Maxim MAX3480BEPI, MAX3480BCPI, MAX3480AEPI, MAX3480ACPI Datasheet

19-0453; Rev 0; 1/96

Complete, Isolated, 3.3V

RS-485/RS-422 Data Interface

_______________General Description

The MAX3480A/MAX3480B are electrically isolated RS-485/RS-422 data-communications interfaces. Transceivers, optocouplers, and a transformer are all included in one low-cost, 28-pin DIP package. A single +3.3V supply on the logic side powers both sides of the interface.

The MAX3480B features reduced-slew-rate drivers that minimize EMI and reduce reflections caused by improperly terminated cables, allowing error-free data transmission at data rates up to 250kbps. The MAX3480A’s driver slew rate is not limited, allowing transmission rates up to 2.5Mbps.

These devices typically draw 180mA of quiescent supply current. The MAX3480B provides a low-power shutdown mode in which it consumes only 0.2µA.

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 the input is open circuit.

The MAX3480A/MAX3480B typically withstand 1600V (1 minute) or 2000V

(1 second). Their isolated inputs

RMS

and outputs meet RS-485/RS-422 specifications.

________________________Applications

Isolated RS-485/RS-422 Data Interface Transceivers for EMI-Sensitive Applications Industrial-Control Local Area Networks Automatic Test Equipment HVAC/Building Control Networks

______________Ordering Information

DATA

PART

MAX3480ACPI

MAX3480AEPI MAX3480BCPI MAX3480BEPI -40°C to +85°C 28 Plastic DIP

TEMP. RANGE PIN-PACKAGE

0°C to +70°C

-40°C to +85°C 0°C to +70°C

28 Plastic DIP 28 Plastic DIP 28 Plastic DIP

RATE (kbps)

2500 2500 250 250

____________________________Features

♦ Isolated Data Interface to 1600V ♦ Slew-Rate-Limited Data Transmission (MAX3480B) ♦ High-Speed, Isolated, 2.5Mbps RS-485 Interface

(MAX3480A)

♦ -7V to +12V Common-Mode Input Voltage Range

with Respect to Isolated Ground

♦ Single +3.3V Supply ♦ Current Limiting and Thermal Shutdown for

Driver Overload Protection

♦ Standard 28-Pin DIP Package

RMS

(1 minute)

__________________Pin Configuration

TOP VIEW

MAX3480A/B

V

CC1

V

CC2

GND1

CC3

V

CC4

GND2

V

CC5

1 2

D1

3

D2

4 5

MAX845

6

FS SD

7 8

DI

9

10

DE

11 12

RO

13 14

MAX485 MAX487

28 27 26 25 24 23 22 21 20 19 18 17 16 15

AC1 AC2 ISO V

CC1

B ISO RO DRV A ISO DI IN ISO DE INV ISO COM1

ISO DI DRV ISO V

CC2

ISO DE DRV ISO COM2

ISO RO LED

MAX3480A/MAX3480B

ISOLATION BARRIER

DIP

________________________________________________________________

Maxim Integrated Products

1

For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800

Complete, Isolated, 3.3V RS-485/RS-422 Data Interface

ABSOLUTE MAXIMUM RATINGS

With Respect to GND:

V

Supply Voltage (V Supply Voltage (V

CC

2,

CC

1,

) ..........................................-0.3V to +7V

CC3

Control Input Voltage (SD, FS)................-0.3V to (V

Receiver Output Voltage (RO

).................-0.3V to (VCC+ 0.3V)

).........-0.3V to +3.8V

CC

4,

5

CC

+ 0.3V)

With Respect to ISO COM:

Control Input Voltage (ISO DE _) .........-0.3V to (ISO V

Driver Input Voltage (ISO DI _).........-0.3V to (ISO V

Receiver Output Voltage (ISO RO _)......-0.3V to (ISO V

CC

+ 0.3V)

Driver Output Voltage (A, B)................................-8V to +12.5V

Receiver Input Voltage (A, B)..............................-8V to +12.5V

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

(VCC= V

= V

V

CC

MAX3480A/MAX3480B

Switch Frequency

Operating Supply Current

FS Input Threshold FS Input Pull-Up Current

FS Input Leakage Current Input High Voltage Input Low Voltage Isolation Resistance Isolation Capacitance Differential Driver Output (no load) V

Differential Driver Output (with load)

CC1

= V

CC2

= V

CC4

= V

= 3.0V to 3.6V, FS = 0V, TA= T

CC5

= V

= 3.3V and TA= +25°C.) (Notes 1, 2, 3)

CC5

V

S

f

SWL

f

SWH

FS = 0V FS = VCCor open MAX3480A,

= VCCor open

DE

I

CC

I

SHDN

FSH

FSL

FSM

ISO ISO

V

OD1

IH IL

´

MAX3480B,

= V

DE

´

SD = V High Low FS low FS high DE´, DI´(Figure 1) DE´, DI´(Figure 1) TA= +25°C, V TA= +25°C, V

