 VL = 1.8V 1 2 3 4 OUTPUT CURRENT (ABS VALUE) (mA) 1 5 0 1 2 3 4 OUTPUT CURRENT (ABS VALUE) (mA) TXD to RXD Recessive Propagation Delay vs Temperature 190 250 185 240 180 230 VCC2 = 3.3V 175 170 VCC2 = 5V 165 210 155 180 0 25 50 75 TEMPERATURE (C) 100 125 2889 G08 VCC2 = 5V 200 190 -25 VCC2 = 3.3V 220 160 150 -50 5 2889 G06 TXD to RXD Dominant Propagation Delay vs Temperature VCC = 5V 2.0 3 2889 G05 2.4 80 4 VL = 5V 2889 G04 TXD Timeout Time vs Temperature 70 VL = 5V 0.6 0 60 40 20 30 40 50 60 OUTPUT CURRENT (mA) 5 tPTXRXR (ns) -100 -60 10 Receiver Recessive Output Voltage vs Output Current RECEIVER OUTPUT VOLTAGE (V) RECEIVER OUTPUT VOLTAGE (V) 0 0 2889 G03 0.7 50 IOS(D) (mA) 0 125 Receiver Dominant Output Voltage vs Output Current CANL VCC = 3.3V 2889 G02 Driver Output Current vs Differential Output Voltage (Dominant) tTOTXD (ms) 2.0 0.5 1.5 -50 125 2.5 1.0 1.7 0 25 50 75 TEMPERATURE (C) VCC = 5V 3.0 1.5 1.9 VCC = 3.3V 1.7 4.5 VOD(D) (V) 2.9 VOC(D) (V) VOD(D) (V) 5.0 2.9 170 -50 -25 0 25 50 75 TEMPERATURE (C) 100 125 2889 G09 2889fa 12 For more information www.linear.com/LTM2889 LTM2889 TYPICAL PERFORMANCE CHARACTERISTICS Unless otherwise noted, the following conditions apply: TA = 25C, PVCC = VCC = 3.3V for the LTM2889-3, PVCC = VCC = 5.0V for the LTM2889-5, VL = 3.3V, GND = GND2 = S = RE = 0V, ON = VL. TXD to Bus Recessive Propagation Delay vs Temperature 175 115 165 110 155 VCC2 = 3.3V 105 VCC2 = 5V 100 90 115 -25 0 25 50 75 TEMPERATURE (C) 100 67 VCC2 = 3.3V 135 125 85 -50 69 145 95 VCC2 = 5V -25 0 25 50 75 TEMPERATURE (C) 100 2889 G10 590 1080 tPTXRXRS (ns) tPTXRXDS (ns) 530 1020 1000 510 68 0 25 50 75 TEMPERATURE (C) 100 VCC2 = 3.3V 960 490 -50 125 -25 0 25 50 75 TEMPERATURE (C) 100 600 TXD to Bus Recessive Propagation Delay vs Temperature, Slow Slew 1100 RSL = 200k VCC2 = 5V RSL = 200k tPTXBRS (ns) tPTXBDS (ns) 1050 VCC2 = 3.3V 1025 1000 520 500 -50 VCC2 = 3.3V 975 -25 0 25 50 75 TEMPERATURE (C) 100 125 2889 G16 VCC2 = 5V 0.60 VCC2 = 5V 540 0 25 50 75 TEMPERATURE (C) 950 -50 100 125 VCC2 Power Efficiency 0.70 1075 560 -25 2889 G15 POWER OUT/ POWER IN 580 940 -50 125 2889 G14 2889 G13 TXD to Bus Dominant Propagation Delay vs Temperature, Slow Slew 125 1040 VCC2 = 3.3V 550 100 RSL = 200k VCC2 = 5V 1060 980 -25 0 25 50 75 TEMPERATURE (C) TXD to RXD Recessive Propagation Delay vs Temperature, Slow Slew 570 74 66 -50 -25 2889 G12 RSL = 200k VCC2 = 5V tPBRRX (ns) 59 -50 125 TXD to RXD Dominant Propagation Delay vs Temperature, Slow Slew 76 70 63 2889 G11 Bus Recessive to RXD Propagation Delay vs Temperature 72 65 61 105 -50 125 Bus Dominant to RXD Propagation Delay vs Temperature tPBDRX (ns) 120 tPTXBR (ns) tPTXBD (ns) TXD to Bus Dominant Propagation Delay vs Temperature 0.50 LTM2889-5 LTM2889-3 0.40 0.30 0.20 0.10 -25 0 25 50 75 TEMPERATURE (C) 100 125 2889 G17 0 0 25 50 75 100 125 150 175 200 ICC2 (mA) 2889 G18 2889fa For more information www.linear.com/LTM2889 13 LTM2889 TYPICAL PERFORMANCE CHARACTERISTICS Unless otherwise noted, the following conditions apply: TA = 25C, PVCC = VCC = 3.3V for the LTM2889-3, PVCC = VCC = 5.0V for the LTM2889-5, VL = 3.3V, GND = GND2 = S = RE = 0V, ON = VL. VCC Supply Current vs Transmitting Data Rate PVCC Supply Current vs Transmitting Data Rate 3.8 VL Supply Current vs Transmitting Data Rate 600 100.0 3.7 3.4 LTM2889-5 3.3 80.0 PICC (mA) 70.0 60.0 LTM2889-3 3.1 3.0 0.1 1 TRANSMITTING DATA RATE (Mbps) LTM2889-5; VCC2 = 3.3V 50.0 0.1 10 2889 G19 240 TRANSMITTING AT 1Mbps 1 TRANSMITTING DATA RATE (Mbps) 10 ICC2 (mA) LTM2889-5; VCC2 = 5V VCC2 vs Temperature (5V) 5.02 ICC2 = 0mA LTM2889-5; VCC2 = 5V 5.00 160 140 LTM2889-3; VCC2 = 3.3V 120 100 60 LTM2889-5; VCC2 = 3.3V 4.96 LTM2889-3; VCC2 = 5V 4.94 100 60 -50 125 -25 0 25 50 75 TEMPERATURE (C) 100 4.92 -50 125 -25 0 25 50 75 TEMPERATURE (C) 2889 G23 2889 G22 100 125 2889 G24 Derating for 125C Maximum Internal Operating Temperature VCC2 vs Temperature (3.3V) 3.32 160 ICC2 LOAD CURRENT (mA) ICC2 = 0mA 3.30 VCC2 (V) ICC2 = 100mA 4.98 80 0 25 50 75 TEMPERATURE (C) 3.28 ICC2 = 100mA 3.26 3.24 140 LTM2889-5 (CAN OFF) 120 LTM2889-5(CAN ON) 100 -25 0 25 50 75 TEMPERATURE (C) 100 125 LTM2889-3 (CAN OFF) 80 LTM2889-3 (CAN ON) 60 40 20 3.22 -50 10 180 80 -25 1 TRANSMITTING DATA RATE (Mbps) 2889 G21 200 LTM2889-5; VCC2 = 3.3V 50 -50 VL = 1.65V 0 0.1 TRANSMITTING AT 4Mbps 220 LTM2889-3; VCC2 = 3.3V PICC (mA) 100 VCC2 Surplus Current vs Temperature LTM2889-3; VCC2 = 5V 90 VL = 3.3V 2889 G20 PVCC Supply Current vs Temperature 100 VL = 5V 300 200 LTM2889-5; VCC2 = 5V 3.2 70 400 LTM2889-3; VCC2 = 3.3V VCC2 (V) ICC (mA) 3.5 500 LTM2889-3; VCC2 = 5V IL (A) 90.0 3.6 0 CAN ICC2 = 20mA 25 2889 G25 50 75 100 125 TEMPERATURE (C) 2889 G26 2889fa 14 For more information www.linear.com/LTM2889 LTM2889 PIN FUNCTIONS LOGIC SIDE: (I/O pins referenced to VL and GND) RE (Pin A1): Receiver Output Enable. A logic low enables the receiver output, RXD. A logic high disables the receiver output. RE has a weak pull-down to GND. In typical usage, RE is tied to ground. RXD (Pin A2): Receiver Output. When the CAN bus is in the dominant state, RXD is low. When the CAN bus is in the recessive state, RXD is high. When the receiver output is disabled, RXD is high-Z