FREI MAX 3491 CPD Datasheet

AVAILABLE

For pricing, delivery, and

ordering information, please contact Maxim Direct

at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.

MAX3483/MAX3485/MAX3486/

MAX3488/MAX3490/MAX3491

3.3V-Powered, 10Mbps and Slew-Rate-Limited
True RS-485/RS-422 Transceivers

_______________General Description

The MAX3483, MAX3485, MAX3486, MAX3488,
MAX3490, and MAX3491 are 3.3V, low-power trans­ceivers for RS-485 and RS-422 communication. Each
part contains one driver and one receiver. The
MAX3483 and MAX3488 feature slew-rate-limited dri­vers that minimize EMI and reduce reflections caused
by improperly terminated cables, allowing error-free
data transmission at data rates up to 250kbps. The par­tially 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 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 both
inputs are open circuit.

The MAX3488, MAX3490, and MAX3491 feature full­duplex communication, while the MAX3483, MAX3485,
and MAX3486 are designed for half-duplex communi­cation.

________________________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

PART

MAX3483CPA

MAX3483CSA
MAX3483C/D 0°C to +70°C
MAX3483EPA
MAX3483ESA -40°C to +85°C
MAX3485CPA

MAX3485CSA
MAX3485C/D 0°C to +70°C
MAX3485EPA
MAX3485ESA -40°C to +85°C

Ordering Information continued at end of data sheet.

* Contact factory for for dice specifications.

TEMP. RANGE PIN-PACKAGE

0°C to +70°C

0°C to +70°C

-40°C to +85°C 8 Plastic DIP

0°C to +70°C 8 Plastic DIP

0°C to +70°C

-40°C to +85°C 8 Plastic DIP

8 Plastic DIP

8 SO
Dice*

8 SO

8 SO
Dice*

8 SO

______________________________________________________________Selection Table

PART

NUMBER

MAX3483

MAX3485

MAX3486

MAX3488

MAX3490

MAX3491

GUARANTEED

DATA RATE

(Mbps)

0.25 Half Yes Yes 2 8

10 Half No Yes 2 8

2.5 Half Yes Yes 2 8

0.25 Full Yes No — 8

10 Full No No — 8

10

SUPPLY

VOLTAGE

(V)

3.0 to 3.6

HALF/FULL

DUPLEX

Full No Yes 2 14

SLEW-RATE

LIMITED

RECEIVER

DRIVER/

ENABLE

SHUTDOWN

CURRENT

(nA)

PIN

COUNT

19-0333; Rev 0; 12/94

3.3V-Powered, 10Mbps and Slew-Rate-Limited

MAX3483/MAX3485/MAX3486/
MAX3488/MAX3490/MAX3491

2

Maxim Integrated

True RS-485/RS-422 Transceivers

ABSOLUTE MAXIMUM RATINGS

Supply Voltage (VCC)...............................................................7V

Control Input Voltage (RE

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 (V

Continuous Power Dissipation (T

8-Pin Plastic DIP (derate 9.09mW/°C above +70°C) .....727mW

8-Pin SO (derate 5.88mW/°C above +70°C)..................471mW

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.

, DE) ...................................-0.3V to 7V

+ 0.3V)

= +70°C)

A

CC

DC ELECTRICAL CHARACTERISTICS

(VCC= 3.3V ±0.3V, TA= T

MIN

to T

, unless otherwise noted. Typical values are at TA= +25°C)

MAX

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

Differential Driver Output

Change in Magnitude of Driver
Differential Output Voltage for
Complementary Output States
(Note 1)

Driver Common-Mode Output
Voltage

Change in Magnitude of
Common-Mode Output Voltage
(Note 1)

Input High Voltage

Input Low Voltage

Logic Input Current

Input Current (A, B)

Output Leakage (Y, Z)

