MAXIM MAX3480EA, MAX3480EB User Manual

General Description

The MAX3480EA/MAX3480EB are electrically isolated RS-485/RS-422 data-communications interfaces. The RS-485/RS-422 I/O pins are protected against ±15kV electrostatic discharge (ESD) shocks, without latchup. Transceivers, optocouplers, and a transformer are all included in one low-cost, 28-pin PDIP package. A single +3.3V supply on the logic side powers both sides of the interface.

The MAX3480EB 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 160kbps. The MAX3480EA’s driver slew rate is not limited, allowing transmission rates up to 2.5Mbps.

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 MAX3480EA/MAX3480EB are guaranteed to withstand 1260V

RMS

(1min) or 1520V

RMS

(1s). Their isolated

inputs 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

Telecom

____________________________Features

♦ Isolated Data Interface Guaranteed to 1260V

RMS

(1min)

♦ ±15kV ESD Protection for I/O Pins

♦ Slew-Rate-Limited Data Transmission (160kbps for

MAX3480EB)

♦ High-Speed, Isolated, 2.5Mbps RS-485 Interface

(MAX3480EA)

♦ Single +3.3V Supply

♦ Current Limiting and Thermal Shutdown for

Driver Overload Protection

♦ Standard 28-Pin PDIP Package

♦ Allows Up to 128 Transceivers on the Bus

MAX3480EA/MAX3480EB

±15kV ESD-Protected, Isolated, 3.3V

RS-485/RS-422 Data Interfaces

________________________________________________________________ Maxim Integrated Products 1

AC1

AC2

ISO V

CC1

CC2

CC1

ISO RO DRV

ISO DI IN

ISO DE INV

CC3

GND1

ISO COM1

ISO DI DRV

ISO V

CC2

ISO DE DRV

GND2

CC4

ISO COM2

ISO RO LED

CC5

MAX1487E

MAX487E

ISOLATION BARRIER

TOP VIEW

MAX3480EA MAX3480EB

PDIP

MAX845

Pin Configuration

19-1941; Rev 1; 3/06

Ordering Information

PART

TEMP

RANGE

PI N -

D A T A

PKG

CODE

MAX3480EACPI

28 PDIP

P28M-1

MAX3480EAEPI

28 PDIP

P28M-1

MAX3480EBCPI

28 PDIP

P28M-1

MAX3480EBEPI

28 PDIP

P28M-1

*See the Reliability section at end of data sheet.

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

0°C to + 70°C

- 40°C to + 85°C

0°C to + 70°C

- 40°C to + 85°C

PA C K A G E*

R A T E

( k b p s )

2500

250

MAX3480EA/MAX3480EB

±15kV ESD-Protected, Isolated, 3.3V RS-485/RS-422 Data Interfaces

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VCC= V

CC1

= V

CC2

= V

CC4

= V

CC5

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

MIN

to T

MAX

, unless otherwise noted. Typical values are at V

+3.3V and T

= +25°C.) (Notes 1, 2)

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.

With Respect to GND

Supply Voltage (V

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

Supply Voltage (V

CC3

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

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

CC3

+ 0.3V)

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

CC5

+ 0.3V)

With Respect to ISO COM

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

CC_

+ 0.3V)

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

CC_

+ 0.3V)

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

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

Continuous Power Dissipation (T

= +70°C)

28-Pin PDIP (derate 9.09mW/°C above +70°C)............727mW

Operating Temperature Ranges

MAX3480E_CPI..................................................0°C to +70°C

MAX3480E_EPI...............................................-40°C to +85°C

Storage Temperature Range .............................-65°C to +150°C

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

PARAMETER

CONDITIONS

UNITS

SWL

FS = 0 60

Switch Frequency

SWH

FS = VCC or open

kHz

RL = ∞

MAX3480EA, DE´ = V

or open

= 54Ω

RL = ∞ 80

Operating Supply Current I

MAX3480EB, DE´ = V

or open

= 54Ω

Shutdown Supply Current (Note 3)

SHDN

SD = V

CC3

0.2 µA

FSH

High 2.4

FS Input Threshold

FSL

Low 0.8

FS Input Pullup Current I

FSL

FS low 50 µA

FS Input Leakage Current I

FSM

FS high 10 pA

Input High Voltage V

DE´, DI´, Figure 1 VCC - 0.4 V

Input Low Voltage V

DE´, DI´, Figure 1 0.4 V

Isolation Voltage V

ISO

TA = +25°C, 1min (Note 4)