and has a weak pull-up to VL. Under the condition of an isolation communication failure, the receiver output is disabled. TXD (Pin A3): Transmit Driver Input. When S is low, a low on TXD puts the driver into the dominant state, driving CANH high and CANL low. A high on TXD forces the driver into the recessive state, with both CANH and CANL in a high impedance state. If TXD and S are both held low for longer than tTOTXD, the driver reverts to the recessive state. TXD has a weak pull-up to VL. S (Pin A4): Transmit Driver Silent. A high on S forces the driver into the recessive state, with both CANH and CANL in a high impedance state. S has a weak pull-down to GND. ON (Pin A5): Enable. Enables the power and data communications through the isolation barrier. If ON is high the LTM2889 is enabled and power and communications are functional to the isolated side. If ON is low, the logic side is held in reset and the isolated side is unpowered. ON has a weak pull-down to GND. VL (Pin A6): Logic Supply. Interface supply voltage for pins RE, RXD, TXD, S, and ON. Operating voltage is 1.62V to 5.5V. Internally bypassed to GND with 1F. VCC (Pins A7, B7): Supply Voltage. Operating voltage is 3V to 5.5V for both LTM2889-3 and LTM2889-5. Internally bypassed to GND with 1F. PVCC (Pins A8, B8): Isolated Power Supply Input. Operating voltage is 3V to 3.6V for LTM2889-3 and 4.5V to 5.5V for LTM2889-5. Internally bypassed to GND with 2.2F. In typical usage, PVCC is tied to VCC. GND (Pins B1-B8): Logic Side Circuit Ground ISOLATED SIDE: (I/O pins referenced to VCC2 and GND2) CANL (Pin L1): Low Level CAN Bus Line. 60V tolerant, 25kV ESD. SPLIT (Pin L2): Common Mode Stabilization Output for Optional Split Termination. 60V tolerant, 25kV ESD. If unused, leave open. Internally bypassed to GND2 with 4.7nF. CANH (Pin L3): High Level CAN Bus Line. 60V tolerant, 25kV ESD. GND2 (Pins L4, K1-K4, K6-K8): Isolated Side Circuit Ground. RS (Pin L5): Shutdown Mode/Slew Control Input. A voltage on RS higher than VIH_RS puts the CAN transceiver in a low power shutdown state. The CAN bus and RXD will be in the recessive state, the CAN receiver will be disconnected from the bus, and the power converter will continue to operate. A voltage on RS lower than VIL_RS enables the CAN transceiver. A resistor between RS and GND2 can be used to control the slew rate. See Applications Information section for details. ADJ (Pin L6): Adjust pin to override the default 5V regulation voltage of the isolated power supply. May be used to set VCC2 to 3.3V in either the LTM2889-3 or LTM2889-5 versions. Leave floating for 5V output. See Applications Information section for details. VCC2 (Pin L7-L8): Isolated Power Supply Output. Internally generated from PVCC by an isolated DC/DC converter and regulated to 5V. Internally bypassed to GND2 with 10F. DNC (Pin K5): Do not make electrical connection to this pin. Do not connect to GND2. 2889fa For more information www.linear.com/LTM2889 15 LTM2889 BLOCK DIAGRAM VCC PVCC 1F 2.2F 5V REG (ADJUSTABLE) ISOLATED DC/DC CONVERTER VL VCC2 10F ADJ 1F CANH TXD CAN TXD S SPLIT CANL ISOLATED COMM INTERFACE ON ISOLATED COMM INTERFACE RS 4.7nF RXD CAN RXD RE GND GND2 2889 BD01 = ISOLATED SIDE COMMON = LOGIC SIDE COMMON Figure 9. LTM2889 Simplified Block Diagram 2889fa 16 For more information www.linear.com/LTM2889 LTM2889 APPLICATIONS INFORMATION OVERVIEW VCC2 Output The LTM2889 isolated CAN Module transceiver provides a galvanically-isolated robust CAN interface, powered by an integrated, regulated DC/DC converter, complete with decoupling capacitors. The LTM2889 is ideal for use in networks where grounds can take on different voltages. Isolation in the LTM2889 blocks high voltage differences, eliminates ground loops and is extremely tolerant of common mode transients between ground planes. Error-free operation is maintained through common mode events greater than 30kV/s providing excellent noise isolation. The on-board DC/DC converter provides isolated 5V power to output VCC2. VCC2 is capable of supplying up to 750mW of power at 5V in the LTM2889-5 option and up to 500mW of power in the LTM2889-3 option. This power is available to external applications. The amount of surplus current is dependent upon the implementation and current delivered to the CAN driver and line load. An example of available surplus current is shown in the Typical Performance Characteristics graph, VCC2 Surplus Current vs Temperature. VCC2 is bypassed internally with a 10F capacitor. The LTM2889 utilizes isolator Module technology to translate signals and power across an isolation barrier. Signals on either side of the barrier are encoded into pulses and translated across the isolation boundary using coreless transformers formed in the Module substrate. This system, complete with data refresh, error checking, safe shutdown on fail, and extremely high common mode immunity, provides a robust solution for bidirectional signal isolation. The Module technology provides the means to combine the isolated signaling with multiple regulators and a powerful isolated DC/DC converter in one small package. 