Output Leakage (Y, Z)
in Shutdown Mode

Receiver Differential
Threshold Voltage

Receiver Input Hysteresis

Receiver Output High Voltage

Receiver Output Low Voltage

Three-State (High Impedance)
Output Current at Receiver

Receiver Input Resistance

V

IN1

I

IN2

I

I

OZR

R

= 100Ω (RS-422), Figure 4

L

R

OD

OD

OC

OC

IH

IL

O

O

TH

TH

OH

OL

IN

= 54Ω (RS-485), Figure 4

L

R

= 60Ω (RS-485), V

L

R

= 54Ω or 100Ω, Figure 4

L

R

= 54Ω or 100Ω, Figure 4

L

R

= 54Ω or 100Ω, Figure 4

L

DE, DI, RE

DE, DI, RE

DE, DI, RE

DE = 0V,

= 0V or 3.6V

V

CC

DE = 0V, RE = 0V,
VCC= 0V or 3.6V, MAX3491

DE = 0V, RE = VCC,
VCC= 0V or 3.6V, MAX3491

-7V ≤ VCM≤ 12V

VCM= 0V

I

= -1.5mA, VID= 200mV, Figure 6

OUT

I

= 2.5mA, VID= 200mV, Figure 6

OUT

V

= 3.6V, 0V ≤ V

CC

-7V ≤ VCM≤ 12V

CONDITIONS

= 3.3V, Figure 5

CC

≤ V

OUT

VIN= 12V

VIN= -7V

V

OUT

V

OUT

V

OUT

V

OUT

CC

= 12V

= -7V

= 12V

= -7V

2.0

1.5

1.5

1.0

-0.8

20

-20

1

-1

UNITSMIN TYP MAXSYMBOLPARAMETER

V

V0.2∆V

V3V

V0.2∆V

V2.0V

V0.8V

µA±2I

mA

µA

µA

V-0.2 0.2V

mV50∆V

VVCC- 0.4V

V0.4V

µA±1I

kΩ12R

3.3V-Powered, 10Mbps and Slew-Rate-Limited

Maxim Integrated

3

MAX3483/MAX3485/MAX3486/

MAX3488/MAX3490/MAX3491

True RS-485/RS-422 Transceivers

DC ELECTRICAL CHARACTERISTICS (continued)

(VCC= 3.3V ±0.3V, TA= T

Supply Current

Supply Current in Shutdown Mode

Driver Short-Circuit Output
Current

Receiver Short-Circuit Output
Current

DRIVER SWITCHING CHARACTERISTICS—MAX3485, MAX3490, and MAX3491

(VCC= 3.3V, TA= +25°C)

MIN

to T

, unless otherwise noted. Typical values are at TA= +25°C)

MAX

CONDITIONS

DE = VCC,

I

CC

No load,
DI = 0V or V

CC

RE = 0V or V

DE = 0V,
RE = 0V

SHDN

I

OSD

OSR

DE = 0V, RE = VCC, DI = VCCor 0V

V

= -7V

OUT

V

= 12V

OUT

0V ≤ VRO≤ V

CC

CC

1.1 2.2

0.95 1.9

-250

250

UNITSMIN TYP MAXSYMBOLPARAMETER

mA

µA0.002 1I

mA

mA±8 ±60I

CONDITIONS

Driver Differential Output Delay

Driver Differential Output Transition Time

Driver Propagation Delay, Low-to-High Level

Driver Propagation Delay, High-to-Low Level

t

- t

|

PLH

Driver Propagation Delay Skew (Note 2)

PHL|

PLH

PHL

PDS

DD

TD

R

= 60Ω, Figure 7

L

R

= 60Ω, Figure 7

L

R

= 27Ω, Figure 8

L

R

= 27Ω, Figure 8

L

R

= 27Ω, Figure 8

L

DRIVER OUTPUT ENABLE/DISABLE TIMES (MAX3485/MAX3491 only)

Driver Output Enable Time to Low Level

Driver Output Enable Time to High Level

Driver Output Disable Time from High Level

Driver Output Disable Time from Low Level R

Driver Output Enable Time from Shutdown to Low Level

Driver Output Enable Time from Shutdown to High Level

PZL

PZH

PHZ

PLZ

PSL

PSH

R

= 110Ω, Figure 10

L

R

= 110Ω, Figure 9

L

R

= 110Ω, Figure 9

L

= 110Ω, Figure 10

L

R

= 110Ω, Figure 10

L

R

= 110Ω, Figure 9

L

DRIVER SWITCHING CHARACTERISTICS—MAX3486

(VCC= 3.3V, TA= +25°C)

CONDITIONS

Driver Differential Output Delay

Driver Differential Output Transition Time

Driver Propagation Delay, Low-to-High Level

Driver Propagation Delay, High-to-Low Level

t

- t

|

PLH

Driver Propagation Delay Skew (Note 2)

