Datasheet SP3481CN, SP3481CP, SP3481EN, SP3481EP, SP3485CN Datasheet (Sipex Corporation)

O

®

SP3481/SP3485

+3.3V Low Power Half-Duplex RS-485

Transceivers with 10Mbps Data Rate

■ RS-485 and RS-422 Transceivers

■ Operates from a single +3.3V supply

■ Interoperable with +5.0V logic

■ Driver/Receiver Enable

■ Low Power Shutdown Mode (SP3481)

■ -7V to +12V Common-Mode Input

Voltage Range

■ Allows up to 32 transceivers on
the serial bus

■ Compatibility with the industry
standard 75176 pinout

■ Driver Output Short-Circuit Protection

DESCRIPTION

The SP3481 and the SP3485 are a family of +3.3V low power half-duplex transceivers that
meet the specifications of the RS-485 and RS-422 serial protocols. These devices are pin-to­pin compatible with the Sipex SP481, SP483, and SP485 devices as well as popular industry
standards. The SP3481 and the SP3485 feature Sipex's BiCMOS process, allowing low power
operation without sacrificing performance. The SP3481 and SP3485 meet the electrical
specifications of RS-485 and RS-422 serial protocols up to 10Mbps under load. The SP3481
is equipped with a low power Shutdown mode.

R

1

RE

2

RE

DE

3

DI

4

SP3481/3485DS/21 SP3481/3485 Low Power Half-Duplex RS485 Transceivers © Copyright 2000 Sipex Corporation

R

D

SP3481 and SP3485

1

Vcc

8

B

7

A

6

GND

5

ABSOLUTE MAXIMUM RATINGS

These are stress ratings only and functional operation of the device at
these ratings or any other above those indicated in the operation sections
of the specifications below is not implied. Exposure to absolute maximum
rating conditions for extended periods of time may affect reliability.

VCC............................................................................................................+7V

Input Voltages

Output Voltages

Storage Temperature.......................................................-65˚C to +150˚C

Power Dissipation per Package

8-pin NSOIC (derate 6.90mW/oC above +70oC)..........................600mW

8-pin PDIP (derate 11.8mW/oC above +70oC)...........................1000mW

Logic........................................................-0.3V to (VCC+0.5V)

Drivers..................................................-0.3V to (VCC+0.5V)

Receivers................................................................. ±15V

Logic........................................................-0.3V to (VCC+0.5V)

Drivers...................................................................... ±15V

Receivers............................................-0.3V to (VCC+0.5V)

SPECIFICATIONS

T

= T

to T

AMB

PARAMETERS MIN. TYP. MAX. UNITS CONDITIONS
SP3481/SP3485 DRIVER

DC Characteristics

Differential Output Voltage GND V
Differential Output Voltage 2 V

Differential Output Voltage 1.5 V
Change in Magnitude of Driver
Differential Output Voltage for
Complimentary States 0.2 Volts R = 27Ω or R = 50Ω;
Driver Common-Mode
Output Voltage 3 Volts R = 27Ω or R = 50Ω;
Input High Voltage 2.0 Volts Applies to DE, DI, RE
Input Low Voltage 0.8 Volts Applies to DE, DI, RE
Input Current ±10 µA Applies to DE, DI, RE
Driver Short-Circuit Current
V
V

SP3481/SP3485 DRIVER
AC Characteristics

Maximum Data Rate 10 Mbps RE = VCC, DE = V
Driver Input to Output, t
Driver Input to Output, t
Differential Driver Skew 2 10 ns t

Driver Rise or Fall Time 5 20 ns From 10% to 90% ;
Driver Enable to Output High 52 120 ns
Driver Enable to Output Low 60 120 ns
Driver Disable Time from Low 40 120 ns
Driver Disable Time from High 60 120 ns

SP3481/SP3485
DC Characteristics

Differential Input Threshold -0.2 +0.2 Volts -7V ≤ V
Input Hysteresis 20 mV VCM = 0V
Output Voltage High VCC-0.4 Volts VID = +200mV, -1.5mA
Output Voltage Low 0.4 Volts VID = -200mV, 2.5mA
Three-State (High Impedance)
Output Current +1 µA 0V ≤ VO ≤ VCC; RE = V
Input Resistance 12 15 kΩ -7V ≤ V
Input Current (A, B); VIN = 12V 1.0 mA DE = 0V, VCC = 0V or 3.6V, VIN = 12V
Input Current (A, B); VIN = -7V -0.8 mA DE = 0V, VCC = 0V or 3.6V, VIN = -7V
Short-Circuit Current 7 60 mA 0V ≤ VCM ≤ V

and VCC = +3.3V ± 5% unless otherwise noted.

