MAX3080_07 [MAXIM]

Fail-Safe, High-Speed (10Mbps),Slew-Rate-Limited RS-485/RS-422 Transceivers; 失效保护,高速( 10Mbps的) ,限摆率限制RS - 485 / RS -422收发器
MAX3080_07
型号: MAX3080_07
厂家: MAXIM INTEGRATED PRODUCTS    MAXIM INTEGRATED PRODUCTS
描述:

Fail-Safe, High-Speed (10Mbps),Slew-Rate-Limited RS-485/RS-422 Transceivers
失效保护,高速( 10Mbps的) ,限摆率限制RS - 485 / RS -422收发器

文件: 总20页 (文件大小:622K)
中文:  中文翻译
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19-1138; Rev 3; 12/05  
Fail-Safe, High-Speed (10Mbps),  
Slew-Rate-Limited RS-485/RS-422 Transceivers  
General Description  
Next Generation Device Features  
The MAX3080–MAX3089 high-speed transceivers for  
RS-485/RS-422 communication contain one driver and  
one receiver. These devices feature fail-safe circuitry,  
which guarantees a logic-high receiver output when the  
receiver inputs are open or shorted. This means that  
the receiver output will be a logic high if all transmitters  
on a terminated bus are disabled (high impedance).  
The MAX3080/MAX3081/MAX3082 feature reduced  
slew-rate drivers that minimize EMI and reduce reflec-  
tions caused by improperly terminated cables, allowing  
error-free data transmission up to 115kbps. The  
MAX3083/MAX3084/MAX3085 offer higher driver out-  
put slew-rate limits, allowing transmit speeds up to  
500kbps. The MAX3086/MAX3087/MAX3088’s driver  
slew rates are not limited, making transmit speeds up  
to 10Mbps possible. The MAX3089’s slew rate is  
selectable between 115kbps, 500kbps, and 10Mbps  
by driving a selector pin with a single three-state driver.  
For Fault-Tolerant Applications:  
MAX3430: 80V Fault-Protected, Fail-Safe, 1/4-  
Unit Load, +3.3V RS-485 Transceiver  
For Low-Voltage Applications:  
MAX3362: +3.3V, High-Speed, RS-485/RS-422  
Transceiver in a SOT23 Package  
For Multiple Transceiver Applications:  
MAX3030E–MAX3033E: 15kV ESD-Protected,  
+3.3V, Quad, RS-422 Transmitters  
MAX3040–MAX3045: 10kV ESD-Protected, Quad,  
+5V, RS-485/RS-422 Transmitters  
Applications  
RS-422/RS-485 Communications  
Level Translators  
These transceivers typically draw 375µA of supply  
current when unloaded, or when fully loaded with the  
drivers disabled.  
Transceivers for EMI-Sensitive Applications  
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. The  
MAX3082/MAX3085/MAX3088 are intended for half-  
duplex communications, while the MAX3080/MAX3081/  
MAX3083/MAX3084/MAX3086/MAX3087 are intended  
for full-duplex communications. The MAX3089 is selec-  
table between half-duplex and full-duplex operation. It  
also features independently programmable receiver  
and transmitter output phase via separate pins.  
Ordering Information  
PART  
TEMP RANGE  
0°C to +70°C  
0°C to +70°C  
-40°C to +85°C  
-40°C to +85°C  
PIN-PACKAGE  
14 SO  
MAX3080CSD  
MAX3080CPD  
MAX3080ESD  
MAX3080EPD  
14 Plastic DIP  
14 SO  
14 Plastic DIP  
Ordering Information continued at end of data sheet.  
Selection Table  
Data  
Rate  
(Mbps)  
Slew  
Rate  
Limited  
Low-  
Power  
Shutdown  
Receiver/ Quiescent Transceivers  
Industry-  
Standard  
Pinout  
Half/Full  
Duplex  
Pin  
Count  
Part  
Driver  
Current  
(µA)  
On  
Enable  
Bus  
MAX3080  
MAX3081  
MAX3082  
MAX3083  
MAX3084  
MAX3085  
MAX3086  
MAX3087  
MAX3088  
Full  
Full  
Half  
Full  
Full  
Half  
Full  
Full  
Half  
0.115  
0.115  
0.115  
0.5  
Yes  
Yes  
Yes  
Yes  
Yes  
Yes  
No  
Yes  
No  
Yes  
No  
375  
375  
375  
375  
375  
375  
375  
375  
375  
375  
256  
256  
256  
256  
256  
256  
256  
256  
256  
256  
14  
8
75180  
75179  
75176  
75180  
75179  
75176  
75180  
75179  
75176  
75180*  
Yes  
Yes  
No  
Yes  
Yes  
No  
8
14  
8
0.5  
0.5  
Yes  
Yes  
No  
Yes  
Yes  
No  
8
10  
14  
8
10  
No  
10  
No  
Yes  
Yes  
Yes  
Yes  
8
MAX3089 Selectable Selectable Selectable  
14  
*Pin-compatible with 75180, with additional features implemented using pins 1, 6, 8, and 13.  
________________________________________________________________ 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 www.maxim-ic.com.  
Fail-Safe, High-Speed (10Mbps),  
Slew-Rate-Limited RS-485/RS-422 Transceivers  
ABSOLUTE MAXIMUM RATINGS  
Supply Voltage (V ) ............................................................+7V  
Continuous Power Dissipation  
CC  
Control Input Voltage (RE, DE)...................-0.3V to (V  
Special Input Voltage  
(H/F, SRL, TXP, RXP)..................................-0.3V to (V  
Driver Input Voltage (DI).............................-0.3V to (V  
Driver Output Voltage (A, B, Y, Z)........................................ 13V  
Receiver Input Voltage (A, B) .............................................. 13V  
Receiver Input Voltage, Full Duplex (A, B) .......................... 25V  
+ 0.3V)  
8-Pin Plastic DIP (derate 9.09mW/°C above +70°C) ...727mW  
8-Pin SO (derate 5.88mW/°C above +70°C)................471mW  
14-Pin Plastic DIP (derate 10.0mW/°C above +70°C) ....800mW  
14-Pin SO (derate 8.33mW/°C above +70°C)..............667mW  
Operating Temperature Ranges  
MAX308_C_ _ .....................................................0°C to +70°C  
MAX308_E_ _...................................................-40°C to +85°C  
Storage Temperature Range.............................-65°C to +150°C  
Lead Temperature (soldering, 10s) .................................+300°C  
CC  
+ 0.3V)  
+ 0.3V)  
CC  
CC  
Receiver Output Voltage (RO)....................-0.3V to (V  
+ 0.3V)  
CC  
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional  
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to  
absolute maximum rating conditions for extended periods may affect device reliability.  