3.3V VCC2 Output The VCC2 supply may be adjusted to an output voltage of 3.3V by connecting a resistor divider between VCC2, the ADJ pin, and GND2 as shown in Figure 10. Operating the CAN transceiver at 3.3V reduces PVCC current and may reduce EMI when used in a system with other 3.3V CAN transceivers. For a 5V VCC2 output no resistor divider is used, and the ADJ pin should be left unconnected. LTM2889 TXD RXD VCC DC/DC Converter VCC The LTM2889 contains a fully integrated DC/DC converter, including the transformer, so that no external components are necessary. The logic side contains a full-bridge driver, running at 2MHz, and is AC-coupled to a single transformer primary. A series DC blocking capacitor prevents transformer saturation due to driver duty cycle imbalance. The transformer scales the primary voltage, and is rectified by a full-wave voltage doubler. This topology allows for a single diode drop, as in a center tapped full-wave bridge, and eliminates transformer saturation caused by secondary imbalances. The DC/DC converter is connected to a low dropout regulator (LDO) to provide a regulated 5V output. PVCC VL GND S RE ISOLATION BARRIER Isolator Module Technology VCC2 3.3V 56.2k ADJ GND2 13.0k GND GND2 2889 F10 Figure 10. Adjusting VCC2 for 3.3V Output. PVCC Power Supply The integrated DC/DC converter is powered by separate PVCC supply pins. In typical operation, PVCC is connected to the same supply as VCC. The LTM2889 may be operated with an external isolated supply powering the isolated CAN transceiver instead of the internal converter. This is accomplished by applying an external source of isolated power between the VCC2 and GND2 pins, and dis- 2889fa For more information www.linear.com/LTM2889 17 LTM2889 APPLICATIONS INFORMATION abling the internal converter by grounding the PVCC pins (Figure 25). In this configuration, both the LTM2889-3 and the LTM2889-5 may be supplied with a voltage between 3V and 5.5V on the VCC pin, and either 3.3V or 5V on the VCC2 pin. The ADJ pin should be left unconnected. VL Logic Supply A separate logic supply pin VL allows the LTM2889 to interface with any logic signal from 1.62V to 5.5V as shown in Figure 11. Simply connect the desired logic supply to VL. There is no interdependency between VCC, PVCC, or VL; they may simultaneously operate at any voltage within their specified operating ranges and sequence in any order. VL is bypassed internally with a 1F capacitor. 3V TO 3.6V LTM2889-3 4.5V TO 5.5V LTM2889-5 ANY VOLTAGE FROM 1.62V TO 5.5V 3V TO 5.5V 5V OUTPUT VL VCC PVCC VDD CAN CONTROLLER ON RXD RE GND PWR ISOLATION BARRIER TXD S VCC2 LTM2889 CANH CANL GND 120 GND2 2889 F11 LOGIC INTERFACE LEVELS: GND TO VL Figure 11. VCC and VL Are Independent Normal Mode With the ON pin high and S pin low, the LTM2889 operates in Normal mode. The transceiver can transmit and receive data via the bus lines CANH and CANL. The differential receiver delivers a logic low level on RXD if the bus lines are dominant or a logic high level if the bus lines are recessive. The slope of the output signals on the bus lines is controlled and optimized to minimize common mode perturbations and electromagnetic emissions (EME). Silent Mode Silent mode is entered by bringing the S pin high. In this state, the LTM2889 driver outputs become recessive, independent of the TXD input. As shown in the block diagram, the TXD and S pins are logically OR'd together into the data path of the LTM2889. OFF Mode and Unpowered State When the ON pin is low, the device enters OFF mode and all functions on both sides of the isolation boundary are shut down. The isolated DC/DC converter stops operating and the isolated supply voltage, VCC2 collapses. The CANH and CANL lines are not driven and their common mode bias releases control. RXD will be high-Z and passively pulled to VL, whether VL is powered or low. A device that is OFF draws no more than 10A of current from PVCC, VCC and VL. CAN TRANSCEIVER OPERATING MODES The LTM2889 supports various modes of operation as summarized in Table 1. Table 1. Operating Modes* INPUTS 60V Fault Protection OUTPUTS ON TXD S RE CANH, CANL RXD MODE 1 0 0 0 DOMINANT** 0** NORMAL 1 1 0 0 RECESSIVE 1 NORMAL 1 X 1 0 RECESSIVE 1 SILENT 0 X X X HI-Z HI-Z OFF X X X 1 *1 = logic HIGH; 0 = logic LOW; X = either logic state ** if TXD dominant timeout timer has not expired Hi-Z The LTM2889 contains a robust, high performance integrated CAN transceiver featuring fault protection, high ESD tolerance, and a wide common mode operating range. The LTM2889 features 60V fault protection on its CAN Bus interface pins (CANH, CANL, SPLIT) with respect to GND2. The high breakdown voltage provides protection during all states of operation, including dominant and recessive states, shutdown, and powered off. The driver outputs use a progressive foldback current limit to protect against overvoltage faults while still allowing high current output drive. The LTM2889 is protected from 60V bus 2889fa 18 For more information www.linear.com/LTM2889 LTM2889 APPLICATIONS INFORMATION faults even with the loss of GND2 or VCC2 (GND2 open faults are not tested in production). In the case of VCC2 shorted to GND2, the transceiver is off and the bus pins remain in the high impedance state. 