AVAILABLE
Functional Diagrams
Pin Configurations appear at end of data sheet.
Functional Diagrams continued at end of data sheet.
UCSP is a trademark of Maxim Integrated Products, Inc.
For pricing, delivery, and ordering information, please contact Maxim Direct
at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.
_______________General Description
The MAX3483, MAX3485, MAX3486, MAX3488,
MAX3490, and MAX3491 are 3.3V, low-power trans-
ceivers for RS-485 and RS-422 communication. Each
part contains one driver and one receiver. The
MAX3483 and MAX3488 feature slew-rate-limited dri-
vers that minimize EMI and reduce reflections caused
by improperly terminated cables, allowing error-free
data transmission at data rates up to 250kbps. The par-
tially slew-rate-limited MAX3486 transmits up to
2.5Mbps. The MAX3485, MAX3490, and MAX3491
transmit at up to 10Mbps.
Drivers are short-circuit current limited and are protect-
ed 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 both
inputs are open circuit.
The MAX3488, MAX3490, and MAX3491 feature full-
duplex communication, while the MAX3483, MAX3485,
and MAX3486 are designed for half-duplex communi-
cation.
________________________Applications
Low-Power RS-485/RS-422 Transceivers
Telecommunications
Transceivers for EMI-Sensitive Applications
Industrial-Control Local Area Networks
____________________________Features
♦Operate from a Single 3.3V Supply—
No Charge Pump!
♦Interoperable with +5V Logic
♦8ns Max Skew (MAX3485/MAX3490/MAX3491)
♦Slew-Rate Limited for Errorless Data Transmission
(MAX3483/MAX3488)
♦2nA Low-Current Shutdown Mode
(MAX3483/MAX3485/MAX3486/MAX3491)
♦-7V to +12V Common-Mode Input Voltage Range
♦Allows up to 32 Transceivers on the Bus
♦Full-Duplex and Half-Duplex Versions Available
♦Industry Standard 75176 Pinout
(MAX3483/MAX3485/MAX3486)
♦Current-Limiting and Thermal Shutdown for
Driver Overload Protection
______________Ordering Information
Ordering Information continued at end of data sheet.
* Contact factory for for dice specifications.
3.3V-Powered, 10Mbps and Slew-Rate-Limited
True RS-485/RS-422 Transceivers
19-0333; Rev 0; 12/94
PART
MAX3483CPA
MAX3483CSA
MAX3483C/D 0°C to +70°C
0°C to +70°C
0°C to +70°C
TEMP. RANGE PIN-PACKAGE
8 Plastic DIP
8 SO
Dice*
PART
NUMBER
GUARANTEED
DATA RATE
(Mbps)
SUPPLY
VOLTAGE
(V)
HALF/FULL
DUPLEX
SLEW-RATE
LIMITED
DRIVER/
RECEIVER
ENABLE
SHUTDOWN
CURRENT
(nA)
PIN
COUNT
MAX3483 0.25 Half Yes Yes 2 8
MAX3485 10 Half No Yes 2 8
MAX3486 2.5 Half Yes Yes 2 8
MAX3488 0.25 Full Yes No — 8
MAX3490 10 Full No No — 8
MAX3491 10
3.0 to 3.6
Full No Yes 2 14
______________________________________________________________Selection Table
MAX3483EPA
MAX3483ESA -40°C to +85°C
-40°C to +85°C 8 Plastic DIP
8 SO
MAX3485CPA
MAX3485CSA
MAX3485C/D 0°C to +70°C
0°C to +70°C
0°C to +70°C 8 Plastic DIP
8 SO
Dice*
MAX3485EPA
MAX3485ESA -40°C to +85°C
-40°C to +85°C 8 Plastic DIP
8 SO
MAX3483/MAX3485/MAX3486/
MAX3488/MAX3490/MAX3491
3.3V-Powered, 10Mbps and Slew-Rate-Limited
True RS-485/RS-422 Transceivers
ABSOLUTE MAXIMUM RATINGS
DC ELECTRICAL CHARACTERISTICS
(VCC = 3.3V ±0.3V, TA= TMIN to TMAX, unless otherwise noted. Typical values are at TA= +25°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.