DC ELECTRICAL CHARACTERISTICS  
(V  
= +5V 5%, T = T  
A
to T  
, unless otherwise noted. Typical values are at V  
= +5V and T = +25°C.) (Note 1)  
CC A  
CC  
MIN  
MAX  
PARAMETER  
SYMBOL  
CONDITIONS  
MIN  
TYP  
MAX  
UNITS  
DRIVER  
Differential Driver Output  
(no load)  
V
V
Figure 5  
5
V
V
OD1  
Figure 5, R = 50(RS-422)  
Figure 5, R = 27(RS-485)  
2.0  
1.5  
Differential Driver Output  
OD2  
Change in Magnitude of  
Differential Output Voltage  
(Note 2)  
V  
Figure 5, R = 50or R = 27Ω  
0.2  
V
OD  
Driver Common-Mode Output  
Voltage  
V
Figure 5, R = 50or R = 27Ω  
Figure 5, R = 50or R = 27Ω  
3
V
V
OC  
Change In Magnitude of  
Common-Mode Voltage (Note 2)  
V  
0.2  
OC  
Input High Voltage  
Input Low Voltage  
V
2.0  
10  
V
V
DE, DI, RE, H/F, TXP, RXP  
DE, DI, RE, H/F, TXP, RXP  
IH1  
V
0.8  
IL1  
MAX3080–MAX3085, and MAX3089 with  
SRL = V or unconnected  
DI Input Hysteresis  
SRL Input Current  
V
100  
mV  
µA  
HYS  
CC  
I
I
2
DE, DI, RE  
IN1  
IN2  
40  
H/F, TXP, RXP, internal pulldown  
Input High Voltage  
Input Middle Voltage  
Input Low Voltage  
V
SRL  
V
- 0.8  
CC  
V
V
V
IH2  
V
SRL (Note 3)  
SRL  
0.4V  
0.6V  
CC  
IM2  
CC  
V
0.8  
75  
IL2  
SRL = V  
CC  
SRL Input Current  
I
I
µA  
µA  
µA  
IN3  
SRL = GND (Note 3)  
-75  
V
V
V
V
= 12V  
= -7V  
= 12V  
= -7V  
125  
-75  
IN  
IN  
IN  
IN  
Input Current (A and B)  
Full Duplex  
DE = GND,  
IN4  
V
= GND or 5.25V  
CC  
125  
Output Leakage (Y and Z)  
Full Duplex  
DE = GND,  
= GND or 5.25V  
I
O
V
CC  
-100  
-250  
-7V V  
0V V  
0V V  
V  
CC  
12V  
V  
CC  
OUT  
Driver Short-Circuit Output  
Current (Note 4)  
V
OD1  
250  
mA  
OUT  
OUT  
25  
2
_______________________________________________________________________________________  
Fail-Safe, High-Speed (10Mbps),  
Slew-Rate-Limited RS-485/RS-422 Transceivers  
DC ELECTRICAL CHARACTERISTICS (continued)  
(V  
= +5V 5%, T = T  
A
to T  
, unless otherwise noted. Typical values are at V  
= +5V and T = +25°C.) (Note 1)  
CC A  
CC  
MIN  
MAX  
PARAMETER  
SYMBOL  
CONDITIONS  
MIN  
TYP  
MAX  
UNITS  
RECEIVER  
Receiver Differential Threshold  
Voltage  
Receiver Input Hysteresis  
Receiver Output High Voltage  
Receiver Output Low Voltage  
V
-7V V  
+12V  
CM  
-200  
-125  
25  
-50  
mV  
TH  
V  
mV  
V
V
TH  
V
I
I
= -4mA, V = -50mV  
= 4mA, V = -200mV  
V
-1.5  
OH  
O
ID  
CC  
V
OL  
0.4  
1
O
ID  
Three-State Output Current at  
Receiver  
I
0.4V V 2.4V  
µA  
kΩ  
mA  
OZR  
O
Receiver Input Resistance  
R
-7V V  
+12V  
CM  
96  
IN  
Receiver Output Short-Circuit  
Current  
I
0V V  
V  
CC  
7
95  
OSR  
RO  
SUPPLY CURRENT  
No load,  
RE = DI = GND  
DE = V  
430  
375  
475  
420  
900  
600  
CC  
µA  
DE = GND  
DE = V  
or V , SRL = V  
CC  
CC  
Supply Current  
I
CC  
No load,  
RE = DI = GND  
1000  
800  
CC  
µA  
µA  
DE = GND  
or V , SRL = GND  
CC  
Supply Current in Shutdown  
Mode  
I
DE = GND, V = V  
CC  
0.001  
10  
SHDN  
RE  
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: V  
and V  
are the changes in V  
and V , respectively, when the DI input changes state.  
OD  
OC  
OD OC  
Note 3: The SRL pin is internally biased to V / 2 by a 100k/100kresistor divider. It is guaranteed to be V / 2 if left  
CC  
CC  
unconnected.  
Note 4: Maximum current level applies to peak current just prior to foldback-current limiting; minimum current level applies during  
current limiting.  
_______________________________________________________________________________________  
3
Fail-Safe, High-Speed (10Mbps),  
Slew-Rate-Limited RS-485/RS-422 Transceivers  
SWITCHING CHARACTERISTICS—MAX3080–MAX3082, and MAX3089 with  
SRL = Unconnected  
(V  
CC  
= +5V 5%, T = T  
A
to T  
, unless otherwise noted. Typical values are at V  
= +5V and T = +25°C.)  
CC A  
MIN  
MAX  
PARAMETER  
SYMBOL  
CONDITIONS  
MIN  
500  
500  
TYP  
2030  
2030  
MAX  
2600  
2600  
UNITS  
t
t
DPLH  
DPHL  
Figures 7 and 9, R  
= 54,  
= 54,  
= 54,  
DIFF  
Driver Input to Output  
ns  
C
= C = 100pF  
L1  
L2  
Driver Output Skew  
Figures 7 and 9, R  
DIFF  
t
-3  
200  
ns  
ns  
DSKEW  
C
L1  
= C = 100pF  
t
- t  
L2  
| DPLH DPHL |  
Figures 7 and 9, R  
DIFF  
Driver Rise or Fall Time  
t
, t  
DR DF  
667  
115  
1320  
2500  
C
L1  
= C = 100pF  
L2  
Maximum Data Rate  
f
kbps  
ns  
MAX  
Driver Enable to Output High  
Driver Enable to Output Low  
Driver Disable Time from Low  
Driver Disable Time from High  
t
Figures 8 and 10, C = 100pF, S2 closed  
3500  
3500  
100  
DZH  
L
t
Figures 8 and 10, C = 100pF, S1 closed  
ns  
DZL  
DLZ  
DHZ  
L
t
Figures 8 and 10, C = 15pF, S1 closed  
ns  
L
t
Figures 8 and 10, C = 15pF, S2 closed  
100  
ns  
L
t
t
,
Figures 11 and 13; V  
2.0V;  
rise and fall time of V 15ns  
RPLH  
|
ID |  
Receiver Input to Output  
127  
3
200  
30  
ns  
ns  
RPHL  
ID  
t
- t  
Differential  
Figures 11 and 13; V  
2.0V;  
rise and fall time of V 15ns  
| RPLH RPHL |  
Receiver Skew  
|
ID |  
t
RSKD  
ID  
Receiver Enable to Output Low  
t
Figures 6 and 12, C = 100pF, S1 closed  
20  
20  
20  
50  
50  
50  
ns  
ns  
ns  
RZL  
L
Receiver Enable to Output High  
Receiver Disable Time from Low  
t
Figures 6 and 12, C = 100pF, S2 closed  
L
RZH  
t
Figures 6 and 12, C = 100pF, S1 closed  
L
RLZ  
Receiver Disable Time from  
High  
t
Figures 6 and 12, C = 100pF, S2 closed  
L
20  
50  
ns  
ns  
ns  
RHZ  
Time to Shutdown  
t
(Note 5)  
50  
200  
600  
SHDN  
Driver Enable from Shutdown to  
Output High  
t
t
Figures 8 and 10, C = 15pF, S2 closed  
6000  
DZH(SHDN)  
L
Driver Enable from Shutdown to  
Output Low  
t
Figures 8 and 10, C = 15pF, S1 closed  
6000  
3500  
3500  
ns  
ns  
ns  
DZL(SHDN)  
L
Receiver Enable from Shutdown  
to Output High  
Figures 6 and 12, C = 100pF, S2 closed  
RZH(SHDN)  
L
Receiver Enable from Shutdown  
to Output Low  
t
Figures 6 and 12, C = 100pF, S1 closed  
L
RZL(SHDN)  
4
_______________________________________________________________________________________  
Fail-Safe, High-Speed (10Mbps),  
Slew-Rate-Limited RS-485/RS-422 Transceivers  
SWITCHING CHARACTERISTICS—MAX3083–MAX3085, and MAX3089 with SRL = V  
CC  
(V  
= +5V 5%, T = T  
A
to T  
, unless otherwise noted. Typical values are at V  
= +5V and T = +25°C.)  
