RS-485

SP339E RS-232/RS-485/RS-422 TRANSCEIVER WITH INTERNAL TERMINATION OCT 2011 REV. 1.0.0 GENERAL DESCRIPTION The SP339 is an advanced multiprotocol transceiver supporting RS-232, RS-485, and RS-422 serial standards in a 40 pin QFN package. Integrated cable termination and four configuration modes allow all three protocols to be used interchangeably over a single cable or connector with no additional switching components. Full operation requires only four external charge pump capacitors. The RS-485/422 modes feature one driver and one receiver (1TX/1RX) in both half and full duplex configurations. The RS-232 mode (3TX/5RX) provides full support of all eight signals commonly used with the DB9 RS-232 connector. A dedicated diagnostic loopback mode is also provided. The high speed drivers operate up to 20Mbps in RS485/422 modes, and up to 1Mbps in RS-232 mode. All drivers can be slew limited to 250kbps in any mode to minimize electromagnetic interference (EMI). All transmitter outputs and receiver inputs feature robust electrostatic discharge (ESD) protection to ±15kV Human Body Model (HBM) and ±8kV IEC61000-4-2 Contact. Each receiver output has full failsafe protection to avoid system lockup, oscillation, or indeterminate states by defaulting to logic-high output level when the inputs are open, shorted, or terminated but undriven. No external biasing resistors are required. The RS-232 receiver inputs include a 5kΩ pull-down to ground. The RS-485/422 receiver inputs are high impedance (>96kΩ when termination is disabled), allowing up to 256 devices on a single communication bus (1/8th unit load). The SP339E operates from a single power supply, either 3.3V or 5V, with low idle current (2mA typical in all modes). The shutdown mode consumes less than 10µA for low power standby operation. FEATURES • Pin selectable Cable Termination • No external resistors required for RS-485/422 termination and biasing • 3.3V or 5V Single Supply Operation • Robust ESD Protection on bus pins ■ ■ ±15kV Human Body Model (HBM) ±8kV IEC 61000-4-2 (Contact) • Max Data Rate of 20Mbps in RS-485/422 Modes and up to 1Mbps in RS-232 Modes • Pin selectable 250kbps Slew Limiting • 3 Drivers, 5 Receivers RS-232/V.28 • 1 Driver, 1 Receiver RS-485/422 ■ ■ Full and Half Duplex Configuration 1/8th Unit Load, up to 256 receivers on bus • RS-485/422 Enhanced Failsafe for open, shorted, or terminated but idle inputs • Space saving 6mm x 6mm QFN-40 Package • Pin compatible with SP338E TYPICAL APPLICATIONS • Dual Protocol Serial Ports (RS-232 or RS-485/422) • Industrial Computers • Industrial and Process Control Equipment • Point-Of-Sale Equipment • Networking Equipment • HVAC Controls Equipment • Building Security and Automation Equipment ORDERING INFORMATION PART NUMBER SP339EER1-L SP339EER1-L/TR SP339ECR1-L SP339ECR1-L/TR PACKAGE 40-pin QFN 40-pin QFN 40-pin QFN 40-pin QFN OPERATING TEMPERATURE RANGE -40°C to +85°C -40°C to +85°C 0°C to +70°C 0°C to +70°C DEVICE STATUS Active Active Active Active Exar Corporation 48720 Kato Road, Fremont CA, 94538 • (510) 668-7000 • FAX (510) 668-7017 • www.exar.com SP339E RS-232/RS-485/RS-422 TRANSCEIVER WITH INTERNAL TERMINATION REV. 1.0.0 ABSOLUTE MAXIMUM