Supply Voltage (VCC)...............................................................7V
Control Input Voltage (RE, DE) ...................................-0.3V to 7V
Driver Input Voltage (DI) .............................................-0.3V to 7V
Driver Output Voltage (A, B, Y, Z)..........................-7.5V to 12.5V
Receiver Input Voltage (A, B) ................................-7.5V to 12.5V
Receiver Output Voltage (RO)....................-0.3V to (VCC + 0.3V)
Continuous Power Dissipation (TA= +70°C)
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 10mW/°C above +70°C) ......800mW
14-Pin SO (derate 8.33mW/°C above +70°C)................667mW
Operating Temperature Ranges
MAX34_ _C_ _.......................................................0°C to +70°C
MAX34_ _E_ _....................................................-40°C to +85°C
Storage Temperature Range .............................-65°C to +160°C
Lead Temperature (soldering, 10sec) .............................+300°C
DE = 0V,
VCC = 0V or 3.6V
DE = 0V, RE = VCC,
VCC = 0V or 3.6V, MAX3491
DE = 0V, RE = 0V,
VCC = 0V or 3.6V, MAX3491
kΩ12RIN
Receiver Input Resistance
µA±1IOZR
Three-State (High Impedance)
Output Current at Receiver
V0.4VOL
Receiver Output Low Voltage
VVCC - 0.4VOH
Receiver Output High Voltage
mV50∆VTH
Receiver Input Hysteresis
V-0.2 0.2VTH
Receiver Differential
Threshold Voltage
µA
-1
IO
Output Leakage (Y, Z)
in Shutdown Mode
1
µA
-20
IO
Output Leakage (Y, Z)
V0.2∆VOD
Change in Magnitude of Driver
Differential Output Voltage for
Complementary Output States
(Note 1)
V
1.5
VOD
2.0
Differential Driver Output
20
mA
-0.8
IIN2
Input Current (A, B) 1.0
µA±2IIN1
Logic Input Current
V3VOC
Driver Common-Mode Output
Voltage
V0.2∆VOC
Change in Magnitude of
Common-Mode Output Voltage
(Note 1)
V2.0VIH
Input High Voltage
V0.8VIL
Input Low Voltage
UNITSMIN TYP MAXSYMBOLPARAMETER
RL= 54Ωor 100Ω, Figure 4
-7V ≤VCM ≤12V
RL= 54Ω(RS-485), Figure 4
VCC = 3.6V, 0V ≤VOUT ≤VCC
RL= 100Ω(RS-422), Figure 4
IOUT = 2.5mA, VID = 200mV, Figure 6
IOUT = -1.5mA, VID = 200mV, Figure 6
VCM = 0V
VOUT = 12V
VIN = -7V
-7V ≤VCM ≤12V
VOUT = -7V
VIN = 12V
DE, DI, RE
RL= 54Ωor 100Ω, Figure 4
RL= 54Ωor 100Ω, Figure 4
DE, DI, RE
VOUT = 12V
DE, DI, RE
VOUT = -7V
CONDITIONS
RL= 60Ω(RS-485), VCC = 3.3V, Figure 5
1.5
MAX3483/MAX3485/MAX3486/
MAX3488/MAX3490/MAX3491
2
Maxim Integrated
3.3V-Powered, 10Mbps and Slew-Rate-Limited
True RS-485/RS-422 Transceivers
No load,
DI = 0V or VCC
µA0.002 1ISHDN
Supply Current in Shutdown Mode
0.95 1.9
mA
1.1 2.2
ICC
Supply Current
mA
-250
IOSD 250
Driver Short-Circuit Output
Current
mA±8 ±60IOSR
Receiver Short-Circuit Output
Current
UNITSMIN TYP MAXSYMBOLPARAMETER
DE = 0V, RE = VCC, DI = VCC or 0V
DE = 0V,
RE = 0V
DE = VCC,
RE = 0V or VCC
VOUT = -7V
VOUT = 12V
0V ≤VRO ≤VCC
CONDITIONS
DC ELECTRICAL CHARACTERISTICS (continued)
(VCC = 3.3V ±0.3V, TA= TMIN to TMAX, unless otherwise noted. Typical values are at TA= +25°C)
ns72235t
PLH
Driver Propagation Delay, Low-to-High Level
ns3825t
TD
ns12235t
DD
Driver Differential Output Delay
Driver Differential Output Transition Time
ns650 900tPSH
Driver Output Enable Time from Shutdown to High Level
ns650 900tPSL
Driver Output Enable Time from Shutdown to Low Level
ns40 80tPHZ
Driver Output Disable Time from High Level
ns72235t
PHL
Driver Propagation Delay, High-to-Low Level
ns8tPDS
|tPLH - tPHL|Driver Propagation Delay Skew (Note 2)
ns45 90tPZL
Driver Output Enable Time to Low Level
ns45 90tPZH
Driver Output Enable Time to High Level
UNITSMIN TYP MAXSYMBOLPARAMETER
RL= 27Ω, Figure 8
RL= 60Ω, Figure 7
RL= 60Ω, Figure 7
RL= 110Ω, Figure 9
RL= 110Ω, Figure 10
RL= 110Ω, Figure 9
RL= 27Ω, Figure 8
RL= 27Ω, Figure 8
RL= 110Ω, Figure 10