RMS

SDH

High 2.4 1

Shutdown Input Threshold

SDL

Low 1 0.8

Isolation Resistance R

ISO

TA = +25°C, V

ISO

= ±50VDC

MΩ

Isolation Capacitance C

ISO

f = 1MHz 10 pF

ESD Protection ESD

A, B, Y, and Z pins, tested at Human Body Model

Differential Driver Output (No Load)

OD1

R = 50Ω (RS-422) 2

Differential Driver Output V

OD2

R = 27Ω (RS-485), Figure 3 1.5 5.0

Differential 0.3

Change in Magnitude of Driver Output Voltage for Complementary Output States

∆V

R = 27Ω or 50Ω, Figure 3

Common mode 0.3

SYMBOL

MIN TYP MAX

900

130 250

220

180

1260

100 10,000

±15

200

MAX3480EA/MAX3480EB

±15kV ESD-Protected, Isolated, 3.3V

RS-485/RS-422 Data Interfaces

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(VCC= V

CC1

= V

CC2

= V

CC4

= V

CC5

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

MIN

to T

MAX

, unless otherwise noted. Typical values are at V

+3.3V and T

= +25°C.) (Notes 1, 2)

SWITCHING CHARACTERISTICS—MAX3480EA

(VCC= V

CC1

= V

CC2

= V

CC4 =VCC5

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

MIN

to T

MAX

, unless otherwise noted. Typical values are at

= +3.3V and TA= +25°C.)

PARAMETER SYMBOL MIN TYP MAX UNITS



PLH

PHL

Differential

Receiver Skew

Driver Input to Output Propagation Delay

PLH 100 275

Driver Output Skew

SKEW 25 100 ns

Driver Rise or Fall Time

tR, t

F 15 50 ns

Driver Enable to Output High

ZH 0.5 1.8 µs

Driver Enable to Output Low

ZL 0.5 1.8 µs

Driver Disable Time from High

HZ 0.6 1.8 µs

CONDITIONS

Figures 4, 6; R

DIFF

= 54Ω,

CL1= CL2= 100pF

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

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

Figures 4, 6; R

DIFF

= 54Ω,

CL1= CL2= 100pF (Note 5)

Figures 4, 6; R

DIFF

= 54Ω,

CL1= CL2= 100pF

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

Driver Disable Time from Low

LZ 0.6 1.8 µsFigures 5, 7; C

= 15pF, S1 closed

SKD

100 225

Receiver Input to Output Propagation Delay

PLH

Figures 4, 8; R

DIFF

= 54Ω,

= CL2= 100pF

20 100

Figures 4, 8; R

DIFF

= 54Ω,

= CL2= 100pF

Maximum Data Rate

MAX 2.5 Mbps

SKEW, tSKD ≤ 25% of data period

PHL

PHL 100 275

120 225

Driver Common-Mode Output V

Input Current (A, B) ISO I

Receiver Input Resistance R

Receiver Differential Threshold V Receiver Input Hysteresis ∆V

Receiver Output Low Voltage V

Receiver Output High Current I

Driver Short-Circuit Current ISO I

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

OSD

R = 27Ω or 50Ω, Figure 4 4 V

DE´ = 0, V

= 0 or

+3.6V

MAX3480EA

MAX3480EB

-7V ≤ VCM ≤ 12V 48 kΩ

-7V ≤ VCM ≤ 12V -0.2 +0.2 V

VCM = 0 70 mV

DI´ = V

= +3.6V, DI´ = 0 250 µA

OUT

-7V ≤ VO ≤ 12V (Note 5) 100 mA

VIN = +12V 0.25

= -7V -0.2

VIN = +12V 0.25

= -7V -0.2

0.4 V

±15kV ESD-Protected, Isolated, 3.3V RS-485/RS-422 Data Interfaces

4 _______________________________________________________________________________________

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

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

Note 2: For DE

and DI´pin descriptions, see the Block Diagram and the Typical Application Circuit (Figure 1 for

MAX3480EA/MAX3480EB).

Note 3: Shutdown supply current is the current at V

CC1

when shutdown is enabled.

Note 4: Limit guaranteed by applying 1520V

RMS

for 1s. Test voltage is applied between all pins on one side of the package to all

pins on the other side of the package. For example, between pins 1 and 14, and 15 and 28.

Note 5: Applies to peak current. See the Typical Operating Characteristics and the Applications Information section.