36V Extended Common Mode Range The LTM2889 CAN Bus receiver features an extended common mode operating range of -36V to 36V with respect to GND2 when operating from a 5V VCC2 supply, and -25V to 25V when operating from a 3.3V VCC2 supply. The wide common mode increases the reliability of operation in environments with high common mode voltages created by electrical noise or local ground potential differences between bus nodes on the isolated side of the network due to ground loops. This extended common mode range allows the LTM2889 to transmit and receive under conditions that would cause data errors and possible device damage in competing products. 25kV ESD Protection The LTM2889 features exceptionally robust ESD protection. The transceiver interface pins (CANH, CANL, SPLIT) feature protection with respect to GND2 to 25kV HBM without latchup or damage, during all modes of operation or while unpowered. The LTM2889 features 10kV HBM protection across the isolation barrier for discharges between any one of the interface pins (CANH, CANL, SPLIT, VCC2, GND2) and any one of the supply pins referenced to GND (VCC, PVCC, VL, GND). 4Mbps Operation The LTM2889 features a high speed receiver and transmitter capable of operating up to 4Mbps. In order to operate at this data rate, the transmitter must be set at its maximum slew rate by pulling the RS pin low to GND2 with no more than 4k of resistance, including the output impedance of the buffer driving the RS input (see RS Pin and Variable Slew Rate Control below). CAN Bus Driver The driver provides full CAN compatibility. When TXD is low with the chip enabled (RS low), the dominant state is asserted on the CAN bus lines (subject to the TXD timeout tTOTXD); the CANH driver pulls high and the CANL driver pulls low. When TXD is high and RS is low, the driver is in the recessive state; both the CANH and CANL drivers are in the Hi-Z state and the bus termination resistor equalizes the voltage on CANH and CANL. In the recessive state, the impedance on CANH and CANL is determined by the receiver input resistance, RIN. When RS is high the transceiver is in shutdown; the CANH and CANL drivers are in the Hi-Z state, and the receiver input resistance RIN is disconnected from the bus by a FET switch. Transmit Dominant Timeout Function The LTM2889 CAN transceiver includes a 2ms (typical) timer to limit the time that the transmitter can hold the bus in the dominant state. If TXD is held low, a dominant state is asserted on CANH and CANL until the TXD timer times out at tTOTXD, after which the transmitter reverts to the recessive state. The timer is reset when TXD is brought high. The transmitter asserts a dominant state upon the next TXD low. tTOTXD RECESSIVE TXD DOMINANT TRANSMITTER DISABLED CANH BUS TRANSMITTER ENABLED CANL VDIFF TIME 2889 F12 Figure 12. Transmitter Dominant Timeout Function Driver Overvoltage, Overcurrent, and Overtemperature Protection The driver outputs are protected from short circuits to any voltage within the absolute maximum range of -60V to 60V with respect to GND2. The driver includes a progressive foldback current limiting circuit that continuously reduces the driver current limit with increasing output fault voltage. The fault current is typically 10mA for fault voltages of 60V. Refer to the "Driver Output Current vs Differential Output Voltage (Dominant)" plot in the Typical Performance Characteristics section. 2889fa For more information www.linear.com/LTM2889 19 LTM2889 APPLICATIONS INFORMATION The LTM2889 CAN transceiver also features thermal shutdown protection that disables the driver in case of excessive power dissipation during a fault on the CAN bus (see Notes 3 and 4). When the transceiver die temperature exceeds 170C (typical), the transmitter is forced into the recessive state. All other functions remain active during the transceiver thermal shutdown, including the CAN bus receiver and the module isolated communication and power converter. Other chips in the LTM2889 also contain thermal shutdown circuits that will shut down all module operations at approximately 170C. Power-Up/Down Glitch-Free Outputs The LTM2889 CAN transceiver employs a supply undervoltage detection circuit to control the activation of the circuitry on-chip. During power-up, the CANH, CANL, RXD and SPLIT outputs remain in the high impedance state until the supply reaches a voltage sufficient to reliably operate the transceiver. At this point, the transceiver activates if RS is low. The receiver output goes active after a short delay tENRX and reflects the state at the CAN bus pins, and the SPLIT output goes active at approximately the same time. The transmitter powers up in the high-Z recessive state until the VCC2 supply reaches the power-good voltage, at which time the transmitter outputs become active and reflect the state of the TXD pin. This assures that the transmitter does not disturb the bus by glitching to the dominant state during power-up. During power down, the reverse occurs; the supply undervoltage detection circuit senses low supply voltage and immediately puts the transceiver into shutdown. The CANH, CANL, RXD, and SPLIT outputs go to the high impedance