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_______________General Description
The MAX1481/MAX1484/MAX1485/MAX1486 provide
software-selectable, half-/full-duplex, low-power, slew-
rate-limited, and high-speed (12Mbps) RS-485/RS-422
operation in a 10-pin MAX package--the smallest
10-pin package available.
The software-selectable, half-/full-duplex MAX1485/
MAX1486 make obsolete the normally larger and more
expensive solutions required for selectable half-/full-
duplex RS-485/RS-422 operation: 1) a 14-pin, full-
duplex transceiver configured via jumpers between
receiver and transmitter lines, or 2) two 8-pin, half-
duplex transceivers, which require an additional invert-
er logic gate for software selectability.
The MAX1481/MAX1484 are functionally equivalent to
the industry-standard MAX491 and 75180, and are
designed for space-constrained, full-duplex RS-422
applications.
All parts contain one driver and one receiver and fea-
ture a 1/8-unit-load receiver input impedance, allowing
up to 256 transceivers on the bus. The MAX1481/
MAX1485 feature reduced-slew-rate drivers that mini-
mize EMI and reduce reflections caused by improperly
terminated cables, allowing error-free data transmission
up to 250kbps. The MAX1484/MAX1486 driver slew
rates are not limited, allowing them to transmit up to
12Mbps.
The MAX1481/MAX1484/MAX1485/MAX1486 draw only
300A of supply current. The MAX1481 has a low-power
shutdown mode that reduces supply current to only
0.1A. All devices operate from a single 5V supply.
Drivers are output short-circuit current limited and are
protected against excessive power dissipation by
thermal-shutdown circuitry that places the driver outputs
into a high-impedance state. The receiver input has a fail-
safe feature that guarantees a logic-high output if the
input is open circuit.
____________________________Features
o
10-Pin MAX Package: Smallest 10-Pin Package
o
Software-Selectable Half-/Full-Duplex Operation
(MAX1485/MAX1486)
o
0.1A Low-Current Shutdown Mode (MAX1481)
o
Slew-Rate Limiting Allows Error-Free Data
Transmission (MAX1481/MAX1485)
o
12Mbps High-Speed Operation
(MAX1484/MAX1486)
o
Allow up to 256 Transceivers on the Bus
________________________Applications
Low-Power RS-422/RS-485 Communications
Level Translators
Hand-Held Equipment
Battery-Powered Equipment
Transceiver for EMI-Sensitive Applications
Industrial-Control Local Area Networks
MAX1481/MAX1484/MAX1485/MAX1486
Software-Selectable, Half-/Full-Duplex, Slew-Rate-Limited,
12Mbps, RS-485/RS-422 Transceivers in MAX Package
________________________________________________________________
Maxim Integrated Products
1
19-1312; Rev 0; 10/97
PART
MAX1481
CUB
MAX1481EUB
MAX1484
CUB
0C to +70C
-40C to +85C
0C to +70C
TEMP. RANGE
PIN-PACKAGE
10 MAX
10 MAX
10 MAX
______________Ordering Information
______________________________________________________________Selection Table
Half/Full
Duplex
Data
Rate
(Mbps)
MAX1481
Full
0.250
MAX1484
Full
12
Part
MAX1485
Selectable
0.250
MAX1486
Selectable
12
Slew-
Rate
Limited
Yes
No
Yes
No
Low-
Power
Shutdown
Driver
Enable
Yes
Yes
No
Yes
No
Yes
No
Yes
Quiescent
Current
(A)
300
300
300
300
Transceivers
on Bus
256
256
256
256
Pin-
Package
10 MAX
10 MAX
10 MAX
10 MAX
MAX1484EUB
-40C to +85C
10 MAX
Receiver
Enable
Yes
Yes
No
No
MAX1485
CUB
MAX1485EUB
MAX1486
CUB
0C to +70C
-40C to +85C
0C to +70C
10 MAX
10 MAX
10 MAX
MAX1486EUB
-40C to +85C
10 MAX
MAX1481/MAX1484/MAX1485/MAX1486
Software-Selectable, Half-/Full-Duplex, Slew-Rate-Limited,
12Mbps, RS-485/RS-422 Transceivers in MAX Package
2
_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V
CC
= +5V 5%, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
CC
= +5V and T
A
= +25C.) (Note 1)
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.