RL= 110Ω, Figure 9
CONDITIONS
DRIVER SWITCHING CHARACTERISTICS—MAX3485, MAX3490, and MAX3491
(VCC = 3.3V, TA= +25°C)
ns40 80tPLZ
Driver Output Disable Time from Low Level RL= 110Ω, Figure 10
DRIVER SWITCHING CHARACTERISTICS—MAX3486
(VCC = 3.3V, TA= +25°C)
ns45 80tPLZ
Driver Output Disable Time from Low Level RL= 110Ω, Figure 10
ns20 48 70tPLH
Driver Propagation Delay, Low-to-High Level
ns15 35 60tTD
ns24 48 70tDD
Driver Differential Output Delay
Driver Differential Output Transition Time
ns700 1000tPSH
Driver Output Enable Time from Shutdown to High Level
ns700 1000tPSL
Driver Output Enable Time from Shutdown to Low Level
ns45 80tPHZ
Driver Output Disable Time from High Level
ns20 48 70tPHL
Driver Propagation Delay, High-to-Low Level
ns11tPDS
|tPLH - tPHL|Driver Propagation Delay Skew (Note 2)
ns55 100tPZL
Driver Output Enable Time to Low Level
ns55 100tPZH
Driver Output Enable Time to High Level
UNITSMIN TYP MAXSYMBOLPARAMETER
RL= 27Ω, Figure 8
RL= 60Ω, Figure 7
RL= 60Ω, Figure 7
RL= 110Ω, Figure 9
RL= 110Ω, Figure 10
RL= 110Ω, Figure 9
RL= 27Ω, Figure 8
RL= 27Ω, Figure 8
RL= 110Ω, Figure 10
RL= 110Ω, Figure 9
CONDITIONS
DRIVER OUTPUT ENABLE/DISABLE TIMES (MAX3485/MAX3491 only)
Maxim Integrated
3
MAX3483/MAX3485/MAX3486/
MAX3488/MAX3490/MAX3491
3.3V-Powered, 10Mbps and Slew-Rate-Limited
True RS-485/RS-422 Transceivers
DRIVER SWITCHING CHARACTERISTICS—MAX3483 and MAX3488
(VCC = 3.3V, TA= +25°C)
ns50 80tPLZ
Driver Output Disable Time from Low Level RL= 110Ω, Figure 10
ns700 1000 1500tPLH
Driver Propagation Delay, Low-to-High Level
ns400 700 1200tTD
ns600 900 1400tDD
Driver Differential Output Delay
Driver Differential Output Transition Time
µs2.2 3.0tPSH
Driver Output Enable Time from Shutdown to High Level
µs1.9 2.7tPSL
Driver Output Enable Time from Shutdown to Low Level
ns50 80tPHZ
Driver Output Disable Time from High Level
ns700 1000 1500tPHL
Driver Propagation Delay, High-to-Low Level
ns100tPDS
|tPLH - tPHL|Driver Propagation Delay Skew (Note 2)
ns900 1300tPZL
Driver Output Enable Time to Low Level
ns600 800tPZH
Driver Output Enable Time to High Level
UNITSMIN TYP MAXSYMBOLPARAMETER
RL= 27Ω, Figure 8
RL= 60Ω, Figure 7
RL= 60Ω, Figure 7
RL= 110Ω, Figure 9
RL= 110Ω, Figure 10
RL= 110Ω, Figure 9
RL= 27Ω, Figure 8
RL= 27Ω, Figure 8
RL= 110Ω, Figure 10
RL= 110Ω, Figure 9
CONDITIONS
RECEIVER SWITCHING CHARACTERISTICS
(VCC = 3.3V, TA= +25°C)
ns25 45tPRLZ
Receiver Output Disable
Time from Low Level
CL= 15pF, Figure 12,
MAX3483/MAX3485/MAX3486/MAX3491 only
ns
25 65 90
ns80 190 300tSHDN
Time to Shutdown
ns720 1400tPRSH
Receiver Output Enable Time
from Shutdown to High Level
ns720 1400tPRSL
Receiver Output Enable Time
from Shutdown to Low Level
ns25 45tPRHZ
Receiver Output Disable
Time from High Level
ns
25 65 90
ns
10
ns25 50tPRZL
Receiver Output Enable Time
to Low Level
ns25 50tPRZH
Receiver Output Enable Time
to High Level
UNITSMIN TYP MAXSYMBOLPARAMETER
VID = 0V to 3.0V, CL= 15pF, Figure 11
MAX3483/MAX3485/MAX3486/MAX3491 only
(Note 3)
CL= 15pF, Figure 12,
MAX3483/MAX3485/MAX3486/MAX3491 only
CL= 15pF, Figure 12,
MAX3483/MAX3485/MAX3486/MAX3491 only
CL= 15pF, Figure 12,
MAX3483/MAX3485/MAX3486/MAX3491 only
VID = 0V to 3.0V, CL= 15pF, Figure 11
VID = 0V to 3.0V, CL= 15pF, Figure 11
CL= 15pF, Figure 12,
MAX3483/MAX3485/MAX3486/MAX3491 only
CL= 15pF, Figure 12,
MAX3483/MAX3485/MAX3486/MAX3491 only
CONDITIONS
25 75 120
tRPLH
Receiver Propagation Delay,
Low-to-High Level MAX3483/MAX3488
25 75 120
tRPHL
Receiver Propagation Delay,
High-to-Low Level MAX3483/MAX3488
20
tRPDS
|tPLH - tPHL|Receiver
Propagation Delay Skew MAX3483/MAX3488
Note 1: ∆VOD and ∆VOC are the changes in VOD and VOC, respectively, when the DI input changes state.