RATINGS These are stress ratings only and functional operation of the device at these ratings or any other above those indicated in the operation sections to the specifications below is not implied. Exposure to absolute maximum rating conditions for extended periods of time may affect reliability and cause permanent damage to the device. Supply Voltage VCC Receiver Input Voltage (from Ground) Driver Output Voltage (from Ground) Short Circuit Duration, TX out to Ground Voltage at TTL Input Pins Storage Temperature Range Lead Temperature (soldering, 10s) Power Dissipation 40-pin QFN (derate 17mW/°C above +70°C) -0.3V to +6.0V ±20V ±20V Continuous -0.3V to VCC+0.5V -65°C to +150°C +300°C 500mW CAUTION: ESD (ElectroStatic Discharge) sensitive device. Permanent damage may occur on unconnected devices subject to high energy electrostatic fields. Unused devices must be stored in conductive foam or shunts. Personnel should be properly grounded prior to handling this device. The protective foam should be discharged to the destination socket before devices are removed. ESD PROTECTION MIN. R1-R9 Tx Output & Rx Input Pins All Other Pins TYP. ±15 ±8 ±2 MAX. UNITS kV kV kV Human Body Model (HBM) IEC 61000-4-2 (Contact) Human Body Model (HBM) 2 SP339E REV. 1.0.0 RS-232/RS-485/RS-422 TRANSCEIVER WITH INTERNAL TERMINATION PIN DESCRIPTIONS BY MODE (MODE1, MODE0) Pin 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Name L1 L2 L3 L4 L6 L7 L8 L9 VCC GND SLEW DIR1 N/C MODE0 MODE1 N/C TERM N/C ENABLE VCC 0 0 00, Figure 1 R1 Output R2 Output T1 Input T2 Input R3 Output T3 Input R4 Output R5 Output VCC Ground SLEW = VCC enables 250kbps slew limiting T1 Enable, R1 Disable This pin is not used and is disconnected internally 1 0 0 1 1 1 T1 Enable 1 1 1 1 1 1 01, Figure 2 10, Figure 3 1 R1 Output T1 Input 11, Figure 4 1 R1 Output T1 Input This pin is not used and is disconnected internally Enables RS-485/422 receiver termination This pin is not used and is disconnected internally ENABLE = VCC for operation, ENABLE = 0V for shutdown VCC 3 SP339E RS-232/RS-485/RS-422 TRANSCEIVER WITH INTERNAL TERMINATION REV. 1.0.0 PIN DESCRIPTIONS BY MODE (MODE1, MODE0) Pin 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 Name R9 R8 GND R7 R6 GND R4 R3 GND R2 R1 VCC VSS C2C1GND C1+ VCC C2+ VDD R2 Input R1 Input T2 Output T1 Output Ground R1 Input A, T1 Out A R1 Input B, T1 Out B VCC VSS - Charge pump negative supply, 0.1µF from ground C2+ - Charge pump cap 2 negative lead C1- - Charge pump cap 1 negative lead Ground C1+ - Charge pump cap 1 positive lead, 0.1µF VCC C2+ - Charge pump cap 2 positive lead, 0.1µF VDD - Charge pump positive supply, 0.1µF to ground T1 Out A T1 Out B T3 Output R3 Input Ground R1 Input B R2 Input A 00, Figure 1 01, Figure 2 R5 Input R4 Input Ground 10, Figure 3 11, Figure 4 4 SP339E REV. 1.0.0 RS-232/RS-485/RS-422 TRANSCEIVER WITH INTERNAL TERMINATION ELECTRICAL CHARACTERISTICS UNLESS OTHERWISE NOTED: VCC = +3.3V ±5% or +5.0V ±5%, C1-C4 = 0.1µF; TA = TMIN to TMAX. Typical values are at VCC = 3.3V, TA = +25°C. SYMBOL DC CHARACTERISTICS ICC ICC ICC Supply Current (RS-232) Supply Current (RS-485) Vcc Shutdown Current 2 2 1 8 8 10 mA mA µA No load, idle inputs No load, idle