19-1138; Rev 3; 12/05

Fail-Safe, High-Speed (10Mbps),

Slew-Rate-Limited RS-485/RS-422 Transceivers

The MAX3080–MAX3089 high-speed transceivers forRS-485/RS-422 communication contain one driver and For Fault-Tolerant Applications:

one receiver. These devices feature fail-safe circuitry,MAX3430: ±80V Fault-Protected, Fail-Safe, 1/4-which guarantees a logic-high receiver output when theUnit Load, +3.3V RS-485 Transceiverreceiver inputs are open or shorted. This means that For Low-Voltage Applications:

the receiver output will be a logic high if all transmitterson a terminated bus are disabled (high impedance).MAX3362: +3.3V, High-Speed, RS-485/RS-422The MAX3080/MAX3081/MAX3082 feature reducedTransceiver in a SOT23 Packageslew-rate drivers that minimize EMI and reduce reflec- For Multiple Transceiver Applications:

tions caused by improperly terminated cables, allowingMAX3030E–MAX3033E: ±15kV ESD-Protected,error-free data transmission up to 115kbps. TheMAX3083/MAX3084/MAX3085 offer higher driver out-+3.3V, Quad, RS-422 Transmitters

put slew-rate limits, allowing transmit speeds up toMAX3040–MAX3045: ±10kV ESD-Protected, Quad,500kbps. The MAX3086/MAX3087/MAX3088’s driver+5V, RS-485/RS-422 Transmitters

slew rates are not limited, making transmit speeds upto 10Mbps possible. The MAX3089’s slew rate is Applications

selectable between 115kbps, 500kbps, and 10MbpsRS-422/RS-485 Communicationsby driving a selector pin with a single three-state driver.Level Translators

These transceivers typically draw 375µA of supply Transceivers for EMI-Sensitive Applicationscurrent when unloaded, or when fully loaded with thedrivers disabled.

Industrial-Control Local Area Networks

All devices have a 1/8-unit-load receiver input imped-ance that allows up to 256 transceivers on the bus. TheMAX3082/MAX3085/MAX3088 are intended for half-duplex communications, while the MAX3080/MAX3081/MAX3083/MAX3084/MAX3086/MAX3087 are intendedfor full-duplex communications. The MAX3089 is selec-table between half-duplex and full-duplex operation. Italso features independently programmable receiverand transmitter output phase via separate pins.

Ordering Information continued at end of data sheet.

________________________________________________________________Maxim Integrated Products

1

For pricing, delivery, and ordering information,please contact Maxim/Dallas Direct!at 1-888-629-4642, or visit Maxim’s website at http://.

MAX3080–MAX3089

Fail-Safe, High-Speed (10Mbps),

Slew-Rate-Limited RS-485/RS-422 Transceivers

MAX3080–MAX3089

ABSOLUTE MAXIMUM RATINGS

Supply Voltage (VCC) ............................................................+7VControl Input Voltage (RE, DE)...................-0.3V to (VCC+ 0.3V)Special Input Voltage

(H/F, SRL, TXP, RXP)..................................-0.3V to (VCC+ 0.3V)Driver Input Voltage (DI).............................-0.3V to (VCC+ 0.3V)Driver Output Voltage (A, B, Y, Z)........................................±13VReceiver Input Voltage (A, B)..............................................±13VReceiver Input Voltage, Full Duplex (A, B)..........................±25VReceiver Output Voltage (RO)....................-0.3V to (VCC+ 0.3V)

Continuous Power Dissipation

8-Pin Plastic DIP (derate 9.09mW/°C above +70°C)...727mW8-Pin SO (derate 5.88mW/°C above +70°C)................471mW14-Pin Plastic DIP (derate 10.0mW/°C above +70°C)....800mW14-Pin SO (derate 8.33mW/°C above +70°C)..............667mWOperating Temperature Ranges

MAX308_C_ _.....................................................0°C to +70°C MAX308_E_ _...................................................-40°C to +85°CStorage Temperature Range.............................-65°C to +150°CLead Temperature (soldering, 10s).................................+300°C

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functionaloperation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure toabsolute maximum rating conditions for extended periods may affect device reliability.

