SP338E EXAR | Alldatasheet

Document overview

  • Manufacturer or author: Provided By ALLDATASHEET.COM(FREE DATASHEET DOWNLOAD SITE)
  • PDF pages: 25

Technical content

Exar Corporation 48720 Kato Road, Fremont CA, 94538 • (510) 668-7000 • FAX (510) 668-7017 • www.exar.com SP338E RS-232/RS-485/RS-422 TRANSCEIVER WITH INTERNAL TERMINATION NOVEMBER 2011 REV. 1.0.0 GENERAL DESCRIPTION The SP338 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 up to two drivers and four receivers (2TX/4RX) in half, full, and mixed 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 RS- 485/422 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 IEC- 61000-4-2 Contact. Each receiver output has full fail- safe protection to avoid sy stem 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 5k Ω pull-down to ground. The RS-485/422 receiver inputs are high impedance (>96k Ω when termination is disabled), allowing up to 256 devices on a single communication bus (1/8th unit load). The SP338 operates from a single power supply, either 3.3V or 5V, with low idle current. 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
  • 2 Drivers, 4 Receivers RS-485/422 ■ Full, Half, and Mixed Duplex Configurations ■ 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 SP339E 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 PACKAGE OPERATING TEMPERATURE RANGE DEVICE STATUS SP338EER1-L 40-pin QFN -40°C to +85°C Active SP338EER1-L/TR 40-pin QFN -40°C to +85°C Active SP338ECR1-L 40-pin QFN 0°C to +70°C Active SP338ECR1-L/TR 40-pin QFN 0°C to +70°C Active

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 specificati ons 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 -0.3V to +6.0V Receiver Input Voltage (from Ground) ±18V Driver Output Voltage (from Ground) ±18V Short Circuit Duration, TX out to Ground Continuous Voltage at TTL Input Pins -0.3V to (VCC + 0.5V) Storage Temperature Range -65°C to +150°C Lead Temperature (soldering, 10s) +300°C Power Dissipation 40-pin QFN (derate 17mW/°C above +70°C) 500mW SP338E RS-232/RS-485/RS-422 TRANSCEIVER WITH INTERNAL TERMINATION REV. 1.0.0 CAUTION: ESD (ElectroStatic Discharge) sensitive device. Perman ent 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. TYP. MAX. UNITS R1-R9 Tx Output & Rx Input Pins ±15 kV Human Body Model (HBM) ±8 kV IEC 61000-4-2 (Contact) All Other Pins ±2 kV Human Body Model (HBM)

REV. 1.0.0 RS-232/RS-485/RS-422 TRANSCEIVER WITH INTERNAL TERMINATION PIN DESCRIPTIONS BY MODE (MODE2, MODE1, MODE0) Pin Name 000, Figure 1 001, Figure 2 010, Figure 3 011, Figure 4 100, Figure 5 101, Figure 6 110, Figure 7 111, Figure 8

1 L1 R1 Output 1 1 1 1 1 1

2 L2 R2 Output R1 Output R1 Output R1 Output R1 Output R1 Output R1 Output

3 L3 T1 Input T1 Input T1 Input T1 Input T1 Input T1 Input T1 Input

4 L4 T2 Input

5 L6 R3 Output 1 1 1 1 1 R2 Output

6 L7 T3 Input T2 Input T2 Input

7 L8 R4 Output 1 1 R2 Output 1 1 R3 Output

8 L9 R5 Output 1 1 1 1 1 R4 Output

9 VCC VCC

10 GND Ground

11 SLEW SLEW = VCC enables 250kbps slew limiting

12 DIR1 T1 Enable,

R1 Disable T1 Enable T1 Enable T1 Enable T1 Enable, R1 Disable T1 Enable, R1 Disable

13 DIR2 T2 Enable T2 Enable,

14 MODE0 0 1 0 1 0 1 0 1

15 MODE1 0 0 1 1 0 0 1 1

16 MODE2 0 0 0 0 1 1 1 1

17 TERM Enables RS-485/422 receiver termination

18 INVDIR Inverts DIR1 and DIR2, where applicable

19 ENABLE ENABLE = VCC for operation, ENABLE = 0V for shutdown

20 VCC VCC

RS-232/RS-485/RS-422 TRANSCEIVER WITH INTERNAL TERMINATION REV. 1.0.0 PIN DESCRIPTIONS BY MODE (MODE2, MODE1, MODE0) Pin Name 000, Figure 1 001, Figure 2 010, Figure 3 011, Figure 4 100, Figure 5 101, Figure 6 110, Figure 7 111, Figure 8