PHL|

Driver Output Enable Time to Low Level

Driver Output Enable Time to High Level

Driver Output Disable Time from High Level

Driver Output Disable Time from Low Level R

Driver Output Enable Time from Shutdown to Low Level

Driver Output Enable Time from Shutdown to High Level

PLH

PHL

PDS

PZL

PZH

PHZ

PLZ

PSL

PSH

DD

TD

R

= 60Ω, Figure 7

L

R

= 60Ω, Figure 7

L

R

= 27Ω, Figure 8

L

R

= 27Ω, Figure 8

L

R

= 27Ω, Figure 8

L

R

= 110Ω, Figure 10

L

R

= 110Ω, Figure 9

L

R

= 110Ω, Figure 9

L

= 110Ω, Figure 10

L

R

= 110Ω, Figure 10

L

R

= 110Ω, Figure 9

L

UNITSMIN TYP MAXSYMBOLPARAMETER

ns12235t

ns3825t

ns72235t

ns72235t

ns8t

ns45 90t

ns45 90t

ns40 80t

ns40 80t

ns650 900t

ns650 900t

UNITSMIN TYP MAXSYMBOLPARAMETER

ns24 48 70t

ns15 35 60t

ns20 48 70t

ns20 48 70t

ns11t

ns55 100t

ns55 100t

ns45 80t

ns45 80t

ns700 1000t

ns700 1000t

3.3V-Powered, 10Mbps and Slew-Rate-Limited

MAX3483/MAX3485/MAX3486/
MAX3488/MAX3490/MAX3491

4

Maxim Integrated

True RS-485/RS-422 Transceivers

DRIVER SWITCHING CHARACTERISTICS—MAX3483 and MAX3488

(VCC= 3.3V, TA= +25°C)

UNITSMIN TYP MAXSYMBOLPARAMETER

ns600 900 1400t

ns400 700 1200t

ns700 1000 1500t

ns700 1000 1500t

ns100t

ns900 1300t

ns600 800t

ns50 80t

ns50 80t

µs1.9 2.7t

µs2.2 3.0t

Driver Differential Output Delay

Driver Differential Output Transition Time

Driver Propagation Delay, Low-to-High Level

Driver Propagation Delay, High-to-Low Level

t

- t

|

PLH

DRIVER OUTPUT ENABLE/DISABLE TIMES (MAX3483 only)

Driver Output Enable Time to Low Level

Driver Output Enable Time to High Level

Driver Output Disable Time from High Level

Driver Output Disable Time from Low Level R

Driver Output Enable Time from Shutdown to Low Level

Driver Output Enable Time from Shutdown to High Level

Driver Propagation Delay Skew (Note 2)

PHL|

DD

TD

PLH

PHL

PDS

PZL

PZH

PHZ

PLZ

PSL

PSH

RECEIVER SWITCHING CHARACTERISTICS

(VCC= 3.3V, TA= +25°C)

CONDITIONS

R

= 60Ω, Figure 7

L

R

= 60Ω, Figure 7

L

R

= 27Ω, Figure 8

L

R

= 27Ω, Figure 8

L

R

= 27Ω, Figure 8

L

R

= 110Ω, Figure 10

L

R

= 110Ω, Figure 9

L

R

= 110Ω, Figure 9

L

= 110Ω, Figure 10

L

R

= 110Ω, Figure 10

L

R

= 110Ω, Figure 9

L

CONDITIONS

Time to Shutdown

Receiver Propagation Delay,
Low-to-High Level

Receiver Propagation Delay,
High-to-Low Level

t

- t

|

PLH

Propagation Delay Skew

Receiver Output Enable Time
to Low Level

Receiver Output Enable Time
to High Level

Receiver Output Disable
Time from High Level

Receiver Output Disable
Time from Low Level

Receiver Output Enable Time
from Shutdown to Low Level

Receiver Output Enable Time
from Shutdown to High Level

Note 1: ∆VODand ∆V

Note 2: Measured on
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

Receiver

PHL|

are the changes in VODand VOC, respectively, when the DI input changes state.