CC A  
CC  
MIN  
MAX  
PARAMETER  
SYMBOL  
CONDITIONS  
MIN  
250  
250  
TYP  
720  
720  
MAX  
1000  
1000  
UNITS  
t
t
DPLH  
DPHL  
Figures 7 and 9, R  
= 54,  
= 54,  
= 54,  
DIFF  
Driver Input to Output  
ns  
C
= C = 100pF  
L1  
L2  
Driver Output Skew  
Figures 7 and 9, R  
DIFF  
t
-3  
100  
750  
ns  
ns  
DSKEW  
C
= C = 100pF  
t
- t  
L1  
L2  
| DPLH DPHL |  
Figures 7 and 9, R  
DIFF  
Driver Rise or Fall Time  
t
t
200  
500  
530  
DR, DF  
C
= C = 100pF  
L1  
L2  
Maximum Data Rate  
f
kbps  
ns  
MAX  
Driver Enable to Output High  
Driver Enable to Output Low  
Driver Disable Time from Low  
Driver Disable Time from High  
t
Figures 8 and 10, C = 100pF, S2 closed  
2500  
2500  
100  
DZH  
L
t
Figures 8 and 10, C = 100pF, S1 closed  
ns  
DZL  
DLZ  
DHZ  
L
t
Figures 8 and 10, C = 15pF, S1 closed  
ns  
L
t
Figures 8 and 10, C = 15pF, S2 closed  
100  
ns  
L
t
t
,
Figures 11 and 13; V  
2.0V;  
ID  
|
RPLH  
|
Receiver Input to Output  
127  
3
200  
30  
ns  
ns  
rise and fall time of V 15ns  
RPHL  
ID  
t
- t  
Differential  
Figures 11 and 13; V  
rise and fall time of V 15ns  
ID  
2.0V;  
ID  
|
RPLH RPHL  
|
|
|
t
RSKD  
Receiver Skew  
Receiver Enable to Output Low  
t
Figures 6 and 12, C = 100pF, S1 closed  
20  
20  
20  
50  
50  
50  
ns  
ns  
ns  
RZL  
L
Receiver Enable to Output High  
Receiver Disable Time from Low  
t
Figures 6 and 12, C = 100pF, S2 closed  
L
RZH  
t
Figures 6 and 12, C = 100pF, S1 closed  
L
RLZ  
Receiver Disable Time from  
High  
t
Figures 6 and 12, C = 100pF, S2 closed  
L
20  
50  
ns  
RHZ  
Time to Shutdown  
t
(Note 5)  
50  
200  
600  
ns  
ns  
SHDN  
Driver Enable from Shutdown to  
Output High  
t
t
Figures 8 and 10, C = 15pF, S2 closed  
4500  
DZH(SHDN)  
L
Driver Enable from Shutdown to  
Output Low  
t
Figures 8 and 10, C = 15pF, S1 closed  
4500  
ns  
DZL(SHDN)  
L
Receiver Enable from Shutdown  
to Output High  
Figures 6 and 12, C = 100pF, S2 closed  
3500  
3500  
ns  
ns  
RZH(SHDN)  
L
Receiver Enable from Shutdown  
to Output Low  
t
Figures 6 and 12, C = 100pF, S1 closed  
L
RZL(SHDN)  
_______________________________________________________________________________________  
5
Fail-Safe, High-Speed (10Mbps),  
Slew-Rate-Limited RS-485/RS-422 Transceivers  
SWITCHING CHARACTERISTICS—MAX3086–MAX3088, and MAX3089 with SRL = GND  
(V  
CC  
= +5V 5%, T = T  
A
to T  
, unless otherwise noted. Typical values are at V  
= +5V and T = +25°C.)  
CC A  
MIN  
MAX  
PARAMETER  
SYMBOL  
CONDITIONS  
MIN  
TYP  
34  
MAX  
60  
UNITS  
t
t
DPLH  
DPHL  
Figures 7 and 9, R  
= 54,  
= 54,  
= 54,  
DIFF  
Driver Input to Output  
ns  
C
= C = 100pF  
L1  
L2  
34  
60  
Driver Output Skew  
Figures 7 and 9, R  
DIFF  
t
-2.5  
14  
10  
25  
ns  
ns  
DSKEW  
C
= C = 100pF  
t
- t  
L1  
L2  
| DPLH DPHL |  
Figures 7 and 9, R  
DIFF  
Driver Rise or Fall Time  
t
t
DR, DF  
C
= C = 100pF  
L1  
L2  
Maximum Data Rate  
f
10  
Mbps  
ns  
MAX  
Driver Enable to Output High  
Driver Enable to Output Low  
Driver Disable Time from Low  
Driver Disable Time from High  
t
Figures 8 and 10, C = 100pF, S2 closed  
150  
150  
100  
100  
DZH  
L
t
Figures 8 and 10, C = 100pF, S1 closed  
ns  
DZL  
DLZ  
DHZ  
L
t
Figures 8 and 10, C = 15pF, S1 closed  
ns  
L
t
Figures 8 and 10, C = 15pF, S2 closed  
ns  
L
t
t
,
Figures 11 and 13; V  
2.0V;  
RPLH  
|
ID |  
Receiver Input to Output  
106  
0
150  
10  
ns  
ns  
rise and fall time of V 15ns  
RPHL  
ID  
t
- t  
Differential  
Figures 11 and 13; V  
2.0V;  
| RPLH RPHL |  
Receiver Skew  
|
ID |  
t
RSKD  
rise and fall time of V 15ns  
ID  
Receiver Enable to Output Low  
t
Figures 6 and 12, C = 100pF, S1 closed  
20  
20  
20  
50  
50  
50  
ns  
ns  
ns  
RZL  
L
Receiver Enable to Output High  
Receiver Disable Time from Low  
t
Figures 6 and 12, C = 100pF, S2 closed  
L
RZH  
t
Figures 6 and 12, C = 100pF, S1 closed  
L
RLZ  
Receiver Disable Time from  
High  
t
Figures 6 and 12, C = 100pF, S2 closed  
L
20  
50  
ns  
RHZ  
Time to Shutdown  
t
(Note 5)  
50  
200  
600  
250  
ns  
ns  
SHDN  
Driver Enable from Shutdown to  
Output High  
t
t
Figures 8 and 10, C = 15pF, S2 closed  
L
DZH(SHDN)  
Driver Enable from Shutdown to  
Output Low  
t
Figures 8 and 10, C = 15pF, S1 closed  
250  
ns  
DZL(SHDN)  
L
Receiver Enable from Shutdown  
to Output High  
Figures 6 and 12, C = 100pF, S2 closed  
3500  
3500  
ns  
ns  
RZH(SHDN)  
L
Receiver Enable from Shutdown  
to Output Low  
t
Figures 6 and 12, C = 100pF, S1 closed  
L
RZL(SHDN)  
Note 5: The device is put into shutdown by bringing RE high 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 guaranteed  
to have entered shutdown.  
