SP V Low Power Slew Rate Limited Half-Duplex RS-485 Transceiver

Transcription

1 SP Low Power Slew Rate Limited Half-uplex RS-485 Transceiver RS-485 and RS-4 Transceiver Operates from a single +3. Supply Interoperable with +5. logic river/receiver Enable Low Power Shutdown mode -7V to +1V Common-Mode Input Voltage Range Allows up to 3 transceivers on the serial bus Compatibility with the industry standard pinout river Output Short-Circuit Protection Slew Rate Limited river for Low EMI ESCRIPTION The SP3483 device is part of a family of +3. low power half-duplex transceivers that meet the specifications of the RS-485 and RS-4 serial protocols. This device is pin-to-pin compatible with the Exar SP483 device as well as popular industry standards. The SP3483 features Exar's BiCMOS design allowing low power operation without sacrificing performance. The SP3483 is slew rate limited to reduce EMI and can meet the requirements of the RS-485 and RS-4 protocols up to 50kbps. TRUTH TABLES INPUTS RE E I PUTS LINE CONITION B A X 1 1 No Fault 0 1 X 1 0 No Fault 1 0 X 0 X X Z Z Table 1. Transmit Function Truth Table INPUTS PUTS RE E A - B R V V Inputs Open X Z Table. Receive Function Truth Table

2 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 of the specifications below is not implied. Exposure to absolute maximum rating conditions for extended periods of time may affect reliability. V CC Input Voltages Logic to +6. rivers to +6. Receivers...+/-15V Output Voltages rivers...+/-15v Receivers to +6. Storage Temperature C to +150 C Power issipation 8-pin NSOIC...500mW (derate 6.14mW/ºC above +70ºC) T MIN to T MAX and V CC = +3. +/-5% unless otherwise noted. ELECTRICAL CHARACTERISTICS PARAMETERS MIN. TYP. MAX. UNITS CONITIONS RIVER C Characteristics ifferential Output Voltage GN Vcc Volts Unloaded; R = ; Figure 1 ifferential Output Voltage Vcc Volts With Load; R = (RS-4); Figure 1 ifferential Output Voltage 1.5 Vcc Volts With Load; R = 7Ω (RS-485); Figure 1 Change in Magnitude of river ifferential Output Voltage for Complimentary states river Common Mode Output Voltage 0. Volts R = 7Ω or R = ; Figure 1 3 Volts R = 7Ω or R = ; Figure 1 Input High Voltage.0 Volts Applies to E, I, RE Input Low Voltage 0.8 Volts Applies to E, I, RE Input Current +/-10 µa Applies to E, I, RE river Short Circuit Current, V = HIGH river Short Circuit Current, V = LOW RIVER AC Characteristics +/-50 ma -7V V O +1V; Figure 8 +/-50 ma -7V V O +1V; Figure 8 Max. Transmission Rate 50 kbps RE = Vcc, E = Vcc river Input to Output, t PLH ns Figures & 9 river Input to Output, t PHL ns Figures & 9 ifferential river Skew 10 ns t O1 - t O, Figures and 10, river Rise or Fall Time ns From 10%-90%; Figures 3 and 10