OC

t

PLH

|

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

(Y) - t

SHDN

t

RPLH

t

RPHL

t

RPDS

PRZL

PRZH

PRHZ

PRLZ

PRSL

PRSH

PHL

MAX3483/MAX3485/MAX3486/MAX3491 only
(Note 3)

VID= 0V to 3.0V, CL= 15pF, Figure 11

MAX3483/MAX3488

VID= 0V to 3.0V, CL= 15pF, Figure 11

MAX3483/MAX3488

VID= 0V to 3.0V, CL= 15pF, Figure 11

MAX3483/MAX3488

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

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

(Y)|and |t

Low-Power Shutdown Mode

PLH

(Z) - t

PHL

(Z)

|.

section.

25 65 90

25 75 120

25 65 90

25 75 120

10

20

UNITSMIN TYP MAXSYMBOLPARAMETER

ns80 190 300t

ns

ns

ns

ns25 50t

ns25 50t

ns25 45t

ns25 45t

ns720 1400t

ns720 1400t

3.3V-Powered, 10Mbps and Slew-Rate-Limited

Maxim Integrated

5

MAX3483/MAX3485/MAX3486/

MAX3488/MAX3490/MAX3491

True RS-485/RS-422 Transceivers

__________________________________________Typical Operating Characteristics

(VCC= 3.3V, TA= +25°C, unless otherwise noted.)

OUTPUT CURRENT vs.

RECEIVER OUTPUT LOW VOLTAGE

25

20

15

10

OUTPUT CURRENT (mA)

5

0

0 0.5 1.0 1.5 2.0 2.5 3.53.0

OUTPUT LOW VOLTAGE (V)

RECEIVER OUTPUT LOW VOLTAGE

vs. TEMPERATURE

0.8

0.7

0.6

0.5

0.4

0.3

0.2

OUTPUT LOW VOLTAGE (V)

0.1

0

-40 -20 0 20 40 60 10080
TEMPERATURE (°C)

IRO = 2.5mA

-20

-18

MAX3483-01

-16

-14

-12

-10

-8

-6

OUTPUT CURRENT (mA)

-4

-2

0

0 0.5 1.0 1.5 2.0 2.5 3.53.0

100

90

MAX3483-04

80

70

60

50

40

30

OUTPUT CURRENT (mA)

20

10

0

0 0.5 1.0 1.5 2.0 2.5 3.53.0

OUTPUT CURRENT vs.

RECEIVER OUTPUT HIGH VOLTAGE

OUTPUT HIGH VOLTAGE (V)

DRIVER OUTPUT CURRENT vs.

DIFFERENTIAL OUTPUT VOLTAGE

DIFFERENTIAL OUTPUT VOLTAGE (V)

RECEIVER OUTPUT HIGH VOLTAGE

3.30

MAX3483-02

3.25

3.20

3.15

3.10

OUTPUT HIGH VOLTAGE (V)

3.05

3.00

-40 -20 0 20 40 60 10080

DRIVER DIFFERENTIAL OUTPUT

VOLTAGE vs.TEMPERATURE

2.6

2.5

MAX3483-05

2.4

2.3

2.2

2.1

2.0

1.9

1.8

DIFFERENTIAL OUTPUT VOLTAGE (V)

1.7

1.6

-40 -20 0 20 40 60 10080

vs. TEMPERATURE

IRO = 1.5mA

MAX3483-03

TEMPERATURE (°C)

R = 54Ω

MAX3483-06

TEMPERATURE (°C)

OUTPUT CURRENT vs.

DRIVER OUTPUT LOW VOLTAGE

175

150

125

100

75

50

OUTPUT CURRENT (mA)

25

0

0246 81012

OUTPUT LOW VOLTAGE (V)

MAX3483-07

OUTPUT CURRENT vs.

DRIVER OUTPUT HIGH VOLTAGE

-100

-80

-60

-40

OUTPUT CURRENT (mA)

-20

0

-7 -6 -3-4-5 -2 -1
OUTPUT HIGH VOLTAGE (V)

MAX3483-08

543210

3.3V-Powered, 10Mbps and Slew-Rate-Limited

MAX3483/MAX3485/MAX3486/
MAX3488/MAX3490/MAX3491

6

Maxim Integrated

True RS-485/RS-422 Transceivers

_____________________________Typical Operating Characteristics (continued)

SUPPLY CURRENT

vs. TEMPERATURE

1.2

1.1

1.0

0.9

SUPPLY CURRENT (mA)

0.8

0.7

-40 -20 0 20 40 60 10080

DE = 0, RE = 0

TEMPERATURE (°C)