DC ELECTRICAL CHARACTERISTICS

(VCC= +5V ±5%, TA= TMINto TMAX, unless otherwise noted. Typical values are at VCC= +5V and TA= +25°C.) (Note 1)

Fail-Safe, High-Speed (10Mbps),

Slew-Rate-Limited RS-485/RS-422 Transceivers

DC ELECTRICAL CHARACTERISTICS (continued)

(VCC= +5V ±5%, TA= TMINto TMAX, unless otherwise noted. Typical values are at VCC= +5V and TA= +25°C.) (Note 1)

Note 1:All currents into the device are positive; all currents out of the device are negative. All voltages are referred to device

ground unless otherwise noted.

Note 2: VODand VOCare the changes in VODand VOC, respectively, when the DI input changes state.

Note 3:The SRL pin is internally biased to VCC / 2 by a 100k /100k resistor divider. It is guaranteed to be VCC / 2 if left

unconnected.

Note 4:Maximum current level applies to peak current just prior to foldback-current limiting; minimum current level applies during

current limiting.

_______________________________________________________________________________________3

MAX3080–MAX3089

Fail-Safe, High-Speed (10Mbps),

Slew-Rate-Limited RS-485/RS-422 TransceiversMAX3080–MAX3089

SWITCHING CHARACTERISTICS—MAX3080–MAX3082, and MAX3089 with SRL = Unconnected

(VCC= +5V ±5%, TA= TMINto TMAX, unless otherwise noted. Typical values are at VCC= +5V and TA= +25°C.)

4_______________________________________________________________________________________

Fail-Safe, High-Speed (10Mbps),

Slew-Rate-Limited RS-485/RS-422 Transceivers

SWITCHING CHARACTERISTICS—MAX3083–MAX3085, and MAX3089 with SRL = VCC

(VCC= +5V ±5%, TA= TMINto TMAX, unless otherwise noted. Typical values are at VCC= +5V and TA= +25°C.)

_______________________________________________________________________________________5

MAX3080–MAX3089

Fail-Safe, High-Speed (10Mbps),

Slew-Rate-Limited RS-485/RS-422 TransceiversMAX3080–MAX3089

SWITCHING CHARACTERISTICS—MAX3086–MAX3088, and MAX3089 with SRL = GND

(VCC= +5V ±5%, TA= TMINto TMAX, unless otherwise noted. Typical values are at VCC= +5V and TA= +25°C.)

Note 5:The device is put into shutdown by bringing REhigh and DE low. If the enable inputs are in this state for less than 50ns, the

device is guaranteed not to enter shutdown. If the enable inputs are in this state for at least 600ns, the device is guaranteedto have entered shutdown.

6_______________________________________________________________________________________

Fail-Safe, High-Speed (10Mbps),

Slew-Rate-Limited RS-485/RS-422 Transceivers

Typical Operating Characteristics

(VCC= +5V, TA = +25°C, unless otherwise noted.)

NO-LOAD SUPPLY CURRENT

OUTPUT CURRENT

OUTPUT CURRENT

vs. TEMPERATURE

vs. RECEIVER OUTPUT LOW VOLTAGE

vs. RECEIVER OUTPUT HIGH VOLTAGE

525

2

3

60-30-CCOOTT 9988)

00A50033//µ008800(33 5025XXT)

A)

AN475AMAMEmmR(( R450T40T20UNNCEE Y425RRLRRPUUPC30C15 U400TTSUU DPA375T10OU20PTULOO-O350N105325300

-60-40-200

20

40

60

80

100

012345012345

TEMPERATURE (°C)OUTPUT LOW VOLTAGE (V)OUTPUT HIGH VOLTAGE (V)

SHUTDOWN CURRENT RECEIVER OUTPUT LOW VOLTAGE

RECEIVER OUTPUT HIGH VOLTAGE

vs. TEMPERATURE

vs. TEMPERATURE

vs. TEMPERATURE

201

-0.504.5COT 981800.453/4.408)

03)AXVAn16M(( TE0.40)