3 T MIN to T MAX and V CC = +3. +/-5% unless otherwise noted. ELECTRICAL CHARACTERISTICS PARAMETERS MIN. TYP. MAX. UNITS CONITIONS RIVER (continued) AC Characteristics river Enable to Output High ns Figures 4 and 11, river Enable to Output Low ns Figures 5 and 11 river isable Time from High ns Figures 5 and 11 river isable Time from Low ns Figures 4 and 11 RECEIVER C Characteristics ifferential Input Threshold Volts -7V V CM +1V Input Hysteresis 0 mv V CM = Output Voltage High Vcc-0.4 Volts I O = -1.5mA, V I = +00mV Output Voltage Low 0.4 Volts I O = +.5mA, V I = -00mV Three-State ( High Impedance) Output Current +/-1 µa V O Vcc; RE = Vcc Input Resistance 1 15 kω -7V V CM +1V Input Current (A, B); V IN = 1V +1.0 ma E =, V CC = or 3.6V, V IN = 1V Input Current (A, B); V IN = -7V -0.8 ma E =, V CC = or 3.6V, V IN = -7V Short Circuit Current 7 60 ma V CM V CC RECEIVER AC Characteristics Max. Transmission Rate 50 kbps RE =, E = Receiver Input to Output, t RPLH ns Figures 6 and 1 Receiver Input to Output, t RPHL ns Figures 6 and 1 ifferential Receiver Skew 50 ns t RPHL - t RPLH, Figures 6 and 1 Receiver Enable to Output Low ns Figures 7 and 13; S 1 Closed, S Receiver Enable to Output High ns Figures 7 and 13; S Closed, S 1 Receiver isable from LOW ns Figures 7 and 13; S 1 Closed, S Receiver isable from High ns Figures 7 and 13; S Closed, S 1 3

4 T MIN to T MAX and V CC = +3. +/-5% unless otherwise noted. ELECTRICAL CHARACTERISTICS PARAMETERS MIN. TYP. MAX. UNITS CONITIONS Shutdown Timing Time to Shutdown ns RE = 5V, E = river Enable from Shutdown to Output High river Enable from Shutdown to Output Low Receiver Enable from Shutdown to Output High Receiver Enable from Shutdown to Output Low POWER REQUIREMENTS Supply Current 000 ns Figures 4 and ns Figures 5 and ns Figures 7 and 13; S Closed, S ns Figures 7 and 13; S 1 Closed, S No Load µa RE, I = or V CC ; E = V CC µa RE =, I = or 5V; E = Shutdown Mode 10 µa E =, RE = V CC Pin 1 - RO - Receiver Output PIN FUNCTION Pin - RE - Receiver Output Enable Active LOW Pin 3 - E - river Output Enable Active HIGH Pin 4 - I - river Input Pin 5 - GN - Ground Connection Pin 6 - A - river Output / Receiver Input Non-Inverting Pin 7 - B - river Output / Receiver Input Inverting Pin 8 - Vcc - Positive Supply 4

5 Test Circuits VM R S1 R L = 7Ω Vcc V O R V OC C L = 15pF (NOTE ) VOH + VOL = Figure 1. river C Test Load Circuit Figure. river Propagation elay Test Circuit S1 C L R L = 60Ω CL = 50pF (NOTE ) RL = 110Ω C L = 15pF (NOTE ) VOH = + VOL Figure 3. river ifferential Output elay and Transition Time Circuit. Figure 4. river Enable and isable Timing Circuit, Output High OR S1 C L = 50pF (NOTE ) RL = 110Ω V I R CL = 15pF (NOTE ) = Figure 5. river Enable and isable Timing Circuit, Output Low Figure 6. Receiver Propagation elay Test Circuit - S3 VI R 1k S1 S E = 0 or Vcc I = 0 or Vcc A/Y IOS CL = 15pF (NOTE ) B/Z 100Ω -7V to +1V V Figure 7. Receiver Enable and isable Timing Circuit Figure 8. river Short Circuit Current Limit Test 5

6 SWITCHING WAVEFORMS INPUT A PUT VOH tplh tphl IN to1 to VOL B PUT VOH tphl tplh 90% 90% 50% 50% 10% 10%. -. VOL tt tt = VOH + VOL» Figure 9. river Propagation elay Waveforms Figure 10. river ifferential Output elay and Transition Time Waveforms E PUT HIGH VOH tpzh tphz 0.5V INPUT trplh trphl PUT LOW VOL = tpzl VOH + VOL tplz 0.5V PUT = Figure 11. river Enable and isable Timing Waveforms Figure 1. Receiver Propagation elay Waveforms RE PUT VOH S1 is S is closed S3 = tprhz 10% tprzh tprsh RE PUT VOL S1 is closed S is S3 = - 10% tprlz tprzl tprsl Figure 13. Receiver Enable and isable Waveforms NOTE 1: The input pulse is supplied by a generator with the following characteristics: PRR = 50kHz, 50% duty cycle, t R < 6.0ns, Z O =. NOTE : C L includes probe and stray capacitance. 6