21 R9 R5 Input R2 Input B R1 Input B R4 Input B

22 R8 R4 Input R2 Input A R4 Input A

23 GND Ground

24 R7 T3 Output T2 Out A R1 Input A R3 Input A

25 R6 R3 Input T2 Out B R3 Input B

26 GND Ground

27 R4 T2 Output R1 Input B R1 Input B T1 Out A R1 Input A

28 R3 T1 Output R2 Input A R1 Input A R2 Input A

29 GND Ground

30 R2 R2 Input R1 Input A

T1 Out A T1 Out A T1 Out A R1 Input A T1 Out A

31 R1 R1 Input R1 Input B

T1 Out B T1 Out B T1 Out B T1 Out B R1 Input B T1 Out B R1 Input B T1 Out B

32 VCC VCC

33 VSS VSS - Charge pump negative supply, 0.1uF from ground

34 C2- C2+ - Charge pump cap 2 negative lead

35 C1- C1- - Charge pump cap 1 negative lead

36 GND Ground

37 C1+ C1+ - Charge pump cap 1 positive lead, 0.1uF

38 VCC VCC

39 C2+ C2+ - Charge pump cap 2 positive lead, 0.1uF 40 VDD VDD - Charge pump positive supply, 0.1uF to ground

REV. 1.0.0 RS-232/RS-485/RS-422 TRANSCEIVER WITH INTERNAL TERMINATION

ELECTRICAL CHARACTERISTICS

UNLESS OTHERWISE NOTED: SYMBOL PARAMETERS MIN. TYP. MAX. UNITS CONDITIONS DC CHARACTERISTICS ICC Supply Current (RS-232) 2 10 mA No load, idle inputs ICC Supply Current (RS-485) 4 10 mA No load, idle inputs ICC Vcc Shutdown Current 1 10 µA ENABLE = 0V TRANSMITTER and LOGIC INPUT PINS: Pins 3, 4, 6, 11-19 VIH Logic Input Voltage High 2.0 V VCC = 3.3V VIH Logic Input Voltage High 2.4 V VCC = 5.0V VIL Logic Input Voltage Low 0.8 V IIL Logic Input Leakage Current Low 1 µA Input Low (VIN = 0V) IIH Logic Input Leakage Current High 1 µA Input High (VIN = VCC), pins 3, 4 and 6 IPD Logic Input Pull-down Current 50 µA Input High (VIN = VCC), pins 11-19 VHYS Logic Input Hysteresis 200 mV RECEIVER OUTPUTS: Pins 1, 2, 5, 7, 8 VOH Receiver Output Voltage High VCC-0.6 V IOUT = -1.5mA VOL Receiver Output Voltage Low 0.4 V IOUT = 2.5mA IOSS Receiver Output ShortCircuit Current ±20 ±60 mA 0 ≤ VO ≤ VCC IOZ Receiver Output Leakage Current ±0.1 ±1 µA 0 ≤ VO ≤ VCC, Receivers disabled

UNLESS OTHERWISE NOTED: SYMBOL PARAMETERS MIN. TYP. MAX. UNITS CONDITIONS SINGLE-ENDED RECEIVER INPUTS (RS-232) VIN Input Voltage Range -15 +15 V VIL Input Threshold Low 0.6 1.2 V VCC = 3.3V 0.8 1.5 V VCC = 5.0V VIH Input Threshold High 1.5 2.0 V VCC = 3.3V 1.8 2.4 V VCC = 5.0V VHYS Input Hysteresis 0.3 V RIN Input Resistance 3 5 7 kΩ -15V ≤ VIN ≤ +15V SINGLE-ENDED DRIVER OUTPUTS (RS-232) VO Output Voltage Swing ±5.0 ±5.5 V Output loaded with 3kΩ to Gnd ±7.0 V No load output ISC Short Circuit Current ±60 mA VO = 0V ROFF Power Off Impedance 300 10M Ω VCC = 0V, VO = ±2V SP338E RS-232/RS-485/RS-422 TRANSCEIVER WITH INTERNAL TERMINATION REV. 1.0.0 ELECTRICAL CHARACTERISTICS (Continued)