MIN

MAX

Volts Unloaded; R = ∞;

CC

Volts with load; R = 50Ω; (RS-422);

CC

Volts with load; R = 27Ω; (RS-485);

CC

= HIGH ±250 mA -7V ≤ VO ≤ +12V

OUT

= LOW ±250 mA -7V ≤ VO ≤ +12V

OUT

PLH

PHL

20 40 60 ns
20 40 60 ns

Figures 2 and 8

Figures 2 and 8

- t

DO1

DO2

Figures 4 and 10
Figures 5 and 10
Figures 5 and 10
Figures 4 and 10

RECEIVER

Figure 1

CC

Figures 2 and 9

≤ +12V

CM

≤ +12V

CM

CC

Figure 1

Figure 1
Figure 1

Figures 3 and

CC

Figure 1

9

SP3481/3485DS/21 SP3481/3485 Low Power Half-Duplex RS485 Transceivers © Copyright 2000 Sipex Corporation

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SPECIFICATIONS (continued)

T

= T

to T

AMB

PARAMETERS MIN. TYP. MAX. UNITS CONDITIONS
SP3481/SP3485 RECEIVER

AC Characteristics

Maximum Data Rate 10 Mbps RE = 0V, DE = 0V
Receiver Input to Output, t

and VCC = +3.3V ± 5% unless otherwise noted.

MIN

MAX

PLH

40 70 100 ns

70 ns T

Figures 6 and 11

= +25oC, VCC = +3.3V,

AMB

Figures 6 and 11

Receiver Input to Output, t

Differential Receiver Skew 4 ns t
Receiver Enable to
Output Low 35 60 ns

40 70 100 ns

PHL

70 ns T

Figures 6 and 11

= +25oC, VCC = +3.3V,

AMB

Figures 6 and 11

RSKEW = tRPHL - tRPLH

Figures 7 and 12

; S1 closed, S2 open

,

Figures 6 and 11

Receiver Enable to
Output High 35 60 ns
Receiver Disable from Low 35 60 ns
Receiver Disable from High 35 60 ns

Figures 7 and 12
Figures 7 and 12
Figures 7 and 12

; S2 closed, S1 open
; S1 closed, S2 open
; S2 closed, S1 open

SP3481 Shutdown Timing

Time to Shutdown 50 75 200 ns RE = 3.3V, DE = 0V
Driver Enable from Shutdown
to Output High 65 150 ns

Figures 4 and 10

Driver Enable from Shutdown
to Output Low 65 150 ns

Figures 5 and 10

Receiver Enable from
Shutdown to Output High 50 200 ns

Figures 7 and 12;

S2 closed, S1 open
Receiver Enable from
Shutdown to Output Low 50 200 ns

Figures 7 and 12;

S1 closed, S2 open

POWER REQUIREMENTS

Supply Current

SP3481/3485

No Load 1000 2000 µA RE, DI = 0V or VCC; DE = V

800 1500 µA RE = 0V, DI = 0V or VCC; DE = 0V

SP3481

Shutdown Mode 10 µA DE = 0V, RE=V

CC

CC

SP3481/3485DS/21 SP3481/3485 Low Power Half-Duplex RS485 Transceivers © Copyright 2000 Sipex Corporation

3

RO 1

RE 2

DE 3

DI 4

SP3481/SP3485

Pinout (Top View)

R

D

SP485

Top View

8 V

CC

7 B

6 A

5 GND

PIN FUNCTION

Pin 1 – RO – Receiver Output.
Pin 2 – RE – Receiver Output Enable Active LOW.
Pin 3 – DE – Driver Output Enable Active HIGH.
Pin 4 – DI – Driver Input.
Pin 5 – GND – Ground Connection.
Pin 6 – A – Driver Output/Receiver Input

Non-inverting.
Pin 7 – B – Driver Output/Receiver Input Inverting.

Pin 8 – V

CC

DESCRIPTION

The SP3481 and the SP3485 are 2 members
in the family of +3.3V low power half-duplex
transceivers that meet the specifications of the
RS-485 and RS-422 serial protocols. These
devices are pin-to-pin compatible with the Sipex
SP481, SP483, and SP485 devices as well as
popular industry standards. The SP3481 and
the SP3485 feature Sipex's BiCMOS process
allowing low power operation without sacrificing
performance.

Drivers

The driver outputs of the SP3481 and SP3485
are differential outputs meeting the RS-485 and
RS-422 standards. The typical voltage output
swing with no load will be 0 Volts to +3.3 Volts.
With a load of 54Ω across the differential
outputs, the drivers maintain greater than

1.5V voltage levels. The drivers of the SP3481
and SP3485 have an enable control line which
is active HIGH. A logic HIGH on DE (pin 3)
will enable the differential driver outputs.
A logic LOW on DE (pin 3) will tri-state the
driver outputs.

