SP481E/SP485E®

Enhanced Low Power Half-Duplex
RS-485 Transceivers■ +5V Only
■ Low Power BiCMOS■ Driver/Receiver Enable for Multi-Dropconfigurations■ Low Power Shutdown Mode
(SP481E)■ Enhanced ESD Specifications:+15KV Human Body Model+15KV IEC1000-4-2 Air Discharge+8KV IEC1000-4-2 Contact Discharge

DESCRIPTIONThe SP481E and the SP485E are a family of half-duplex transceivers that meet the
specifications of RS-485 and RS-422 serial protocols with enhanced ESD performance. The
ESD tolerance has been improved on these devices to over +15KV for both Human Body
Model and IEC1000-4-2 Air Discharge Method. These devices are pin-to-pin compatible with
Sipex's SP481 and SP485 devices as well as popular industry standards. As with the original
versions, the SP481E and the SP485E feature Sipex's BiCMOS design allowing low power
operation without sacrificing performance. The SP481E and SP485E meet the requirementsof the RS-485 and RS-422 protocols up to 10Mbps under load. The SP481E is equipped witha low power Shutdown mode.

RO 1

8 Vcc

R

RE 2

7B

DE 3

6A

DI 4

D

5 GND

SP481E and SP485E

Rev. 5/16/03

SP481E Low Power Half-Duplex RS485 Transceivers

1© Copyright 2003 Sipex Corporation

ABSOLUTE MAXIMUM RATINGS
These are stress ratings only and functional operation of the device atthese ratings or any other above those indicated in the operation sectionsof the specifications below is not implied. Exposure to absolute maximum
rating conditions for extended periods of time may affect reliability.
VCC............................................................................................................+7V
Input Voltages
Logic........................................................-0.3V to (VCC+0.5V)
Drivers..................................................-0.3V to (VCC+0.5V)
Receivers................................................................. ±15V

Output Voltages
Logic........................................................-0.3V to (VCC+0.5V)
Drivers...................................................................... ±15V
Receivers............................................-0.3V to (VCC+0.5V)
Storage Temperature.......................................................-65˚C to +150˚C
Power Dissipation per Package
8-pin NSOIC (derate 6.60mW/oC above +70oC)...........................550mW
8-pin PDIP (derate 11.8mW/oC above +70oC)............................1000mW

SPECIFICATIONSTMIN to TMAX and VCC = 5V ± 5% unless otherwise noted.

PARAMETERS
SP481E/SP485E DRIVER
DC Characteristics
Differential Output Voltage
Differential Output Voltage

MAX.

UNITS

CONDITIONS

GND
2

VCC
VCC

Volts
Volts

Differential Output Voltage
Change in Magnitude of Driver
Differential Output Voltage forComplimentary States
Driver Common-Mode
Output Voltage
Input High Voltage
Input Low Voltage
Input Current
Driver Short-Circuit Current
VOUT = HIGH
VOUT = LOW
SP481E/SP485E DRIVER
AC Characteristics
Maximum Data Rate

1.5

VCC

Volts

Unloaded; R = ∞ ; see Figure 1
with load; R = 50Ω; (RS-422);
see Figure 1
with load; R = 27Ω; (RS-485);see Figure 1

0.2

Volts

R = 27Ω or R = 50Ω; see Figure 1

3
0.8
±10

Volts
Volts
Volts
µA

R = 27Ω or R = 50Ω; see Figure 1
Applies to DE, DI, RE
Applies to DE, DI, RE
Applies to DE, DI, RE

±250
±250

mA
mA

-7V ≤ VO ≤ +12V
-7V ≤ VO ≤ +12V

Mbps

Driver Input to Output

20

30

60

ns

Driver Input to Output(SP485EMN ONLY)

20

30

80

ns

RE = 5V, DE = 5V; RDIFF = 54Ω,
CL1 = CL2 = 100pF
tPLH; RDIFF = 54Ω, CL1 = CL2 = 100pF;
see Figures 3 and 5
tPLH; RDIFF = 54Ω, CLI = CL2 = 100pF;
See Figures 3 and 5

Driver Input to Output

20

30

60

ns

Driver Input to Output(SP485EMN ONLY)
Driver Skew

20

30

80

ns

5

10

ns

Driver Rise or Fall Time

3

15

40

ns

40

70

ns

tPHL; RDIFF = 54Ω, CL1 = CL2 = 100pF;
see Figures 3 and 5
tPHL; RDIFF = 54Ω, CL1 = CL2 = 100pF;
see Figures 3 and 5
see Figures 3 and 5,
tSKEW = | tDPLH - tDPHL |From 10% to 90%; RDIFF = 54Ω,
CL1 = CL2 = 100pF; see Figures 3 & 6
CL = 100pF; see Figures 4 & 6; S2

40

70

ns

CL = 100pF; see Figures 4 & 6; S1

40

70

ns

CL = 100pF; see Figures 4 & 6; S1

40

70

ns

CL = 100pF; see Figures 4 & 6; S2

Driver Enable to Output HighclosedDriver Enable to Output Low
closedDriver Disable Time from Low
closedDriver Disable Time from HighclosedRev. 5/16/03

MIN.