state. The voltage on RXD is pulled high by an internal pull-up resistor. Common Mode Voltage vs Supply Voltage When operating from the default 5V VCC2 supply voltage the LTM2889 CAN transceiver adheres to the ISO 11898-2 CAN bus standard by maintaining drive levels that are symmetric around VCC2/2 = 2.5V with respect to GND2. An internal common mode reference of VCC2/2 is buffered to supply the termination of the receiver input resistors. A second buffer with a high voltage tolerant output supplies VCC2/2 to the SPLIT output. If the output from the internal isolated converter is set to 3.3V using a resistor divider on the ADJ pin (Figure 10), the 2.5V nominal common mode voltage specified in the ISO 11898-2 standard is too close to the 3.3V supply to provide symmetric drive levels while maintaining the necessary differential output voltage. To maintain driver symmetry the common mode reference voltage is lowered during 3.3V operation. The typical output common mode voltage is 1.95V in the dominant state. The internal common mode reference is set to VCC2/2 + 0.3V = 1.95V to match the dominant state output common mode voltage. This reference is independently buffered to supply the termination of the receiver input resistors and the SPLIT voltage output. As the LTM2889 CAN transceiver operates over a very wide common mode range, this small shift of -0.55V in the common mode when operating from 3.3V does not degrade data transmission or reception. An LTM2889 CAN transceiver operating at 3.3V may share a bus with other CAN transceivers operating at 5V. However, the electromagnetic emissions (EME) may be larger if transceivers powered by different voltages share a bus, due to the fluctuation in the common mode voltage from 1.95V (when a CAN transceiver on a 3.3V supply is dominant) to 2.5V (when a CAN transceiver on a 5V supply is dominant). RS Pin and Variable Slew Rate Control The driver features adjustable slew rate for improved EME performance. The slew rate is set by the amount of current that is sourced by the RS pin when it is pulled below approximately 1.1V (referenced to GND2). This allows the slew rate to be set by a single slew control resistor RSL in series with the RS pin (Figure 1). The relationship between the series slew control resistor RSL and the transmitter slew rate can be observed in Figure 13. RSL 4k is recommended for high data rate communication. RSL should be less than 200k to ensure that the RS pin can be reliably pulled below VIL_RS to enable the chip. 2889fa 20 For more information www.linear.com/LTM2889 LTM2889 APPLICATIONS INFORMATION RS pin. When the RS pin is pulled low towards ground by an external driver, RSL limits the amount of current drawn from the RS pin and sets the transmitter slew rate. Alternatively, the slew rate may be controlled by an external voltage or current source. SLEW RATE (V/s) (CANH-CANL) 60 50 VCC2 = 5V 40 VCC2 = 3.3V 30 VCC2 20 IPU RS 250k 10 IRS 0 1 10 RSL (k) IDEAL DIODE + ISC (-100A LIMIT) V 100 Figure 13. Slew Rate vs Slew Control Resistor RSL When a voltage between 1.1V and VCC2 is applied, the RS pin acts as a high impedance receiver. A voltage above VIH_RS puts the chip in shutdown, while a voltage below VIL_RS but above 1.1V activates the chip and sets the transmitter to the minimum slew rate. The slew control circuit on the RS pin is activated at applied voltages below 1.1V. The RS pin can be approximately modeled as a 1.1V voltage source with a series resistance of 2k and a current compliance limit of -100A, and a 250k pull-up resistor to VCC2 (Figure 14). Lowering the voltage on RS increases the slew control current ISC being drawn from the slew control circuit until the voltage reaches ~0.9V, where the current drawn from the circuit is ~ -100A. Below an applied voltage of ~ 0.9V, the slew control circuit sources no additional current, and the current drawn from it remains at ~ -100A down to 0V. The total current IRS drawn from the RS pin for input voltage 0.9V VRS 1.1V is the sum of the internal pull-up resistor current IRS and the slew control current ISC. IRS(0.9V VRS 1.1V) = IPU +ISC 1.1V 2889 F14 Figure 14. Equivalent Circuit of RS Pin High Symmetry Driver with Variable Slew Rate The electromagnetic emissions spectrum of a differential line transmitter is largely determined by the variation in the common mode voltage during switching, as the differential component of the emissions from the two lines cancel, while the common mode emissions of the two lines add. The LTM2889 transmitter has been designed to maintain highly symmetric transitions on the CANH and CANL lines to minimize the perturbation of the common mode voltage during switching (Figure 15), resulting in low EME. The common mode switching symmetry is guaranteed by the VSYM specification. 