6
_______________________________________________________________________________________  
Fail-Safe, High-Speed (10Mbps),  
Slew-Rate-Limited RS-485/RS-422 Transceivers  
Typical Operating Characteristics  
(V  
CC  
= +5V, T = +25°C, unless otherwise noted.)  
A
NO-LOAD SUPPLY CURRENT  
vs. TEMPERATURE  
OUTPUT CURRENT  
vs. RECEIVER OUTPUT LOW VOLTAGE  
OUTPUT CURRENT  
vs. RECEIVER OUTPUT HIGH VOLTAGE  
525  
500  
60  
30  
25  
20  
15  
10  
5
A: MAX3086–MAX3088,  
MAX3089 WITH  
SRL = GND  
50  
40  
30  
20  
10  
0
475  
DE = V  
CC  
450  
425  
400  
375  
350  
A
DE = GND  
B
A
B: MAX3080–MAX3085,  
MAX3089 WITH  
B
325  
300  
SRL = OPEN OR V  
CC  
0
-60 -40 -20  
0
20 40 60 80 100  
0
1
2
3
4
5
0
1
2
3
4
5
TEMPERATURE (°C)  
OUTPUT LOW VOLTAGE (V)  
OUTPUT HIGH VOLTAGE (V)  
SHUTDOWN CURRENT  
vs. TEMPERATURE  
RECEIVER OUTPUT HIGH VOLTAGE  
vs. TEMPERATURE  
RECEIVER OUTPUT LOW VOLTAGE  
vs. TEMPERATURE  
20  
18  
4.5  
4.4  
4.3  
0.50  
0.45  
0.40  
I
RO  
= 8mA  
I
RO  
= 8mA  
16  
14  
12  
0.35  
0.30  
0.25  
4.2  
4.1  
10  
8
6
4
2
4.0  
3.9  
3.8  
0.20  
0.15  
0.10  
0
-60 -40 -20  
0
20 40 60 80 100  
-60 -40 -20  
0
20 40 60 80 100  
-60 -40 -20  
0
20 40 60 80 100  
TEMPERATURE (°C)  
TEMPERATURE (°C)  
TEMPERATURE (°C)  
DRIVER PROPAGATION DELAY  
(115kbps MODE) vs. TEMPERATURE  
RECEIVER PROPAGATION DELAY  
(500kbps MODE) vs. TEMPERATURE  
RECEIVER PROPAGATION DELAY  
(10Mbps MODE) vs. TEMPERATURE  
2.20  
2.15  
2.10  
2.05  
2.00  
1.95  
140  
112  
C
= 100pF  
LOAD  
C
= 100pF  
R = 54  
LOAD  
t
110  
108  
135  
130  
106  
104  
102  
100  
98  
125  
120  
115  
96  
94  
1.90  
-60 -40 -20  
0
20 40 60 80 100  
-60 -40 -20  
0
20 40 60 80 100  
-60 -40 -20  
0
20 40 60 80 100  
TEMPERATURE (°C)  
TEMPERATURE (°C)  
TEMPERATURE (°C)  
_______________________________________________________________________________________  
7
Fail-Safe, High-Speed (10Mbps),  
Slew-Rate-Limited RS-485/RS-422 Transceivers  
Typical Operating Characteristics (continued)  
(V  
CC  
= +5V, T = +25°C, unless otherwise noted.)  
A
DRIVER DIFFERENTIAL OUTPUT VOLTAGE  
vs. TEMPERATURE  
DRIVER PROPAGATION DELAY  
(500kbps MODE) vs. TEMPERATURE  
60  
DRIVER PROPAGATION DELAY  
(10Mbps MODE) vs. TEMPERATURE  
1.90  
1.89  
920  
880  
840  
800  
760  
720  
680  
640  
600  
560  
520  
R = 54Ω  
t
R = 54Ω  
t
R = 54Ω  
t
55  
50  
45  
1.88  
1.87  
1.86  
1.85  
1.84  
1.83  
40  
35  
30  
25  
20  
-60 -40 -20  
0
20 40 60 80 100  
-60 -40 -20  
0
20 40 60 80 100  
-60 -40 -20  
0
20 40 60 80 100  
TEMPERATURE (°C)  
TEMPERATURE (°C)  
TEMPERATURE (°C)  
DRIVER OUTPUT CURRENT  
vs. DIFFERENTIAL OUTPUT VOLTAGE  
OUTPUT CURRENT vs.  
DRIVER OUTPUT HIGH VOLTAGE  
OUTPUT CURRENT vs.  
DRIVER OUTPUT LOW VOLTAGE  
100  
-100  
-90  
-80  
-70  
140  
120  
10  
1
100  
-60  
-50  
80  
60  
-40  
-30  
40  
20  
0
0.1  
-20  
-10  
0
0.01  
0
1
2
3
4
5
-8  
-6  
-4  
-2  
0
2
4
6
0
2
4
6
8
10  
12  
DIFFERENTIAL OUTPUT VOLTAGE (V)  
OUTPUT HIGH VOLTAGE (V)  
OUTPUT LOW VOLTAGE (V)  
8
_______________________________________________________________________________________  
Fail-Safe, High-Speed (10Mbps),  
Slew-Rate-Limited RS-485/RS-422 Transceivers  
Typical Operating Characteristics (continued)  
(V  
CC  
= +5V, T = +25°C, unless otherwise noted.)  