N14GV( 4.3E

AERTLR12O0.35GAUVTL4.2C N10

W0.30OV

WO8OLT DT0.25U4.1PTTUH6UPUTS4UO0.20O4.020.15

3.90

-60-40-20

20

40

60

80

100

0.10

3.8

-60-40

-20

20

40

60

80

100

-60-40-20020406080100

TEMPERATURE (°C)

TEMPERATURE (°C)

TEMPERATURE (°C)

RECEIVER PROPAGATION DELAY RECEIVER PROPAGATION DELAY DRIVER PROPAGATION DELAY (500kbps MODE) vs. TEMPERATURE

(10Mbps MODE) vs. TEMPERATURE

(115kbps MODE) vs. TEMPERATURE

140

1122.20

110)

2.15s)

s

)

n135n108s(

( mYY( AAYLL106A2.10EELD130

DE DNN104 NOOOIII2.05TTTAA102AGGGA125AAPPOO100PO2.00RRRP120

P98P1.9596

115

94

1.90

-60-40-20

20

40

60

80

100

-60-40-20

20

40

60

80

100

-60-40-20020406080100

TEMPERATURE (°C)

TEMPERATURE (°C)

TEMPERATURE (°C)

_______________________________________________________________________________________7

MAX3080–MAX3089

Fail-Safe, High-Speed (10Mbps),

Slew-Rate-Limited RS-485/RS-422 TransceiversMAX3080–MAX3089

Typical Operating Characteristics (continued)

(VCC= +5V, TA = +25°C, unless otherwise noted.)

DRIVER PROPAGATION DELAY (500kbps MODE) vs. TEMPERATURE

DRIVER PROPAGATION DELAY (10Mbps MODE) vs. TEMPERATURE

DRIVER DIFFERENTIAL OUTPUT VOLTAGE

vs. TEMPERATURE

1.89OUTPUT VOLTAGE (V)1.881.871.861.851.84

1.83

920

880PROPAGATION DELAY (ns)

840800760720680640600560520

-60-40-20

20

40

60

80

6055PROPAGATION DELAY (ns)

5045403530

2520

1.90

100-60-40-20020406080100-60-40-20020406080100

TEMPERATURE (°C)TEMPERATURE (°C)TEMPERATURE (°C)

DRIVER OUTPUT CURRENT

vs. DIFFERENTIAL OUTPUT VOLTAGE

MAX3080 TOC-12

OUTPUT CURRENT vs.DRIVER OUTPUT LOW VOLTAGE

OUTPUT CURRENT vs.DRIVER OUTPUT HIGH VOLTAGE

-90OUTPUT CURRENT (mA)

-80-70-60-50-40-30

-20-100

100

140120OUTPUT CURRENT (mA)

10080604020

-100

OUTPUT CURRENT (mA

)

10

1

0.1

0.01

1

2

3

4

5

DIFFERENTIAL OUTPUT VOLTAGE (V)

00

2

4

6

8

10

12

OUTPUT LOW VOLTAGE (V)

-8-6-4-20246

OUTPUT HIGH VOLTAGE (V)

8_______________________________________________________________________________________

Fail-Safe, High-Speed (10Mbps),

Slew-Rate-Limited RS-485/RS-422 Transceivers

Typical Operating Characteristics (continued)

(V

CC= +5V, TA = +25°C, unless otherwise noted.)