TYP.

2.0

10

SP481E Low Power Half-Duplex RS485 Transceivers

2© Copyright 2003 Sipex Corporation

SPECIFICATIONS (continued)
TMIN to TMAX and VCC = 5V ± 5% unless otherwise noted.

PARAMETERS
MIN.
SP481E/SP485E RECEIVER
DC Characteristics
Differential Input Threshold-0.2
Differential Input Threshold-0.4(SP485EMN ONLY)
Input Hysteresis
Output Voltage High
3.5
Output Voltage Low
Three-State (High Impedance)
Output Current
Input Resistance
12
Input Current (A, B); VIN = 12V
Input Current (A, B); VIN = -7V
Short-Circuit Current
7
SP481E/SP485E RECEIVER
AC Characteristics
Maximum Data Rate
10
Receiver Input to Output
20

TYP.

Receiver Input to Output

20

Diff. Receiver Skew ItPLH-tPHLIUNITSCONDITIONS

+0.2
+0.4

Volts
Volts

-7V ≤ VCM ≤ +12V
-7V ≤ VCM ≤ +12V

0.4

mV
Volts
Volts

VCM = 0V
IO = -4mA, VID = +200mVIO = +4mA, VID = -200mV

+1.0
-0.8
95

µA
kΩ
mA
mA
mA

0.4V ≤ VO ≤ 2.4V; RE = 5V
-7V ≤ VCM ≤ +12V
DE = 0V, VCC = 0V or 5.25V, VIN = 12V
DE = 0V, VCC = 0V or 5.25V, VIN = -7V
0V ≤ VO ≤ VCC

45

100

Mbps
ns

45

100

ns

RE = 0V, DE = 0V
tPLH; RDIFF = 54Ω,
CL1 = CL2 = 100pF; Figures 3 & 7
tPHL; RDIFF = 54Ω,
CL1 = CL2 = 100pF; Figures 3 & 7
RDIFF = 54Ω; CL1 = CL2 = 100pF;
Figures 3 & 7

20

±1
15

13

Receiver Enable to
Output Low
Receiver Enable to
Output High
Receiver Disable from Low
Receiver Disable from High
SP481E
Shutdown Timing
Time to Shutdown
50
Driver Enable from Shutdown
to Output High
Driver Enable from Shutdown
to Output Low
Receiver Enable fromShutdown to Output High
Receiver Enable fromShutdown to Output Low
POWER REQUIREMENTS
Supply Voltage+4.75
Supply Current
SP481E/485E
No Load
SP481E
Shutdown Mode
ENVIRONMENTAL AND MECHANICAL
Operating Temperature
Commercial (_C_)
0
Industrial (_E_)
-40
(_M_)
-40
Storage Temperature-65
Package
Plastic DIP (_P)
NSOIC (_N)
Rev. 5/16/03

MAX.

ns

45

70

ns

CRL = 15pF; Figures 2 & 8; S1 closed

45
45
45

70
70
70

ns
ns
ns

CRL = 15pF; Figures 2 & 8; S2 closed
CRL = 15pF; Figures 2 & 8; S1 closed
CRL = 15pF; Figures 2 & 8; S2 closed

200

600

ns

RE = 5V, DE = 0V

40

100

ns

CL = 100pF; See Figures 4 & 6; S2 closed

40

100

ns

CL = 100pF; See Figures 4 & 6; S1 closed

300

1000

ns

CL = 15pF; See Figures 2 & 8; S2 closed

300

1000

ns

CL = 15pF; See Figures 2 & 8; S1 closed

+5.25

Volts

900
600

µA
µA

RE, DI = 0V or VCC; DE = VCC
RE = 0V, DI = 0V or 5V; DE = 0V

10µA

DE = 0V, RE=VCC

+70
+85
+125
+150

°C
°C
°C
°C

SP481E Low Power Half-Duplex RS485 Transceivers

3© Copyright 2003 Sipex Corporation

PIN FUNCTIONR

Pin 1 – RO – Receiver Output.

