19-1312; Rev 0; 10/97
Software-Selectable, Half-/Full-Duplex, Slew-Rate-Limited,
12Mbps, RS-485/RS-422 Transceivers in µMAX Package
_______________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 µMAX 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
300µA of supply current. The MAX1481 has a low-power
shutdown mode that reduces supply current to only
0.1µA. 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 µMAX Package: Smallest 10-Pin Package
o
Software-Selectable Half-/Full-Duplex Operation
(MAX1485/MAX1486)
o
0.1µA 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
MAX1481/MAX1484/MAX1485/MAX1486
______________Ordering Information
PART
MAX1481CUB
MAX1481EUB
MAX1484CUB
MAX1484EUB
MAX1485CUB
MAX1485EUB
MAX1486CUB
MAX1486EUB
TEMP. RANGE
0°C to +70°C
-40°C to +85°C
0°C to +70°C
-40°C to +85°C
0°C to +70°C
-40°C to +85°C
0°C to +70°C
-40°C to +85°C
PIN-PACKAGE
10 µMAX
10 µMAX
10 µMAX
10 µMAX
10 µMAX
10 µMAX
10 µMAX
10 µMAX
________________________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
______________________________________________________________Selection Table
Part
MAX1481
MAX1484
MAX1485
MAX1486
Half/Full
Duplex
Full
Full
Selectable
Selectable
Data
Rate
(Mbps)
0.250
12
0.250
12
Slew-
Rate
Limited
Yes
No
Yes
No
Low-
Power
Shutdown
Yes
No
No
No
Driver
Enable
Yes
Yes
Yes
Yes
Receiver
Enable
Yes
Yes
No
No
Quiescent
Current
(µA)
300
300
300
300
Transceivers
on Bus
256
256
256
256
Pin-
Package
10 µMAX
10 µMAX
10 µMAX
10 µMAX
1
________________________________________________________________
Maxim Integrated Products
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 408-737-7600 ext. 3468.
Software-Selectable, Half-/Full-Duplex, Slew-Rate-Limited,
12Mbps, RS-485/RS-422 Transceivers in µMAX Package
MAX1481/MAX1484/MAX1485/MAX1486
ABSOLUTE MAXIMUM RATINGS
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 µMAX (derate 5.6mW/°C above +70°C) ............444mW
Operating Temperature Ranges
MAX148_C_ _ ......................................................0°C to +70°C
MAX148_E_ _....................................................-40°C to +85°C
Storage Temperature Range .............................-65°C to +160°C
Lead Temperature (soldering, 10sec) .............................+300°C
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.
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
= +25°C.) (Note 1)
PARAMETER
DRIVER
V
OD1
Differential Driver Output
Change in Magnitude of
Differential Output Voltage
(Note 2)
Driver Common-Mode Output
Voltage
Change in Magnitude of
Common-Mode Voltage (Note 2)
Input High Voltage
Input Low Voltage
Input Current
Input Current (Y and Z for Half
Duplex, A and B for Full Duplex)
Output Leakage (Y and Z)
(MAX1481/MAX1484 Only)
Output Leakage (Y and Z)
(MAX1485/MAX1486 Only)
Driver Output Short-Circuit
Current (Note 3)
V
OD2
No load, Figure 5
R = 50Ω (RS-422), Figure 5
R = 27Ω (RS-485), Figure 5
R = 50Ω or 27Ω, Figure 5
2.0
1.5
5
0.2
V
5
V
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
∆V
OD
V
OC
∆V
OC
V
IH1
V
IL1
I
IN1
I
IN2
I
O
I
O
I
OSD
R = 50Ω or 27Ω, Figure 5
R = 50Ω or 27Ω, Figure 5
DE, DI,
RE,
H/F
DE, DI,
RE,
H/F
DE, DI,
RE,
H/F
DE = GND,
V
CC
= GND or 5.25V
DE = GND
DE = GND
-7V
≤
V
OUT
≤
12V
V
IN
= 12V
V
IN
= -7V
V
IN
= 12V
V
IN
= -7V
V
IN
= 12V
V
IN
= -7V
35
2.0
3
0.2
V
V
V
0.8
±2
0.125
-0.1
10
-10
125
-100
250
V
µA
mA
µA
µA
mA
2
_______________________________________________________________________________________
Software-Selectable, Half-/Full-Duplex, Slew-Rate-Limited,
12Mbps, RS-485/RS-422 Transceivers in µMAX Package
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
= +25ºC.) (Note 1)
PARAMETER
RECEIVER
Receiver Differential Threshold
Voltage
Receiver Input Hysteresis
Receiver Output High Voltage
Receiver Output Low Voltage
Three-State Output Current at
Receiver
Receiver Input Resistance
Receiver Output Short-Circuit
Current
SUPPLY CURRENT
No-Load Supply Current
Supply Current in Shutdown
Mode (MAX1481 Only)
I
CC
I
SHDN
RE
= GND, DE = V
CC
DE = GND,
RE
= V
CC
300
0.1
600
10
µA
µA
V
TH
∆V
TH
V
OH
V
OL
I
OZR
R
IN
I
OSR
I
O
= -4mA, V
ID
= 200mV
I
O
= 4mA, V
ID
= -200mV
0.4V
≤
V
O
≤
2.4V
-7V
≤
V
CM
≤
12V
0V
≤
V
RO
≤
V
CC
96
±95
3.5
0.4
±1
-7V
≤
V
CM
≤
12V
-200
70
200
mV
mV
V
V
µA
kΩ
mA
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX1481/MAX1484/MAX1485/MAX1486
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
= +25°C.)