Supply Voltage (V
CC
) ............................................................+7V
Control Input Voltage (RE, DE, H/F) ...........-0.3V to (V
CC
+ 0.3V)
Driver Input Voltage (DI).............................-0.3V to (V
CC
+ 0.3V)
Driver Output Voltage (A, B, Y, Z) ..........................-8V to +12.5V
Receiver Input Voltage, Half Duplex (Y, Z) ............-8V to +12.5V
Receiver Input Voltage, Full Duplex (A, B).............-8V to +12.5V
Receiver Output Voltage (RO)....................-0.3V to (V
CC
+ 0.3V)
Continuous Power Dissipation
10-Pin MAX (derate 5.6mW/C above +70C) ............444mW
Operating Temperature Ranges
MAX148_C_ _ ......................................................0C to +70C
MAX148_E_ _....................................................-40C to +85C
Storage Temperature Range .............................-65C to +160C
Lead Temperature (soldering, 10sec) .............................+300C
R = 50
(RS-422), Figure 5
No load, Figure 5
-7V
V
OUT
12V
DE = GND
DE, DI, RE, H/F
DE, DI, RE, H/F
R = 50
or 27
, Figure 5
R = 50
or 27
, Figure 5
R = 50
or 27
, Figure 5
DE = GND,
V
CC
= GND or 5.25V
DE, DI, RE, H/F
CONDITIONS
mA
35
250
I
OSD
Driver Output Short-Circuit
Current (Note 3)
A
-10
I
O
10
Output Leakage (Y and Z)
(MAX1481/MAX1484 Only)
mA
0.125
I
IN2
Input Current (Y and Z for Half
Duplex, A and B for Full Duplex)
A
2
I
IN1
Input Current
2.0
V
OD1
Differential Driver Output
5
V
0.8
V
IL1
Input Low Voltage
V
2.0
V
IH1
Input High Voltage
V
0.2
V
OC
Change in Magnitude of
Common-Mode Voltage (Note 2)
V
0.2
V
OD
Change in Magnitude of
Differential Output Voltage
(Note 2)
V
3
V
OC
Driver Common-Mode Output
Voltage
UNITS
MIN
TYP
MAX
SYMBOL
PARAMETER
DE = GND
-100
I
O
A
125
Output Leakage (Y and Z)
(MAX1485/MAX1486 Only)
V
OD2
R = 27
(RS-485), Figure 5
V
1.5
5
V
IN
= 12V
V
IN
= -7V
V
IN
= 12V
V
IN
= -7V
V
IN
= 12V
V
IN
= -7V
-0.1
DRIVER
Driver Input to Output
MAX1481/MAX1484/MAX1485/MAX1486
Software-Selectable, Half-/Full-Duplex, Slew-Rate-Limited,
12Mbps, RS-485/RS-422 Transceivers in MAX Package
_______________________________________________________________________________________
3
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= +5V 5%, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
CC
= +5V and T
A
= +25C.) (Note 1)
SWITCHING CHARACTERISTICS (MAX1484/MAX1486)
(V
CC
= 5V 5%, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
CC
= +5V and T
A
= +25C.)
-7V
V
CM
12V
-7V
V
CM
12V
I
O
= 4mA, V
ID
= -200mV
I
O
= -4mA, V
ID
= 200mV
0.4V
V
O
2.4V
CONDITIONS
k
96
R
IN
Receiver Input Resistance
A
1
I
OZR
Three-State Output Current at
Receiver
mV
70
V
TH
Receiver Input Hysteresis
mV
-200
200
V
TH
Receiver Differential Threshold
Voltage
V
0.4
V
OL
Receiver Output Low Voltage
V
3.5
V
OH
Receiver Output High Voltage
UNITS
MIN
TYP
MAX
SYMBOL
PARAMETER
0V
V
RO
V
CC
RE = GND, DE = V
CC
mA
95
I
OSR
Receiver Output Short-Circuit
Current
A
300
600
I
CC
No-Load Supply Current
DE = GND, RE = V
CC
A
0.1
10
I
SHDN
Supply Current in Shutdown
Mode (MAX1481 Only)