Note 2: Measured on |tPLH (Y) - tPHL (Y)|and |tPLH (Z) - tPHL (Z)|.
Note 3: The transceivers are put into shutdown by bringing RE high and DE low. If the inputs are in this state for less than 80ns, the
parts are guaranteed not to enter shutdown. If the inputs are in this state for at least 300ns, the parts are guaranteed to
have entered shutdown. See
Low-Power Shutdown Mode
section.
DRIVER OUTPUT ENABLE/DISABLE TIMES (MAX3483 only)
MAX3483/MAX3485/MAX3486/
MAX3488/MAX3490/MAX3491
4
Maxim Integrated
3.3V-Powered, 10Mbps and Slew-Rate-Limited
True RS-485/RS-422 Transceivers
__________________________________________Typical Operating Characteristics
(VCC = 3.3V, TA= +25°C, unless otherwise noted.)
25
20
15
10
5
0
0 0.5 1.0 1.5 2.0 2.5 3.53.0
OUTPUT CURRENT vs.
RECEIVER OUTPUT LOW VOLTAGE
MAX3483-01
OUTPUT LOW VOLTAGE (V)
OUTPUT CURRENT (mA)
-20
-18
-16
-14
-12
-10
-8
-6
-4
-2
0
0 0.5 1.0 1.5 2.0 2.5 3.53.0
OUTPUT CURRENT vs.
RECEIVER OUTPUT HIGH VOLTAGE
MAX3483-02
OUTPUT HIGH VOLTAGE (V)
OUTPUT CURRENT (mA)
3.00
3.05
3.10
3.15
3.20
3.25
3.30
-40 -20 0 20 40 60 10080
RECEIVER OUTPUT HIGH VOLTAGE
vs. TEMPERATURE
MAX3483-03
TEMPERATURE (°C)
OUTPUT HIGH VOLTAGE (V)
IRO = 1.5mA
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
-40 -20 0 20 40 60 10080
RECEIVER OUTPUT LOW VOLTAGE
vs. TEMPERATURE
MAX3483-04
TEMPERATURE (°C)
OUTPUT LOW VOLTAGE (V)
IRO = 2.5mA
25
0
50
75
100
125
150
175
0246 81012
OUTPUT CURRENT vs.
DRIVER OUTPUT LOW VOLTAGE
MAX3483-07
OUTPUT LOW VOLTAGE (V)
OUTPUT CURRENT (mA)
100
90
80
70
60
50
40
30
20
10
0
0 0.5 1.0 1.5 2.0 2.5 3.53.0
DRIVER OUTPUT CURRENT vs.
DIFFERENTIAL OUTPUT VOLTAGE
MAX3483-05
DIFFERENTIAL OUTPUT VOLTAGE (V)
OUTPUT CURRENT (mA)
1.6
1.7
1.8
1.9
2.0
2.1
2.2
2.3
2.4
2.6
2.5
-40 -20 0 20 40 60 10080
DRIVER DIFFERENTIAL OUTPUT
VOLTAGE vs.TEMPERATURE
MAX3483-06
TEMPERATURE (°C)
DIFFERENTIAL OUTPUT VOLTAGE (V)
R = 54Ω
0
-100
-80
-60
-40
-20
543210
-7 -6 -3-4-5 -2 -1
OUTPUT CURRENT vs.
DRIVER OUTPUT HIGH VOLTAGE
MAX3483-08
OUTPUT HIGH VOLTAGE (V)
OUTPUT CURRENT (mA)
Maxim Integrated
5
MAX3483/MAX3485/MAX3486/
MAX3488/MAX3490/MAX3491
3.3V-Powered, 10Mbps and Slew-Rate-Limited
True RS-485/RS-422 Transceivers
0.8
0.7
0.9
1.0
1.1
1.2
-40 -20 0 20 40 60 10080
SUPPLY CURRENT
vs. TEMPERATURE
MAX3483-09
TEMPERATURE (°C)
SUPPLY CURRENT (mA)
X = DON’T CARE
DE = VCC, RE = X
DE = 0, RE = 0
_____________________________Typical Operating Characteristics (continued)
0
10
20
30
40
50
60
70
80
100
90
-40 -20 0 20 40 60 10080
SHUTDOWN CURRENT
vs. TEMPERATURE
MAX3483-10
TEMPERATURE (°C)
SHUTDOWN CURRENT (nA)
______________________________________________________________Pin Description
—
—
3
4
5
6
—
8
—
7
1
—
MAX3483/
MAX3485/
MAX3486
21
2
3
4
5
—
—
6
—
7
—
8
—
2Receiver Output. If A > B by 200mV, RO will be high; if A < B by 200mV,
RO will be low.
3
Receiver Output Enable. RO is enabled when RE is low; RO is high imped-
ance when RE is high. If RE is high and DE is low, the device will enter a
low-power shutdown mode.
4
Driver Output Enable. The driver outputs are enabled by bringing DE high.