PARAMETER
Driver Input to Output
Driver Input to Output
Driver Output Skew
|
t
DPLH
- t
DPHL
|
Driver Rise or Fall Time
Maximum Data Rate
Driver Enable to Output Low
Driver Enable to Output High
Driver Disable Time from Low
Driver Disable Time from High
Receiver Input to Output
SYMBOL
t
DPLH
t
DPHL
t
DSKEW
t
DR
, t
DF
f
MAX
t
DZL
t
DZH
t
DLZ
t
DHZ
t
RPLH
,
t
RPHL
t
RSKD
t
RZL
t
RZH
t
RLZ
t
RHZ
C
L
= 100pF, S1 closed, Figures 8 and 10
C
L
= 100pF, S2 closed, Figures 8 and 10
C
L
= 15pF, S1 closed, Figures 8 and 10
C
L
= 15pF, S2 closed, Figures 8 and 10
Figures 11 and 13
Figures 11 and 13
C
L
= 100pF, S1 closed, Figures 6 and 12
C
L
= 100pF, S2 closed, Figures 6 and 12
C
L
= 100pF, S1 closed, Figures 6 and 12
C
L
= 100pF, S2 closed, Figures 6 and 12
CONDITIONS
R
DIFF
= 54Ω, C
L1
= C
L2
= 100pF,
Figures 7 and 9
R
DIFF
= 54Ω, C
L1
= C
L2
= 100pF,
Figures 7 and 9
R
DIFF
= 54Ω, C
L1
= C
L2
= 100pF,
Figures 7 and 9
5
12
40
40
40
40
90
5
20
20
20
20
50
50
50
50
70
70
70
70
150
MIN
TYP
30
30
5
15
MAX
60
60
10
35
UNITS
ns
ns
ns
Mbps
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
|
t
RPLH
- t
RPHL
|
Differential
Receiver Skew
Receiver Enable to Output Low
Receiver Enable to Output High
Receiver Disable Time from Low
Receiver Disable Time from High
_______________________________________________________________________________________
3
Software-Selectable, Half-/Full-Duplex, Slew-Rate-Limited,
12Mbps, RS-485/RS-422 Transceivers in µMAX Package
MAX1481/MAX1484/MAX1485/MAX1486
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
= +25°C.)