inputs ENABLE = 0V PARAMETERS MIN. TYP. MAX. UNITS CONDITIONS TRANSMITTER and LOGIC INPUT PINS: Pins 3, 4, 6, 11, 12, 14, 15, 17-19 VIH VIH VIL IIL IIH IPD VHYS Logic Input Voltage High Logic Input Voltage High Logic Input Voltage Low Logic Input Leakage Current Low Logic Input Leakage Current High Logic Input Pull-down Current Logic Input Hysteresis 200 2.0 2.4 0.8 1 1 50 V V V µA µA µA mV Input Low (VIN = 0V) Input High (VIN = VCC), pins 3, 4 and 6 Input High (VIN = VCC), pins 11, 12, 14, 15, 17-19 VCC = 3.3V VCC = 5.0V RECEIVER OUTPUTS: Pins 1, 2, 5, 7, 8 VOH VOL IOSS IOZ Receiver Output Voltage High Receiver Output Voltage Low Receiver Output ShortCircuit Current Receiver Output Leakage Current ±20 ±0.1 VCC-0.6 V 0.4 ±60 ±1 V mA µA IOUT = -1.5mA IOUT = 2.5mA 0 ≤ VO ≤ VCC 0 ≤ VO ≤ VCC, Receivers disabled 5 SP339E RS-232/RS-485/RS-422 TRANSCEIVER WITH INTERNAL TERMINATION REV. 1.0.0 ELECTRICAL CHARACTERISTICS (Continued) UNLESS OTHERWISE NOTED: VCC = +3.3V ±5% or +5.0V ±5%, C1-C4 = 0.1µF; TA = TMIN to TMAX. Typical values are at VCC = 3.3V, TA = +25°C. SYMBOL PARAMETERS MIN. TYP. MAX. UNITS CONDITIONS SINGLE-ENDED RECEIVER INPUTS (RS-232) VIN VIL Input Voltage Range Input Threshold Low -15 0.6 0.8 1.2 1.5 1.5 1.8 0.3 3 5 7 2.0 2.4 +15 V V V V V V kΩ -15V ≤ VIN ≤ +15V VCC = 3.3V VCC = 5.0V VCC = 3.3V VCC = 5.0V VIH VHYS RIN Input Threshold High Input Hysteresis Input Resistance SINGLE-ENDED DRIVER OUTPUTS (RS-232) VO ISC ROFF Output Voltage Swing Short Circuit Current Power Off Impedance 300 10M ±5.0 ±5.5 ±7.0 ±60 V V mA Ω Output loaded with 3kΩ to Gnd No load output VO = 0V VCC = 0V, VO = ±2V 6 SP339E REV. 1.0.0 RS-232/RS-485/RS-422 TRANSCEIVER WITH INTERNAL TERMINATION ELECTRICAL CHARACTERISTICS (Continued) UNLESS OTHERWISE NOTED: VCC = +3.3V ±5% or +5.0V ±5%, C1-C4 = 0.1µF; TA = TMIN to TMAX. Typical values are at VCC = 3.3V, TA = +25°C. SYMBOL PARAMETERS MIN. TYP. MAX. UNITS CONDITIONS DIFFERENTIAL RECEIVER INPUTS (RS-485 / RS-422) RIN VTH ∆VTH IIN Receiver Input Resistance Receiver Differential Threshold Voltage Receiver Input Hysteresis Receiver Input Current 96 -200 -125 25 125 -100 100 120 155 -50 kΩ mV mV µA µA Ω Ω VCM = 0V VIN = +12V VIN = -7V TERM = VCC, Figure 5 -7V ≤ VCM ≤ +12V TERM = VCC, Figure 5 VCM = 0V TERM = 0V, -7V ≤ VIN ≤ +12V RTERM RTERM Termination Resistance Termination Resistance 100 120 140 DIFFERENTIAL DRIVER OUTPUTS (RS-485 / RS-422) 2 VOD Differential Driver Output 1.5 1.5 1.5 ∆VOD VCM ∆VCM IOSD IO Change In Magnitude of Differential Output Voltage Driver CommonMode Output Voltage Change In Magnitude of Common Mode Output Voltage Driver Output Short Circuit Current Driver Output Leakage Current -0.2 VCC VCC VCC VCC +0.2 3 0.2 ±250 ±100 V V V V V V V mA µA RL = 100Ω (RS-422), Figure 6 RL = 54Ω (RS-485), Figure 6 VCM = -7V, Figure 7 VCM = +12V, Figure 7 RL = 54Ω or 100Ω, Figure 6 RL = 54Ω or 100Ω, Figure 6 RL = 54Ω or 100Ω, Figure 6 -7V ≤ VO ≤ +12V, Figure 8 DIR1 = 0V in Mode 11, or ENABLE = 0V, -7V ≤ VO ≤ +12V 7 SP339E RS-232/RS-485/RS-422 TRANSCEIVER WITH INTERNAL TERMINATION REV. 1.0.0 TIMING CHARACTERISTICS UNLESS OTHERWISE NOTED: VCC = +3.3V ±5% or +5.0V ±5%, C1-C4 = 0.1µF; TA = TMIN to TMAX. Typical values are at VCC = 