They are high impedance when DE is low. If RE is high and DE is low, the
device will enter a low-power shutdown mode. If the driver outputs are
enabled, the parts function as line drivers. While they are high impedance,
they function as line receivers if RE is low.
5Driver Input. A low on DI forces output Y low and output Z high. Similarly, a
high on DI forces output Y high and output Z low.
6, 7 Ground
9 Noninverting Driver Output
10 Inverting Driver Output
— Noninverting Receiver Input and Noninverting Driver Output
12 Noninverting Receiver Input
RO
–
RE
DE
DI
GND
Y
Z
A
A
— B Inverting Receiver Input and Inverting Driver Output
11 B Inverting Receiver Input
13, 14 VCC Positive Supply: 3.0V ≤VCC ≤3.6V
1, 8 N.C. No Connect—not internally connected
MAX3488/
MAX3490
PIN
FUNCTION
MAX3491
FUNCTION
NAME
NAME
MAX3483/MAX3485/MAX3486/
MAX3488/MAX3490/MAX3491
6
Maxim Integrated
3.3V-Powered, 10Mbps and Slew-Rate-Limited
True RS-485/RS-422 Transceivers
MAX3483
MAX3485
MAX3486
TOP VIEW
NOTE: PIN LABELS Y AND Z ON TIMING, TEST, AND WAVEFORM DIAGRAMS REFER TO PINS A AND B WHEN DE IS HIGH.
1
2
3
4
8
5
VCC
GND
DI
DE
RE
RO R
D
Rt
Rt
7
6
D
R
DE
RE
DI
RO
A
B
1
2
3
4
8
7
6
5
VCC
B
A
GND
DI
DE
RE
RO
DIP/SO
R
D
B
A
MAX3488
MAX3490
TOP VIEW
1
2
3
4
RO
DI
GND
8
7
6
5
A
B
Z
Y
VCC
DIP/SO
R
D
Rt
Rt
VCC
5
6
7
8
RO
DI
GND
4
GND
DI
RO
3
2
A
B
Y
Z
VCC
DR
RD
1
MAX3491
DIP/SO
TOP VIEW
Rt
Rt
DE VCC
RE GND
VCC RE
GND DE
RO
DI
9
10
12
11
B
A
Z
Y
5
RO
N.C.
DI
2
1, 8
3 6, 7
13, 144
1
2
3
4
5
6
7
14
13
12
11
10
9
8
VCC
VCC
N.C.
A
B
Z
Y
N.C.
RO
RE
DE
DI
GND
GND
R
D
D
RD
R
Figure 2. MAX3488/MAX3490 Pin Configuration and Typical Operating Circuit
Figure 3. MAX3491 Pin Configuration and Typical Operating Circuit
Figure 1. MAX3483/MAX3485/MAX3486 Pin Configuration and Typical Operating Circuit
Maxim Integrated
7
MAX3483/MAX3485/MAX3486/
MAX3488/MAX3490/MAX3491
3.3V-Powered, 10Mbps and Slew-Rate-Limited
True RS-485/RS-422 Transceivers
VCC
DVOD
VOC
2
RL
2
RL
R
0V
VOH IOH
(-)
IOL
(+)
VOL
VID
VCC
DVOD RL
VCM =
-7V to +12V
375Ω
375Ω
VCC
50Ω
RL =
60Ω
CL = 15pF (NOTE 5)
GENERATOR
(NOTE 4)
DOUT
CL
CL
tDO
tTD
50%
1.5V
10%
OUT
IN
90%
50%
1.5V
10%
90%
3V
0V
≈ 2.0V
≈ -2.0V
tDO
tTD
Figure 4. Driver VOD and VOC
Figure 7. Driver Differential Output Delay and Transition Times
Figure 6. Receiver VOH and VOL
Figure 5. Driver VOD with Varying Common-Mode Voltage
MAX3483/MAX3485/MAX3486/
MAX3488/MAX3490/MAX3491
8
Maxim Integrated
3.3V-Powered, 10Mbps and Slew-Rate-Limited
True RS-485/RS-422 Transceivers
VCC
VOM
3V
0V
VOH
VOM
VOM
VOM
VOM
VOL
VOH
VOL
50Ω
RL = 27Ω
CL = 15pF
(NOTE 5)
GENERATOR
(NOTE 4)
D
tPLH
1.5V
Y
OUT
Z
OUT
OUT
S1
IN 1.5V
≈ 1.5V
tPHL
tPHL tPLH
VOH + VOL
2
VOM =
3V
0V
VOH
VOM
0V
RL = 110Ω
CL = 50pF
(NOTE 5)
D0V OR 3V
50Ω
GENERATOR
(NOTE 4)
tPZH
1.5V
0.25V
OUT
OUT
S1
IN 1.5V
≈ 1.5V
tPHZ
VOH + VOL
2
VOM =
VCC
RL = 110Ω
CL = 50pF
(NOTE 5)
D
50Ω
GENERATOR
(NOTE 4)
OUT
S1
3V
0V
VCC
VOL
VOM
tPSL
1.5V
0.25V
OUT
IN 1.5V
tPLZ
0V OR 3V
Figure 8. Driver Propagation Times
Figure 9. Driver Enable and Disable Times (tPZH, tPSH, tPHZ)
Figure 10. Driver Enable and Disable Times (tPZL, tPSL, tPLZ)
Maxim Integrated