R
DIFF
= 54
, C
L1
= C
L2
= 100pF,
Figures 7 and 9
R
DIFF
= 54
, C
L1
= C
L2
= 100pF,
Figures 7 and 9
CONDITIONS
ns
5
10
t
DSKEW
Driver Output Skew
|
t
DPLH
- t
DPHL
|
30
60
t
DPLH
ns
30
60
t
DPHL
Driver Input to Output
UNITS
MIN
TYP
MAX
SYMBOL
PARAMETER
C
L
= 15pF, S1 closed, Figures 8 and 10
C
L
= 100pF, S2 closed, Figures 8 and 10
C
L
= 100pF, S1 closed, Figures 8 and 10
ns
40
70
t
DLZ
Driver Disable Time from Low
ns
40
70
t
DZH
Driver Enable to Output High
ns
40
70
t
DZL
Driver Enable to Output Low
Mbps
12
f
MAX
Maximum Data Rate
C
L
= 15pF, S2 closed, Figures 8 and 10
C
L
= 100pF, S2 closed, Figures 6 and 12
C
L
= 100pF, S1 closed, Figures 6 and 12
ns
20
50
t
RZH
Receiver Enable to Output High
ns
20
50
t
RZL
Receiver Enable to Output Low
ns
40
70
t
DHZ
Driver Disable Time from High
C
L
= 100pF, S2 closed, Figures 6 and 12
C
L
= 100pF, S1 closed, Figures 6 and 12
ns
20
50
t
RHZ
Receiver Disable Time from High
ns
20
50
t
RLZ
Receiver Disable Time from Low
Figures 11 and 13
ns
5
t
RSKD
|
t
RPLH
- t
RPHL
|
Differential
Receiver Skew
Figures 11 and 13
ns
90
150
t
RPLH
,
t
RPHL
Receiver Input to Output
R
DIFF
= 54
, C
L1
= C
L2
= 100pF,
Figures 7 and 9
ns
5
15
35
t
DR
, t
DF
Driver Rise or Fall Time
RECEIVER
SUPPLY CURRENT
MAX1481/MAX1484/MAX1485/MAX1486
Software-Selectable, Half-/Full-Duplex, Slew-Rate-Limited,
12Mbps, RS-485/RS-422 Transceivers in MAX Package
4
_______________________________________________________________________________________
SWITCHING CHARACTERISTICS (MAX1481/MAX1485) (continued)
(V
CC
= 5V 5%, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
CC
= +5V and T
A
= +25C.)
Note 1:
All currents into the device are positive; all currents out of the device are negative. All voltages are referenced to device
ground unless otherwise noted.
Note 2:
V
OD
and
V
OC
are the changes in V
OD
and V
OC
, respectively, when the DI input changes state.
Note 3:
Maximum current level applies to peak current just prior to foldback-current limiting; minimum current level applies during
current limiting.
Note 4:
Shutdown is enabled by bringing RE high and DE low. If the enable inputs are in this state for less than 50ns, the MAX1481
is guaranteed not to enter shutdown. If the enable inputs are in this state for at least 600ns, the MAX1481 is guaranteed to
have entered shutdown.
C
L
= 15pF, S1 closed, Figures 8 and 10
C
L
= 100pF, S2 closed, Figures 8 and 10
R
DIFF
= 54
, C
L1
= C
L2
= 100pF,
Figures 7 and 9
C
L
= 100pF, S1 closed, Figures 8 and 10
R
DIFF
= 54
, C
L1
= C
L2
= 100pF,
Figures 7 and 9
ns
200
t
DLZ
C
L
= 100pF, S2 closed, Figures 6 and 12
Driver Disable Time from Low
C
L
= 100pF, S1 closed, Figures 6 and 12
R
DIFF
= 54
, C
L1
= C
L2
= 100pF,
Figures 7 and 9
ns
3000
t
DZH
Driver Enable to Output High
ns
3000
CONDITIONS
t
DZL
Driver Enable to Output Low
kbps
250
f
MAX
Maximum Data Rate
C
L
= 15pF, S2 closed, Figures 8 and 10
C
L
= 100pF, S2 closed, Figures 6 and 12
C
L
= 100pF, S1 closed, Figures 6 and 12
ns
10
200
t
DSKEW
Driver Output Skew