A
RECEIVER PROPAGATION DELAY  
MAX3080–MAX3085, AND MAX3089  
RECEIVER PROPAGATION DELAY  
MAX3086–MAX3088, AND MAX3089  
WITH SRL = OPEN OR V  
CC  
WITH SRL = GND  
MAX3080/3089 TYP-17  
MAX3080/3089 TYP-18  
V
A
- V  
2V/div  
5V/div  
B
V
A
- V  
2V/div  
5V/div  
B
RO  
RO  
50ns/div  
50ns/div  
DRIVER PROPAGATION DELAY  
MAX3080/MAX3081/MAX3082, AND MAX3089  
WITH SRL = OPEN  
MAX3080/3089 TYP-20  
DI  
5V/div  
V
Y
- V  
Z
2.5V/div  
2µs/div  
DRIVER PROPAGATION DELAY  
MAX3083/MAX3084/MAX3085, AND MAX3089  
DRIVER PROPAGATION DELAY  
MAX3086/MAX3087/MAX3088, AND MAX3089  
WITH SRL = V  
WITH SRL = GND  
CC  
MAX3080/3089 TYP-21  
MAX3080/3089 TYP-22  
DI  
5V/div  
DI  
5V/div  
V
Y
- V  
Z
2.5V/div  
V
Y
- V  
Z
2.5V/div  
500ns/div  
50ns/div  
_______________________________________________________________________________________  
9
Fail-Safe, High-Speed (10Mbps),  
Slew-Rate-Limited RS-485/RS-422 Transceivers  
Pin Description  
PIN  
MAX3080 MAX3081 MAX3082  
MAX3083 MAX3084 MAX3085  
MAX3086 MAX3087 MAX3088  
MAX3089  
NAME  
FUNCTION  
HALF-  
FULL-  
HALF-  
FULL-DUPLEX  
DUPLEX DUPLEX DUPLEX  
DEVICES  
DEVICES  
MODE  
MODE  
Half/Full-Duplex Selector Pin. Connect H/F to V  
mode; connect to GND or leave unconnected for full-duplex mode.  
for half-duplex  
CC  
2
1
1
H/F  
Receiver Output. When RE is low and if A - B -50mV, RO will be  
high; if A - B -200mV, RO will be low.  
2
3
1
2
2
3
2
3
RO  
Receiver Output Enable. Drive RE low to enable RO; RO is high  
impedance when RE is high. Drive RE high and DE low to enter  
low-power shutdown mode.  
3
RE  
DE  
DI  
Driver Output Enable. Drive DE high to enable driver outputs. These  
outputs are high impedance when DE is low. Drive RE high and DE  
low to enter low-power shutdown mode.  
4
5
3
4
4
5
4
5
Driver Input. With DE high, a low on DI forces noninverting  
output low and inverting output high. Similarly, a high on DI  
forces noninverting output high and inverting output low.  
Slew-Rate-Limit Selector Pin. Connect SRL to GND for 10Mbps  
6, 7  
4
5
6
7
8
6
7
8
SRL communication rate; connect to V  
for 500kbps communication  
CC  
rate. Leave unconnected for 115kbps communication rate.  
GND Ground  
Transmitter Phase. Connect TXP to GND, or leave floating for normal  
TXP transmitter phase/polarity. Connect to V  
to invert the transmitter  
CC  
phase/polarity.  
9
5
6
7
9
9
Y
Y
Z
Z
B
B
B
Noninverting Driver Output  
10  
11  
10  
11  
Noninverting Receiver Input and Noninverting Driver Output*  
Inverting Driver Output  
10  
11  
7
Inverting Receiver Input and Inverting Driver Output*  
Inverting Receiver Input  
Receiver Input Resistors*  
Inverting Receiver Input and Inverting Driver Output  
10 ______________________________________________________________________________________  
Fail-Safe, High-Speed (10Mbps),  
Slew-Rate-Limited RS-485/RS-422 Transceivers  
Pin Description (continued)  
PIN  
MAX3080 MAX3081 MAX3082  
MAX3083 MAX3084 MAX3085  
MAX3086 MAX3087 MAX3088  
MAX3089  
NAME  
FUNCTION  
HALF-  
FULL-  
DUPLEX DUPLEX  
MODE  
12  
HALF-  
FULL-DUPLEX  
DUPLEX  
DEVICES  
DEVICES  
MODE  
12  
8
6
A
A
A
Noninverting Receiver Input  
Receiver Input Resistors*  
12  
Noninverting Receiver Input and Noninverting Driver Output  
Receiver Phase. Connect RXP to GND, or leave unconnected for  
13  
13  
RXP normal transmitter phase/polarity. Connect to V to invert the  
CC  
receiver phase/polarity.  
14  
1
8
14  
14  
V
Positive Supply; 4.75V V  
5.25V  
CC  
CC  
1, 8, 13  
N.C. Not Connected. Not internally connected.  
*(MAX3089 only.) In half-duplex mode, the driver outputs serve as receiver inputs. The full-duplex receiver inputs (A and B) will still  
have a 1/8-unit load, but are not connected to the receiver.  
Function Tables  
MAX3080/MAX3083/MAX3086  
MAX3081/MAX3084/MAX3087  
TRANSMITTING  
OUTPUTS  
TRANSMITTING  
INPUT  
INPUTS  
OUTPUTS  
DI  
1
Z
0
1
Y
1
0
DE  
1
DI  
1
Z
0
1
Y
RE  
X
1
0
0
X
1
0
0
0
X
X
High-Z  
High-Z  
1
0
Shutdown  
RECEIVING  
INPUTS  
OUTPUT  
A-B  
-0.05V  
RO  
1
RECEIVING  
INPUTS  
OUTPUT  
-0.2V  
0
DE  
X
A-B  
RO  
RE  
Open/shorted  
1
0
0
0
1
1
-0.05V  
1
X
-0.2V  
0
1
X
Open/shorted  
1
X
X
High-Z  
Shutdown  
0
X = Don’t care  
Shutdown mode, driver and receiver outputs high impedance  
______________________________________________________________________________________ 11  
Fail-Safe, High-Speed (10Mbps),  
Slew-Rate-Limited RS-485/RS-422 Transceivers  
Function Tables (continued)  
MAX3082/MAX3085/MAX3088  
MAX3089  
TRANSMITTING  
INPUTS  
DE  
TRANSMITTING  
OUTPUTS  
INPUTS  
OUTPUTS  
TXP  
0
DI  
1
Z
Y
RE  
X
DE  
1
DI  
1
B/Z  
A/Y  
RE  
X
1
1
1
1
0
0
0
1
0
1
1
0
0
X
0
1
0
X
1
0
1
X
1
1
0
0
1
0
0
X
X
High-Z  
High-Z  
1
X
0
1
0
Shutdown  
X
0
X
X
High-Z  
High-Z  
X
1
Shutdown  
RECEIVING  
INPUTS  
OUTPUT  
DE  
X
A-B  
RO  
RE  
RECEIVING  
INPUTS  
0
0
0
1
1
-0.05V  
1
OUTPUT  
X
-0.2V  
0
1
RXP  
DE  
X
X
X
X
0
A-B  
-0.05V  
-0.2V  
-0.05V  
-0.2V  
X
Y-Z  
X
RO  
1
H/F  
0
RE  
X
Open/shorted  
0
0
1
1
0
0
1
1
0
0
0
0
0
0
0
0
1
X
X
High-Z  
Shutdown  
0
X
0
0
0
X
0
0
X
1
1
-0.05V  
-0.2V  
-0.05V  
-0.2V  
1
1
0
X
0
1
0
X
0
1
0
X
1
Open/  
shorted  
0
1
0
1
0
0
1
1
0
0
0
0
X
0
X
0
X
1
1
0
0
Open/  
shorted  
X
Open/  
shorted  
X
Open/  
shorted  
X
X
X
X
X
1
1
1
0
X
X
X
X
High-Z  
Shutdown  
12 ______________________________________________________________________________________  
Fail-Safe, High-Speed (10Mbps),  
Slew-Rate-Limited RS-485/RS-422 Transceivers  
V
CC  
DE  
V
CC  
RE  
TOP VIEW  
0.1µF  
4
14  
MAX3080  
MAX3083  
MAX3086  
N.C.  
