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SP485R 1/10th Unit Load RS-485 Transceiver
FEATURES * Allows Over 400 Transceivers On A Transmission Line (/0th Unit Load) * High Impedance on Receiver Inputs (RIN = 150k typical) * Half-Duplex Configuration Consistent With Industry Standard Pinout * -7V to +2V Common Mode Input Voltage Range * Low Power Consumption (250mW) * Separate Driver and Receiver Enable DESCRIPTION The SP485R is a pin-to-pin equivalent to our existing SP485 product and offers a high receiver input impedance. The higher receiver input impedance allows for connecting over 400 transceivers on a single transmission line without degrading the RS-485 driver signal. The device is packaged in a 8-pin plastic DIP or 8-pin narrow SOIC.
Figure 1. Typical Application Circuit
Exar Corporation 48720 Kato Road, Fremont CA, 94538 * 50-668-707 * www.exar.com
SP485R_00_072309
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. VCC.......................................................................+7V Storage Temperature.......................-65C to +150C
Typically 25C @ VCC = +5V unless otherwise noted.
Power Dissipation 8-pin NSOIC.................................................000mW (OJA = 62C/W) 8-pin PDIP....................................................000mW (OJA = 62C/W)
ELECTRICAL CHARACTERISTICS
TYP. MAX. 0.8 UNITS Volts Volts 0.4 Volts Volts 6.0 Volts Volts Volts Volts mA +/-250 mA Mbps 30 60 60 5 00 00 5 ns ns ns ns RL = 54 Terminated in -7V to +2V RL = 54, Rise/fall time, 0% to 90% See Figures 4 & 6, RDIFF = 54, CL = CL2 = 00pF See Figures 4 & 6, RDIFF = 54, CL = CL2 = 00pF see Figures 4 and 6, tSKEW = |tDPHL - tDPLH| RL = 54, CL = 50pF |VT| - |VT| IOUT = -3.2mA IOUT = .0mA CONDITIONS
PARAMETERS LOGIC INPUTS VIL VIH LOGIC OUTPUTS VOL VOH Open Circuit Voltage Differential Output Voltage Balance Common-Mode Output Output Current Short Circuit Current
MIN.
2.0
2.4
RS-485 DRIVER DC Characteristics .5 5.0 +/-0.2 3.0 28.0
RS-485 DRIVER AC Characteristics Maximum Data Rate Output Transition Time Propagation Delay, tPLH Propagation Delay, tPHL Driver Output Skew RS-485 RECEIVER DC Characteristics Output Voltage Low, VOL Output Voltage High, VOH Tri-State Output Current 2.4 +/- 0.4 Volts Volts A 0.4V VOUT 2.4V; RE = Vcc 5
Exar Corporation 48720 Kato Road, Fremont CA, 94538 * 50-668-707 * www.exar.com
SP485R_00_072309
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Typically 25C @ VCC = +5V unless otherwise noted.