7 ESCRIPTION The SP3483 device is part of a family of +3. low power half-duplex transceivers that meet the specifications of the RS-485 and RS-4 serial protocols. This device is pin-to-pin compatible with the Exar SP483 device as well as popular industry standards. The SP3483 features Exar's BiCMOS process allowing low power operation without sacrificing performance. The RS-485 standard is ideal for multi-drop applications and for long-distance interfaces. RS-485 allows up to 3 drivers and 3 receivers to be connected to a data bus, making it an ideal choice for multi-drop applications. Since the cabling can be as long as 4,000 feet, RS-485 transceivers are equipped with a wide (-7V to +1V) common mode range to accommodate ground potential differences. Because RS-485 is a differential interface, data is virtually immune to noise in the transmission line. rivers The driver outputs of the SP3483 are differential outputs meeting the RS-485 and RS-4 standards. The typical voltage output swing with no load will be 0 Volts to +3.3 Volts. With worst case loading of 54Ω across the differential outputs, the drivers can maintain greater than voltage levels. The drivers have an enable control line which is active HIGH. A logic HIGH on E (pin 3) will enable the differential driver outputs. A logic LOW on the E (pin 3) will force the driver outputs into high impedance (high-z). Receivers The SP3483 receiver has differential inputs with an input sensitivity as low as ±00mV. Input impedance of the receivers is typically 15kΩ (1kΩ minimum). A wide common mode range of -7V to +1V allows for large ground potential differences between systems. The receiver of the SP3483 has a tristate enable control input RE (Pin ). A logic LOW on RE will enable the receiver, a logic HIGH on RE will disable the receiver. The receiver of the SP3483 will operate up to 50kbps. The receiver is equipped with the fail-safe feature. Fail-safe guarantees that the receiver output will be in a HIGH state when the input is left unconnected ( circuit). Shutdown Mode The SP3483 is equipped with a Shutdown mode. To enable the shutdown state, both driver and receiver must be disabled simultaneously. A logic LOW on E (pin 3) and a Logic HIGH on RE (pin ) will put the SP3483 into Shutdown mode. In Shutdown, supply current will drop to typically 1µA, 10µA maximum. The SP3483 has internally slew rate limited driver outputs to minimize EMI. The transceivers will operate up to 50kbps. The 50mA I SC maximum limit on the driver output allows the SP3483 to withstand an infinite short circuit over the -7. to +1V common mode range without catastrophic damage to the IC. 7

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9 ORERING INFORMATION Model Temperature Range Package Types SP3483CN-L... 0 C to +70 C...8-pin NSOIC SP3483CN-L/TR... 0 C to +70 C...8-pin NSOIC SP3483EN-L C to +85 C...8-pin NSOIC SP3483EN-L/TR C to +85 C...8-pin NSOIC Note: /TR = Tape and Reel ATE REVISION ESCRIPTION 06/3/04 -- Legacy Sipex atasheet revision history 01/09/ Convert to Exar Format. Update ordering information as a result of discontinued Lead type package options. Add new Figure 8 - river Short Circuit Current Limit Test Circuit. Correct type error for no load supply current. Notice EXAR Corporation reserves the right to make changes to any products contained in this publication in order to improve design, performance or reliability. EXAR Corporation assumes no representation that the circuits are free of patent infringement. Charts and schedules contained herein 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 01 EXAR Corporation atasheet January 01 Send your serial transceiver technical inquiry with technical details to: serialtechsupport@exar.com Reproduction, in part or whole, without the prior written consent of EXAR Corporation is prohibited. 9

10 Mouser Electronics Authorized istributor Click to View Pricing, Inventory, elivery & Lifecycle Information: Exar: SP3483CN-L SP3483EN-L SP3483CN-L/TR SP3483EN-L/TR