RO  
1
2
3
4
5
6
7
14  
V
CC  
9
Y
R
13 N.C.  
5
Rt  
DI  
RO  
DI  
D
R
10  
RE  
12  
11  
10  
9
A
Z
DE  
B
12  
11  
A
2
Rt  
DI  
Z
RO  
NC  
R
D
D
GND  
GND  
Y
B
1, 8, 13  
8
N.C.  
3
6, 7  
GND  
DIP/SO  
RE  
GND DE  
Figure 1. MAX3080/MAX3083/MAX3086 Pin Configuration and Typical Full-Duplex Operating Circuit  
0.1µF  
V
CC  
TOP VIEW  
MAX3081  
MAX3084  
MAX3087  
V
CC  
1
Y
Z
5
6
3
2
Rt  
DI  
RO  
D
R
V
1
2
3
4
R
8
7
6
5
A
B
Z
Y
CC  
RO  
DI  
8
7
A
B
Rt  
RO  
DI  
R
D
GND  
D
DIP/SO  
4
GND  
GND  
Figure 2. MAX3081/MAX3084/MAX3087 Pin Configuration and Typical Full-Duplex Operating Circuit  
TOP VIEW  
0.1µF  
MAX3082  
MAX3085  
MAX3088  
DE  
D
DI  
R
R
RO  
RE  
DE  
DI  
1
2
3
4
RO  
RE  
DE  
DI  
1
2
3
4
8
7
8
7
6
5
V
V
CC  
CC  
B
B
A
B
Rt  
Rt  
6
A
A
RO  
R
D
D
5
GND  
GND  
RE  
NOTE: PIN LABELS Y AND Z ON TIMING, TEST, AND WAVEFORM DIAGRAMS REFER TO PINS A AND B WHEN DE IS HIGH.  
DIP/SO  
Figure 3. MAX3082/MAX3085/MAX3088 Pin Configuration and Typical Half-Duplex Operating Circuit  
______________________________________________________________________________________ 13  
Fail-Safe, High-Speed (10Mbps),  
Slew-Rate-Limited RS-485/RS-422 Transceivers  
The MAX3082/MAX3085/MAX3088 are half-duplex  
Detailed Description  
transceivers, while the MAX3080/MAX3081/MAX3083/  
The MAX3080–MAX3089 high-speed transceivers for  
MAX3084/MAX3086/MAX3087 are full-duplex trans-  
RS-485/RS-422 communication contain one driver and  
ceivers. The MAX3089 is selectable between half- and  
one receiver. These devices feature fail-safe circuitry,  
full-duplex communication by driving a selector pin  
which guarantees a logic-high receiver output when the  
high or low, respectively.  
receiver inputs are open or shorted, or when they are  
All of these parts operate from a single +5V supply.  
Drivers are output short-circuit current limited. Thermal  
shutdown circuitry protects drivers against excessive  
power dissipation. When activated, the thermal shut-  
down circuitry places the driver outputs into a high-  
impedance state.  
connected to a terminated transmission line with all  
drivers disabled (see Fail-Safe section). The MAX3080/  
MAX3081/MAX3082 feature reduced slew-rate drivers  
that minimize EMI and reduce reflections caused by  
improperly terminated cables, allowing error-free data  
transmission up to 115kbps (see Reduced EMI and  
Reflections section). The MAX3083/MAX3084/MAX3085  
offer higher driver output slew-rate limits, allowing  
transmit speeds up to 500kbps. The MAX3086/  
MAX3087/MAX3088’s driver slew rates are not limited,  
making transmit speeds up to 10Mbps possible. The  
MAX3089’s slew rate is selectable between 115kbps,  
500kbps, and 10Mbps by driving a selector pin with a  
three-state driver.  
Receiver Input Filtering  
The receivers of the MAX3080–MAX3085, and the  
MAX3089 when operating in 115kbps or 500kbps  
mode, incorporate input filtering in addition to input  
hysteresis. This filtering enhances noise immunity with  
differential signals that have very slow rise and fall  
times. Receiver propagation delay increases by 20%  
due to this filtering.  
V
CC  
RE  
MAX3089  
A
RD  
TOP VIEW  
B
H/F  
RO  
1
2
3
4
5
6
7
14  
V
CC  
13 RXP  
RE  
12  
11  
10  
9
A
MAX3089  
DE  
B
H/F  
Z
DI  
Z
TXP  
SRL  
GND  
Y
8
TXP  
DIP/SO  
Y
DI  
NOTE: SWITCH POSITIONS  
INDICATED FOR H/F = GND  
GND DE  
SRL  
Figure 4. MAX3089 Pin Configuration and Functional Diagram  
14 ______________________________________________________________________________________  
Fail-Safe, High-Speed (10Mbps),  
Slew-Rate-Limited RS-485/RS-422 Transceivers  
Y
1kΩ  
TEST POINT  
RECEIVER  
OUTPUT  
R
R
V
CC  
S1  
S2  
C
RL  
1kΩ  
V
OD  
15pF  
V
OC  
Z
Figure 5. Driver DC Test Load  
Figure 6. Receiver Enable/Disable Timing Test Load  
TXP and RXP low, connect them to ground, or leave  
them unconnected (internal pulldown). To invert the dri-  
Fail-Safe  
The MAX3080 family guarantees a logic-high receiver  
output when the receiver inputs are shorted or open, or  
when they are connected to a terminated transmission  
line with all drivers disabled. This is done by setting the  
receiver threshold between -50mV and -200mV. If the  
differential receiver input voltage (A-B) is greater than  
or equal to -50mV, RO is logic high. If A-B is less than  
or equal to -200mV, RO is logic low. In the case of a  
terminated bus with all transmitters disabled, the  
receiver’s differential input voltage is pulled to 0V by  
the termination. With the receiver thresholds of the  
MAX3080 family, this results in a logic high with a 50mV  
minimum noise margin. Unlike previous fail-safe  
devices, the -50mV to -200mV threshold complies with  
the 200mV EIA/TIA-485 standard.  
ver phase, drive TXP high or connect it to V . To  
CC  
invert the receiver phase, drive RXP high or connect it  
to V . Note that the receiver threshold is positive  
CC  
when RXP is high.  
The MAX3089 can operate in full- or half-duplex mode.  
Drive the H/F pin low, leave it unconnected (internal  
pulldown), or connect it to GND for full-duplex opera-  
tion, and drive it high for half-duplex operation. In full-  
duplex mode, the pin configuration of the driver and  
receiver is the same as that of a MAX3080 (Figure 4). In  
half-duplex mode, the receiver inputs are switched to  
the driver outputs, connecting outputs Y and Z to inputs  
A and B, respectively. In half-duplex mode, the internal  
full-duplex receiver input resistors are still connected to  
pins 11 and 12.  