|
t
DPLH
- t
DPHL
|
Figures 11 and 13
ns
ns
20
50
t
RZH
Receiver Enable to Output High
ns
20
50
t
RZL
Receiver Enable to Output Low
ns
200
t
DHZ
Driver Disable Time from High
ns
ns
20
50
t
RHZ
Receiver Disable Time from High
90
150
t
RPLH
,
t
RPHL
Receiver Input to Output
250
1000
t
DR
, t
DF
Driver Rise or Fall Time
ns
20
50
t
RLZ
Receiver Disable Time from Low
Figures 11 and 13
ns
15
t
RSKD
|
t
RPLH
- t
RPHL
|
Differential
Receiver Skew
600
1000
t
DPLH
ns
600
1000
t
DPHL
Driver Input to Output
UNITS
MIN
TYP
MAX
SYMBOL
PARAMETER
MAX1481 only (Note 4)
ns
50
200
600
t
SHDN
Time to Shutdown
MAX1481 only, C
L
= 15pF, S2 closed,
Figures 8 and 10
ns
3000
t
DZH(SHDN)
Driver Enable from Shutdown to
Output High
MAX1481 only, C
L
= 15pF, S1 closed,
Figures 8 and 10
ns
3000
t
DZL(SHDN)
Driver Enable from Shutdown to
Output Low
MAX1481 only, C
L
= 100pF, S1 closed,
Figures 6 and 12
ns
1000
t
RZL(SHDN)
Receiver Enable from Shutdown
to Output Low
MAX1481 only, C
L
= 100pF, S2 closed,
Figures 6 and 12
ns
500
t
RZH(SHDN)
Receiver Enable from Shutdown
to Output High
MAX1481/MAX1484/MAX1485/MAX1486
Software-Selectable, Half-/Full-Duplex, Slew-Rate-Limited,
12Mbps, RS-485/RS-422 Transceivers in MAX Package
_______________________________________________________________________________________
5
220
260
240
300
280
340
320
360
-60
-20
0
-40
20
40
60
80
100
NO-LOAD SUPPLY CURRENT
vs. TEMPERATURE
MAX1481/4/5/6-01
TEMPERATURE (C)
SUPPLY CURRENT (
A)
MAX1481/MAX1485
MAX1484/MAX1486
0
10
30
20
50
40
60
0
1
2
3
4
5
OUTPUT CURRENT vs.
RECEIVER OUTPUT LOW VOLTAGE
MAX1481/4/5/6-02
OUTPUT LOW VOLTAGE (V)
OUTPUT CURRENT (mA)
0
5
15
10
25
20
30
0
1
2
3
4
5
OUTPUT CURRENT vs.
RECEIVER OUTPUT HIGH VOLTAGE
MAX1481/4/5/6-03
OUTPUT LOW VOLTAGE (V)
OUTPUT CURRENT (mA)
94
98
106
102
110
114
-60
-20
0
-40
20
40
60
80
100
SHUTDOWN CURRENT
vs. TEMPERATURE
MAX1481/4/5/6-04
TEMPERATURE (C)
SHUTDOWN CURRENT (nA)
75
80
90
85
100
95
105
-60
-20
0
-40
20
40
60
80
100
MAX1481/MAX1485 RECEIVER
PROPAGATION DELAY vs. TEMPERATURE
MAX1481/4/5/6-07
TEMPERATURE (C)
PROPAGATION DELAY (ns)
C
LOAD
= 15pF
0.10
0.20
0.15
0.35
0.30
0.25
0.45
0.40
0.50
-60
-20
0
-40
20
40
60
80
100
RECEIVER OUTPUT LOW VOLTAGE
vs. TEMPERATURE
MAX1481/4/5/6-05
TEMPERATURE (C)
OUTPUT LOW VOLTAGE (V)
I
RO
= 8mA
3.8
4.0
3.9
4.2
4.1
4.4
4.3
4.5
-60
-20
0
-40
20
40
60
80
100
RECEIVER OUTPUT HIGH VOLTAGE
vs. TEMPERATURE
MAX1481/4/5/6-06
TEMPERATURE (C)
OUTPUT VOLTAGE (V)
I
RO
= 8mA
86
87
90
89
88
93
92
91
94
-60
-20
0
-40
20
40
60
80
100
MAX1484/MAX1486 RECEIVER
PROPAGATION DELAY vs. TEMPERATURE
MAX1481/4/5/6-08
TEMPERATURE (C)
PROPAGATION DELAY (ns)
C
LOAD
= 15pF
540
580
560
620
600
660
640
680
-60
-20
0
-40
20
40
60
80
100
MAX1481/MAX1485 DRIVER
PROPAGATION DELAY vs. TEMPERATURE
MAX1481/4/5/6-09
TEMPERATURE (C)
PROPAGATION DELAY (ns)
R
DIFF
= 54
C
L1 =
C
L2 = 100pF
__________________________________________Typical Operating Characteristics
(V
CC
= +5V, T
A
= +25C, unless otherwise noted.)
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