9
MAX3483/MAX3485/MAX3486/
MAX3488/MAX3490/MAX3491
3.3V-Powered, 10Mbps and Slew-Rate-Limited
True RS-485/RS-422 Transceivers
VID
50ΩCL = 15pF
(NOTE 5)
GENERATOR
(NOTE 4)
ROUT
tRPLH
1.5V
OUT
1.5V
0V
IN 1.5V
3.0V
0V
tRPHL
VCC
VOM VOM
0V
VCC
2
VOM =
3V
0V
VCC
VOL
CL
(NOTE 5)
R
1.5V
-1.5V
50Ω
GENERATOR
(NOTE 4)
VCC
VID
1.5V
OUT
S1
S2
1k
IN 1.5V
S1 CLOSED
S2 OPEN
S3 = -1.5V
tPRZL
tPRSL
3V
0V
VOH
0V
1.5V
OUT
IN 1.5V
S1 OPEN
S2 CLOSED
S3 = 1.5V
tPRZH
tPRSH
3V
0V
VCC
VOL
0.25V
OUT
IN 1.5V
S1 CLOSED
S2 OPEN
S3 = -1.5V
tPRLZ
3V
0V
VOH
0V
0.25V
1.5V
OUT
IN
S1 OPEN
S2 CLOSED
S3 = 1.5V
tPRHZ
S3
Figure 11. Receiver Propagation Delay
Figure 12. Receiver Enable and Disable Times
Note 4: The input pulse is supplied by a generator with the following characteristics: PRR = 250kHz, 50% duty cycle, t
r≤6.0ns, ZO= 50Ω.
Note 5: CLincludes probe and stray capacitance.
MAX3483/MAX3485/MAX3486/
MAX3488/MAX3490/MAX3491
10
Maxim Integrated
____________________Function Tables
Devices with Receiver/Driver Enable
(MAX3483/MAX3485/MAX3486/MAX3491)
Table 1. Transmitting
* B and A outputs are Z and Y, respectively, for full-duplex part
(MAX3491).
X = Don’t care; High-Z = High impedance
Table 2. Receiving
* DE is a “don’t care” (x) for the full-duplex part (MAX3491).
X = Don’t care; High-Z = High impedance
Devices without Receiver/Driver Enable
(MAX3488/MAX3490)
Table 3. Transmitting Table 4. Receiving
__________Applications Information
The MAX3483/MAX3485/MAX3486/MAX3488/MAX3490/
MAX3491 are low-power transceivers for RS-485 and
RS-422 communications. The MAX3483 and MAX3488
can transmit and receive at data rates up to 250kbps,
the MAX3486 at up to 2.5Mbps, and the MAX3485/
MAX3490/MAX3491 at up to 10Mbps. The MAX3488/
MAX3490/MAX3491 are full-duplex transceivers, while
the MAX3483/MAX3485/MAX3486 are half-duplex.
Driver Enable (DE) and Receiver Enable (RE) pins are
included on the MAX3483/MAX3485/MAX3486/
MAX3491. When disabled, the driver and receiver out-
puts are high impedance.
Reduced EMI and Reflections
(MAX3483/MAX3486/MAX3488)
The MAX3483/MAX3488 are slew-rate limited, minimiz-
ing EMI and reducing reflections caused by improperly
terminated cables. Figure 13 shows both the driver
output waveform of a MAX3485/MAX3490/MAX3491
transmitting a 125kHz signal and the Fourier analysis of
that waveform. High-frequency harmonics with large
amplitudes are evident. Figure 14 shows the same infor-
mation, but for the slew-rate-limited MAX3483/MAX3488
transmitting the same signal. The high-frequency har-
monics have much lower amplitudes, and the potential for
EMI is significantly reduced.
Low-Power Shutdown Mode
(MAX3483/MAX3485/MAX3486/MAX3491)
A low-power shutdown mode is initiated by bringing both
RE high and DE low. The devices will not shut down
unless both the driver and receiver are disabled (high
impedance). In shutdown, the devices typically draw
only 2nA of supply current.
For these devices, the tPSH and tPSL enable times
assume the part was in the low-power shutdown mode;
the tPZH and tPZL enable times assume the receiver or
driver was disabled, but the part was not shut down.