RECEIVER PROPAGATION DELAYRECEIVER PROPAGATION DELAYMAX3086–MAX3088, AND MAX3089

MAX3080–MAX3085, AND MAX3089

WITH SRL = GND

WITH SRL = OPEN OR VCC

MAX3080/3089 TYP-18

MAX3080/3089 TYP-17

VA - VB2V/div

VA - VB2V/div

RO5V/div

RO5V/div

50ns/div

50ns/div

DRIVER PROPAGATION DELAY

MAX3080/MAX3081/MAX3082, AND MAX3089

WITH SRL = OPEN

MAX3080/3089 TYP-20

DI5V/div

VY - VZ2.5V/div

2

µs/div

DRIVER PROPAGATION DELAY

DRIVER PROPAGATION DELAY

MAX3083/MAX3084/MAX3085, AND MAX3089

MAX3086/MAX3087/MAX3088, AND MAX3089

WITH SRL = VCCWITH SRL = GND

MAX3080/3089 TYP-21

MAX3080/3089 TYP-22

DI5V/divDI5V/div

VY - VZ2.5V/div

VY - VZ2.5V/div

500ns/div50ns/div

_______________________________________________________________________________________9

MAX3080–MAX3089

Fail-Safe, High-Speed (10Mbps),

Slew-Rate-Limited RS-485/RS-422 TransceiversMAX3080–MAX3089

Pin Description

10______________________________________________________________________________________

Fail-Safe, High-Speed (10Mbps),

Slew-Rate-Limited RS-485/RS-422 Transceivers

Pin Description (continued)

X = Don’t care

Shutdown mode, driver and receiver outputs high impedance

______________________________________________________________________________________11

MAX3080–MAX3089

Fail-Safe, High-Speed (10Mbps),

Slew-Rate-Limited RS-485/RS-422 TransceiversMAX3080–MAX3089

Function Tables (continued)

MAX3082/MAX3085/MAX3088

TRANSMITTING

INPUTS

REXX01

DE1100

DI10XX

01High-Z

ShutdownOUTPUTSB/Z

A/Y10High-Z

RECEIVINGINPUTS

RE00011

DEXXX10

A-B≥-0.05V≤-0.2VOpen/shorted

XX

OUTPUTRO101High-ZShutdown

MAX3089

12______________________________________________________________________________________

Fail-Safe, High-Speed (10Mbps),

Slew-Rate-Limited RS-485/RS-422 Transceivers

Figure 1. MAX3080/MAX3083/MAX3086 Pin Configuration and Typical Full-Duplex Operating Circuit

Figure 2. MAX3081/MAX3084/MAX3087 Pin Configuration and Typical Full-Duplex Operating Circuit

______________________________________________________________________________________

13

MAX3080–MAX3089

Fail-Safe, High-Speed (10Mbps),

Slew-Rate-Limited RS-485/RS-422 TransceiversMAX3080–MAX3089

Detailed Description

The MAX3080–MAX3089 high-speed transceivers forRS-485/RS-422 communication contain one driver andone receiver. These devices feature fail-safe circuitry,which guarantees a logic-high receiver output when thereceiver inputs are open or shorted, or when they areconnected to a terminated transmission line with all drivers disabled (see Fail-Safesection). The MAX3080/MAX3081/MAX3082 feature reduced slew-rate driversthat minimize EMI and reduce reflections caused byimproperly terminated cables, allowing error-free datatransmission up to 115kbps (see Reduced EMI andReflectionssection). The MAX3083/MAX3084/MAX3085offer higher driver output slew-rate limits, allowingtransmit speeds up to 500kbps. The MAX3086/MAX3087/MAX3088’s driver slew rates are not limited,making transmit speeds up to 10Mbps possible. TheMAX3089’s slew rate is selectable between 115kbps,500kbps, and 10Mbps by driving a selector pin with athree-state driver.

The MAX3082/MAX3085/MAX3088 are half-duplextransceivers, while the MAX3080/MAX3081/MAX3083/MAX3084/MAX3086/MAX3087 are full-duplex trans-ceivers. The MAX3089 is selectable between half- andfull-duplex communication by driving a selector pinhigh or low, respectively.

All of these parts operate from a single +5V supply.Drivers are output short-circuit current limited. Thermalshutdown circuitry protects drivers against excessivepower dissipation. When activated, the thermal shut-down circuitry places the driver outputs into a high-impedance state.

Receiver Input Filtering

The receivers of the MAX3080–MAX3085, and theMAX3089 when operating in 115kbps or 500kbpsmode, incorporate input filtering in addition to inputhysteresis. This filtering enhances noise immunity withdifferential signals that have very slow rise and falltimes. Receiver propagation delay increases by 20%due to this filtering.