3.3V, TA = +25°C. SYMBOL ALL MODES tENABLE tSHUTDOWN Enable from Shutdown Enable to Shutdown 1000 1000 ns ns PARAMETERS MIN. TYP. MAX. UNITS CONDITIONS RS-232, DATA RATE = 250kbps (SLEW = Vcc), ONE TRANSMITTER SWITCHING Maximum Data Rate tRHL, tRLH ⏐tRHL-tRLH⏐ tDHL, tDLH ⏐tDHL-tDLH⏐ Receiver Propagation Delay Receiver Propagation Delay Skew Driver Propagation Delay Driver Propagation Delay Skew 1400 600 250 100 100 kbps ns ns ns ns RL = 3kΩ, CL = 1000pF CL = 150pF, Figure 9 RL = 3kΩ, CL = 2500pF, Figure 10 tSHL, tSLH Transition Region Slew Rate from +3.0V to -3.0V or -3.0V to +3.0V VCC = 3.3V, RL = 3kΩ to 7kΩ, 4 30 V/µs CL = 150pF to 2500pF, Figure 10 VCC = 3.3V, RL = 3kΩ to 7kΩ, 6 30 V/µs CL = 150pF to 2500pF, TA = 25°C, Figure 10 tSHL, tSLH Transition Region Slew Rate from +3.0V to -3.0V or -3.0V to +3.0V RS-232, DATA RATE = 1Mbps (SLEW = 0V), ONE TRANSMITTER SWITCHING Maximum Data Rate tRHL, tRLH ⏐tRHL-tRLH⏐ tDHL, tDLH ⏐tDHL-tDLH⏐ Receiver Propagation Delay Receiver Propagation Delay Skew Driver Propagation Delay Driver Propagation Delay Skew 300 150 1 100 100 Mbps RL = 3kΩ, CL = 250pF ns ns ns ns CL = 150pF, Figure 9 RL = 3kΩ, CL = 1000pF, Figure 10 tSHL, tSLH Transition Region Slew Rate from +3.0V to -3.0V or -3.0V to +3.0V VCC = 3.3V, RL = 3kΩ to 7kΩ, 15 150 V/µs CL = 150pF to 1000pF, Figure 10 VCC = 3.3V, RL = 3kΩ to 7kΩ, 24 150 V/µs CL = 150pF to 1000pF, TA = 25°C, Figure 10 tSHL, tSLH Transition Region Slew Rate from +3.0V to -3.0V or -3.0V to +3.0V 8 SP339E REV. 1.0.0 RS-232/RS-485/RS-422 TRANSCEIVER WITH INTERNAL TERMINATION TIMING CHARACTERISTICS (Continued) UNLESS OTHERWISE NOTED: VCC = +3.3V ±5% or +5.0V ±5%, C1-C4 = 0.1µF; TA = TMIN to TMAX. Typical values are at VCC = 3.3V, TA = +25°C. SYMBOL PARAMETERS MIN. TYP. MAX. UNITS CONDITIONS RS-485/RS-422, DATA RATE = 250kbps (SLEW = Vcc), ONE TRANSMITTER SWITCHING Maximum Data Rate tRPHL, tRPLH Receiver Propagation Delay 250 50 150 20 500 1000 100 300 650 1200 kbps ns ns ns ns ns RL = 54Ω, CL = 50pF, Figure 12 RL = 54Ω, CL = 50pF CL = 15pF, Figure 11 ⏐tRPHL-tRPLH⏐ Receiver Propagation Delay Skew tDPHL, tDPLH Driver Propagation Delay ⏐tDPHL-tDPLH⏐ Driver Propagation Delay Skew tDR, tDF Driver Rise and Fall Time tRZH, tRZL tRHZ, tRLZ tDZH, tDZL tDHZ, tDLZ Receiver Output Enable Time Receiver Output Disable Time Driver Output Enable Time Driver Output Disable Time 200 200 1000 200 ns ns ns ns Figure 13 Figure 14 RS-485/RS-422, DATA RATE = 20Mbps (SLEW = 0V), ONE TRANSMITTER SWITCHING Maximum Data Rate tRPHL, tRPLH Receiver Propagation Delay 20 50 150 10 30 100 10 10 20 Mbps RL = 54Ω, CL = 50pF ns ns ns ns ns RL = 54Ω, CL = 50pF, Figure 12 CL = 15pF, Figure 11 ⏐tRPHL-tRPLH⏐ Receiver Propagation Delay Skew tDPHL, tDPLH Driver Propagation Delay ⏐tDPHL-tDPLH⏐ Driver Propagation Delay Skew tDR, tDF Driver Rise and Fall Time tRZH, tRZL tRHZ, tRLZ tDZH, tDZL tDHZ, tDLZ Receiver Output Enable Time Receiver Output Disable Time Driver Output Enable Time Driver Output Disable Time 200 200 200 200 ns ns ns ns Figure 13 Figure 14 9 SP339E RS-232/RS-485/RS-422 TRANSCEIVER WITH INTERNAL TERMINATION REV. 1.0.0 BLOCK DIAGRAM BY MODE (MODE1, MODE0) FIGURE 1. MODE 00 - LOOPBACK 10 SP339E REV. 1.0.0 RS-232/RS-485/RS-422 