8

VCC

RE 2

7

B

DE 3

6

A

5

GND

RO 1

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.

D
DI 4

SP485

Pin 6 – A – Driver Output/Receiver Input
Non-inverting.

Top View

Pin 7 – B – Driver Output/Receiver Input Inverting.

SP481E and SP485E
Pinout (Top View)

Pin 8 – Vcc – Positive Supply 4.75V<Vcc< 5.25V.

A
VOD
R

Test Point

ReceiverOutput

R

CRL

VOC

1k

B

A

VCC

S1

S2

Figure 1. RS-485 Driver DC Test Load Circuit

DI

1k

CL1
RDIFF

A

Figure 2. Receiver Timing Test Load Circuit

RO

OutputUnder C
L
Test

B

B
CL2

15pF

Figure 4. RS-485 Driver Timing Test Load #2 Circuit

1.5V

1.5V

0V
DRIVEROUTPUTVCC

f = 1MHz; tR < 10ns; tF < 10ns

DI
B

S1

S2

Figure 3. RS-485 Driver/Receiver Timing Test Circuit

+3V

500

tPLH

tPHL

VO 1/2VO

1/2VO

A
tDPLH

DIFFERENTIAL VO+
OUTPUT 0V
VA – VB VO–

tDPHL

tR

tF

tSKEW = | tDPLH - tDPHL |Figure 5. Driver Propagation Delays
Rev. 5/16/03

SP481E Low Power Half-Duplex RS485 Transceivers

4© Copyright 2003 Sipex Corporation

INPUTSREX
X
XX

OUTPUTSLINE
DI CONDITION
1
No Fault
0
No Fault
X
X
X
Fault

DE
1
1
0
1

B
0
1
Z
Z

INPUTS
RE
DE
0
0
0
0
0
0
1
0

A
1
0
Z
Z

OUTPUTS
A-B
R
+0.2V
1
-0.2V
0
Inputs Open
1
X
Z

Table 2. Receive Function Truth Table

Table 1. Transmit Function Truth Table

f = 1MHz; tR < 10ns; tF < 10ns

+3V

1.5V

DE

1.5V

0V

tZL

tLZ

5V
2.3V

A, B
VOL
VOH
A, B

2.3V
0V

Output normally LOW

0.5V

Output normally HIGH

0.5V

tZH

tHZ

Figure 6. Driver Enable and Disable Times

V0D2+
A–B

0V

INPUT

V0D2–
VOH

1.5V

R
VOL

tPHL

OUTPUT

0V

1.5V

tPLH
f = 1MHz; tR < 10ns; tF < 10nstSKEW = | tPHL - tPLH |Figure 7. Receiver Propagation Delays

+3V
1.5V

RE
0V

f = 1MHz; tR < 10ns; tF < 10ns
tZL

1.5V
tLZ

5V
1.5V

R
VIL

Output normally LOW

0.5V

Output normally HIGH

0.5V

VIH
R

1.5V
0V

tZH

tHZ

Figure 8. Receiver Enable and Disable TimesRev. 5/16/03

SP481E Low Power Half-Duplex RS485 Transceivers

5© Copyright 2003 Sipex Corporation

DESCRIPTION

Receivers

The SP481E and SP485E are half-duplex differential transceivers that meet the requirements of
RS-485 and RS-422. Fabricated with a Sipex
proprietary BiCMOS process, all three products
require a fraction of the power of older bipolar
designs.

The SP481E and SP485E receivers have differential inputs with an input sensitivity as low as±200mV. Input impedance of the receivers istypically 15kΩ (12kΩ minimum). A wide common mode range of -7V to +12V allows for large
ground potential differences between systems.
The receivers of the SP481E and SP485E havea 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 RS-485 standard is ideal for multi-drop
applications and for long-distance interfaces.
RS-485 allows up to 32 drivers and 32 receivers
to be connected to a data bus, making it an ideal
choice for multi-drop applications. Since thecabling can be as long as 4,000 feet, RS-485
transceivers are equipped with a wide (-7V to+12V) common mode range to accommodate
ground potential differences. Because RS-485 isa differential interface, data is virtually immune
to noise in the transmission line.

The receiver for the SP481E and SP485E will
operate up to at least 10Mbps. The receiver foreach of the two devices is equipped with the
fail-safe feature. Fail-safe guarantees that thereceiver output will be in a HIGH state when
the input is left unconnected.
Shutdown Mode
SP481E

Drivers
The driver outputs of the SP481E and SP485E
are differential outputs meeting the RS-485 andRS-422 standards. The typical voltage output
swing with no load will be 0 Volts to +5 Volts.
With worst case loading of 54Ω across the differential outputs, the drivers can maintain greaterthan 1.5V voltage levels. The drivers of the
SP481E, and SP485E 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 thedriver outputs.