R = 50Ω (RS-422)

V

OD2

R = 27Ω (RS-485), Figure 3 1.5 5

CC

CC3

LED Forward Current (DI, DE, ISO RO LED) ......................50mA

Continuous Power Dissipation (TA= +70°C)

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

Operating Temperature Ranges

MAX3480_CPI......................................................0°C to +70°C

MAX3480_EPI...................................................-40°C to +85°C

Storage Temperature Range.............................-65°C to +160°C

Lead Temperature (soldering, 10sec).............................+300°C

to T

MIN

, unless otherwise noted. Typical values are at

MAX

CONDITIONS

3.0 3.3 3.6Supply Voltage 600 900 180 260 280 120 200 240

or open

RL= ∞ RL= 54Ω RL= ∞ RL= 54Ω

2.4V

0.8V

- 0.4V

CC

= 50V

ISO ISO

= 50V

DC DC

8

2

UNITSMIN TYP MAXSYMBOLPARAMETER

V

kHz

mA

µAShutdown Supply Current (Note 3) 0.2

V

µA50I pA10I

VV V0.4V

MΩ100 10,000R

pF10C

V

Change in Magnitude of Driver Output Voltage for Complementary Output States

Driver Common-Mode Output V

∆V

R = 27Ω or 50Ω,

OD

Figure 3

R = 27Ω or 50Ω, Figure 4

OC

Differential

2 _______________________________________________________________________________________

0.3

0.3Common Mode 4

V

Complete, Isolated, 3.3V

RS-485/RS-422 Data Interface

ELECTRICAL CHARACTERISTICS (continued)

(VCC= V

= V

V

CC

Input Current (A, B)

Receiver Input Hysteresis Receiver Output/Receiver Output

Low Voltage Receiver Output/Receiver Output

High Current Driver Short-Circuit Current

CC1

= V

CC2

= V

CC4

= V

= 3.0V to 3.6V, FS = 0V, TA= T

CC5

= V

= 3.3V and TA= +25°C.) (Notes 1, 2, 3)

CC5

IN

TH

OL

OSD

DE´= 0V,

= 0V or 3.6V

V

CC

-7V ≤ VCM≤ 12V

-7V ≤ VCM≤ 12V -0.2 0.2V VCM= 0V

DI´= V

V

= 3.6V, DI´= 0V

OUT

-7V ≤ VO≤ 12V (Note 4) mA100ISO I

ISO I

R

OH

CONDITIONS

CC

SWITCHING CHARACTERISTICS—MAX3480A

(VCC= V

= V

V

CC

Driver Input to Output Propagation Delay

Driver Output Skew (Note 5)

Driver Rise or Fall Time Driver Enable to Output High

Driver Enable to Output Low Driver Disable Time from High Driver Disable Time from Low

Receiver Input to Output Propagation Delay

t

PLH - tPHL



Receiver Skew Maximum Data Rate

= V

CC1

= V

CC1

PARAMETER SYMBOL MIN TYP MAX UNITS

CC2

= V

CC2

Differential



= V

CC4 =VCC5

= V

CC4

= 3.0V to 3.6V, FS = 0V, TA= T

= 3.3V and TA= +25°C.)

CC5

t

PLH 100 275

t

PHL 100 275

t

SKEW 25 90 ns

tR, t

t

ZH 0.2 1.5 µs

t

HZ 0.3 1.5 µs

t

PLH

t

PHL

t

SKD

f

MAX 2.5 Mbps

Figures 4, 6; R CL1= CL2= 100pF

Figures 4, 6; R

F 15 40 ns

CL1= CL2= 100pF Figures 5, 7; CL= 100pF, S2 closed

ZL 0.2 1.5 µs

Figures 5, 7; CL= 100pF, S1 closed Figures 5, 7; CL= 15pF, S2 closed

LZ 0.3 1.5 µsFigures 5, 7; C

Figures 4, 8; R CL1= CL2= 100pF

t

PLH, tPHL < 50% of data period

CONDITIONS

DIFF

L DIFF

DIFF

to T

MIN

MAX3480A

MAX3480B MAX3480A

, unless otherwise noted. Typical values are at

MAX

VIN= 12V

VIN= 12V VIN= -7V VIN= 12V VIN= -7V

12

MAX3480B 48

MIN

to T

, unless otherwise noted. Typical values are at

MAX

= 54Ω,

= 15pF, S1 closed

= 54Ω,

1.0

0.8

-0.8

0.25

-0.2

70∆V

100 225 100 225

20

MAX3480A/MAX3480B

UNITSMIN TYP MAXSYMBOLPARAMETER

mA

kΩReceiver Input Resistance

VReceiver Differential Threshold

mV

V0.4V

µA250I

ns

_______________________________________________________________________________________ 3

Complete, Isolated, 3.3V RS-485/RS-422 Data Interface

SWITCHING CHARACTERISTICS—MAX3480B

(VCC= V

= V

V

CC

Driver Input to Output Propagation Delay

Driver Output Skew t

Driver Rise or Fall Time tR, t Driver Enable to Output High t

Driver Enable to Output Low t Driver Disable Time from Low t Driver Disable Time from High t

Receiver Input to Output Propagation Delay

t



PLH

MAX3480A/MAX3480B

Receiver Skew Maximum Data Rate f

Note 1: All currents into device pins are positive; all currents out of device pins are negative. All voltages are referenced to

Note 2: For DE

Note 3: Shutdown supply current is the current at V Note 4: Applies to peak current. See

= V

CC1

= V

CC1

PARAMETER SYMBOL MIN TYP MAX UNITS

- t

PHL

logic-side ground (GND1, GND2), unless otherwise specified.