X = DON’T CARE

DE = VCC, RE = X

MAX3483-09

100

90

80

70

60

50

40

30

SHUTDOWN CURRENT (nA)

20

10

0

-40 -20 0 20 40 60 10080

SHUTDOWN CURRENT

vs. TEMPERATURE

MAX3483-10

TEMPERATURE (°C)

______________________________________________________________Pin Description

PIN

MAX3483/
MAX3485/

MAX3486

2

3

4

5

—

—

6

—

7

—

8

—

MAX3488/
MAX3490

21

—

—

3

4

5

6

—

8

—

7

1

—

MAX3491

2

3

4

5

6, 7 Ground

9 Noninverting Driver Output

10 Inverting Driver Output

— Noninverting Receiver Input and Noninverting Driver Output

12 Noninverting Receiver Input

— B Inverting Receiver Input and Inverting Driver Output

11 B Inverting Receiver Input

13, 14 V

1, 8 N.C. No Connect—not internally connected

NAME

NAME

RO

–
RE

DE

DI

GND

Y

Z

A

A

CC

FUNCTION

FUNCTION

Receiver Output. If A > B by 200mV, RO will be high; if A < B by 200mV,
RO will be low.

Receiver Output Enable. RO is enabled when RE is low; RO is high imped­ance when RE

is high. If RE is high and DE is low, the device will enter a

low-power shutdown mode.

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.

Driver 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.

Positive Supply: 3.0V ≤ VCC≤ 3.6V

3.3V-Powered, 10Mbps and Slew-Rate-Limited

Maxim Integrated

7

MAX3483/MAX3485/MAX3486/

MAX3488/MAX3490/MAX3491

True RS-485/RS-422 Transceivers

TOP VIEW

MAX3483
MAX3485

RO

2

RE

3

DE

4

DI

D

8

V

CC

7

B

6

A

5

GND

R

1

RO

RE

DE

DI

R

1

2

3

4

D

8

V

CC

B

7

Rt

6

A

5

GND

MAX3486

B

Rt

A

DE

D

R

DI

RO

DIP/SO

NOTE: PIN LABELS Y AND Z ON TIMING, TEST, AND WAVEFORM DIAGRAMS REFER TO PINS A AND B WHEN DE IS HIGH.

Figure 1. MAX3483/MAX3485/MAX3486 Pin Configuration and Typical Operating Circuit

V

TOP VIEW

V

GND

3

A

1

CC

RO

DI

R

2

3

4

D

8

B

7

6

Z

Y

5

DI

2

RO

CC

1

Y

5

DR

6

Z

8

A

R

Rt

7

B

DIP/SO

4

GND

Figure 2. MAX3488/MAX3490 Pin Configuration and Typical Operating Circuit

MAX3488
MAX3490

RE

V

CC

Rt

D

GND

RO

DI

TOP VIEW

N.C.

RO

RE

DE

GND

GND

14

13

12

11

10

V

CC

V

CC

A

B

Z

9

Y

8

N.C.

N.C.

DI

RO

1, 8

1

2

3

4

5

DI

6

7

R

D

DE V

5

D

2

DIP/SO

Figure 3. MAX3491 Pin Configuration and Typical Operating Circuit

CC

13, 144

9

Y

10

Z

12

A

RD

11

B

3 6, 7

RE GND

MAX3491

Rt

VCCRE

Rt

R

GND DE

RO

DI

3.3V-Powered, 10Mbps and Slew-Rate-Limited

MAX3483/MAX3485/MAX3486/
MAX3488/MAX3490/MAX3491

8

Maxim Integrated

True RS-485/RS-422 Transceivers

375Ω

R

L

2

V

D

V

CC

OD

R

L

V

OC

2

V

D

CC

V

OD

R

L

375Ω

VCM =

-7V to +12V

Figure 4. Driver VODand V

V

ID

R

0V

OC

V

OL

Figure 6. Receiver VOHand V

D

GENERATOR

(NOTE 4)

50Ω

V

Figure 5. Driver VODwith Varying Common-Mode Voltage

V

I
(+)

OL

C

L

CC

C

L

OH

OL

R
60Ω

= 15pF (NOTE 5)

C

L

I

OH

(-)