1Mbps LTM2889-3 PVCC = VCC = 3.3V CANH 500mV/DIV COMMON MODE 500mV/DIV CANL 500mV/DIV VCC2 - VRS 1.1V - VRS + 250k 2k 200ns/DIV The transmitter slew rate is controlled by the slew control current ISC with increasing current magnitude corresponding to higher slew rates. The slew rate can be controlled using a single slew control resistor RSL in series with the - GND2 2889 F13 = 2k 2889 F15 Figure 15. Low Perturbation of Common Mode Voltage During Switching 2889fa For more information www.linear.com/LTM2889 21 LTM2889 APPLICATIONS INFORMATION In addition to full compliance with the ISO 11898-2 standard, LTM2889 meets the more stringent requirements of ISO 11898-5 for bus driver symmetry. This requires that the common mode voltage stay within the limits not only during the static dominant and recessive states, but during the bit transition states as well. Ultra-high speed peak detect circuits are used during manufacturing test to ensure that VSYM limits are not exceeded at any point during the switching cycle. The high frequency content may be reduced by choosing a lower data rate and a slower slew rate for the signal transitions. The LTM2889 CAN transceiver provides an approximate 20 to 1 reduction in slew rate, with a corresponding decrease in the high frequency content. The lowest slew rate is suitable for data communication at 200kbps or below, while the highest slew rate supports 4Mbps. The slew rate limit circuit maintains consistent control of transmitter slew rates across voltage and temperature to ensure predictable performance under all operating conditions. Figure 16 demonstrates the reduction in high frequency content of the common mode voltage achieved by the lowest slew rate compared to the highest slew rate when operating at 200kbps. RSL = 0 0dB 20dB/DIV RSL = 200k 0dB 20dB/DIV 500kHz/DIV 2889 F16 Figure 16. Power Spectrum of Common Mode Voltage Showing High Frequency Reduction of Lowest Slew Rate (RSL = 200k) Compared to Highest Slew Rate (RSL = 0) SPLIT Pin Output for Split Termination Support Split termination is an optional termination technique to reduce common mode voltage perturbations that can produce EME. A split terminator divides the single line-end termination resistor (nominally 120) into two series resistors of half the value of the single termination resistor (Figure 2). The center point of the two resistors is connected to a low impedance voltage source that sets the recessive common mode voltage. Split termination suppresses common mode voltage perturbations by providing a low impedance load to common mode noise sources such as transmitter noise or coupling to external noise sources. In the case of single resistor termination, the only load on a common mode noise source is the parallel impedance of the input resistors of the CAN transceivers on the bus. This results in a common mode impedance of several kilohms for a small network. The split termination, on the other hand, provides a common mode load equal to the parallel resistance of the two split termination resistors, or 1/4 the resistance of the single termination resistor (30). This low common mode impedance results in a reduction of the common mode noise voltage compared to the much higher common mode impedance of the single resistor termination. The SPLIT pin on the LTM2889 provides a buffered voltage to bias the mid-point of the split termination resistors. The voltage on the SPLIT pin matches the common mode voltage established by the transmitter in the dominant state and the receiver input resistor bias during the recessive state: 2.5V when VCC2 = 5V and 1.95V when VCC2 = 3.3V. SPLIT is decoupled to GND2 with an internal 4.7nF capacitor to lower the AC impedance to better suppress fast transients. SPLIT is a high voltage fault tolerant output that tolerates the same 60V overvoltage faults and 25kV ESD discharges as CANH and CANL. One disadvantage of the SPLIT termination is higher power supply current if the two terminating transceivers differ in their common mode voltage due to differences in VCC2 or GND2 potential or to chip to chip variations in the internal reference voltages. This will result in the transceiver with the higher common mode voltage sourcing current into the bus lines through its SPLIT pin, while the transceiver with the lower common mode voltage will sink current through its SPLIT pin. 2889fa 22 For more information www.linear.com/LTM2889 LTM2889 APPLICATIONS INFORMATION Ideal Passive Behavior to CAN Bus With Supply Off When the power supply is removed or the chip is in shutdown, the CANH and CANL pins are in a high impedance state. The receiver inputs are isolated from the CANH and CANL nodes by FET switches which open in the absence of power, thereby preventing the resistor dividers on the receiver input from loading the bus. The high impedance state of the receiver is limited by ESD clamps inboard of the 40k input resistors to a typical range of -0.5V to 11V. For bus voltages outside this range, the current flowing into the receiver is governed by the conduction voltages of the ESD device and the 40k nominal receiver input resistance. DeviceNet Compatibility DeviceNet is a network standard based on the CAN bus. The DeviceNet standard places requirements on the transceiver that exceed those of the ISO 11898-2 standard. The LTM2889 meets the DeviceNet requirements listed in Table 2. DeviceNet employs a 5-pin connector with conductors for Power+, Power-, CANH, CANL, and Drain. The power is 24VDC, and the Drain wire is connected to the cable shield for shielded cables. The Power- pin