The SP481E is equipped with a Shutdown mode.
To enable the Shutdown state, both the driverand receiver must be disabled simultaneously.
A logic LOW on DE (pin 3) and a logic HIGH on
RE (pin 2) will put the SP481E into Shutdown
mode. In Shutdown, supply current will drop to
typically 1µA.
ESD TOLERANCEThe SP481E Family incorporates ruggedized
ESD cells on all driver output and receiver input
pins. The ESD structure is improved over our
previous family for more rugged applications
and environments sensitive to electro-static discharges and associated transients. The improved
ESD tolerance is at least ±15kV without damage
nor latch-up.

The transmitters of the SP481E and SP485E
will operate up to at least 10Mbps.

There are different methods of ESD testing
applied:a) MIL-STD-883, Method 3015.7b) IEC1000-4-2 Air-Dischargec) IEC1000-4-2 Direct Contact

Rev. 5/16/03

SP481E Low Power Half-Duplex RS485 Transceivers

6© Copyright 2003 Sipex Corporation

systems. For system manufacturers, they must
guarantee a certain amount of ESD protection
since the system itself is exposed to the outsideenvironment and human presence. The premisewith IEC1000-4-2 is that the system is required
to withstand an amount of static electricity when
ESD is applied to points and surfaces of theequipment that are accessible to personnel during
normal usage. The transceiver IC receives mostof the ESD current when the ESD source isapplied to the connector pins. The test circuit for
IEC1000-4-2 is shown on Figure 8. There are
two methods within IEC1000-4-2, the Air
Discharge method and the Contact Discharge
method.

The Human Body Model has been the generally
accepted ESD testing method for semiconductors.
This method is also specified in MIL-STD-883,
Method 3015.7 for ESD testing. The premise ofthis ESD test is to simulate the human body’s
potential to store electro-static energy anddischarge it to an integrated circuit. The
simulation is performed by using a test model asshown in Figure 7. This method will test theIC’s capability to withstand an ESD transient
during normal handling such as in manufacturing
areas where the ICs tend to be handled frequently.
The IEC-1000-4-2, formerly IEC801-2, isgenerally used for testing ESD on equipment and

R
RS
S

R
RC
C

SW2
SW2

SW1
SW1

Device
Under
Test

C
CS
S

DC Power
SourceFigure 7. ESD Test Circuit for Human Body Model

Contact-Discharge Module

R
RS
S

R
RC
C

RV
SW2
SW2

SW1
SW1

Device
Under
Test

C
CS
S

DC Power
SourceRS and RV add up to 330Ω
330Ω ffor
or IEC1000-4-2.

Figure 8. ESD Test Circuit for IEC1000-4-2
Rev. 5/16/03

SP481E Low Power Half-Duplex RS485 Transceivers

7© Copyright 2003 Sipex Corporation

i➙With the Air Discharge Method, an ESD voltage
is applied to the equipment under test (EUT)
through air. This simulates an electrically charged
person ready to connect a cable onto the rear of
the system only to find an unpleasant zap justbefore the person touches the back panel. The
high energy potential on the person discharges
through an arcing path to the rear panel of thesystem before he or she even touches the system.
This energy, whether discharged directly or
through air, is predominantly a function of thedischarge current rather than the discharge
voltage. Variables with an air discharge such as
approach speed of the object carrying the ESD
potential to the system and humidity will tend tochange the discharge current. For example, therise time of the discharge current varies with theapproach speed.

30A

15A

0A
t=0ns

voltage stored in the capacitor is then applied
through RS, the current limiting resistor, onto thedevice under test (DUT). In ESD tests, the SW2
switch is pulsed so that the device under test
receives a duration of voltage.
For the Human Body Model, the current limiting
resistor (RS) and the source capacitor (CS) are
1.5kΩ an 100pF, respectively. For IEC-1000-42, the current limiting resistor (RS) and the source
capacitor (CS) are 330Ω an 150pF, respectively.
The higher CS value and lower RS value in the
IEC1000-4-2 model are more stringent than the
Human Body Model. The larger storage capacitor
injects a higher voltage to the test point whenSW2 is switched on. The lower current limiting
resistor increases the current charge onto the test
point.