3V

IN

OUT

=

L

OUT

1.5V

t

DO

90%

50%

10%

t

TD

1.5V

90%

0V

t

DO

≈ 2.0V

50%

10%

t

TD

≈ -2.0V

Figure 7. Driver Differential Output Delay and Transition Times

3.3V-Powered, 10Mbps and Slew-Rate-Limited

Maxim Integrated

9

MAX3483/MAX3485/MAX3486/

MAX3488/MAX3490/MAX3491

True RS-485/RS-422 Transceivers

D

GENERATOR

(NOTE 4)

50Ω

V

CC

V

OM

Figure 8. Driver Propagation Times

S1

D0V OR 3V

= 50pF

C

L

GENERATOR

(NOTE 4)

50Ω

(NOTE 5)

VOH + V

=

V

OM

S1

2

=

OL

VOH + V

2

≈ 1.5V

OL

V

R

L

≈ 1.5V

OM

R

= 27Ω

L

CL = 15pF
(NOTE 5)

OUT

= 110Ω

OUT

IN

OUT

OUT

OUT

3V

1.5V

t

PLH

Y

Z

IN

V

OM

t

PHL

V

OM

1.5V

t

PZH

V

OM

1.5V

1.5V

0V

t

PHL

V

OH

V

OM

V

OL

t

PLH

V

OH

V

OM

V

OL

3V

0V

t

PHZ

V

OH

0.25V

0V

Figure 9. Driver Enable and Disable Times (t

S1

0V OR 3V

GENERATOR

(NOTE 4)

D

CL = 50pF

(NOTE 5)

50Ω

Figure 10. Driver Enable and Disable Times (t

, t

, t

OUT

PSL

, t

PHZ

PLZ

)

)

PZH

PSH

V

CC

R

= 110Ω

L

, t

PZL

OUT

3V

IN

t

1.5V

PSL

V

OM

1.5V

0V

t

PLZ

V

CC

0.25V
V

OL

3.3V-Powered, 10Mbps and Slew-Rate-Limited

MAX3483/MAX3485/MAX3486/
MAX3488/MAX3490/MAX3491

10

Maxim Integrated

True RS-485/RS-422 Transceivers

V

ID

GENERATOR

(NOTE 4)

1.5V

0V

50Ω

R

Figure 11. Receiver Propagation Delay

t

PRZH

tPRSH

S3

GENERATOR

(NOTE 4)

1.5V

1.5V

1.5V

-1.5V

IN

OUT

CC

OL

3.0V

0V

V

CC

0V

S1 CLOSED
S2 OPEN
S3 = -1.5V

OUT

C

= 15pF

L

(NOTE 5)

V

CC

=

V

OM

2

V

ID

R

CL
(NOTE 5)

50Ω

3V

S1 OPEN
S2 CLOSED
S3 = 1.5V

0V

V

OH

0V

IN

t

RPLH

OUT

1k

IN

OUT

1.5V

S1

S2

V

OM

t

PRZL

tPRSL

1.5V

1.5V

t

RPHL

V

OM

V

CC

3V

1.5V

0V

V

V

3V

0V

V

0V

S1 OPEN
S2 CLOSED
S3 = 1.5V

OH

OUT

IN

0.25V

1.5V

t

PRHZ

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
Note 5: C

includes probe and stray capacitance.

L

OUT

3V

IN

1.5V

t

PRLZ

0.25V

r

S1 CLOSED
S2 OPEN
S3 = -1.5V

0V

V

CC

V

OL

≤ 6.0ns, ZO= 50Ω.

3.3V-Powered, 10Mbps and Slew-Rate-Limited

Maxim Integrated

11

MAX3483/MAX3485/MAX3486/

MAX3488/MAX3490/MAX3491

True RS-485/RS-422 Transceivers

____________________Function Tables

Devices with Receiver/Driver Enable

(MAX3483/MAX3485/MAX3486/MAX3491)

Table 1. Transmitting

INPUTS OUTPUTS

RE DE DI B* A*

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

* 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

INPUTS

RE DE A, B RO

0 0* ≥ +0.2V 1 Normal
0 0* ≤-0.2V 0 Normal

0 0* Inputs Open 1 Normal

1 0 X High-Z Shutdown

* 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

OUTPUTS

(MAX3488/MAX3490)

Table 3. Transmitting Table 4. Receiving

INPUT OUTPUTS

DI Z Y

1 0 1

0 1 0

INPUTS OUTPUT

A, B RO

≥+0.2V 1

≤-0.2V 0

Inputs Open 1

MODE

MODE

__________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 out­puts are high impedance.

Reduced EMI and Reflections

(MAX3483/MAX3486/MAX3488)

The MAX3483/MAX3488 are slew-rate limited, minimiz­ing 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 infor­mation, but for the slew-rate-limited MAX3483/MAX3488
transmitting the same signal. The high-frequency har­monics 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 t
assume the part was in the low-power shutdown mode;
the t

PZH

and t

enable times assume the receiver or

PZL

driver was disabled, but the part was not shut down.