PARAMETER
Driver Input to Output
Driver Output Skew
|
t
DPLH
- t
DPHL
|
Driver Rise or Fall Time
Maximum Data Rate
Driver Enable to Output Low
Driver Enable to Output High
Driver Disable Time from Low
Driver Disable Time from High
Receiver Input to Output
SYMBOL
t
DPLH
t
DPHL
t
DSKEW
t
DR
, t
DF
f
MAX
t
DZL
t
DZH
t
DLZ
t
DHZ
t
RPLH
,
t
RPHL
t
RSKD
t
RZL
t
RZH
t
RLZ
t
RHZ
t
SHDN
t
DZH(SHDN)
t
DZL(SHDN)
t
RZH(SHDN)
t
RZL(SHDN)
C
L
= 100pF, S1 closed, Figures 8 and 10
C
L
= 100pF, S2 closed, Figures 8 and 10
C
L
= 15pF, S1 closed, Figures 8 and 10
C
L
= 15pF, S2 closed, Figures 8 and 10
Figures 11 and 13
Figures 11 and 13
C
L
= 100pF, S1 closed, Figures 6 and 12
C
L
= 100pF, S2 closed, Figures 6 and 12
C
L
= 100pF, S1 closed, Figures 6 and 12
C
L
= 100pF, S2 closed, Figures 6 and 12
MAX1481 only (Note 4)
MAX1481 only, C
L
= 15pF, S2 closed,
Figures 8 and 10
MAX1481 only, C
L
= 15pF, S1 closed,
Figures 8 and 10
MAX1481 only, C
L
= 100pF, S2 closed,
Figures 6 and 12
MAX1481 only, C
L
= 100pF, S1 closed,
Figures 6 and 12
50
90
15
20
20
20
20
200
50
50
50
50
600
3000
3000
500
1000
CONDITIONS
R
DIFF
= 54Ω, C
L1
= C
L2
= 100pF,
Figures 7 and 9
R
DIFF
= 54Ω, C
L1
= C
L2
= 100pF,
Figures 7 and 9
R
DIFF
= 54Ω, C
L1
= C
L2
= 100pF,
Figures 7 and 9
250
250
3000
3000
200
200
150
MIN
TYP
600
600
10
MAX
1000
1000
200
1000
UNITS
ns
ns
ns
kbps
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
|
t
RPLH
- t
RPHL
|
Differential
Receiver Skew
Receiver Enable to Output Low
Receiver Enable to Output High
Receiver Disable Time from Low
Receiver Disable Time from High
Time to Shutdown
Driver Enable from Shutdown to
Output High
Driver Enable from Shutdown to
Output Low
Receiver Enable from Shutdown
to Output High
Receiver Enable from Shutdown
to Output Low
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.
4
_______________________________________________________________________________________
Software-Selectable, Half-/Full-Duplex, Slew-Rate-Limited,
12Mbps, RS-485/RS-422 Transceivers in µMAX Package
__________________________________________Typical Operating Characteristics
(V
CC
= +5V, T
A
= +25°C, unless otherwise noted.)
MAX1481/MAX1484/MAX1485/MAX1486
NO-LOAD SUPPLY CURRENT
vs. TEMPERATURE
MAX1481/4/5/6-01
OUTPUT CURRENT vs.
RECEIVER OUTPUT LOW VOLTAGE
MAX1481/4/5/6-02
OUTPUT CURRENT vs.
RECEIVER OUTPUT HIGH VOLTAGE
MAX1481/4/5/6-03
360
340
SUPPLY CURRENT (µA)
320
300
280
MAX1484/MAX1486
260
240
220
-60
-40
-20
0
20
40
60
80
MAX1481/MAX1485
60
50
OUTPUT CURRENT (mA)
40
30
20
10
0
30
25
OUTPUT CURRENT (mA)
20
15
10
5
0
100
0
1
2
3
4
5
0
1
2
3
4
5
TEMPERATURE (°C)
OUTPUT LOW VOLTAGE (V)
OUTPUT LOW VOLTAGE (V)
SHUTDOWN CURRENT
vs. TEMPERATURE
MAX1481/4/5/6-04
RECEIVER OUTPUT LOW VOLTAGE
vs. TEMPERATURE
I
RO
= 8mA
0.45
OUTPUT LOW VOLTAGE (V)
0.40
0.35
0.30
0.25
0.20
0.15
MAX1481/4/5/6-05
RECEIVER OUTPUT HIGH VOLTAGE
vs. TEMPERATURE
I
RO
= 8mA
4.4
OUTPUT VOLTAGE (V)
4.3
4.2
4.1
4.0
3.9
3.8
MAX1481/4/5/6-06
114
0.50
4.5
SHUTDOWN CURRENT (nA)
110
106
102
98
94
-60
-40
-20
0
20
40
60
80
100
TEMPERATURE (°C)
0.10
-60
-40
-20
0
20
40
60
80
100
TEMPERATURE (°C)
-60
-40
-20
0
20
40
60
80
100
TEMPERATURE (°C)
MAX1481/MAX1485 RECEIVER
PROPAGATION DELAY vs. TEMPERATURE
MAX1481/4/5/6-07
MAX1484/MAX1486 RECEIVER
PROPAGATION DELAY vs. TEMPERATURE
MAX1481/4/5/6-08
MAX1481/MAX1485 DRIVER
PROPAGATION DELAY vs. TEMPERATURE
R
DIFF
= 54Ω
C
L1 =
C
L2 = 100pF
MAX1481/4/5/6-09
105
C
LOAD
= 15pF
100
PROPAGATION DELAY (ns)
95
90
85
80
75
-60
-40
-20
0
20
40
60
80
94
93
PROPAGATION DELAY (ns)
92
91
90
89
88
87
86
C
LOAD
= 15pF
680
660
PROPAGATION DELAY (ns)
640
620
600
580
560
540
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)
_______________________________________________________________________________________
5
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