REV. 1.0.0 RS-232/RS-485/RS-422 TRANSCEIVER WITH INTERNAL TERMINATION ELECTRICAL CHARACTERISTICS (Continued) UNLESS OTHERWISE NOTED: SYMBOL PARAMETERS MIN. TYP. MAX. UNITS CONDITIONS DIFFERENTIAL RECEIVER INPUTS (RS-485 / RS-422) RIN Receiver Input Resistance 96 kΩ TERM = 0V, -7V ≤ VIN ≤ +12V VTH Receiver Differential Threshold Voltage -200 -125 -50 mV ∆VTH Receiver Input Hysteresis 25 mV VCM = 0V IIN Receiver Input Current 125 µA VIN = +12V -100 µA VIN = -7V RTERM Termination Resistance 100 120 155 Ω TERM = VCC, Figure 9 -7V ≤ VCM ≤ +12V RTERM Termination Resistance 100 120 140 Ω TERM = VCC, Figure 9 VCM = 0V DIFFERENTIAL DRIVER OUTPUTS (RS-485 / RS-422) VOD Differential Driver Output

2 VCC V RL = 100Ω (RS-422), Figure 10

1.5 VCC V RL = 54Ω (RS-485), Figure 10

1.5 VCC V VCM = -7V, Figure 11

1.5 VCC V VCM = +12V, Figure 11

∆VOD Change In Magnitude of Differential Output Voltage -0.2 +0.2 V RL = 54Ω or 100Ω, Figure 10 VCM Driver CommonMode Output Voltage 3 V RL = 54Ω or 100Ω, Figure 10 ∆VCM Change In Magnitude of Common Mode Output Voltage 0.2 V RL = 54Ω or 100Ω, Figure 10 IOSD Driver Output Short Circuit Current ±250 mA -7V ≤ VO ≤ +12V, Figure 12 IO Driver Output Leakage Current ±100 µA ENABLE = 0V, or DIR1 = 0V and DIR2 = 0V in full duplex modes, -7V ≤ VO ≤ +12V

FIGURE 1. MODE 000 - LOOPBACK

FIGURE 2. MODE 001 - RS-232

FIGURE 3. MODE 010 - RS-485 HALF DUPLEX #1

FIGURE 4. MODE 011 - RS-485/422 FULL DUPLEX #1

FIGURE 5. MODE 100 - RS-485/422 FULL DUPLEX #2

FIGURE 6. MODE 101 - RS-485/422 FULL DUPLEX #3

FIGURE 7. MODE 110 - RS-485 HALF DUPLEX #2

FIGURE 8. MODE 111 - RS-485/422 MIXED DUPLEX

FIGURE 18. RS-485/422 DRIVER OUTPUT ENABLE/DISABLE TIMES

REV. 1.0.0 RS-232/RS-485/RS-422 TRANSCEIVER WITH INTERNAL TERMINATION PRODUCT SUMMARY The SP338 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 si ngle cable or connector with no additi onal switching components. The RS- 485/422 modes feature up to two drivers and four receivers (2TX/4RX) in ha lf, full, and mixed duplex configurations. The RS-232 mode (3TX/5RX) provides fu ll 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 la rgest challenges system designers face when sharing a single connector or pair of lines bet ween multiple serial protoc ols. A termination resistor may be necessary for accurate RS-485/422 communication, but must be removed when the lines are used for RS-232. SP338 provides an elegant so lution 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 receiver s will be in an indetermin ate state whenever the data bus is not being actively driven. The enhanced failsafe feature of the SP338 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/TIA- 485 standard of ±200mV. No external biasing resistor s 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 electros tatic 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 SP338: ±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 SP338 has passed both HBM and IEC 61000-4-2 testing without damage. DIAGNOSTIC LOOPBACK MODE The SP338 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 receiv er outputs, bypassing the analog driver and receiver circuitry. The analog/bus pins are internally disconnected in this mode.

FIGURE 19. QFN40

REVISION HISTORY

November 2011 1.0.0 Production Release NOTICE EXAR Corporation reserves the right to make changes to the products contained in this publication in order to improve design, performanc e or reliability. EXAR Corp oration 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 infr ingement. Charts and schedules contai ned 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 re commend the use of any of its products in life suppo rt applications where the failure or malfunction of the product can reasonably be ex pected 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, assuranc es to its satisfaction that: (a) th e risk of injury or damage has been minimized; (b) th e user assumes all such ris ks; (c) potential liability of EXAR Corporation is adequately protected under the circumstances. Copyright 2011 EXAR Corporation Datasheet November 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. SP338E RS-232/RS-485/RS-422 TRANSCEIVER WITH INTERNAL TERMINATION REV. 1.0.0