PSH

and t

enable times

PSL

10dB/div

5MHz500kHz/div0Hz

Figure 13. Driver Output Waveform and FFT Plot of MAX3485/
MAX3490/MAX3491 Transmitting a 125kHz Signal

10dB/div

5MHz500kHz/div0Hz

Figure 14. Driver Output Waveform and FFT Plot of MAX3483/
MAX3488 Transmitting a 125kHz Signal

3.3V-Powered, 10Mbps and Slew-Rate-Limited

MAX3483/MAX3485/MAX3486/
MAX3488/MAX3490/MAX3491

12

Maxim Integrated

True RS-485/RS-422 Transceivers

B

1V/div

DI

2V/div

Z

1V/div

A

1V/div

Y

1V/div

20ns/div

Figure 15. MAX3485/MAX3490/MAX3491 Driver Propagation
Delay

DI

2V/div

Z

1V/div

Y

1V/div

1µs/div

Figure 17. MAX3483/MAX3488 Driver Propagation Delay

RO

2V/div

20ns/div

Figure 16. MAX3485/MAX3490/MAX3491 Receiver
Propagation Delay Driven by External RS-485 Device

B

1V/div

A

1V/div

RO

2V/div

1µs/div

Figure 18. MAX3483/MAX3488 Receiver Propagation Delay

DI

5V/div

VY - V

Z

2V/div

RO

5V/div

2µs/div

Figure 19. MAX3483/MAX3488 System Differential Voltage at
125kHz Driving 4000 ft of Cable

DI

5V/div

VY - V

Z

2V/div

RO

5V/div

2µs/div

Figure 20. MAX3485/MAX3490/MAX3491 System Differential
Voltage at 125kHz Driving 4000 ft of Cable

3.3V-Powered, 10Mbps and Slew-Rate-Limited

Maxim Integrated

13

MAX3483/MAX3485/MAX3486/

MAX3488/MAX3490/MAX3491

True RS-485/RS-422 Transceivers

120Ω

DI

D

DE

RO

RE

Figure 21. MAX3483/MAX3485/MAX3486 Typical RS-485 Network

R

MAX3483
MAX3485
MAX3486

B

A

B

A

R

D

DI RO DE

DE

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

Operating Characteristics

). In addition, a thermal shut-

Typical

down circuit forces the driver outputs into a high-imped­ance 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, |t
(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.

PRLH

- t

, is under 10ns

PRHL|

120Ω

B

D

B

A

R

D

DI

RO

A

R

RERE

DE

DI

RO
RE

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 120Ω loads.

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 net­work 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.

3.3V-Powered, 10Mbps and Slew-Rate-Limited

MAX3483/MAX3485/MAX3486/
MAX3488/MAX3490/MAX3491

14

Maxim Integrated

True RS-485/RS-422 Transceivers

A

RO

RE

DE

DI

R

D

120Ω

B

Z

120Ω

Y

Z

Y

AA

BB

R

D

DI DIRO RO

DE DE

RE

NOTE: RE AND DE ON MAX3491 ONLY.

Figure 22. MAX3488/MAX3490/MAX3491 Full-Duplex RS-485 Network

MAX3488
MAX3490

120Ω

120Ω

MAX3491

DATA IN

DATA OUT

RO

RE

DE

DI

R

D

A

B

Z

Y

Y

120Ω

Z

B

120Ω

Z

Y

A

D

R

R

D

MAX3488
MAX3490
MAX3491

RE

DI

DE

RE
RO

NOTE: RE AND DE ON MAX3491 ONLY.