MAX3089 Programming  
The MAX3089 has several programmable operating  
modes. Transmitter rise and fall times are programma-  
ble between 2500ns, 750ns, and 25ns, resulting in  
maximum data rates of 115kbps, 500kbps, and  
10Mbps, respectively. To select the desired data rate,  
drive SRL to one of three possible states by using a  
Applications Information  
256 Transceivers on the Bus  
The standard RS-485 receiver input impedance is 12k  
(one-unit load), and the standard driver can drive up to  
32 unit loads. The MAX3080 family of transceivers have  
a 1/8-unit-load receiver input impedance (96k), allow-  
ing up to 256 transceivers to be connected in parallel  
on one communication line. Any combination of these  
devices and/or other RS-485 transceivers with a total of  
32 unit loads or less can be connected to the line.  
three-state driver, by connecting it to V  
or GND, or  
CC  
by leaving it unconnected. For 115kbps operation, set  
the three-state device in high-impedance mode or  
leave SRL unconnected. For 500kbps operation, drive  
SRL high or connect it to V . For 10Mbps operation,  
CC  
drive SRL low or connect it to GND. SRL can be  
changed during operation without interrupting data  
communications.  
Reduced EMI and Reflections  
The MAX3080–MAX3085, and MAX3089 with SRL = V  
CC  
or unconnected, are slew-rate limited, minimizing EMI  
and reducing reflections caused by improperly termi-  
nated cables. Figure 14 shows the driver output wave-  
form and its Fourier analysis of a 20kHz signal  
transmitted by a MAX3086/MAX3087/MAX3088, and  
MAX3089 with SRL = GND. High-frequency harmonic  
Occasionally, twisted-pair lines are connected back-  
ward from normal orientation. The MAX3089 has two  
pins that invert the phase of the driver and the receiver  
to correct for this problem. For normal operation, drive  
______________________________________________________________________________________ 15  
Fail-Safe, High-Speed (10Mbps),  
Slew-Rate-Limited RS-485/RS-422 Transceivers  
3V  
DE  
C
L1  
V
CC  
Y
Z
S1  
S2  
500Ω  
R
DIFF  
DI  
OUTPUT  
UNDER TEST  
V
ID  
C
L
C
L2  
Figure 7. Driver Timing Test Circuit  
Figure 8. Driver Enable/Disable Timing Test Load  
3V  
3V  
DE  
DI  
1.5V  
1.5V  
1.5V  
1.5V  
V
0V  
0V  
t
t
PHL  
PLH  
1/2 V  
O
t
t
, t  
LZ  
ZL(SHDN) ZL  
Z
Y, Z  
2.3V  
V
+0.5V  
-0.5V  
O
OUTPUT NORMALLY LOW  
OUTPUT NORMALLY HIGH  
OL  
V
OL  
Y
1/2 V  
O
V
= V (Y) - V (Z)  
DIFF  
Y, Z  
0V  
V
O
V
2.3V  
OH  
V
DIFF  
90%  
90%  
0V  
-V  
10%  
10%  
O
t
, t  
t
HZ  
ZH(SHDN) ZH  
t
R
t
F
t
t
- t  
SKEW = | PLH PHL |  
Figure 9. Driver Propagation Delays  
Figure 10. Driver Enable and Disable Times (except  
MAX3081/MAX3084/MAX3087)  
3V  
RE  
1.5V  
1.5V  
0V  
V
OH  
RO  
1.5V  
1.5V  
V
OL  
OUTPUT  
t
LZ  
t
, t  
ZL(SHDN) ZL  
V
RO  
CC  
t
t
PLH  
PHL  
A
B
1V  
1.5V  
V
V
+ 0.5V  
- 0.5V  
OUTPUT NORMALLY LOW  
OUTPUT NORMALLY HIGH  
OL  
-1V  
INPUT  
RO  
1.5V  
OH  
0V  
t
, t  
t
HZ  
ZH(SHDN) ZH  
Figure 11. Receiver Propagation Delays  
Figure 12. Receiver Enable and Disable Times (except  
MAX3081/MAX3084/MAX3087)  
16 ______________________________________________________________________________________  
Fail-Safe, High-Speed (10Mbps),  
Slew-Rate-Limited RS-485/RS-422 Transceivers  
B
RECEIVER  
OUTPUT  
V
ID  
R
20dB/div  
ATE  
A
0Hz  
100kHz/div  
1MHz  
Figure 13. Receiver Propagation Delay Test Circuit  
Figure 14. Driver Output Waveform and FFT Plot of  
MAX3086/MAX3087/MAX3088, and MAX3089 with  
SRL = GND, Transmitting a 20kHz Signal  
A
A
B
B
20dB/div  
20dB/div  
0Hz  
100kHz/div  
1MHz  
0Hz  
100kHz/div  
1MHz  
Figure 15. Driver Output Waveform and FFT Plot of  
MAX3083/MAX3084/MAX3085, and MAX3089  
Figure 16. Driver Output Waveform and FFT Plot of  
MAX3080/MAX3081/MAX3082, and MAX3089  
with SRL = Unconnected, Transmitting a 20kHz Signal  
with SRL = V  
Transmitting a 20kHz Signal  
CC,  
components with large amplitudes are evident. Figure  
15 shows the same signal displayed for a MAX3083/  
MAX3084/MAX3085, and MAX3089 with SRL = VCC),  
transmitting under the same conditions. Figure 15’s  
high-frequency harmonic components are much lower  
in amplitude, compared with Figure 14’s, and the poten-  
tial for EMI is significantly reduced. Figure 16  
shows the same signal displayed for a MAX3080/  
MAX3081/MAX3082, and MAX3089 with SRL = uncon-  
nected, transmitting under the same conditions. Figure  
16’s high-frequency harmonic components are even  
lower.  
In general, a transmitter’s rise time relates directly to the  
length of an unterminated stub, which can be driven with  
only minor waveform reflections. The following equation  
expresses this relationship conservatively:  
Length = t  
/ (10 x 1.5ns/ft)  
RISE  
where t  
is the transmitter’s rise time.  
RISE  
For example, the MAX3080’s rise time is typically  
1320ns, which results in excellent waveforms with a stub  
length up to 90 feet. A system can work well with longer  
unterminated stubs, even with severe reflections, if the  
waveform settles out before the UART samples them.  
______________________________________________________________________________________ 17  
Fail-Safe, High-Speed (10Mbps),  
Slew-Rate-Limited RS-485/RS-422 Transceivers  
MAX3080/3089 FIG-18  
MAX3080/MAX3081/MAX3083/  
MAX3084/MAX3086/MAX3087/  
MAX3089 (FULL DUPLEX)  
DI  
5V/div  
A
B
120Ω  
RO  
RE  
R
DATA IN  
V - V  
1V/div  
5V/div  
A
B
DE  
Z
DI  
120Ω  
DATA OUT  
D
Y
RO  
5µs/div  
NOTE: RE AND DE ON MAX3080/MAX3083/MAX3086/MAX3089 ONLY.  
Figure 17. Line Repeater for MAX3080/MAX3081/MAX3083/  
MAX3084/MAX3086/MAX3087, and MAX3089  
in Full-Duplex Mode  
Figure 18. MAX3080/MAX3081/MAX3082, and MAX3089  
with SRL = Unconnected, System Differential Voltage at 50kHz  
Driving 4000 feet of Cable  
Low-Power Shutdown Mode  
(Except MAX3082/MAX3085/MAX3088)  
Low-power shutdown mode is initiated by bringing both  
RE high and DE low. In shutdown, the devices typically  
draw only 1nA of supply current.  