MAX3480A/MAX3480B).

= V

CC2

Differential

and DI´pin descriptions, see

´

= V

CC4

CC4 =VCC5

= V

= 3.0V to 3.6V, FS = 0V, TA= T

= 3.3V and TA= +25°C.)

CC5

Typical Operating Characteristics

t

PLH

t

PHL

SKEW

ZH

HZ

t

PLH

t

PHL

t

SKD

MAX

Figures 4, 6; R CL1= CL2= 100pF

Figures 4, 6; R

F

CL1= CL2= 100pF Figures 5, 7; CL= 100pF, S2 closed

Figures 5, 7; CL= 100pF, S1 closed

ZL

Figures 5, 7; CL= 15pF, S1 closed

LZ

Figures 4, 8; R CL1= CL2= 100pF

, t

PLH

PHL

Detailed Block Diagram

when shutdown is enabled.

CC1

to T

MIN

CONDITIONS

= 54Ω,

DIFF

= 54Ω,

DIFF

= 54Ω,

DIFF

= 54Ω,

DIFF

= 54Ω,

DIFF

< 50% of data period

and

MAX

Typical Application Circuit

Applications Information

, unless otherwise noted. Typical values are at

1.0 2.0

100 800 ns

1.0 2.0 µs 50 100 µs

50 100 µs 13 50 µs 13 50 µsFigures 5, 7; CL= 15pF, S2 closed

0.8 2.0

0.8 2.0 50

0.25 Mbpst

(Figure 1 for

.

µs

ns

4 _______________________________________________________________________________________

Complete, Isolated, 3.3V

RS-485/RS-422 Data Interface

__________________________________________Typical Operating Characteristics

(V

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

CC_

DRIVER DIFFERENTIAL OUTPUT VOLTAGE

vs. TEMPERATURE

3.0

DI´ = HIGH OR OPEN

2.9

= 54Ω

R

L

2.8

2.7

2.6

2.5

2.4

2.3

2.2

DIFFERENTIAL OUTPUT VOLTAGE (V)

2.1

2.0

-40  20 

0-20   6040 80

TEMPERATURE (°C)

RECEIVER OUTPUT LOW VOLTAGE

0.8 MEASURED AT ISO RO DRV

I

= 8mA

RO

0.7

0.6

0.5

0.4

0.3

0.2

OUTPUT LOW VOLTAGE (V)

0.1

0

-40  20 

vs. DRIVER OUTPUT HIGH VOLTAGE

-100

-90

MAX3480A/B-08

-80

-70

-60

-50

-40

-30

OUTPUT CURRENT (mA)

-20

-10 0

-6 -4 -2 2 4 6

vs. TEMPERATURE

0-20   6040 80

TEMPERATURE (°C)

OUTPUT CURRENT

0

OUTPUT HIGH VOLTAGE (V)

MAX3480 A/B-04

180 160

MAX3480 A/B-06

140 120 100

80 60

OUTPUT CURRENT (mA)

40 20

0

RECEIVER OUTPUT HIGH VOLTAGE

vs. TEMPERATURE

5.00 MEASURED AT ISO RO DRV

I

= 8mA

RO

4.75

4.50

4.25

4.00

3.75

3.50

OUTPUT HIGH VOLTAGE (V)

3.25

3.00

-40  20 

0-20   6040 80

TEMPERATURE (°C)

OUTPUT CURRENT

vs. DRIVER OUTPUT LOW VOLTAGE

24681012

OUTPUT LOW VOLTAGE (V)

MAX3480 A/B-03

MAX3480A/MAX3480B

MAX3480 A/B-05

vs. RECEIVER OUTPUT LOW VOLTAGE

OUTPUT CURRENT

80

MEASURED AT ISO RO DRV

70 60 50 40 30

OUTPUT CURRENT (mA)

20 10

0

1.00 3.02.0 5.04.0 OUTPUT LOW VOLTAGE (V)

MAX3480 A/B-01

vs. RECEIVER OUTPUT HIGH VOLTAGE

-30

-25

-20

-15

-10

OUTPUT CURRENT (mA)

-5

0

OUTPUT CURRENT

MEASURED AT ISO RO DRV

MAX3480 A/B-02

1.00 3.02.0 5.04.0 OUTPUT HIGH VOLTAGE (V)

_______________________________________________________________________________________

5