3.3V-Powered, 10Mbps and Slew-Rate-Limited
True RS-485/RS-422 Transceivers
INPUTS OUTPUTS
RE DE DI B* A* MODE
X 1 1 0 1 Normal
X 1 0 1 0 Normal
0 0 X High-Z High-Z Normal
1 0 X High-Z High-Z Shutdown
INPUTS
RE DE A, B RO MODE
0 0* ≥+0.2V 1 Normal
0 0* ≤-0.2V 0 Normal
0 0* Inputs Open 1 Normal
1 0 X High-Z Shutdown
OUTPUTS
INPUTS OUTPUT
A, B RO
≥+0.2V 1
≤-0.2V 0
Inputs Open 1
INPUT OUTPUTS
DI Z Y
1 0 1
0 1 0
5MHz500kHz/div0Hz
10dB/div
5MHz500kHz/div0Hz
10dB/div
Figure 13. Driver Output Waveform and FFT Plot of MAX3485/
MAX3490/MAX3491 Transmitting a 125kHz Signal
Figure 14. Driver Output Waveform and FFT Plot of MAX3483/
MAX3488 Transmitting a 125kHz Signal
Maxim Integrated
MAX3483/MAX3485/MAX3486/
MAX3488/MAX3490/MAX3491
3.3V-Powered, 10Mbps and Slew-Rate-Limited
True RS-485/RS-422 Transceivers
B
1V/div
A
1V/div
RO
2V/div
20ns/div
DI
5V/div
VY - VZ
2V/div
RO
5V/div
2µs/div
B
1V/div
A
1V/div
RO
2V/div
1µs/div
DI
2V/div
20ns/div
Z
1V/div
Y
1V/div
DI
2V/div
Z
1V/div
Y
1V/div
1µs/div
DI
5V/div
VY - VZ
2V/div
RO
5V/div
2µs/div
Figure 15. MAX3485/MAX3490/MAX3491 Driver Propagation
Delay
Figure 17. MAX3483/MAX3488 Driver Propagation Delay
Figure 16. MAX3485/MAX3490/MAX3491 Receiver
Propagation Delay Driven by External RS-485 Device
Figure 18. MAX3483/MAX3488 Receiver Propagation Delay
Figure 19. MAX3483/MAX3488 System Differential Voltage at
125kHz Driving 4000 ft of Cable
Figure 20. MAX3485/MAX3490/MAX3491 System Differential
Voltage at 125kHz Driving 4000 ft of Cable
MAX3483/MAX3485/MAX3486/
MAX3488/MAX3490/MAX3491
12
Maxim Integrated
3.3V-Powered, 10Mbps and Slew-Rate-Limited
True RS-485/RS-422 Transceivers
Driver Output Protection
Excessive output current and power dissipation caused
by faults or by bus contention are prevented by two
mechanisms. A foldback current limit on the output stage
provides immediate protection against short circuits over
the whole common-mode voltage range (see
Typical
Operating Characteristics
). In addition, a thermal shut-
down circuit forces the driver outputs into a high-imped-
ance state if the die temperature rises excessively.
Propagation Delay
Figures 15–18 show the typical propagation delays. Skew
time is simply the difference between the low-to-high and
high-to-low propagation delay. Small driver/receiver
skew times help maintain a symmetrical mark-space
ratio (50% duty cycle).
The receiver skew time, |tPRLH - tPRHL|, is under 10ns
(20ns for the MAX3483/MAX3488). The driver skew
times are 8ns for the MAX3485/MAX3490/MAX3491,
11ns for the MAX3486, and typically under 100ns for
the MAX3483/MAX3488.
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, see
Figure 23.
Figures 19 and 20 show the system differential voltage
for parts driving 4000 feet of 26AWG twisted-pair wire
at 125kHz into 120Ωloads.
Typical Applications
The MAX3483, MAX3485, MAX3486, MAX3488,
MAX3490, and MAX3491 transceivers are designed for
bidirectional data communications on multipoint bus
transmission lines. Figures 21 and 22 show typical net-
work applications circuits. These parts can also be
used as line repeaters, with cable lengths longer than
4000 feet, as shown in Figure 23.
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 MAX3483/MAX3488
and the partially slew-rate-limited MAX3486 are more
tolerant of imperfect termination.
DI RO DE
RE
A
B
RE
RERE
RO
RO
RO
DI
DI
DI
DE
DE
DE
DD
D
R
R
R
BB
B
A
A
A
120Ω120Ω
D
R
MAX3483
MAX3485
MAX3486
Figure 21. MAX3483/MAX3485/MAX3486 Typical RS-485 Network
Maxim Integrated
MAX3483/MAX3485/MAX3486/
MAX3488/MAX3490/MAX3491
3.3V-Powered, 10Mbps and Slew-Rate-Limited
True RS-485/RS-422 Transceivers
120Ω120Ω
R
D
RO
RE
DE
DI
A
B
Y
120Ω120Ω
DI
DI DIRO RO
RO
DE DE
DE
RE
RE
RE
Z
Z
Z
Z
YY
Y
AA
A
BB
B
D
D
D
R
R
R
MAX3488
MAX3490
MAX3491
NOTE: RE AND DE ON MAX3491 ONLY.
120Ω
120ΩDATA IN
DATA OUT
R
D
RO
RE
DE
DI
A
B
Z
Y
MAX3488
MAX3490
MAX3491
NOTE: RE AND DE ON MAX3491 ONLY.