Line Length vs. Data Rate  
The RS-485/RS-422 standard covers line lengths up to  
4000 feet. For line lengths greater than 4000 feet, use  
the repeater application shown in Figure 17.  
Figures 18, 19, and 20 show the system differential volt-  
age for the parts driving 4000 feet of 26AWG twisted-  
pair wire at 110kHz into 120loads.  
RE and DE may be driven simultaneously; the parts are  
guaranteed not to enter shutdown if RE is high and DE  
is low for less than 50ns. If the inputs are in this state  
for at least 600ns, the parts are guaranteed to enter  
shutdown.  
Typical Applications  
The MAX3082/MAX3085/MAX3088/MAX3089 trans-  
ceivers are designed for bidirectional data communica-  
tions on multipoint bus transmission lines. Figures 21  
and 22 show typical network applications circuits.  
These parts can also be used as line repeaters, with  
cable lengths longer than 4000 feet, as shown in Figure 17.  
Enable times t  
and t  
in the Switching Char-  
ZL  
ZH  
acteristics tables assume the part was not in a low-  
power shutdown state. Enable times t and  
ZH(SHDN)  
t
assume the parts were shut down. It takes  
ZL(SHDN)  
drivers and receivers longer to become enabled from  
low-power shutdown mode (t , t ) than  
To minimize reflections, the line should be terminated at  
both ends in its characteristic impedance, and stub  
lengths off the main line should be kept as short as  
possible. The slew-rate-limited MAX3082/MAX3085,  
and the two modes of the MAX3089, are more tolerant  
of imperfect termination.  
ZH(SHDN) ZH(SHDN)  
from driver/receiver-disable mode (t , t ).  
ZH ZL  
Driver Output Protection  
Two mechanisms prevent excessive output current and  
power dissipation caused by faults or by bus con-  
tention. The first, a foldback current limit on the output  
stage, provides immediate protection against short cir-  
cuits over the whole common-mode voltage range (see  
Typical Operating Characteristics). The second, a ther-  
mal shutdown circuit, forces the driver outputs into a  
high-impedance state if the die temperature becomes  
excessive.  
18 ______________________________________________________________________________________  
Fail-Safe, High-Speed (10Mbps),  
Slew-Rate-Limited RS-485/RS-422 Transceivers  
MAX3080/3089 FIG-19  
MAX3080/3089 FIG-20  
DI  
5V/div  
DI  
5V/div  
V - V  
1V/div  
5V/div  
V - V  
1V/div  
5V/div  
A
B
A
B
RO  
RO  
2µs/div  
1µs/div  
Figure 19. MAX3083/MAX3084/MAX3085, and MAX3089 with  
SRL = V System Differential Voltage at 50kHz Driving 4000  
feet of Cable  
Figure 20. MAX3086/MAX3087/MAX3088, and MAX3089 with  
SRL = GND, System Differential Voltage at 200kHz Driving  
4000 feet of Cable  
CC,  
120Ω  
120Ω  
DE  
B/Z*  
A/Y*  
B
DI  
D
D
DI  
DE  
B
A
B
A
A
RO  
RE  
RO  
RE  
R
R
R
R
D
D
MAX3082  
MAX3085  
MAX3088  
*MAX3089 (HALF-DUPLEX)  
DE  
DI  
RO  
RE  
DI  
RO RE  
DE  
Figure 21. Typical Half-Duplex RS-485 Network  
______________________________________________________________________________________ 19  
Fail-Safe, High-Speed (10Mbps),  
Slew-Rate-Limited RS-485/RS-422 Transceivers  
A
Y
120Ω  
120Ω  
120Ω  
RO  
RE  
R
DI  
D
B
Z
Z
DE  
DE  
B
RE  
RO  
120Ω  
DI  
R
D
Y
A
Y
Z
B
A
Y
Z
B
A
R
R
D
D
MAX3080  
MAX3081  
MAX3083  
MAX3084  
MAX3086  
MAX3087  
DI  
DE RE RO  
DI  
DE RE RO  
NOTE: RE AND DE ON MAX3080/MAX3083/MAX3086/MAX3089 ONLY.  
Figure 22. Typical Full-Duplex RS-485 Network  
MAX3089 (FULL-DUPLEX)  
Ordering Information (continued)  
PART  
TEMP RANGE  
0°C to +70°C  
0°C to +70°C  
-40°C to +85°C  
-40°C to +85°C  
0°C to +70°C  
0°C to +70°C  
-40°C to +85°C  
-40°C to +85°C  
0°C to +70°C  
0°C to +70°C  
-40°C to +85°C  
-40°C to +85°C  
0°C to +70°C  
0°C to +70°C  
-40°C to +85°C  
-40°C to +85°C  
PIN-PACKAGE  
14 SO  
PART  
TEMP RANGE  
0°C to +70°C  
0°C to +70°C  
-40°C to +85°C  
-40°C to +85°C  
0°C to +70°C  
0°C to +70°C  
-40°C to +85°C  
-40°C to +85°C  
0°C to +70°C  
0°C to +70°C  
-40°C to +85°C  
-40°C to +85°C  
0°C to +70°C  
0°C to +70°C  
-40°C to +85°C  
-40°C to +85°C  
0°C to +70°C  
0°C to +70°C  
-40°C to +85°C  
-40°C to +85°C  
PIN-PACKAGE  
8 SO  
MAX3086CSD  
MAX3086CPD  
MAX3086ESD  
MAX3086EPD  
MAX3087CSA  
MAX3087CPA  
MAX3087ESA  
MAX3087EPA  
MAX3088CSA  
MAX3088CPA  
MAX3088ESA  
MAX3088EPA  
MAX3089CSD  
MAX3089CPD  
MAX3089ESD  
MAX3089EPD  
MAX3081CSA  
MAX3081CPA  
MAX3081ESA  
MAX3081EPA  
MAX3082CSA  
MAX3082CPA  
MAX3082ESA  
MAX3082EPA  
MAX3083CSD  
MAX3083CPD  
MAX3083ESD  
MAX3083EPD  
MAX3084CSA  
MAX3084CPA  
MAX3084ESA  
MAX3084EPA  
MAX3085CSA  
MAX3085CPA  
MAX3085ESA  
MAX3085EPA  
14 Plastic DIP  
14 SO  
8 Plastic DIP  
8 SO  
14 Plastic DIP  
8 SO  
8 Plastic DIP  
8 SO  
8 Plastic DIP  
8 SO  
8 Plastic DIP  
8 SO  
8 Plastic DIP  
8 SO  
8 Plastic DIP  
14 SO  
8 Plastic DIP  
8 SO  
14 Plastic DIP  
14 SO  
8 Plastic DIP  
14 SO  
14 Plastic DIP  
8 SO  
14 Plastic DIP  
14 SO  
8 Plastic DIP  
8 SO  
14 Plastic DIP  
8 Plastic DIP  
8 SO  
Package Information  
8 Plastic DIP  
8 SO  
For the latest package outline information, go to  
www.maxim-ic.com/packages.  
8 Plastic DIP  
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are  
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.  
20 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600  
© 2007 Maxim Integrated Products  
is a registered trademark of Maxim Integrated Products, Inc.  

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