ELECTRICAL CHARACTERISTICS
TYP. MAX. +2.0 +/-0.2 UNITS Volts Volts k -7V VCM +12V -7V VCM +12V CONDITIONS
PARAMETERS Common Mode Range Receiver Sensitivity Input Impedance
MIN. -7.0
RS-485 RECEIVER DC Characteristics (continued)
20
50
RS-485 RECEIVER AC Characteristics Maximum Data Rate Propagation Delay; tPHL Propagation Delay; tPLH Differential Receiver Skew 60 200 200 Mbps ns ns ns See Figures 4 & 8, RDIFF = 54, CL = CL2 = 00pF See Figures 4 & 8, RDIFF = 54, CL = CL2 = 00pF See Figures 4 & 8, RDIFF = 54, CL = CL2 = 00pF, tSKEW = |tPHL - tPLH| CL = 5pF, see Figures 5 and 7, S closed CL = 5pF, see Figures 5 and 7, S2 closed CL = 5pF, see Figures 5 and 7, S closed CL = 5pF, see Figures 5 and 7, S2 closed CL = 5pF, see Figures 3 and 9, S closed CL = 5pF, see Figures 3 and 9, S2 closed CL = 5pF, see Figures 3 and 9, S closed CL = 5pF, see Figures 3 and 9, S closed
RS-485 DRIVER Enable / Disable Time Driver Enable to Output Low Driver Enable to Output High Driver Disable Time from Low Driver Disable Time from High RS-485 RECEIVER Enable / Disable Time Receiver Enable to Output Low Receiver Enable to Output High Receiver Disable from Low Receiver Disable from High POWER REQUIREMENTS Supply Voltage VCC Supply Current ICC, No Load Supply Current ICC, No Load ENVIRONMENTAL Operating Temperature Commercial (..C..) Industrial (..E..) Storage Temperature 0 -40 -65 +70 +85 +50 C C C +4.75 300 500 +5.25 500 900 Volts A A RE = Vcc or 0V, DE = 0V RE = Vcc or 0V, DE = Vcc 40 40 40 40 500 500 500 500 ns ns ns ns 40 40 40 40 500 500 500 500 ns ns ns ns
Exar Corporation 48720 Kato Road, Fremont CA, 94538 * 50-668-707 * www.exar.com
SP485R_00_072309
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PIN FUNCTION
Pin - RO - Receiver Output Pin 2 - RE - Receiver Output Enable Active LOW Pin 3 - DE - Driver Output Enable Active HIGH Pin 4 DI - Driver Input Pin 5 - GND - Ground Connection Pin 6 - A - Driver Output / Receiver input Non-Inverting Pin 7 - B - Driver Output / Receiver Input Inverting Pin 8 - Vcc - Positive Supply 4.75V Vcc 5.25V
RECEIVER INPUT GRAPH
Standard SP485 Reciever +1.0mA SP485R Reciever +100A
-7V
-3V +6V +12V
-7V
-3V +6V +12V
-0.6mA
1 Unit Load Maximum Input Current versus voltage. (Shaded region)
-60A
1/10 Unit Load Maximum Input Current versus voltage. (Shaded region)
TEST CIRCUITS
A
R VOD R B
Figure 2. Driver DC Test Load Circuit
Receiver Output
VOC
Test Point S1 CRL 1k S2
1k VCC
Figure 3. Receiver Timing Test Load Circuit
DI
A B
CL1 RL CL2
A B
RO 15pF
Output Under Test
500 CL
S1
VCC
S2
Figure 4. RS-485 Driver/Receiver Timing Test Figure 5. Driver Timing Test Load #2 Circuit
SP485R_00_072309 Exar Corporation 48720 Kato Road, Fremont CA, 94538 * 50-668-707 * www.exar.com
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SWITCHING WAVEFORMS
+3V 0V B A VO 1/2VO t DPLH t DPHL f 1MHz; t R 10ns; t F 10ns 1.5V t PLH t PHL 1/2VO 1.5V
DRIVER INPUT
DRIVER OUTPUT
DIFFERENTIAL VO+ 0V OUTPUT VA - VB VO- t SKEW = |t DPLH - t DPHL |
tR
tF
Figure 6. Driver Propagation Delays
DE
+3V 0V 5V VOL VOH 0V
f = 1MHz; t R < 10ns; t F < 10ns 1.5V t ZL 2.3V Output normally LOW Output normally HIGH 1.5V t LZ 0.5V 0.5V t HZ
A, B
A, B
2.3V t ZH
Figure 7. Driver Enable and Disable Times
A- B
VOD2 + VOD2 - VOH VOL t PHL
f = 1MHz; t R 10ns ; t F 10ns 0V INPUT 0V
RECEIVER OUT
1.5V
OUTPUT t PLH
1.5V
Figure 8. Receiver Propagation Delays
RE
+3V 0V 5V VIL VIH
1.5V f = 1MHz; t 10ns; t 10ns R F t ZL 1.5V Output normally LOW Output normally HIGH
1.5V t LZ 0.5V 0.5V t HZ
RECEIVER OUT
RECEIVER OUT
0V
1.5V t ZH
Figure 9. Receiver Enable and Disable Times
Exar Corporation 48720 Kato Road, Fremont CA, 94538 * 50-668-707 * www.exar.com SP485R_00_072309