TRANSCEIVER WITH INTERNAL TERMINATION FIGURE 2. MODE 01 - RS-232 11 SP339E RS-232/RS-485/RS-422 TRANSCEIVER WITH INTERNAL TERMINATION FIGURE 3. MODE 10 - RS-485 HALF DUPLEX REV. 1.0.0 12 SP339E REV. 1.0.0 RS-232/RS-485/RS-422 TRANSCEIVER WITH INTERNAL TERMINATION FIGURE 4. MODE 11 - RS-485/422 FULL DUPLEX 13 SP339E RS-232/RS-485/RS-422 TRANSCEIVER WITH INTERNAL TERMINATION REV. 1.0.0 TEST FIXTURES FIGURE 5. RS-485/422 RECEIVER TERMINATION RESISTANCE FIGURE 6. RS-485/422 DIFFERENTIAL DRIVER OUTPUT VOLTAGE FIGURE 7. RS-485/422 DIFFERENTIAL DRIVER OUTPUT VOLTAGE OVER COMMON MODE 14 SP339E REV. 1.0.0 RS-232/RS-485/RS-422 TRANSCEIVER WITH INTERNAL TERMINATION FIGURE 8. RS-485/422 DRIVER OUTPUT SHORT CIRCUIT CURRENT FIGURE 9. RS-232 RECEIVER PROPAGATION DELAY 15 SP339E RS-232/RS-485/RS-422 TRANSCEIVER WITH INTERNAL TERMINATION FIGURE 10. RS-232 DRIVER PROPAGATION DELAY REV. 1.0.0 FIGURE 11. RS-485/422 RECEIVER PROPAGATION DELAY 16 SP339E REV. 1.0.0 RS-232/RS-485/RS-422 TRANSCEIVER WITH INTERNAL TERMINATION FIGURE 12. RS-485/422 DRIVER PROPAGATION DELAY AND RISE/FALL TIMES FIGURE 13. RS-485/422 RECEIVER OUTPUT ENABLE/DISABLE TIMES 17 SP339E RS-232/RS-485/RS-422 TRANSCEIVER WITH INTERNAL TERMINATION FIGURE 14. RS-485/422 DRIVER OUTPUT ENABLE/DISABLE TIMES REV. 1.0.0 18 SP339E REV. 1.0.0 RS-232/RS-485/RS-422 TRANSCEIVER WITH INTERNAL TERMINATION PRODUCT SUMMARY The SP339 is an advanced multiprotocol transceiver supporting RS-232, RS-485, and RS-422 serial standards in a 40 pin QFN package. Integrated cable termination and four configuration modes allow all three protocols to be used interchangeably over a single cable or connector with no additional switching components. The RS485/422 modes feature one driver and one receiver (1TX/1RX) in both half and full duplex configurations. The RS-232 mode (3TX/5RX) provides full support of all eight signals commonly used with the DB9 RS-232 connector. A dedicated mode is also available for diagnostic loopback testing. INTERNALLY SWITCHED CABLE TERMINATION Enabling and disabling the RS-485/422 termination resistor is one of the largest challenges system designers face when sharing a single connector or pair of lines across multiple serial protocols. A termination resistor may be necessary for accurate RS-485/422 communication, but must be removed when the lines are used for RS-232. SP339E provides an elegant solution to this problem by integrating the termination resistor and switching control, and allowing it to be switched in and out of the circuit with a single pin. No external switching components are required. ENHANCED FAILSAFE Ordinary RS-485 differential receivers will be in an indeterminate state whenever the data bus is not being actively driven. The enhanced failsafe feature of the SP339E guarantees a logic-high receiver output when the receiver inputs are open, shorted, or terminated but idle/undriven. The enhanced failsafe interprets 0V differential as a logic high with a minimum 50mV noise margin, while maintaining compliance with the EIA/TIA485 standard of ±200mV. No external biasing resistors are required, further easing the usage of multiple protocols over a single connector. ±15kV ESD PROTECTION ESD