may be connected to LTM2889 GND2, but the Power+ must not be connected to the LTM2889 VCC2 pin. Table 2: DeviceNet Requirements PARAMETER DeviceNet ISO 11898-2 REQUIREMENT REQUIREMENT LTM2889 Number of Nodes 64 N/A 166 Minimum Differential Input Resistance 20k 10k 50k Differential Input Capacitance 25pF (Max) 10pF (Nom) 8.4pF (Typ) (Note 6) Bus Pin Voltage Range (Survivable) -25V to 18V Bus Pin Voltage Range (Operation) -5V to 10V -2V to 7V -36V to 36V (VCC = 5V) Connector Mis-Wiring Tests, All Pin-Pin Combinations 18V N/A 60V (See Below) -60V to 60V -3V to 16V (for 12V Battery) The DeviceNet mis-wiring tests involve connecting an 18V supply to each of the 20 possible pin pair/polarity combinations on the 5-pin connector. The 60V tolerance of the LTM2889 with respect to GND2 ensures that the LTM2889 will pass all the mis-wiring tests without damage. PCB Layout Considerations The high integration of the LTM2889 makes PCB layout very simple. However, to optimize its electrical isolation characteristics, EMI, and thermal performance, some layout considerations are necessary. * Under heavily loaded conditions PVCC and GND current can exceed 300mA. Sufficient copper must be used on the PCB to insure resistive losses do not cause the supply voltage to drop below the minimum allowed level. Similarly, the VCC2 and GND2 conductors must be sized to support any external load current. These heavy copper traces will also help to reduce thermal stress and improve the thermal conductivity. * Input and Output decoupling is not required, since these components are integrated within the package. An additional bulk capacitor with a value of 6.8F to 22F with 1 to 3 of ESR is recommended. The high ESR of this capacitor reduces board resonances and minimizes voltage spikes caused by hot plugging of the supply voltage. For EMI sensitive applications, an additional low ESL ceramic capacitor of 1F to 4.7F, placed as close to the power and ground terminals as possible, is recommended. Alternatively, a number of smaller value parallel capacitors may be used to reduce ESL and achieve the same net capacitance. * Do not place copper on the PCB between the inner columns of pads. This area must remain open to withstand the rated isolation voltage. * The use of solid ground planes for GND and GND2 is recommended for non-EMI critical applications to optimize signal fidelity, thermal performance, and to minimize RF emissions due to uncoupled PCB trace conduction. The drawback of using ground planes, where EMI is of concern, is the creation of a dipole antenna structure which can radiate differential voltages formed between GND and GND2. If ground planes are used it is recommended to minimize their area, and use contiguous planes as any openings or splits can exacerbate RF emissions. 2889fa For more information www.linear.com/LTM2889 23 LTM2889 APPLICATIONS INFORMATION * For large ground planes a small capacitance ( 330pF) from GND to GND2, either discrete or embedded within the substrate, provides a low impedance current return path for the module parasitic capacitance, minimizing any high frequency differential voltages and substantially reducing radiated emissions. Discrete capacitance will not be as effective due to parasitic ESL. In addition, voltage rating, leakage, and clearance must be considered for component selection. Embedding the capacitance within the PCB substrate provides a near ideal capacitor and eliminates component selection issues; however, the PCB must be 4 layers. Care must be exercised in applying either technique to insure the voltage rating of the barrier is not compromised. The PCB layout in Figures 17-21 show the low EMI demo board for the LTM2889. The demo board uses a combination of EMI mitigation techniques, including both embedded PCB bridge capacitance and discrete GND to GND2 capacitors (C3 + C4). Two safety rated type Y2 capacitors are used in series, manufactured by Murata, part number GA342QR7GF471KW01L. The embedded capacitor effectively suppresses emissions above 400MHz, whereas the discrete capacitors are more effective below 400MHz. EMI performance is shown in Figure 22, measured using a Gigahertz Transverse Electromagnetic (GTEM) cell and method detailed in IEC 61000-4-20, "Testing and Measurement Techniques - Emission and Immunity Testing in Transverse Electromagnetic Waveguides." RF, MAGNETIC FIELD IMMUNITY EN 61000-4-3 Radiated, Radio-Frequency,Electromagnetic Field Immunity EN 61000-4-8 Power Frequency Magnetic Field Immunity EN 61000-4-9 Pulse Magnetic Field Immunity Tests were performed using an unshielded test card designed per the data sheet PCB layout recommendations. Specific limits per test are detailed in Table 3. Table 3. TEST EN61000-4-3 Annex D FREQUENCY FIELD STRENGTH 80MHz to 16Hz 10V/m 1.4MHz to 2Hz 3V/m 2MHz to 2.7Hz 1V/m 50MHz to 60Hz 30A/m EN61000-4-8 Level 5 60Hz 100A/m* EN61000-4-9 Level 5 Pulse 100A/m EN61000-4-8 Level 4 *Non IEC method Operation Above 105C (LTM2889H) Operation of the H temperature grade LTM2889H above 105C is limited by the internal power dissipation of the module, and depends on the PVCC voltage range option, the external ICC2 load current, and whether the CAN transceiver is on or off. Refer to the Typical Performance Characteristics chart labeled Derating for 125C Maximum Internal Operating Temperature on page 13. The CAN transceiver of the LTM2889H may operate up to 125C if VCC2 is supplied by an external power supply and the PVCC pins are grounded. Refer to PVCC Power Supply on page 16. The isolator Module technology used within the LTM2889 has been independently evaluated, and successfully passed the RF and magnetic field immunity testing requirements per European Standard EN 55024, in accordance with the following test standards: 2889fa 24 For more information www.linear.com/LTM2889 LTM2889 APPLICATIONS INFORMATION TECHNOLOGY Figure 17. Low EMI Demo Board Layout Figure 18. Low EMI Demo Board Layout (DC1746A), Top Layer Figure 19. Low EMI Demo Board Layout (DC1746A), Inner Layer 1 2889fa For more information www.linear.com/LTM2889 25 LTM2889 APPLICATIONS INFORMATION Figure 20. Low EMI Demo Board Layout (DC1746A), Inner Layer 2 Figure 21. Low EMI Demo Board Layout (DC1746A), Bottom Layer 60 50 AMPLITUDE (dBV/m) 40 CISPR 22 CLASS B LIMIT DC1903A-A DC1903A-B 30 20 10 0 -10 -20 -30 DETECTOR = QPEAK RBW = 120kHz VBW = 300kHz SWEEP TIME = 17s # OF POINTS = 501 0 100 200 300 400 500 600 700 800 900 1000 FREQUENCY (MHz) 2889 F22 Figure 22. Low EMI Demo Board Emissions 2889fa 26 For more information www.linear.com/LTM2889 LTM2889 TYPICAL APPLICATIONS VCCA VCCB ON S RXD 60 CANL CANH SPLIT 60 60 CANL 60 GND2 GND A VL TXD ON S RXD GND2 GND B RE 2889 F23 Figure 23. Point-to-Point Isolated CAN Communications on an Unshielded Twisted Pair 3.3V (LTM2889-3) OR 5V (LTM2889-5) VCC, PVCC VL TXD ON OFF ON LTM2889 S RXD RE 5V OUTPUT AVAILABLE CURRENT: 150mA (LTM2889-5) 100mA (LTM2889-3) VCC2 PWR ISOLATION BARRIER CANH CANL GND GND2 2889 F24 Figure 24. Using the LTM2889 as a Dedicated Isolated 5V Supply ANY VOLTAGE FROM 1.62V TO 5.5V VDD 3V TO 5.5V VL VCC TXD S CAN CONTROLLER ON RXD RE GND GND PVCC VCC2 LTM2889 ISOLATION BARRIER RE VCC, PVCC LTM2889 CANH SPLIT ISOLATION BARRIER TXD LTM2889 ISOLATION BARRIER VL VCC, PVCC POWER INPUT : 3.3V or 5V AT 60mA CANH CANL 120 GND2 2889 F25 LOGIC INTERFACE LEVELS: GND TO VL Figure 25. Supplying VCC2 From an External Supply 2889fa For more information www.linear.com/LTM2889 27 aaa Z 0.630 0.025 O 32x 3.175 SUGGESTED PCB LAYOUT TOP VIEW 1.905 PACKAGE TOP VIEW E 0.000 4 0.635 PIN "A1" CORNER 0.635 Y X D For more information www.linear.com/LTM2889 6.350 5.080 0.000 5.080 6.350 aaa Z 2.45 - 2.55 SYMBOL A A1 A2 b b1 D E e F G aaa bbb ccc ddd eee NOM 3.42 0.60 2.82 0.75 0.63 15.0 11.25 1.27 12.70 8.89 DIMENSIONS 0.15 0.10 0.20 0.30 0.15 MAX 3.62 0.70 2.92 0.90 0.66 NOTES DETAIL B PACKAGE SIDE VIEW TOTAL NUMBER OF BALLS: 32 MIN 3.22 0.50 2.72 0.60 0.60 b1 0.27 - 0.37 SUBSTRATE ddd M Z X Y eee M Z DETAIL A Ob (32 PLACES) DETAIL B MOLD CAP ccc Z A1 A2 A Z (Reference LTC DWG # 05-08-1851 Rev D) // bbb Z 28 1.905 BGA Package 32-Lead (15mm x 11.25mm x 3.42mm) e b 7 5 G 4 e 3 PACKAGE BOTTOM VIEW 6 2 1 L K J H G F E D C B A DETAILS OF PIN #1 IDENTIFIER ARE OPTIONAL, BUT MUST BE LOCATED WITHIN THE ZONE INDICATED. THE PIN #1 IDENTIFIER MAY BE EITHER A MOLD OR MARKED FEATURE 4 3 TRAY PIN 1 BEVEL COMPONENT PIN "A1" 7 ! PACKAGE IN TRAY LOADING ORIENTATION LTMXXXXXX Module BGA 32 1112 REV D PACKAGE ROW AND COLUMN LABELING MAY VARY AMONG Module PRODUCTS. REVIEW EACH PACKAGE LAYOUT CAREFULLY 6. SOLDER BALL COMPOSITION IS 96.5% Sn/3.0% Ag/0.5% Cu 5. PRIMARY DATUM -Z- IS SEATING PLANE BALL DESIGNATION PER JESD MS-028 AND JEP95 3 2. ALL DIMENSIONS ARE IN MILLIMETERS 7 SEE NOTES PIN 1 SEE NOTES NOTES: 1. DIMENSIONING AND TOLERANCING PER ASME Y14.5M-1994 F b 8 DETAIL A LTM2889 PACKAGE DESCRIPTION Please refer to http://www.linear.com/product/LTM2889#packaging for the most recent package drawings. 2889fa 3.175 4.445 4.445 LTM2889 REVISION HISTORY REV DATE DESCRIPTION A 03/17 Added UL-CSA File Number PAGE NUMBER 1 2889fa 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. For more information www.linear.com/LTM2889 29 LTM2889 TYPICAL APPLICATION VCCA VDD VL VCC, PVCC C + CAN ISOLATION BARRIER BUS MASTER TXD LTM2889-3 S ON RXD CANH CANL 120 RE GND GND GND2 A VCCB SENSOR OR ACTUATOR VDD VCC, PVCC VL C + CAN ISOLATION BARRIER TXD LTM2889-3 S ON RXD CANH CANL RE GND GND GND2 B VCCC VL VCC, PVCC TXD C + CAN LTM2889-5 ISOLATION BARRIER SENSOR OR ACTUATOR VDD S ON RXD CANH CANL 120 CABLE SHIELD OR GND WIRE RE GND GND GND2 C 2889 TA02 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LTC2875 60V, 25kV ESD, Fault Protected 3.3V or 5V 25kV ESD High Speed CAN Transceiver Protected from Overvoltage Line Faults to 60V, 25kV ESD, up to 4Mbps LTM2881 Complete Isolated RS485/RS422 Module Transceiver + Power Integrated Selectable Termination, 20Mbps, 15kV ESD, 2500VRMS Isolation with Power LTM2882 Dual Isolated RS232 Module Transceiver + Power 1Mbps, 10kV ESD, 2500VRMS Isolation with Power LTM2883 SPI/Digital or I2C Module Isolator with Integrated DC/DC Converter 2500VRMS Isolation with Adjustable 12.5V and 5V Power in BGA Package 2889fa 30 LT 0317 REV A * PRINTED IN USA For more information www.linear.com/LTM2889 www.linear.com/LTM2889 LINEAR TECHNOLOGY CORPORATION 2016