The circuit model in Figures 7 and 8 represent
the typical ESD testing circuit used for all threemethods. The CS is initially charged with the DC
power supply when the first switch (SW1) is on.
Now that the capacitor is charged, the second
switch (SW2) is on while SW1 switches off. The

Driver Outputs
Receiver Inputs

Rev. 5/16/03

±15kV
±15kV

t=30nsFigure 9. ESD Test Waveform for IEC1000-4-2

The Contact Discharge Method applies the ESD
current directly to the EUT. This method wasdevised to reduce the unpredictability of the
ESD arc. The discharge current rise time isconstant since the energy is directly transferredwithout the air-gap arc. In situations such as
hand held systems, the ESD charge can be directly
discharged to the equipment from a person alreadyholding the equipment. The current is transferred
on to the keypad or the serial port of the equipment
directly and then travels through the PCB and finallyto the IC.

SP481E, SP485E HUMAN BODY
FAMILYMODELt➙

Air Discharge

IEC1000-4-2
Direct Contact

Level

±15kV
±15kV

±8kV
±8kV

4
4

SP481E Low Power Half-Duplex RS485 Transceivers

8© Copyright 2003 Sipex Corporation

PACKAGE: PLASTIC
DUAL–IN–LINE(NARROW)

E1 E

D1 = 0.005" min.
(0.127 min.)

A1 = 0.015" min.
(0.381min.)D

A = 0.210" max.
(5.334 max).
C

A2
L

B1
B

e = 0.100 BSC(2.540 BSC)ØeA = 0.300 BSC(7.620 BSC)

ALTERNATE
END PINS(BOTH ENDS)DIMENSIONS (Inches)
Minimum/Maximum
(mm)

8–PIN

A2

0.115/0.195(2.921/4.953)

B

0.014/0.022(0.356/0.559)

B1

0.045/0.070(1.143/1.778)

C

0.008/0.014(0.203/0.356)

D

0.355/0.400(9.017/10.160)

E0.300/0.325(7.620/8.255)

E10.240/0.280(6.096/7.112)

L

0.115/0.150(2.921/3.810)

Ø

0°/ 15°(0°/15°)

Rev. 5/16/03

SP481E Low Power Half-Duplex RS485 Transceivers

9© Copyright 2003 Sipex Corporation

PACKAGE: PLASTIC
SMALL OUTLINE (SOIC)(NARROW)E

H

h x 45°DAØe

B

DIMENSIONS (Inches)
Minimum/Maximum(mm)

Rev. 5/16/03

A1

L

8–PIN

A

0.053/0.069(1.346/1.748)

A1

0.004/0.010(0.102/0.249

B

0.014/0.019(0.35/0.49)

D

0.189/0.197(4.80/5.00)

E

0.150/0.157(3.802/3.988)e0.050 BSC
(1.270 BSC)

H

0.228/0.244(5.801/6.198)h0.010/0.020(0.254/0.498)

L

0.016/0.050(0.406/1.270)

Ø

0°/8°
(0°/8°)

SP481E Low Power Half-Duplex RS485 Transceivers

10© Copyright 2003 Sipex Corporation

ORDERING INFORMATION
Model
Temperature Range
Package
SP481ECN ....................................................... 0˚C to +70˚C ............................................... 8-pin Narrow SOIC
SP481ECP ........................................................ 0˚C to +70˚C ................................................... 8-pin Plastic DIP
SP481EEN ...................................................... .-40˚C to +85˚C ............................................. 8-pin Narrow SOIC
SP481EEP ...................................................... -40˚C to +85˚C ................................................. 8-pin Plastic DIP
SP485ECN ....................................................... 0˚C to +70˚C ............................................... 8-pin Narrow SOICSP485ECP ........................................................ 0˚C to +70˚C ................................................... 8-pin Plastic DIP
SP485EEN ...................................................... -40˚C to +85˚C ............................................. 8-pin Narrow SOICSP485EEP ...................................................... -40˚C to +85˚C ................................................. 8-pin Plastic DIP
SP485EMN .................................................... -40˚C to +125˚C ............................................ 8-pin Narrow SOIC
Please consult the factory for pricing and availability on a Tape-On-Reel option.

Corporation

SIGNAL PROCESSING EXCELLENCE
Sipex Corporation
Headquarters andSales Office
233 South Hillview Drive
Milpitas, CA 95035
TEL: (408) 934-7500
FAX: (408) 935-7600

Sales Office
22 Linnell Circle
Billerica, MA 01821
TEL: (978) 667-8700
FAX: (978) 670-9001
e-mail: sales@sipex.com

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

Rev. 5/16/03

SP481E Low Power Half-Duplex RS485 Transceivers

11© Copyright 2003 Sipex Corporation