The tranceivers in the SP3481 and SP3485
operate up to 10Mbps. The 250mA I
maximum limit on the driver output allows

SC

the SP3481 and the SP3485 to withstand an
infinite short circuit over the -7.0V to +12.0V
common mode range without catastrophic
damage to the IC.

Receivers

The SP3481 and SP3485 receivers have
differential inputs with an input sensitivity as
low as ±200mV. Input impedance of the
receivers is typically 15kΩ (12kΩ minimum).
A wide common mode range of -7V to +12V
allows for large ground potential differences
between systems. The receivers of the SP3481
and SP3485 have a tri-state enable control pin.
A logic LOW on RE (pin 2) will enable the
receiver, a logic HIGH on RE (pin 2) will disable
the receiver.

The receivers of the SP3481 and SP3485 operate
up to 10Mbps. The receiver for each of the three
devices is equipped with fail-safe. Fail-safe
guarantees that the receiver output will be in a
HIGH state when the input is left unconnected.

Shutdown Mode for the SP3481

The SP3481 is equipped with a Shutdown mode.
To enable the Shutdown state, both the driver
and receiver must be disabled simultaneously.
A logic LOW on DE (pin 3) and a logic HIGH on
RE (pin 2) will put the SP3481 into Shutdown
mode. In Shutdown, supply current will drop to
typical 1µA, 10µA maximum.

SP3481/3485DS/21 SP3481/3485 Low Power Half-Duplex RS485 Transceivers © Copyright 2000 Sipex Corporation

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D

CC

V

VOD

Figure 1. Driver DC Test Load Circuit

C

L

D

GENERATOR
(NOTE 1)

50Ω

V

CC

R

R

RL =
60Ω

C

L

= 15pF (NOTE 2)

OUT

DM

V

S1

D

GENERATOR

OC

V

(NOTE 1)

50Ω

V

CC

OM

= 1.5V

V

VOH + V
2

RL = 27Ω

OUT

C

L

= 15pF

(NOTE 2)

OL

Figure 2. Driver Propagation Delay Test Circuit

S1

GENERATOR
(NOTE 1)

50Ω

D

C

L

= 50pF

(NOTE 2)

VOH + V

OM

= 1.5V

V

2

OL

OUT

L

R

= 110Ω

Figure 3. Driver Differential Output Delay and Transition
Time Circuit

VCC

R

L = 110Ω

OUT

0V OR 3V

GENERATOR
(NOTE 1)

50Ω

S1

D

C

L = 50pF

(NOTE 2)

Figure 5. Driver Enable and Disable Timing Circuit,

Figure 4. Driver Enable and Disable Timing Circuit,
Output HIGH

GENERATOR
(NOTE 1)

1.5V
0V

50Ω

V

ID

OUT

R

L

= 15pF

C
(NOTE 2)

V

OM

= V

CC

2

Figure 6. Receiver Propagation Delay Test Circuit

Output LOW

S3

1.5V

-1.5V

GENERATOR
(NOTE 1)

ID

V

R

50Ω

L

= 15pF

C
(NOTE 2)

1k

S1

S2

V

CC

Figure 7. Receiver Enable and Disable Timing Circuit

INPUTS OUTPUTS

LINE

RE DE DI CONDITION B A

X 1 1 No Fault 0 1
X 1 0 No Fault 1 0
X0X X ZZ

Table 1. Transmit Function Truth Table

SP3481/3485DS/21 SP3481/3485 Low Power Half-Duplex RS485 Transceivers © Copyright 2000 Sipex Corporation