Figure 22. MAX3488/MAX3490/MAX3491 Full-Duplex RS-485 Network
Figure 23. Line Repeater for MAX3488/MAX3490/MAX3491
MAX3483/MAX3485/MAX3486/
MAX3488/MAX3490/MAX3491
14
Maxim Integrated
TRANSISTOR COUNT: 810
SUBSTRATE CONNECTED TO GROUND
__________________ Chip Topography_Ordering Information (continued)
PART
MAX3486CPA
MAX3486CSA
MAX3486C/D 0°C to +70°C
0°C to +70°C
0°C to +70°C
TEMP. RANGE PIN-PACKAGE
8 Plastic DIP
8 SO
Dice*
MAX3486EPA
MAX3486ESA -40°C to +85°C
-40°C to +85°C 8 Plastic DIP
8 SO
MAX3488CPA
MAX3488CSA
MAX3488C/D 0°C to +70°C
0°C to +70°C
0°C to +70°C 8 Plastic DIP
8 SO
Dice*
MAX3488EPA
MAX3488ESA -40°C to +85°C
-40°C to +85°C 8 Plastic DIP
8 SO
MAX3490CPA
MAX3490CSA
MAX3490C/D 0°C to +70°C
0°C to +70°C
0°C to +70°C 8 Plastic DIP
8 SO
Dice*
MAX3490EPA
MAX3490ESA -40°C to +85°C
-40°C to +85°C 8 Plastic DIP
8 SO
MAX3491CPD
MAX3491CSD
MAX3491C/D 0°C to +70°C
0°C to +70°C
0°C to +70°C 14 Plastic DIP
14 SO
Dice*
MAX3491EPD
MAX3491ESD -40°C to +85°C
-40°C to +85°C 14 Plastic DIP
14 SO
* Contact factory for for dice specifications.
0.146"
(3.71mm)
0.086"
(2.18mm)
Z/B
B
A
Y/A
GND
DI
DE
RE
RO
VCC
GND
Maxim Integrated
MAX3483/MAX3485/MAX3486/
MAX3488/MAX3490/MAX3491
3.3V-Powered, 10Mbps and Slew-Rate-Limited
True RS-485/RS-422 Transceivers
3.3V-Powered, 10Mbps and Slew-Rate-Limited
True RS-485/RS-422 Transceivers
DIM
A
A1
B
C
E
e
H
L
MIN
0.053
0.004
0.014
0.007
0.150
0.228
0.016
MAX
0.069
0.010
0.019
0.010
0.157
0.244
0.050
MIN
1.35
0.10
0.35
0.19
3.80
5.80
0.40
MAX
1.75
0.25
0.49
0.25
4.00
6.20
1.27
INCHES MILLIMETERS
21-0041A
SO
SMALL OUTLINE
PACKAGE
(0.150 in.)
DIM
D
D
D
MIN
0.189
0.337
0.386
MAX
0.197
0.344
0.394
MIN
4.80
8.55
9.80
MAX
5.00
8.75
10.00
INCHES MILLIMETERS
PINS
8
14
16
1.270.050
L
0°-8°
HE
D
e
A
A1 C
0.101mm
0.004in.
B
DIM
A
A1
A2
A3
B
B1
C
D1
E
E1
e
eA
eB
L
MIN
–
0.015
0.125
0.055
0.016
0.045
0.008
0.005
0.300
0.240
0.100
0.300
–
0.115
MAX
0.200
–
0.175
0.080
0.022
0.065
0.012
0.080
0.325
0.310
–
–
0.400
0.150
MIN
–
0.38
3.18
1.40
0.41
1.14
0.20
0.13
7.62
6.10
2.54
7.62
–
2.92
MAX
5.08
–
4.45
2.03
0.56
1.65
0.30
2.03
8.26
7.87
–
–
10.16
3.81
INCHES MILLIMETERS
Plastic DIP
PLASTIC
DUAL-IN-LINE
PACKAGE
(0.300 in.)
DIM
D
D
D
D
D
D
MIN
0.348
0.735
0.745
0.885
1.015
1.14
MAX
0.390
0.765
0.765
0.915
1.045
1.265
MIN
8.84
18.67
18.92
22.48
25.78
28.96
MAX
9.91
19.43
19.43
23.24
26.54
32.13
INCHES MILLIMETERS
PINS
8
14
16
18
20
24
C
AA2
E1
D
E
eA
eB
A3
B1
B
0° - 15°
A1
L
D1
e
________________________________________________________Package Information
MAX3483/MAX3485/MAX3486/
MAX3488/MAX3490/MAX3491
16
Maxim Integrated
MAX3483/MAX3485/MAX3486/
MAX3488/MAX3490/MAX3491
3.3V-Powered, 10Mbps and Slew-Rate-Limited
True RS-485/RS-422 Transceivers
17
Maxim Integrated 160 Rio Robles, San Jose, CA 95134 USA 1-408-601-1000
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. The parametric values (min and max limits) shown in the Electrical
Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
© 1994 Maxim Integrated The Maxim logo and Maxim Integrated are trademarks of Maxim Integrated Products, Inc.
Mouser Electronics
Authorized Distributor
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MAX3488CPA+