ST ST485E User Manual

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±15KV ESD PROTECTED, LOW POWER

■ LOW QUIESCENT CURRENT: 300µA

■ DESIGNED FOR RS-485 INTERFACE

APPLICATIONS

■ -7V TO 12V COMMON MODE INPUT

VOLTAGE RANGE

■ DRIVER MAINTAINS HIGH IMPEDANCE IN

3-STATEORWITHTHEPOWEROFF

■ 70mV TYPICAL INPUT HYSTERESIS

■ 30ns PROPAGATION DELAYS, 5ns SKEW

■ OPERATE FROM A SINGLE 5V SUPPLY

■ CURRENT LIMITING AND THERMAL

SHUTDOWN FOR DRIVER OVERLOAD
PROTECTION

■ ESD PROTECTION:

±15KV (H.B.M.)
±8KV (IEC-1000-4-2 CONTACT

DISCHARGE)

■ ALLOWS UP TO 64 TRANSCEIVERSON

THE BUS

DESCRIPTION

The ST485E is al low power transceiver for
RS-485 and RS-422 communication. Each driver
output and receiver input is protected against
±15KV electrosta tic discharge (H.B.M.) (ESD)
shocks, without latcup. These parts contain one

ST485E

RS-485/RS-422 TRANSCEIVER

DIP SOP

driver and one receiver in half duplex
configuration.
This transceiver draw 300µA (typ.) of sup ply
current when unlo aded or fully loaded with
disabled drivers.
It operates from a single 5V supply.
Driver is short-circuit current limited and is
protected against excessive power dissipation by
thermal shutdown circuitry th at place the driver
outputs into a high-impedance state.
The ST485E is designed f or bi-directional data
communications on multipoint bus transmission
line (half-duplex applications).

ORDERING CODES

Type

ST485ECN 0 to 70 °C DIP-8 50parts per tube / 40tube per box
ST485EBN -40 to 85 °C DIP-8 50parts per tube / 40tube per box
ST485EXN -55 to 125 °C DIP-8 50parts per tube / 40tube per box
ST485ECD 0 to 70 °C SO-8 (Tube) 100parts per tube / 20tube per box
ST485EBD -40 to 85 °C SO-8 (Tube) 100parts per tube / 20tube per box

ST485EXD -55 to 125 °C SO-8 (Tube) 100parts per tube / 20tube per box
ST485ECDR 0 to 70 °C SO-8 (Tape & Reel) 2500 parts per reel
ST485EBDR -40 to 85 °C SO-8 (Tape & Reel) 2500 parts per reel
ST485EXDR -55 to 125 °C SO-8 (Tape & Reel) 2500 parts per reel

Temperature

Range

Package Comments

1/13September 2003

ST485E

PIN CONFIGURATION

PIN DESCRIPTION

PlN N° SYMBOL NAME AND FUNCTION

1 RO Receiver Output
2RE
3 DE Driver Output Enable
4 DI Driver Input
5 GND Ground
6 A Non-inverting Receiver Input and Non-inverting Driver Output
7 B Inverting Receiver Input and Inverting Driver Output
8

Receiver Output Enable

V

CC

Supply Voltage

TRUTH TA BLE (DRIVER)

INPUTS OUTPUTS

RE

XHHLH
XHLHL
XLXZZ

X= Don’t Care; Z=High Impedance

DE DI B A

TRUTH TA BLE (RECEIVER)

INPUTS OUTPUT

RE

LL≥ +0.2V H
LL≤ -0.2V L
L L INPUTS OPEN H

HL X Z

X= Don’t Care; Z=High Impedance

DE A-B RO

ABSOLUTE MAXIMUM RATINGS

Symbol Parameter Value Unit

V

V

V

V

V

V

Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these condition is
not implied.

Supply Voltage

CC

Control Input Voltage (RE, DE) -0.5 to (VCC+ 0.5)

I

Driver Input Voltage (DI) -0.5 to (VCC+ 0.5)

DI

Driver Output Voltage (A, B)

DO

Receiver Input Voltage (A, B)

RI

Receiver Output Voltage (RO) -0.5 to (VCC+ 0.5)

RO

7V

V
V

± 14 V
± 14 V

V

2/13

ST485E

ESD PERFORMANCE: TRANSMITTER OUTPUTS, RE CEIVER INPUTS

Symbol Parameter Test Conditions Min. Typ. Max. Unit

ESD ESD Protection Voltage Human Body Model ±15 KV
ESD ESD Protection Voltage IEC-1000-4-2 ±8KV

DC ELECTRICAL CHARACTERISTICS

=5V± 5%,TA=T

(V

CC

(See Note 1)

Symbol Parameter Test Conditions Min. Typ. Max. Unit

V

V

∆V

V

∆V

V

∆V

V

V

I

I

OSD1

I

OSD2

I

Note 1: All currents into device pins are positive; all cuttents out of device pins are negative; all voltages are referenced to device ground
unless specified.
Note 2: Supply current specification is valid for loaded transmitters when V
Note 3: Applies to peak current. See typical Operating Characteristics.