INPUTS OUTPUTS

RE DE A - B R

0 0 +0.2V 1
0 0 -0.2V 0
0 0 Inputs Open 1
10 X Z

Table 2. Receive Function Truth Table

5

INPUT

Y OUTPUT

Z OUTPUT

3V

1.5V

0V

t

VOM =

PLH

t

PHL

OH

+ V

V

2

V

OH

OL

V

V

OH

V

OL

1.5V

t

PHL

V

V

OM

OM

V

OL

≈ 1.5V

OM

t

PLH

V

OM

IN

OUT

1.5V

t

DO1

50%

10%

TD

t

90%

1.5V

90%

DO2

t

50%

10%

3V

0V

2.0V

-2.0V

t

TD

Figure 8. Driver Propagation Delay Waveforms

3V

DE

1.5V

1.5V

0V

PHZ

t

V

OM

V

OM

OL

≈ 1.5V

0.25V

t

PLZ

0.25V

OUTPUT

HIGH

OUTPUT

LOW

t

V

OH

PZH

0V

t

V

CC

V

OL

PZL

OH

+ V

V

OM

=

V

2

Figure 10. Driver Enable and Disable Timing Waveforms

S1 is open
S2 is closed
S3 = 1.5V

3V

RE

1.5V

1.5V

0V

t
t

PRZH
PRSH

1.5V

OUTPUT

t

PRHZ

OH

V

10%

0V

Figure 9. Driver Differential Output Delay and Transition
Time Waveforms

INPUT

OUTPUT

3V

1.5V

1.5V

0V

V

CC

tRPLH

VOM

t

RPHL

VOM

0V

V

CC

V

OM

=

2

Figure 11. Receiver Propagation Delay Waveforms

S1 is closed
S2 is open
S3 = -1.5V

1.5V

PRLZ

t

10%

1.5V

t

PRZL

t

PRSL

1.5V

RE

OUTPUT

3V

0V

V

CC

V

OL

Figure 12. Receiver Enable and Disable Waveforms

NOTE 1: The input pulse is supplied by a generator with the following characteristics:
PRR=250KHz, 50% duty cycle, tr < 6.0ns, Z0=50Ω.

NOTE 2: CL includes probe and stray capacitance.

SP3481/3485DS/21 SP3481/3485 Low Power Half-Duplex RS485 Transceivers © Copyright 2000 Sipex Corporation

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D1 = 0.005" min.

(0.127 min.)

D

e = 0.100 BSC

(2.540 BSC)

B1

B

ALTERNATE

END PINS

(BOTH ENDS)

PACKAGE: PLASTIC

DUAL–IN–LINE
(NARROW)

E1

E

A1 = 0.015" min.

(0.381min.)

A = 0.210" max.

(5.334 max).

A2

L

C

Ø

eA = 0.300 BSC

(7.620 BSC)

DIMENSIONS (Inches)

Minimum/Maximum

(mm)
A2

B

B1

C

D

E

E1

L

Ø

8–PIN

0.115/0.195

(2.921/4.953)

0.014/0.022

(0.356/0.559)

0.045/0.070

(1.143/1.778)

0.008/0.014

(0.203/0.356)

0.355/0.400

(9.017/10.160)

0.300/0.325

(7.620/8.255)

0.240/0.280

(6.096/7.112)

0.115/0.150

(2.921/3.810)

0°/ 15°

(0°/15°)

SP3481/3485DS/21 SP3481/3485 Low Power Half-Duplex RS485 Transceivers © Copyright 2000 Sipex Corporation

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PACKAGE: PLASTIC

SMALL OUTLINE (SOIC)
(NARROW)

EH

h x 45°

D

A

Ø

Be

A1

DIMENSIONS (Inches)

Minimum/Maximum

(mm)
A

A1

B

D

E

e

H

h

L

Ø

0.053/0.069

(1.346/1.748)

0.004/0.010

(0.102/0.249

0.014/0.019

0.189/0.197

0.150/0.157

(3.802/3.988)

(1.270 BSC)

0.228/0.244

(5.801/6.198)

0.010/0.020

(0.254/0.498)

0.016/0.050

(0.406/1.270)

8–PIN

(0.35/0.49)

(4.80/5.00)

0.050 BSC

0°/8°

(0°/8°)

L

SP3481/3485DS/21 SP3481/3485 Low Power Half-Duplex RS485 Transceivers © Copyright 2000 Sipex Corporation

8

ORDERING INFORMATION

Model Temperature Range Package

SP3481CN.................................................................................... 0˚C to +70˚C ............................................................................ 8-pin Narrow SOIC

SP3481CP .................................................................................... 0˚C to +70˚C ................................................................................ 8-pin Plastic DIP

SP3481EN .................................................................................. .-40˚C to +85˚C .......................................................................... 8-pin Narrow SOIC

SP3481EP ................................................................................... -40˚C to +85˚C .............................................................................. 8-pin Plastic DIP

SP3485CN.................................................................................... 0˚C to +70˚C ............................................................................ 8-pin Narrow SOIC

SP3485CP .................................................................................... 0˚C to +70˚C ................................................................................ 8-pin Plastic DIP

SP3485EN ...................................................................................-40˚C to +85˚C .......................................................................... 8-pin Narrow SOIC

SP3485EP ................................................................................... -40˚C to +85˚C .............................................................................. 8-pin Plastic DIP

Please consult the factory for pricing and availability on a Tape-On-Reel option.

Corporation

SIGNAL PROCESSING EXCELLENCE

Sipex Corporation
Headquarters and

Sales Office

22 Linnell Circle
Billerica, MA 01821
TEL: [phone]
FAX: [phone]
e-mail: [e-mail]

Sales Office

233 South Hillview Drive
Milpitas, CA 95035
TEL: [phone]
FAX: [phone]

Sipex Corporation reserves the right to make changes to any products described herein. Sipex does not assume any liability arising out of the
application or use of any product or circuit described hereing; neither does it convey any license under its patent rights nor the rights of others.

SP3481/3485DS/21 SP3481/3485 Low Power Half-Duplex RS485 Transceivers © Copyright 2000 Sipex Corporation

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