PARAMETER SYMBOL MIN TYP MAX UNITS



PLH

PHL

Differential

Receiver Skew

PLH

1.5 3.0

Driver Input to Output Propagation Delay

µs

Driver Output Skew t

SKEW

300 1200 ns

Driver Rise or Fall Time tR, t

1.0 2.0 µs

Driver Enable to Output High t

1.2 4.5 µs

Driver Enable to Output Low t

1.0 4.5 µs

Driver Disable Time from Low t

1.5 4.5 µs

CONDITIONS

Figures 4, 6; R

DIFF

= 54Ω,

CL1= CL2= 100pF

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

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

Figures 4, 6; R

DIFF

= 54Ω,

CL1= CL2= 100pF

Figures 4, 6; R

DIFF

= 54Ω,

CL1= CL2= 100pF

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

Driver Disable Time from High t

2.0 4.5 µsFigures 5, 7; CL= 15pF, S2 closed

SKD

PLH

0.6 3.0

Receiver Input to Output Propagation Delay

PHL

1.4 3.0

µs

Figures 4, 8; R

DIFF

= 54Ω,

CL1= CL2= 100pF

750 1500

Figures 4, 8; R

DIFF

= 54Ω,

CL1= CL2= 100pF

Maximum Data Rate f

MAX

160 kbpst

SKEW

, t

SKD

≤ 25% of data period

PHL

1.2 3.0

MAX3480EA/MAX3480EB

SWITCHING CHARACTERISTICS—MAX3480EB

(VCC= V

CC1

= V

CC2

= V

CC4 =VCC5

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

MIN

to T

MAX

, unless otherwise noted. Typical values are at

= +3.3V and TA= +25°C.)

MAX3480EA/MAX3480EB

±15kV ESD-Protected, Isolated, 3.3V

RS-485/RS-422 Data Interfaces

_______________________________________________________________________________________ 5

2.0

-40 20

DRIVER DIFFERENTIAL OUTPUT VOLTAGE

vs. TEMPERATURE

MAX3480EA/EB toc01

TEMPERATURE (°C)

DIFFERENTIAL OUTPUT VOLTAGE (V)

0-20 6040 80

2.1

2.2

2.3

2.4

2.5

2.6

2.7

2.8

2.9

3.0

DI´ = HIGH OR OPEN R

= 54Ω

OUTPUT CURRENT

vs. DRIVER OUTPUT HIGH VOLTAGE

MAX3480EA/EB toc02

OUTPUT HIGH VOLTAGE (V)

OUTPUT CURRENT (mA)

-10

-20

-30

-40

-50

-60

-70

-80

-90

-100

-6 -4 -2 2 4 6

OUTPUT CURRENT

vs. DRIVER OUTPUT LOW VOLTAGE

MAX3480EA/EB toc03

OUTPUT LOW VOLTAGE (V)

OUTPUT CURRENT (mA)

160

180

140

100

120

24 681012

-40 20

RECEIVER OUTPUT LOW VOLTAGE

vs. TEMPERATURE

MAX3480EA/EB toc04

TEMPERATURE (°C)

OUTPUT LOW VOLTAGE (V)

0-20 6040 80

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8 MEASURED AT ISO RO DRV I

= 8mA

TEMPERATURE (°C)

3.00

-40 20

RECEIVER OUTPUT HIGH VOLTAGE

vs. TEMPERATURE

MAX3480EA/EB toc05

OUTPUT HIGH VOLTAGE (V)

0-20 6040 80

3.25

3.50

3.75

4.00

4.25

4.50

4.75

5.00 MEASURED AT ISO RO DRV I

= 8mA

__________________________________________Typical Operating Characteristics

CC_

= +3.3V, TA= +25°C, Figure 1, unless otherwise noted.)

OUTPUT CURRENT

vs. RECEIVER OUTPUT HIGH VOLTAGE

MAX3480EA/EB toc07

DIFFERENTIAL OUTPUT VOLTAGE (V)

OUTPUT CURRENT (mA)

1.00 3.02.0 5.04.0

MEASURED AT ISO RO DRV

OUTPUT CURRENT

vs. RECEIVER OUTPUT LOW VOLTAGE

MAX3480EA/EB toc06

OUTPUT LOW VOLTAGE (V)

OUTPUT CURRENT (mA)

MEASURED AT ISO RO DRV

1.003.02.0 5.04.0

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MAXIM MAX3480EA, MAX3480EB User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual