Ultra Rugged ±60V PROFIBUS Transceivers Optimized for True PROFIBUS IEC 61158-2 Compliant Operation The LTC®2876 and LTC2877 are exceptionally rugged, high voltage tolerant PROFIBUS RS485 transceivers to eliminate field failures without the need of costly external protection devices. ±60V overvoltage fault protection on the data transmission lines protects bus pins during operation or when unpowered. Extended ±25V input common mode range and full failsafe operation improve data communication reliability in electrically noisy environments and in the presence of ground loop voltages. Enhanced ESD protection allows these devices to withstand ±52kV HBM on the transceiver pins without latchup or damage; all other pins are protected to ±15kV HBM. Features nn nn nn nn nn nn nn nn ±60V Overvoltage Protection ±52kV ESD Interface Pins, ±15kV All Other Pins ±2kV (Level 4) IEC61000-4-4 Fast Transient Burst Supports All Data Rates Up to 20Mbps ±25V Working Common Mode Range Fully Balanced Differential Receiver Thresholds with 240mV Hysteresis for Superior Noise Tolerance and Low Duty Cycle Distortion 3V to 5.5V Supply Voltage Wide Operating Temperature Range: –40°C to 125°C PART NUMBER LTC2876 LTC2877 LOGIC SUPPLY PIN No Yes An Unprotected LTC2876 Hit Repeatedly with 26kV ESD Discharges While Operating without Damage or Circuit Latchup PACKAGE DFN-8, MSOP-8 DFN-10, MSOP-10 L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. PROFIBUS Multi-Node Network Twisted Pair Cable (Z0 = 150Ω) 5V 5V 390Ω 390Ω B B PROFIBUS MASTER 220Ω 220Ω 390Ω 390Ω A PROFIBUS STATION A PROFIBUS STATION PROFIBUS STATION PROFIBUS adopted much of the TIA/EIA-485-A (RS485) standard, but did make a few changes. As a result, not all RS485 transceivers and cables are suitable for PROFIBUS-DP networks. There are differences in cabling, termination, signal names and driver requirements. Testing the LTC2876/LTC2877 Differential Output Voltage (VOD) Using a PROFIBUS Load VCC VCC LTC2876/LTC2877 B'PP VCC A'PP B' RO 390Ω PB RE HIGH DE HIGH 220Ω PA DI B' B'-A' 0 220Ω RCABLE VOD(PP) A' 390Ω + – A' 0 390Ω RCABLE VBPP–APP = |B'PP – A'PP| VBPP+APP = B'PP – A'PP 390Ω MEASUREMENTS TAKEN AT STEADY STATE The LTC2876/LTC2877 are tested with a PROFIBUS load and with series resistance to simulate cable losses, where the VOD (blue curve) is generated from measurements taken at the “end of the cable” (A’ and B’) to ensure the 7VP-P PROFIBUS-DP limit is met. Be wary of “PROFIBUS-compatible” RS485 transceivers that only specify a VOD minimum value (i.e, 2.1V) without a maximum value, which can easily overdrive the bus. Spotlight App: 3500VRMS Isolated PROFIBUS Node with Termination ISOLATED 5VIN 3V TO 5.5V RO D R DI A6 A5 A4 B1 B2 B3 A3 A2 A1 B4 B5 B6 VCC1 VL1 ON1 OUTD OUTE OUTF INC INB INA EOUTD GND1 GND1 ISOLATION BARRIER LTM2892-S VCC2 VL2 ON2 IND INE INF OUTC OUTB OUTA EOUTA GND2 GND2 J6 J5 J4 J1 J2 J3 H3 H2 H1 H4 H5 H6 8 VCC LTC2876 390Ω 1 RO PB 3 2 RE 3 DE 1 220Ω 7 4 DI 4 6 PA GND 390Ω 5 2 M12 CONNECTOR (FEMALE) ISOLATED GROUND www.linear.com/2876 n 1-800-4-LINEAR 0316