Figure 23. Line Repeater for MAX3488/MAX3490/MAX3491

Maxim Integrated

15

MAX3483/MAX3485/MAX3486/

MAX3488/MAX3490/MAX3491

3.3V-Powered, 10Mbps and Slew-Rate-Limited
True RS-485/RS-422 Transceivers

__________________ Chip Topography_Ordering Information (continued)

V

PART

MAX3486CPA

MAX3486CSA
MAX3486C/D 0°C to +70°C
MAX3486EPA
MAX3486ESA -40°C to +85°C
MAX3488CPA

MAX3488CSA
MAX3488C/D 0°C to +70°C
MAX3488EPA
MAX3488ESA -40°C to +85°C
MAX3490CPA

MAX3490CSA
MAX3490C/D 0°C to +70°C
MAX3490EPA
MAX3490ESA -40°C to +85°C
MAX3491CPD

MAX3491CSD
MAX3491C/D 0°C to +70°C
MAX3491EPD
MAX3491ESD -40°C to +85°C

* Contact factory for for dice specifications.

TEMP. RANGE PIN-PACKAGE

0°C to +70°C

0°C to +70°C

-40°C to +85°C 8 Plastic DIP

0°C to +70°C 8 Plastic DIP

0°C to +70°C

-40°C to +85°C 8 Plastic DIP

0°C to +70°C 8 Plastic DIP

0°C to +70°C

-40°C to +85°C 8 Plastic DIP

0°C to +70°C 14 Plastic DIP

0°C to +70°C

-40°C to +85°C 14 Plastic DIP

8 Plastic DIP

8 SO
Dice*

8 SO

8 SO
Dice*

8 SO

8 SO
Dice*

8 SO

14 SO
Dice*

14 SO

RO

RE

DE

DI

GND

CC

0.086"

(2.18mm)

GND

A

B

Z/B

(3.71mm)

Y/A

0.146"

TRANSISTOR COUNT: 810

SUBSTRATE CONNECTED TO GROUND

3.3V-Powered, 10Mbps and Slew-Rate-Limited

MAX3483/MAX3485/MAX3486/
MAX3488/MAX3490/MAX3491

16

Maxim Integrated

True RS-485/RS-422 Transceivers

________________________________________________________Package Information

DIM

D

A

0.101mm

e

A1

B

0.004in.

C

L

0°-8°

SO

HE

SMALL OUTLINE

PACKAGE

(0.150 in.)

E

D

A3

A2

A

L

A1

e

B1

B

E1

0° - 15°

C

eA

eB

A

A1

B
C
E

H

DIM

D
D
D

DIM

A1
A2
A3

B1

D1

E1

eA
eB

D1

Plastic DIP

PLASTIC

DUAL-IN-LINE

PACKAGE

(0.300 in.)

DIM

D
D
D
D
D
D

INCHES MILLIMETERS

0.053

0.004

0.014

0.007

0.150

e

0.228

L

0.016

PINS

14
16

A

0.015

0.125

0.055

B

0.016

0.045

C

0.008

0.005

E

0.300

0.240

e

0.100

0.300

L

0.115

PINS

14
16
18
20
24

MAX

MIN

0.069

0.010

0.019

0.010

0.157

8

MIN

–

–

8

0.244

0.050

INCHES MILLIMETERS

MIN

MAX

0.189

0.197

0.337

0.344

0.386

0.394

INCHES MILLIMETERS

MAX

0.200
–

0.175

0.080

0.022

0.065

0.012

0.080

0.325

0.310
–
–

0.400

0.150

INCHES MILLIMETERS

MIN

MAX

0.348

0.390

0.735

0.765

0.745

0.765

0.885

0.915

1.015

1.045

1.14

1.265

MIN

1.35

0.10

0.35

0.19

3.80

5.80

0.40

MIN

4.80

8.55

9.80

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

MIN

8.84

18.67

18.92

22.48

25.78

28.96

1.270.050

MAX

1.75

0.25

0.49

0.25

4.00

6.20

1.27

MAX

5.00

8.75

10.00

21-0041A

MAX

5.08
–

4.45

2.03

0.56

1.65

0.30

2.03

8.26

7.87
–
–

10.16

3.81

MAX

9.91

19.43

19.43

23.24

26.54

32.13

MAX3483/MAX3485/MAX3486/

MAX3488/MAX3490/MAX3491

3.3V-Powered, 10Mbps and Slew-Rate-Limited

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.

True RS-485/RS-422 Transceivers