Differential Driver Output

OD1

(No Load)
Differential Driver Output

OD2

(With Load)
Change in Magnitude of

OD

Driver Differential Output
Voltage for Complementary
Output States

Driver Common-Mode

OC

Output Voltage
Change in Magnitude of

OC

Driver Common-Mode
Output Voltage for
Complementary Output
States

V

Input High Voltage RE, DE, DI 2.0 V

IH

V

Input Low Voltage RE, DE, DI 0.8 V

IL

Input Current RE, DE, DI ± 2 µA

I

IN1

Input Current (A, B) VCM= 0V or 5.25V VDE=0V

I

IN2

Receiver Differential

TH

Threshold Voltage
Receiver Input Hysteresis VCM=0V 70 mV

TH

Receiver Output High

OH

Voltage
Receiver Output Low

OL

Voltage
3-State (High Impedance)

OZR

Output Current at Receiver

R

Receiver Input Resistance VCM= -7 to 12V 24 KΩ

IN

No Load Supply Current

I

CC

(Note 2)

Driver Short-Circuit Current,

=High

V

O

Driver Short-Circuit Current,

=Low

V

O

Receiver Short-Circuit

OSR

Current

MIN

to T

, unless otherwise spec ified. Typicalvalues are referred to TA= 25°C)

MAX

5V

RL=27Ω (RS-485) (See Fig. 1)
R

=50Ω (RS-422) (See Fig. 1)

L

=27Ω or 50Ω (See Fig. 1) 0.2 V

R

L

1.5 5
5

RL=27Ω or 50Ω (See Fig. 1) 3 V

=27Ω or 50Ω (See Fig. 1) 0.2 V

R

L

V
V

IN
IN

= 12V
= -7V

1

-0.8

VCM= -7 to 12V -0.2 0.2 V

IO= -4mA VID= 200mV 3.5 V

IO=4mA VID= -200mV 0.4 V

VO= 0.4 to 2.4V ± 1 µA

VRE=0VorV
VDE=V
VDE=0V

V

= -7 to 12V (Note 3) 35 250 mA

O

V

= -7 to 12V (Note 3) 35 250 mA

O

VO=0VtoV

CC

CC

CC

DE

=0V

400
300

900
500

795mA

V
V

mA
mA

µA
µA

3/13

ST485E

DRIVER S WITCHING CHARACTERISTICS

(V

=5V± 5%,TA=T

CC

(See Note 1)

Symbol Parameter Test Conditions Min. Typ. Max. Unit

t

t
t

t

t

t

t

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

Propagation Delay Input to

PLH

Output

t

PHL

t

Output Skew to Output R

SK

Rise or Fall Time R

TLH
THL

Output Enable Time CL= 100pF S2 = Closed

PZH

Output Enable Time CL= 100pF S1 = Closed

PZL

Output Disable Time CL= 15pF S1= Closed

PLZ

Output Disable Time CL= 15pF S2= Closed

PHZ

MIN

toT

,unless otherwise specified. Typical valu es arereferredto TA=25°C)

MAX

R

=54Ω CL1=CL2= 100pF

DIFF

25 45 ns

(See Fig. 3 and 5)

=54Ω CL1=CL2= 100pF

DIFF

25ns

(See Fig. 3 and 5)

=54Ω CL1=CL2= 100pF

DIFF

15 40 ns

(See Fig. 3 and 5)

35 50 ns

(See Fig. 4 and 6)

25 40 ns

(See Fig. 4 and 6)

25 40 ns

(See Fig. 4 and 6)

35 50 ns

(See Fig. 4 and 6)

RECEIVER SWITCHING CHARACTERISTICS

(V

=5V± 5%,TA=T

CC

MIN

to T

, unless otherwise spec ified. Typicalvalues are referred to TA= 25°C)

MAX

(See Note 1)

Symbol Parameter Test Conditions Min. Typ. Max. Unit

t

t

t

t

t

t

f

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

Propagation Delay Input to

PLH

Output

t

PHL

Differential Receiver Skew R

SKD

Output Enable Time CRL= 15pF S2 = Closed

PZH

Output Enable Time CRL= 15pF S1 = Closed

PZL

Output Disable Time CRL= 15pF S1 = Closed

PLZ

Output Disable Time CRL= 15pF S2 = Closed

PHZ

Maximum Data Rate 5 Mbps

MAX

R

=54Ω CL1=CL2= 100pF

DIFF

(See Fig. 3 and 7)

=54Ω CL1=CL2= 100pF

DIFF

(See Fig. 3 and 7)

(See Fig. 2 and 8)

(See Fig. 2 and 8)

(See Fig. 2 and 8)

(See Fig. 2 and 8)

110 130 ns

510ns

11 35 ns

13 35 ns

13 35 ns

11 35 ns

4/13