protection structures are incorporated on all pins to protect against electrostatic discharges encountered during handling and assembly. The bus pins (driver outputs and receiver inputs) have extra protection structures, which have been tested up to ±15kV without damage. These structures withstand high ESD in all states: normal operation, shutdown and powered down. ESD protection is be tested in various ways. Exar uses the following methods to qualify the protection structures designed into SP339E: ±15kV using the Human Body Model (HBM) ±-8kV using IEC 61000-4-2 Contact Discharge The IEC 61000-4-2 standard is more rigorous than HBM, resulting in lower voltage levels compared with HBM for the same level of ESD protection. Because IEC 61000-4-2 specifies a lower series resistance, the peak current is higher than HBM. The SP339E has passed both HBM and IEC 61000-4-2 testing without damage. ±20V FAULT TOLERANCE All bus pins on the SP339E are protected against direct shorts or long term faults, up to ±20V. This allows the part to interoperate with legacy systems using ±15V RS-232 logic levels without damage or failure. DIAGNOSTIC LOOPBACK MODE The SP339E includes a diagnostic digital loop back mode for system testing as shown in Figure 1. The loopback mode connects the TTL driver inputs to the TTL receiver outputs, bypassing the analog driver and receiver circuitry. The analog/bus pins are internally disconnected in this mode. 19 SP339E RS-232/RS-485/RS-422 TRANSCEIVER WITH INTERNAL TERMINATION REV. 1.0.0 PACKAGE DRAWINGS FIGURE 15. QFN40 20 SP339E RS-232/RS-485/RS-422 TRANSCEIVER WITH INTERNAL TERMINATION REV. 1.0.0 REVISION HISTORY DATE October 2011 REVISION 1.0.0 Production Release DESCRIPTION NOTICE EXAR Corporation reserves the right to make changes to the products contained in this publication in order to improve design, performance or reliability. EXAR Corporation assumes no responsibility for the use of any circuits described herein, conveys no license under any patent or other right, and makes no representation that the circuits are free of patent infringement. Charts and schedules contained here in are only for illustration purposes and may vary depending upon a user’s specific application. While the information in this publication has been carefully checked; no responsibility, however, is assumed for inaccuracies. EXAR Corporation does not recommend the use of any of its products in life support applications where the failure or malfunction of the product can reasonably be expected to cause failure of the life support system or to significantly affect its safety or effectiveness. Products are not authorized for use in such applications unless EXAR Corporation receives, in writing, assurances to its satisfaction that: (a) the risk of injury or damage has been minimized; (b) the user assumes all such risks; (c) potential liability of EXAR Corporation is adequately protected under the circumstances. Copyright 2011 EXAR Corporation Datasheet Oct 2011. For technical support please email Exar’s Serial Technical Support group at: serialtechsupport@exar.com. Reproduction, in part or whole, without the prior written consent of EXAR Corporation is prohibited. 21