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DESCRIPTION The SP485R is a low power RS-485 differential transceiver. Similar to the SP485, the SP485R contains a half-duplex driver and receiver with tri-state control. However, the SP485R is intended for increased connections on a single bus compared to the original RS-485 specifcation. The RS-485 standard is ideal for multi-drop applications where one bus can contain many drivers and/or receivers.The RS-485 standard implementation allows up to 32 transceivers to be connected on to the data bus. RS-485 is also specified for driving higher speeds over long cable lengths of up to 4000 feet. The SP485R exceeds the standard by allowing up to 400 receivers to share the bus DRIVERS The driver output complies with the RS485 electrical characteristics as specified by the standard. The output swings from 0V to Vcc and maintains greater than +.5V with a 54 load attached between the two outputs. In adhering to the RS-485 specification, the driver outputs inherently comply with the RS-422 standard. With a load of 100 between the two outputs, the driver can sustain at least +2.0V. The driver contains an enable pin (DE) which tri-states the output when DE is logic LOW. The outputs during the tri-state condition are at high impedance (>100k). A logic HIGH enables the driver for normal operation. The driver can operate to at least 5Mbps. RECEIVERS The SP485R receiver has differential inputs with an input sensitivity of lower than 200mV. As mentioned above, the RS-485 specification allows up to 32 transceivers on the same bus. The SP485R allows over 400 transceivers on the same bus due to its high impedance of at least 120k. This higher capacity allows more components to be attached to the same bus without degrading the signal quality. The drivers are still able to drive an equivalent 54 from the 320
Exar Corporation 48720 Kato Road, Fremont CA, 94538 * 50-668-707 * www.exar.com SP485R_00_072309
transceivers with an input impedance of at least 120k in parallel along with the two 125 cable termination resistors on each end. The receiver contains an enable pin (RE) which enables the receiver when a logic LOW is asserted. A logic HIGH will tri-state the receiver output and the inputs will maintain at least 120k impedance. The reciever can operate to at least Mbps The receiver also contains a fail-safe feature which outputs a logic HIGH when the inputs are open as in a disconnected cable.
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Exar Corporation 48720 Kato Road, Fremont CA, 94538 * 50-668-707 * www.exar.com
SP485R_00_072309
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Exar Corporation 48720 Kato Road, Fremont CA, 94538 * 50-668-707 * www.exar.com
SP485R_00_072309
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Model Temperature Range Package Types SP485RCN-L....................................................................... 0C to +70C ................................................................................................8-pin NSOIC SP485RCN-L/TR................................................................. 0C to +70C ................................................................................................8-pin NSOIC SP485RCP-L....................................................................... 0C to +70C................................................................................................8-pin PDIP SP485REN-L...................................................................... -40C to +85C..............................................................................................8-pin NSOIC SP485REN-L/TR................................................................ -40C to +85C..............................................................................................8-pin NSOIC SP485REP-L...................................................................... -40C to +85C..............................................................................................8-pin PDIP
ORDERING INFORMATION
Note: /TR = Tape and Reel
REVISION HISTORy
DATE 06/2/04 07/23/09 REVISION -.0.0 DESCRIPTION Legacy Sipex Datasheet Convert to Exar Format. Update ordering information as a result of discontinued Lead type package options per PDN 081126-01. Remove all reference to the discontinued SP48R.
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 writting, 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 2009 EXAR Corporation Datasheet July 2009 Send your Interface technical inquiry with technical details to: uarttechsupport@exar.com Reproduction, in part or whole, without the prior written consent of EXAR Corporation is prohibited.
Exar Corporation 48720 Kato Road, Fremont CA, 94538 * 50-668-707 * www.exar.com
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