Figure 4. MAX3089 Pin Configuration and Functional Diagram14

______________________________________________________________________________________

Fail-Safe, High-Speed (10Mbps),

Slew-Rate-Limited RS-485/RS-422 Transceivers

Figure 5. Driver DC Test Load

Figure 6. Receiver Enable/Disable Timing Test Load

Fail-Safe

TXP and RXP low, connect them to ground, or leaveThe MAX3080 family guaranteesa logic-high receiverthem unconnected (internal pulldown). To invert the dri-output when the receiver inputs are shorted or open, orver phase, drive TXP high or connect it to VCC. Towhen they are connected to a terminated transmissioninvert the receiver phase, drive RXP high or connect itline with all drivers disabled. This is done by setting theto Vreceiver threshold between -50mV and -200mV. If thewhen RXP is high.

CC. Note that the receiver threshold is positivedifferential receiver input voltage (A-B) is greater thanor equal to -50mV, RO is logic high. If A-B is less thanThe MAX3089 can operate in full- or half-duplex mode.or equal to -200mV, RO is logic low. In the case of aDrive the H/Fpin low, leave it unconnected (internalterminated bus with all transmitters disabled, thepulldown), or connect it to GND for full-duplex opera-receiver’s differential input voltage is pulled to 0V bytion, and drive it high for half-duplex operation. In full-the termination. With the receiver thresholds of theduplex mode, the pin configuration of the driver andMAX3080 family, this results in a logic high with a 50mVreceiver is the same as that of a MAX3080 (Figure 4). Inminimum noise margin. Unlike previous fail-safehalf-duplex mode, the receiver inputs are switched todevices, the -50mV to -200mV threshold complies withthe driver outputs, connecting outputs Y and Z to inputsthe ±200mV EIA/TIA-485 standard.

A and B, respectively. In half-duplex mode, the internalfull-duplex receiver input resistors are still connected toMAX3089 Programming

pins 11 and 12.

The MAX3089 has several programmable operatingmodes. Transmitter rise and fall times are programma-ble between 2500ns, 750ns, and 25ns, resulting in256 Transceivers on the Bus

maximum data rates of 115kbps, 500kbps, andThe standard RS-485 receiver input impedance is 12k 10Mbps, respectively. To select the desired data rate,(one-unit load), and the standard driver can drive up todrive SRL to one of three possible states by using a32 unit loads. The MAX3080 family of transceivers havethree-state driver, by connecting it to VCCor GND, ora 1/8-unit-load receiver input impedance (96k ), allow-by leaving it unconnected. For 115kbps operation, seting up to 256 transceivers to be connected in parallelthe three-state device in high-impedance mode oron one communication line. Any combination of theseleave SRL unconnected. For 500kbps operation, drivedevices and/or other RS-485 transceivers with a total ofSRL high or connect it to VCC. For 10Mbps operation,32 unit loads or less can be connected to the line.

drive SRL low or connect it to GND. SRL can bechanged during operation without interrupting dataReduced EMI and Reflections

communications.

The MAX3080–MAX3085, and MAX3089 with SRL = VOccasionally, twisted-pair lines are connected back-or unconnected, are slew-rate limited, minimizing EMICCward from normal orientation. The MAX3089 has twoand reducing reflections caused by improperly termi-pins that invert the phase of the driver and the receivernated cables. Figure 14 shows the driver output wave-to correct for this problem. For normal operation, drive

form and its Fourier analysis of a 20kHz signaltransmitted by a MAX3086/MAX3087/MAX3088, andMAX3089 with SRL = GND. High-frequency harmonic

______________________________________________________________________________________15

MAX3080–MAX3089

Fail-Safe, High-Speed (10Mbps),

Slew-Rate-Limited RS-485/RS-422 TransceiversMAX3080–MAX3089

Figure 7. Driver Timing Test CircuitFigure 8. Driver Enable/Disable Timing Test Load

Figure 9. Driver Propagation Delays

Figure 10. Driver Enable and Disable Times (except MAX3081/MAX3084/MAX3087)

Figure 11. Receiver Propagation Delays

Figure 12. Receiver Enable and Disable Times (exceptMAX3081/MAX3084/MAX3087)

16______________________________________________________________________________________